3-D Conformal Radiation Therapy (3D-CRT) — A procedure that uses a computer to create a 3-dimensional (3-D) picture of a brain or spinal cord tumor. This allows doctors to give the highest possible dose of radiation to the tumor, with as little damage to normal tissue as possible.
3-D Mammography — A type of digital mammography in which X-ray machines are used to take pictures of thin slices of the breast from different angles, and computer software is used to reconstruct an image.
Abdominoperineal Resection — Surgery to remove the anus, the rectum and part of the sigmoid colon through an incision made in the abdomen. The end of the intestine is attached to an opening in the surface of the abdomen, and body waste is collected in a disposable bag outside of the body. This opening is called a colostomy. Lymph nodes that contain cancer may also be removed during this operation.
Ablation Therapy — A treatment that involves the removal or destruction of a body part or tissue or its function. Ablation may be performed by surgery, hormones, drugs, radiofrequency, heat or other methods.
Acoustic Neuroma — A type of schwannoma (a benign tumor that begins in Schwann cells, which produce the myelin that protects the acoustic nerve).
Actinic Keratosis — A skin condition that sometimes becomes squamous cell carcinoma.
Acute Myeloid Leukemia (AML) — A cancer of the blood and bone marrow. This type of cancer usually gets worse quickly if it is not treated. It is the most common type of acute leukemia in adults. AML is also called acute myelogenous leukemia, acute myeloblastic leukemia, acute granulocytic leukemia and acute nonlymphocytic leukemia.
Adenocarcinoma — Cancer that begins in glandular (secretory) cells. Glandular cells are found in tissues that lines= certain internal organs. These cells make and release substances in the body, such as mucus, digestive juices or other fluids. Most cancers of the breast, pancreas, lung, prostate and colon are adenocarcinomas.
Adenoid Cystic Carcinoma — A rare type of cancer that usually occurs in the head and neck areas, in particular in the salivary glands.
Adenosquamous Carcinoma — A type of cancer that contains two types of cells: squamous cells (thin, flat cells that line certain organs) and gland-like cells.
Adrenal Glands — Located above each kidney, these glands make hormones called catecholamines that help control heart rate.
Adrenocorticotropic Hormone (ACTH) — A hormone that stimulates the adrenal glands to produce another type of hormone called cortisol.
Aflatoxin — A harmful substance made by certain types of mold (Aspergillus flavus and Aspergillus parasiticus) that is often found on poorly stored grains and nuts. Consumption of foods contaminated with aflatoxin is a risk factor for primary liver cancer.
AIDS — Acquired immunodeficiency syndrome, the final stage of HIV (human immunodeficiency virus) infection. Not everyone who has HIV advances to this stage. People with AIDS have severely damaged immune systems.
Albumin — The most common protein found in the blood. It is used by the body for growth and tissue repair.
Aldrich Syndrome — An inherited immune disorder that occurs in young boys. It causes eczema (a type of skin inflammation), a decrease in the number of platelets (blood cells that help prevent bleeding), and frequent bacterial infections. People with Aldrich syndrome are at increased risk of developing leukemia and lymphoma. Also called Wiskott–Aldrich syndrome.
Allogeneic Bone Marrow Transplant — A procedure in which a person receives stem cells (cells from which all blood cells develop) from a genetically similar, but not genetically identical, donor.
Alpha-Fetoprotein (AFP) — A protein normally produced by a fetus. Alpha-fetoprotein levels are usually undetectable in the blood of healthy adult men or women (who are not pregnant). An elevated level of alpha-fetoprotein suggests the presence of either a primary liver cancer or a germ cell tumor.
Ampullary Cancer — Cancer that forms in the ampulla of Vater (an enlargement of the ducts from the liver and pancreas where they join and enter the small intestine). Symptoms include jaundice, abdominal pain, nausea, vomiting and weight loss. Also called ampulla of Vater cancer.
Amputation — The removal by surgery of a limb (arm or leg) or other body part because of injury or disease, such as diabetes or cancer.
Anal Cancer — Cancer that forms in tissues of the anus. The anus is the opening of the rectum (last part of the large intestine) to the outside of the body.
Anal Fistula — A small channel that forms between the end of the bowel and skin near the anus.
Anaplastic — A term used to describe cancer cells that divide rapidly and have little or no resemblance to normal cells.
Anaplastic Pituitary Cancer — A very rare type of pituitary cancer that occurs most often in people older than 60.
Anaplastic Thyroid Cancer — A very rare type of thyroid cancer that occurs most often in people older than 60.
Anastomosis — A surgical connection between two structures. It usually means a connection that is created between tubular structures, such as blood vessels.
Anemia — A condition in which the number of red blood cells is below normal.
Angiogenesis Inhibitor — A substance that may prevent the formation of blood vessels. In anticancer therapy, an angiogenesis inhibitor may prevent the growth of new blood vessels that tumors need to grow.
Angiogram — An X-ray of blood vessels. The person receives an injection of dye to outline the vessels on the X-ray.
Angiography — A procedure used to X-ray blood vessels. The blood vessels can be seen because of an injection of a dye that shows up in the X-ray.
Anoscopy — An examination of the anus and lower rectum using a short, lighted tube called an anoscope.
Antiandrogens — Substances that keep androgens (male hormones) from binding to proteins called androgen receptors, which can be found in prostate cells and cells of some other tissues. Treatment with antiandrogens may stop prostate cancer cells from growing.
Antifibrinolytic Medicine — A medicine that helps prevent the breakdown of blood clots, used in patients with various von Willebrand diseases when they have minor surgeries, tooth extractions or an injury.
Antigen — Any substance that causes the body to make an immune response against that substance. Antigens include toxins, chemicals, bacteria, viruses or other substances that come from outside the body.
APL (Acute Promyelocytic Leukemia) — A fast-growing type of acute myeloid leukemia in which there are too many immature blood-forming cells in the blood and bone marrow. It is usually marked by an exchange of parts of chromosomes 15 and 17. Also called promyelocytic leukemia.
Aplastic Anemia — A condition in which the bone marrow is unable to produce blood cells.
Areola — The area of dark-colored skin on the breast that surrounds the nipple.
Aristolochia fangchi — A Chinese herb that can be harmful to kidneys and is associated with an increased risk of urinary cancer.
Aromatase Inhibitor — A drug that prevents the formation of estradiol, a female hormone, by interfering with an aromatase enzyme. Aromatase inhibitors are used as a type of hormone therapy for postmenopausal women who have hormone-dependent breast cancer.
Arsenic — A poisonous chemical used to kill weeds and pests. Also used in cancer therapy.
Arterial Embolization — A procedure in which the blood supply to a tumor or an abnormal area of tissue is blocked.
Astrocyte — A star-shaped cell that holds nerve cells in place and helps them develop and work the way they should. An astrocyte is a type of glial cell.
Astrocytoma — A tumor that begins in the brain or spinal cord in small, star-shaped cells called astrocytes.
Autoimmune Disease — A condition in which the body recognizes its own tissues as foreign and directs an immune response against them.
Autologous Transplant — A procedure in which tissue is removed from a person, stored and then given back to the person after intensive treatment.
B Cell — A type of immune cell that makes proteins called antibodies, which bind to microorganisms and other foreign substances and help fight infections. A B cell is a type of white blood cell. Also called B lymphocyte.
Barium Enema — A procedure in which a liquid that contains barium sulfate is put through the anus into the rectum and colon. Barium sulfate is a silver-white metallic compound that helps show pictures of the colon, rectum and anus on an X-ray.
Barium Swallow — The process of getting X-ray pictures of the esophagus or the upper gastrointestinal (GI) tract (esophagus, stomach and duodenum). The X-ray pictures are taken after the patient drinks a liquid that contains barium sulfate (a form of the silver-white metallic element barium). The barium sulfate coats and outlines the inner walls of the esophagus and the upper GI tract so that they can be seen on the X-ray pictures.
Barrett Esophagus — A condition in which the cells lining the lower part of the esophagus have changed or been replaced with abnormal cells that could lead to cancer of the esophagus. The backing up of stomach contents (reflux) may irritate the esophagus and, over time, cause Barrett esophagus.
Basal Cell Carcinoma — A type of skin cancer that arises from the basal cells, small round cells found in the lower part (or base) of the epidermis, the outer layer of the skin.
Basal Cells — Small, round cells found in the lower part (or base) of the epidermis, the outer layer of the skin.
Benign — Not cancerous. Benign tumors may grow larger but do not spread to other parts of the body. Also called nonmalignant.
Benign Hematology — Refers to noncancerous disorders of the blood.
Benign Pituitary Adenoma —A noncancerous tumor that grows very slowly and does not spread to other parts of the body.
Benign Prostatic Hyperplasia (BPH) — A benign (not cancer) condition in which an overgrowth of prostate tissue pushes against the urethra and the bladder, blocking the flow of urine. Also called benign prostatic hypertrophy.
Benzene — A chemical that is used widely by the chemical industry and is also found in tobacco smoke, vehicle emissions and gasoline fumes. Exposure to benzene may increase the risk of developing leukemia.
Beta-2-Microglobulin — A small protein normally found on the surface of many cells, including lymphocytes, and in small amounts in the blood and urine. An increased amount in the blood or urine may be a sign of certain diseases, including some types of cancer, such as multiple myeloma or lymphoma.
Beta-Human Chorionic Gonadotropin — A hormone found in the blood and urine during pregnancy. It may also be found in higher than normal amounts in patients with some types of cancer, including testicular, ovarian, liver, stomach and lung cancers, and other disorders. Measuring the amount of beta-human chorionic gonadotropin in the blood or urine of cancer patients may help to diagnose cancer and find out how well cancer treatment is working. Beta-human chorionic gonadotropin is a type of tumor marker. Also called beta-hCG.
Bilateral Salpingo-oophorectomy — Surgery to remove both ovaries and both fallopian tubes.
Bile — A fluid made by the liver and stored in the gallbladder. Bile is excreted into the small intestine, where it helps digest fat.
Bile Duct — A bile duct is a tube that carries bile (fluid made by the liver that helps digest fat) between the liver and gallbladder and the intestine. Bile ducts include the common hepatic, cystic and common bile ducts.
Bile Duct Cancer — Cancer that forms in a bile duct. A bile duct is a tube that carries bile (fluid made by the liver that helps digest fat) between the liver and gallbladder and the intestine. Bile ducts include the common hepatic, cystic and common bile ducts. Bile duct cancer may be found inside the liver (intrahepatic) or outside the liver (extrahepatic).
Biliary — Having to do with the liver, bile ducts and/or gallbladder.
Biliary Bypass — A surgical procedure in which the gallbladder or bile duct is sewn to the small intestine to create a new pathway around the blocked area. This procedure helps to relieve jaundice caused by the buildup of bile.
Bilirubin — A substance formed when red blood cells are broken down. Bilirubin is part of the bile, which is made in the liver and stored in the gallbladder. The abnormal buildup of bilirubin causes jaundice.
Biological Therapy — A type of treatment that uses substances made from living organisms to treat disease. These substances may occur naturally in the body or may be made in the laboratory. Some biological therapies stimulate or suppress the immune system to help the body fight cancer, infection and other diseases. Other biological therapies attack specific cancer cells, which may help keep them from growing or kill them. They may also lessen certain side effects caused by some cancer treatments. Types of biological therapy include immunotherapy (such as vaccines, cytokines and some antibodies), gene therapy and some targeted therapies. Also called immunotherapy, biological response modifier therapy, biotherapy and BRM therapy.
Biomarker — A biological molecule found in blood, other body fluids or tissues that is a sign of a normal or abnormal process, or of a condition or disease. A biomarker may be used to see how well the body responds to a treatment for a disease or condition. Also called molecular marker and signature molecule.
Biopsy — The removal of cells or tissues for examination by a pathologist. The pathologist may study the tissue under a microscope or perform other tests. There are many different types of biopsy procedures.
Bisphosphonate — A drug or substance used to treat hypercalcemia (abnormally high blood calcium) and bone pain caused by some types of cancer. Forms of bisphosphonates are also used for treating osteoporosis and for bone imaging. Bisphosphonates inhibit a type of bone cell that breaks down bone. Also called diphosphonate.
Bisphosphonate Therapy — A drug therapy that may slow bone loss and reduce bone pain.
Bladder Cancer — Cancer that forms in tissues of the bladder (the organ that stores urine). Most bladder cancers are transitional cell carcinomas (cancers that begin in cells that normally make up the inner lining of the bladder). Other types include squamous cell carcinoma (cancer that begins in thin, flat cells) and adenocarcinoma (cancer that begins in cells that make and release mucus and other fluids). The cells that form squamous cell carcinoma and adenocarcinoma develop in the inner lining of the bladder as a result of chronic irritation and inflammation.
Blasts — Immature blood cells.
Blood Chemistry Analysis — A procedure in which a sample of blood is examined to measure the amounts of certain substances made in the body. An abnormal amount of a substance can be a sign of disease in the organ or tissue that produces it. Also called blood chemistry study.
Blood Creatinine — A blood product normally removed by the kidneys. Levels may be high in a patient with thrombotic thrombocytopenic purpura (TTP).
Blood Smear — A blood test that gives information about the number and shape of blood cells.
Bloom Syndrome — A rare inherited disorder marked by height that is shorter than average, a narrow face with redness and a rash, a high-pitched voice and fertility problems. Patients with this disorder have an increased risk of cancer, especially leukemia and osteosarcoma (bone cancer). Bloom syndrome is caused by changes in a protein that normally helps cells make copies of the DNA. Changes in this protein cause many breaks, rearrangements and other mutations in the DNA. It is a type of autosomal recessive genetic disease. Also called Bloom–Torre–Machacek syndrome.
Bone Marrow — The soft, sponge-like tissue in the center of most bones. It produces white blood cells, red blood cells and platelets.
Bone Marrow Aspiration — A procedure in which a small sample of bone marrow is removed, usually from the hipbone, breastbone or thighbone. A small area of skin and the surface of the bone underneath are numbed with an anesthetic. Then, a special wide needle is pushed into the bone. A sample of liquid bone marrow is removed with a syringe attached to the needle. The bone marrow is sent to a laboratory to be looked at under a microscope. This procedure may be done at the same time as a bone marrow biopsy.
Bone Marrow Biopsy — A procedure in which a small sample of bone with bone marrow inside it is removed, usually from the hipbone. A small area of skin and the surface of the bone underneath are numbed with an anesthetic. Then, a special wide needle is pushed into the bone and rotated to remove a sample of bone with the bone marrow inside it. The sample is sent to a laboratory to be looked at under a microscope. This procedure may be done at the same time as a bone marrow aspiration.
Bone Sarcoma — Cancer that forms in cells of the bone. The most frequent location is the limbs, where the majority of the body’s connective tissue resides.
Bone Scan — A procedure to check for abnormal areas or damage in the bones. A very small amount of radioactive material is injected into a vein and travels through the blood. The radioactive material collects in the bones and is detected by a scanner (a special camera that takes pictures of the inside of the body). A bone scan may be used to diagnose bone tumors or cancer that has spread to the bone. It may also be used to help diagnose fractures, bone infections or other bone problems.
Bortezomib — A drug used to treat multiple myeloma. It is also used to treat mantle cell lymphoma in patients who have already received at least one other type of treatment, and is being studied in the treatment of other types of cancer. It blocks several molecular pathways in a cell and may cause cancer cells to die. Also called PS-341 and Velcade.
Brachytherapy — A type of radiation therapy in which radioactive material sealed in needles, seeds, wires or catheters is placed directly into or near a tumor. Also called implant radiation therapy, internal radiation therapy and radiation brachytherapy.
Brain Stem — The part of the brain that is connected to the spinal cord.
Brain Tumor — The growth of abnormal cells in the tissues of the brain. Brain tumors can be benign (not cancer) or malignant (cancer).
BRCA1 — A gene on chromosome 17 that normally helps to suppress cell growth. A person who inherits certain mutations (changes) in a BRCA1 gene has a higher risk of getting breast, ovarian, prostate and other types of cancer.
BRCA2 — A gene on chromosome 13 that normally helps to suppress cell growth. A person who inherits certain mutations (changes) in a BRCA2 gene has a higher risk of getting breast, ovarian, prostate and other types of cancer.
Breast Cancer — Cancer that forms in tissues of the breast. The most common type of breast cancer is ductal carcinoma, which begins in the lining of the milk ducts, thin tubes that carry milk from the lobules (milk glands) of the breast to the nipple. Another type of breast cancer is lobular carcinoma, which begins in the lobules of the breast. Invasive breast cancer is breast cancer that has spread from where it began in the breast ducts or lobules to surrounding normal tissue. Breast cancer occurs in both men and women, although male breast cancer is rare.
Breast Lobe — A section of the breast that contains the lobules (the glands that make milk).
Breast Lobule — A small part of a lobe in the breast. A breast lobule is a gland that makes milk.
Breast Reconstruction — Surgery to rebuild the shape of the breast after a mastectomy.
Breast Tomosynthesis — A type of digital mammography in which X-ray machines are used to take pictures of thin slices of the breast from different angles, and computer software is used to reconstruct an image. Also known as a 3-D mammogram.
Bronchoscopy — A procedure that uses a bronchoscope to examine the inside of the trachea, bronchi (air passages that lead to the lungs) and lungs. A bronchoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue to be checked under a microscope for signs of disease. The bronchoscope is inserted through the nose or mouth. Bronchoscopy may be used to detect cancer or to perform some treatment procedures.
CA 19-9 — A substance released into the bloodstream by both cancer cells and normal cells. Too much CA 19-9 in the blood can be a sign of pancreatic cancer or other types of cancer or conditions. The amount of CA 19-9 in the blood can be used to help keep track of how well cancer treatments are working or if cancer has come back. It is a type of tumor marker.
Calcium — A mineral needed for healthy teeth, bones and other body tissues. It is the most common mineral in the body. A deposit of calcium in body tissues, such as breast tissue, may be a sign of disease.
Cancer — A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Cancer cells can also spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is a cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is a cancer that begins in bone, cartilage, fat, muscle, blood vessels or other connective or supportive tissue. Leukemia is a cancer that starts in blood-forming tissue, such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord. Also called malignancy.
Carcin — A prefix for cancer, as in carcinoma and carcinogen.
Carcinoembryonic Antigen (CEA) — A substance that may be found in the blood of people who have colon cancer, other types of cancer or diseases, or who smoke tobacco. CEA levels may help keep track of how well cancer treatments are working or if cancer has come back. CEA is a type of tumor marker.
Carcinogen — Any substance that causes cancer.
Carcinoid Syndrome — A group of symptoms associated with carcinoid tumors – tumors of the small intestine, colon, appendix, and bronchial tubes in the lungs.
Carcinoid Tumor — A slow-growing type of tumor usually found in the gastrointestinal system (most often in the appendix), and sometimes in the lungs or other sites. Carcinoid tumors may spread to the liver or other sites in the body, and they may secrete substances such as serotonin or prostaglandins, causing carcinoid syndrome.
Carcinoma — Cancer that begins in the skin or in tissues that line or cover internal organs.
Carfilzomib — A drug used to treat multiple myeloma that has not gotten better with other anticancer drugs. It is also being studied in the treatment of other types of cancer. Carfilzomib blocks the action of enzymes called proteasomes, and may kill cancer cells. It is a type of proteasome inhibitor. Also called Kyprolis.
Carney Complex — A rare inherited disorder marked by dark spots on the skin and tumors in the heart, endocrine glands, skin and nerves. There are two types of Carney complex, which are caused by mutations (changes) in different genes. Also called Carney syndrome.
Catheter — A flexible tube used to deliver fluids into or withdraw fluids from the body.
Celiac Disease — A digestive disease that is caused by an immune response to a protein called gluten, which is found in wheat, rye, barley and oats. Celiac disease damages the lining of the small intestine and interferes with the absorption of nutrients from food. A person with celiac disease may become malnourished no matter how much food is consumed.
Central Nervous System (CNS) Lymphoma — A disease in which malignant (cancer) cells form in the lymph tissue of the brain and/or spinal cord. Also called central nervous system lymphoma.
Cerebellum — The portion of the brain in the back of the head between the cerebrum and the brain stem. The cerebellum controls balance for walking and standing, and other complex motor functions.
Cerebrum — The largest part of the brain. It is divided into two hemispheres, or halves, called the cerebral hemispheres. Areas within the cerebrum control muscle functions and also control speech, thought, emotions, reading, writing and learning.
Cervical Cancer — Cancer that forms in tissues of the cervix (the organ connecting the uterus and vagina). It is usually a slow-growing cancer that may not have symptoms but can be found with regular Pap tests (a procedure in which cells are scraped from the cervix and looked at under a microscope). Cervical cancer is almost always caused by human papillomavirus (HPV) infection.
Cervix — The lower, narrow end of the uterus that forms a canal between the uterus and vagina.
Chemoembolization — A procedure in which the blood supply to a tumor is blocked after anticancer drugs are given in blood vessels near the tumor. Sometimes the anticancer drugs are attached to small beads that are injected into an artery that feeds the tumor. The beads block blood flow to the tumor as they release the drug. This allows a higher amount of drug to reach the tumor for a longer period of time, which may kill more cancer cells. It also causes fewer side effects because very little of the drug reaches other parts of the body. Chemoembolization is used to treat liver cancer. Also called transarterial chemoembolization (TACE).
Chemoimmunotherapy — Chemotherapy combined with immunotherapy. Chemotherapy uses different drugs to kill or slow the growth of cancer cells; immunotherapy uses treatments to stimulate or restore the ability of the immune system to fight cancer.
Chemoprevention — The use of drugs, vitamins or other agents to try to reduce the risk of, or delay the development or recurrence of, cancer.
Chemoradiation — Treatment that combines chemotherapy with radiation therapy. Also called chemoradiotherapy.
Chemotherapy — Treatment with drugs that kill cancer cells.
Chest Radiograph — Also called a chest X-ray. It uses X-rays to show the structures inside the chest. An X-ray is a type of high-energy radiation that can go through the body and onto film, making pictures of areas inside the chest, which can be used to diagnose disease.
Chlorine — A chemical used in manufacturing, as bleach, and to kill bacteria and other organisms in water.
Cholangiocarcinoma — A rare type of cancer that begins in cells that line the bile ducts. A bile duct is a tube that carries fluid called bile from the liver and the gallbladder to the small intestine. Cholangiocarcinoma may be found in the bile ducts inside the liver (intrahepatic) or outside the liver (extrahepatic). Also called bile duct carcinoma.
Cholecystectomy — The surgical removal of the gallbladder.
Chondrosarcoma — A type of bone cancer that forms in bone cartilage. It usually starts in the pelvis (between the hip bones), the shoulder or the ribs, or at the ends of the long bones of the arms and legs. A rare type of chondrosarcoma called extraskeletal chondrosarcoma does not form in bone cartilage. Instead, it forms in the soft tissues of the upper part of the arms and legs. Chondrosarcoma can occur at any age but is more common in people older than 40 years.
Chordoma — A type of bone cancer that usually starts in the lower spinal column or at the base of the skull.
Choriocarcinoma — A malignant, fast-growing tumor that develops from trophoblastic cells (cells that help an embryo attach to the uterus and help form the placenta). Almost all choriocarcinomas form in the uterus after fertilization of an egg by a sperm, but a small number form in a testis or an ovary. Choriocarcinomas spread through the blood to other organs, especially the lungs. They are a type of gestational trophoblastic disease. Also called chorioblastoma, chorioepithelioma and chorionic carcinoma.
Choroid — A layer of blood vessels that supply the eye with oxygen and nutrients. Most ocular melanoma occurs in the choroid.
Christmas Disease — A rare genetic disorder that prevents blood from clotting properly. Also called hemophilia B or factor IX hemophilia.
Chromosome — Part of a cell that contains genetic information. Except for sperm and eggs, all human cells contain 46 chromosomes.
Chronic — A disease or condition that persists or progresses for a long time.
Chronic Lymphoblastic Leukemia (CLL) — A slow-growing cancer in which too many immature lymphocytes (white blood cells) are found mostly in the blood and bone marrow. Sometimes, in later stages of the disease, cancer cells are found in the lymph nodes, and the disease is called small lymphocytic lymphoma. Also called chronic lymphocytic leukemia.
Chronic Myeloid Leukemia (CML) — A slowly progressing disease in which too many white blood cells (not lymphocytes) are made in the bone marrow. Also called chronic granulocytic leukemia and chronic myelogenous leukemia.
Chronic Myelomonocytic Leukemia (CMML) — A slowly progressing type of myelodysplastic/myeloproliferative disease in which too many myelomonocytes (a type of white blood cell) are in the bone marrow, crowding out other normal blood cells, such as other white blood cells, red blood cells and platelets.
Ciliary Body — A ring of tissue and muscle in the eye that changes the size of the pupil and the shape of the eye’s lens. The ciliary body also makes a clear fluid that fills the space between the cornea and iris.
Cirrhosis — A type of chronic, progressive liver disease in which liver cells are replaced by scar tissue.
Clinical Trial — A type of research study that tests how well new medical approaches work in people. These studies test new methods of screening, prevention, diagnosis or treatment of a disease. Also called clinical study.
Colon Cancer — Cancer that forms in the tissues of the colon (the longest part of the large intestine). Most colon cancers are adenocarcinomas (cancers that begin in cells that make and release mucus and other fluids).
Colonoscopy — Examination of the inside of the colon using a colonoscope inserted into the rectum. A colonoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue to be checked under a microscope for signs of disease.
Colostomy — An opening into the colon from the outside of the body. A colostomy provides a new path for waste material to leave the body after part of the colon has been removed.
Colposcopy — A procedure in which a lighted, magnifying instrument called a colposcope is used to examine the cervix, vagina and vulva. During colposcopy, an instrument called a speculum is inserted into the vagina to widen it so that the cervix can be seen more easily. Colposcopy may be used to check for cancers of the cervix, vagina and vulva, and changes that may lead to cancer.
Complete Blood Count (CBC) — A measure of the number of red blood cells, white blood cells and platelets in the blood. The amount of hemoglobin (the substance in the blood that carries oxygen) and the hematocrit (the amount of whole blood that is made up of red blood cells) are also measured. A complete blood count is used to help diagnose and monitor many conditions. Also called blood cell count and full blood count.
Cone Biopsy — A procedure in which a cone-shaped piece of abnormal tissue is removed from the cervix. A scalpel, a laser knife or a thin wire loop heated by an electric current may be used to remove the tissue. The tissue is then checked under a microscope for signs of disease. Cone biopsy may be used to check for cervical cancer or to treat certain cervical conditions. Types of cone biopsy are LEEP (loop electrosurgical excision procedure) and cold knife conization (cold knife cone biopsy). Also called conization.
Congenital Neutropenia — An inherited disorder in which there is a lower than normal number of neutrophils (a type of white blood cell that is important in fighting infections). Infants with the disorder get infections caused by bacteria and are at an increased risk of acute myelogenous leukemia (AML) or myelodysplasia (a bone marrow disorder). Also called genetic infantile agranulocytosis, infantile genetic agranulocytosis, Kostmann disease, Kostmann neutropenia and Kostmann syndrome.
Contraception — Birth control.
Coombs Test — A test that can find out whether Thrombotic Thrombocytopenic Pupura (TTP) is the cause of anemia by determining if proteins are destroying red blood cells. If the test is negative, TTP is the cause.
Cordectomy — An operation on the vocal cords or on the spinal cord.
Corticosteroid — Any steroid hormone made in the adrenal cortex (the outer part of the adrenal gland). Corticosteroids are also made in the laboratory. They have many different effects in the body and are used to treat many different conditions. They may be used as hormone replacement, to suppress the immune system and to treat some side effects of cancer and its treatment. They are also used to treat certain types of lymphoma and lymphoid leukemia.
Cortisol — A hormone that helps control the use of sugar, protein and fats in the body and plays a role in stress response.
Cowden Syndrome — A rare genetic condition that can cause a
variety of noncancerous growths, such as fibrocystic breasts, thyroid nodules and goiters, uterine fibroids and polyps in the intestines. Cowden syndrome also causes skin growths that occur on the face, tongue, mouth and hands. These include papillomatous papules (skin-colored bumps), trichilemmomas (benign tumors of the hair root) and lipomas (fatty growths under the skin). Cancers of the breast and thyroid can be caused by Cowden syndrome. Other cancers that may be seen more frequently in people with Cowden syndrome are uterine (endometrial) cancer, kidney cancer (a type called renal cell carcinoma) and melanoma skin cancer.
Craniopharyngiomas — Tumors that generally occur just above the pituitary gland.
Craniotomy — A type of surgery in which a pituitary tumor is removed through an opening in the skull.
Crohn’s Disease — A type of inflammatory bowel disease (IBD) that can affect any part of the gastrointestinal (GI) tract.
Cryoablation — A procedure in which an extremely cold liquid or an instrument called a cryoprobe is used to freeze and destroy abnormal tissue. A cryoprobe is cooled with substances such as liquid nitrogen, liquid nitrous oxide or compressed argon gas. Cryoablation may be used to treat certain types of cancer and some conditions that may become cancer. Also called cryotherapy.
CSF Leak — Any tear or hole in the membrane that surrounds the brain and spinal cord (dura) that can allow the fluid that surrounds those organs to leak. Also known as cerebrospinal fluid leak.
CT (Computed Tomography) Scan — A procedure that uses a computer linked to an X-ray machine to make a series of detailed pictures of areas inside the body. The pictures are taken from different angles and are used to create 3-dimensional (3-D) views of tissues and organs. A dye may be injected into a vein or swallowed to help the tissues and organs show up more clearly. It may be used to help diagnose disease, plan treatment or find out how well treatment is working.
Curative Surgery — Performed when cancer is found in one bodily area and it is determined that all of the cancer can safely be removed. This may also be used as a complement to radiation therapy or chemotherapy, either before or after. In some cases, radiation treatment is used during an operation and is known as intraoperative radiation therapy.
Cutaneous — Having to do with the skin.
Cyclophosphamide — A drug that is used to treat many types of cancer and is being studied in the treatment of other types of cancer. It is also used to treat some types of kidney disease in children. Cyclophosphamide attaches to DNA in cells and may kill cancer cells. It is a type of alkylating agent. Also called CTX and Cytoxan.
Cyclosporine — A drug used to help reduce the risk of rejection of organ and bone marrow transplants by the body. It is also used in clinical trials to make cancer cells more sensitive to anticancer drugs.
Cyst — A closed, sac-like pocket of tissue that can form anywhere in the body. It may be filled with fluid, air, pus or other material. Most cysts are benign (not cancer).
Cystectomy — Surgery to remove all or part of the bladder (the organ that holds urine) or to remove a cyst (a sac or capsule in the body).
Cytogenetic Analysis — The study of chromosomes and chromosomal abnormalities.
Cytopenia — A condition in which there is an abnormally low number of blood cells.
Debulking Surgery — Surgery to remove only part of the cancer, due to potential danger to nearby organs or tissues. Examples of this would include ovarian cancer and some lymphomas. Once the tumor size is surgically reduced, the remainder can be treated with radiation or chemotherapy.
Denosumab — A drug used to prevent or treat certain bone problems. Under the brand name Xgeva, it is used to prevent broken bones and other bone problems caused by solid tumors that have spread to bone. It is also used in certain patients to treat giant cell tumor of the bone that cannot be removed by surgery. Under the brand name Prolia, it is used to treat osteoporosis (a decrease in bone mass and density) in postmenopausal women who have a high risk of breaking bones. Denosumab is also being studied in the treatment of other conditions and types of cancer. It binds to a protein called RANKL, which keeps RANKL from binding to another protein called RANK on the surface of certain bone cells, including bone cancer cells. This may help keep bone from breaking down and cancer cells from growing. Denosumab is a type of monoclonal antibody. Also called AMG 162, Prolia and Xgeva.
Dermabrasion — A procedure that scrapes away skin cells from the top layer of skin using a rotating wheel.
Dermatology — The branch of medicine that is focused on the diagnosis and treatment of skin disorders or conditions
Desmopressin (DDAVP) — Mild hemophilia may be treated with desmopressin (DDAVP), which helps the body release factor VIII that is stored within the lining of blood vessels.
Dexamethasone — Dexamethasone is used to treat leukemia and lymphoma and may be used to treat some of the problems caused by other cancers and their treatment.
Diagnosis — The process of identifying a disease, condition or injury from its signs and symptoms. A health history, physical exam and tests, such as blood tests, imaging tests and biopsies, may be used to help make a diagnosis.
Diagnostic Screening — Checking for disease when there are no symptoms. Since screening may find diseases at an early stage, there may be a better chance of curing the disease. Examples of cancer screening tests are the mammogram (breast), colonoscopy (colon), and the Pap test and HPV test (cervix). Screening can also include checking for a person’s risk of developing an inherited disease by doing a genetic test.
Diagnostic Surgery — Removing a tissue sample for the purpose of subjecting it to microscopic biopsy tests to determine whether the tissue is cancerous and the type of cancer that may be present.
Diamond Blackfan Anemia (DBA) — A very rare disorder in which the bone marrow doesn’t make enough red blood cells. It is usually seen in the first year of life. Patients may have deformed thumbs and other physical problems. They also have an increased risk of leukemia and sarcoma, especially osteosarcoma (bone cancer).
DIEP Flap — A type of breast reconstruction surgery in which blood vessels called deep inferior epigastric perforators (DIEP), as well as the skin and fat connected to them, are removed from the lower abdomen and used for reconstruction. The muscle is left in place.
Diethylstilbestrol (DES) — A synthetic form of the hormone estrogen that was prescribed to pregnant women between about 1940 and 1971 because it was thought to prevent miscarriages. DES may increase the risk of uterine, ovarian or breast cancer in women who took it. It also has been linked to an increased risk of clear cell carcinoma of the vagina or cervix in daughters exposed to DES before birth.
Dilatation and Curettage — A procedure to remove tissue from the cervical canal or the inner lining of the uterus. The cervix is dilated (made larger) and a curette (a spoon-shaped instrument) is inserted into the uterus to remove tissue. Also called D&C and dilation and curettage.
DNA (Deoxyribonucleic Acid) — The molecules inside cells that carry genetic information and pass it from one generation to the next.
Ductal Carcinoma — The most common type of breast cancer. It begins in the lining of the milk ducts (thin tubes that carry milk from the lobules of the breast to the nipple). Ductal carcinoma may be either ductal carcinoma in situ (DCIS) or invasive ductal carcinoma. DCIS is a noninvasive condition in which abnormal cells are found in the lining of a breast duct and have not spread outside the duct to other tissues in the breast. In some cases, DCIS may become invasive cancer. In invasive ductal carcinoma, cancer has spread outside the breast duct to surrounding normal tissue. It can also spread through the blood and lymph systems to other parts of the body.
Duodenum — The first part of the small intestine. It connects to the stomach. The duodenum helps to further digest food coming from the stomach. It absorbs nutrients (vitamins, minerals, carbohydrates, fats and proteins) and water from food so they can be used by the body.
Dysplasia — Cells that look abnormal under a microscope but are not cancer.
Echocardiography — A procedure that uses ultrasonic waves directed over the chest wall to obtain a graphic record of the heart's position, motion of the walls, or internal parts such as the valves.
Electrocoagulation — A procedure that uses heat from an electric current to destroy abnormal tissue, such as a tumor or other lesion. It may also be used to control bleeding during surgery or after an injury. The electric current passes through an electrode that is placed on or near the tissue. The tip of the electrode is heated by the electric current to burn or destroy the tissue. Electrocoagulation is a type of electrosurgery. Also called electrocautery, electrofulguration and fulguration.
Electrodesiccation — The drying of tissue by a high-frequency electric current applied with a needle-shaped electrode.
Electron Microscopy — A laboratory test in which cells in a sample of tissue are viewed under regular and high-powered microscopes to look for certain changes in the cells.
Electroporation Therapy (EPT) — A treatment that generates electrical pulses through an electrode placed in a tumor to enhance the ability of anticancer drugs to enter tumor cells.
Embolization — A procedure that uses particles, such as tiny gelatin sponges or beads, to block a blood vessel. Embolization may be used to stop bleeding or to block the flow of blood to a tumor or abnormal area of tissue. It may be used to treat some types of liver cancer, kidney cancer and neuroendocrine tumors. It may also be used to treat uterine fibroids, aneurysms and other conditions. Types of embolization are arterial embolization, chemoembolization and radioembolization.
Embryonal Tumor — A mass of rapidly growing cells that begins in embryonic (fetal) tissue. Embryonal tumors may be benign or malignant, and include neuroblastomas and Wilms tumors. Also called embryoma.
En Bloc Resection — Resection of a large bulky tumor virtually without dissection.
Endoanal (Endorectal) Ultrasound — A procedure in which a probe that sends out high-energy sound waves is inserted into the rectum. The sound waves are bounced off internal tissues or organs and make echoes. The echoes form a picture of body tissue called a sonogram. Endorectal ultrasound is used to look for abnormalities in the rectum and nearby structures, including the prostate. Also called ERUS, transrectal ultrasound and TRUS.
Endocervical Curettage — A procedure in which a sample of abnormal tissue is removed from the cervix using a small, spoon-shaped instrument called a curette. The tissue is then checked under a microscope for signs of cervical cancer. This procedure may be done if abnormal cells are found during a Pap test.
Endocrine Cancer — Cancer that occurs in endocrine tissue, the tissue in the body that secretes hormones.
Endocrine Therapy — Treatment that adds, blocks or removes hormones. For certain conditions (such as diabetes or menopause), hormones are given to adjust low hormone levels. To slow or stop the growth of certain cancers (such as prostate and breast cancer), synthetic hormones or other drugs may be given to block the body’s natural hormones. Sometimes surgery is needed to remove the gland that makes a certain hormone. Also called hormonal therapy, hormone therapy and hormone treatment.
Endocrinology — A branch of medicine that specializes in diagnosing and treating disorders of the endocrine system, which includes the glands and organs that make hormones. These disorders include diabetes, infertility and thyroid, adrenal and pituitary gland problems.
Endoluminal Stent Placement — A procedure to insert a stent (a thin, expandable tube) in order to keep a passage (such as arteries or the esophagus) open.
Endometrial Biopsy — A procedure in which a sample of tissue is taken from the endometrium (inner lining of the uterus) for examination under a microscope. A thin tube is inserted through the cervix into the uterus, and gentle scraping and suction are used to remove the sample.
Endometrial Cancer — Cancer that forms in the tissue lining the uterus (the small, hollow, pear-shaped organ in a woman's pelvis in which a fetus develops). Most endometrial cancers are adenocarcinomas (cancers that begin in cells that make and release mucus and other fluids).
Endometrial Hyperplasia — An abnormal overgrowth of the endometrium (the layer of cells that lines the uterus). There are four types of endometrial hyperplasia: simple endometrial hyperplasia, complex endometrial hyperplasia, simple endometrial hyperplasia with atypia, and complex endometrial hyperplasia with atypia. These differ in terms of how abnormal the cells are and how likely it is that the condition will become cancer.
Endometrium — The layer of tissue that lines the uterus.
Endoscopic Retrograde Cholangiopancreatography (ERCP) — A procedure that uses an endoscope (a thin, tube-shaped instrument) to examine and X-ray the pancreatic duct, hepatic duct, common bile duct, duodenal papilla and gallbladder. The endoscope is passed through the mouth and down into the first part of the small intestine (duodenum). A smaller tube (catheter) is then inserted through the endoscope into the bile and pancreatic ducts. A dye is injected through the catheter into the ducts, and an X-ray is taken.
Endoscopic Stent Placement — A procedure that inserts a stent, a hollow device designed to prevent constriction or collapse of a tubular organ, by endoscopy.
Endoscopic Transsphenoidal Surgery — A minimally invasive surgical procedure in which an endoscope is inserted into the nose and sphenoid sinus to remove pituitary tumors. A type of surgery in which instruments are inserted through the nose and sphenoid sinus (a hollow space in a bone in the nose) to remove tumors that are in or near the pituitary gland
Endoscopic Ultrasound — A procedure in which an endoscope is inserted into the body. An endoscope is a thin, tube-like instrument that has a light and a lens for viewing. A probe at the end of the endoscope is used to bounce high-energy sound waves (ultrasound) off internal organs to make a picture (sonogram). Also called endosonography and EUS.
Endoscopy — A procedure that uses an endoscope to examine the inside of the body. An endoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue to be checked under a microscope for signs of disease.
Enucleation — In medicine, the removal of an organ or tumor in such a way that it comes out clean and whole, like a nut from its shell. For example, the surgical removal of the eye and the optic nerve to remove a tumor.
Enzyme — A protein that speeds up chemical reactions in the body.
Ependymoma — A type of brain tumor that begins in cells lining the spinal cord central canal (fluid-filled space down the center) or the ventricles (fluid-filled spaces of the brain). Ependymomas may also form in the choroid plexus (tissue in the ventricles that makes cerebrospinal fluid). Also called ependymal tumor.
Epidemic — A widespread occurrence of an infectious disease in a community at a particular time.
Epidermis — The outer layer of the two main layers of the skin.
Epithelial Cells — The cells that line the internal and external surfaces of the body.
Epstein–Barr Virus (EBV) — A common virus that remains dormant in most people. It causes infectious mononucleosis and has been associated with certain cancers, including Burkitt lymphoma, immunoblastic lymphoma and nasopharyngeal carcinoma.
Erythrocyte Sedimentation Rate (ESR) — The distance red blood cells travel in one hour in a sample of blood as they settle to the bottom of a test tube. The sedimentation rate is increased in inflammation, infection, cancer, rheumatic diseases and diseases of the blood and bone marrow. Also called sedimentation rate.
Esophageal Cancer — Cancer that forms in tissues lining the esophagus (the muscular tube through which food passes from the throat to the stomach). Two types of esophageal cancer are squamous cell carcinoma (cancer that begins in flat cells lining the esophagus) and adenocarcinoma (cancer that begins in cells that make and release mucus and other fluids).
Esophagoscopy — Examination of the esophagus using an esophagoscope. An esophagoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue to be checked under a microscope for signs of disease.
Esophagus — The muscular tube through which food passes from the throat to the stomach.
Estrogen — A type of hormone made by the body that helps develop and maintain female sex characteristics and the growth of long bones. Estrogens can also be made in the laboratory. They may be used as a type of birth control and to treat symptoms of menopause, menstrual disorders, osteoporosis and other conditions.
Estrogen Replacement Therapy — Treatment with the hormone estrogen to increase the amount of estrogen in the body. It is given to women who have gone through menopause or to women who have early menopause caused by cancer treatment or by having their ovaries removed by surgery. Estrogen replacement therapy may help relieve symptoms of menopause, such as hot flashes, night sweats, vaginal dryness and sleep problems. It may also help protect against osteoporosis (thinning of the bones) and lower the risk of breast cancer in postmenopausal women. Also called ERT.
Ewing Sarcoma — A type of cancer that forms in bone or soft tissue. Also called peripheral primitive neuroectodermal tumor and pPNET.
Excision — Removal by surgery.
Exenteration — The surgical removal of the eye, eyelid, muscles, nerves and fat tissue in the eye socket to remove a tumor.
Exfoliative Cytology — A procedure in which cells are collected from the lip or oral regions using either a piece of cotton, a small brush or a small wooden stick. The cells are examined under a microscope by a pathologist for the presence of cancer cells.
Exocrine Cancer — A disease in which malignant (cancer) cells are found in the tissues of the pancreas. Also called pancreatic cancer.
Exocrine Pancreas Cells — Make enzymes that are released into the small intestine to help the body digest food. Most of the pancreas is made of ducts with small sacs at the end of the ducts, which are lined with exocrine cells.
External Beam Radiation Therapy — A type of radiation therapy that uses a machine to aim high-energy rays at the cancer from outside of the body. Also called external radiation therapy.
Extrahepatic Bile Duct — The part of the common hepatic bile duct (tube that collects bile from the liver) that is outside the liver. This duct joins a duct from the gallbladder to form the common bile duct, which carries bile into the small intestine when food is being digested.
Familial Adenomatous Polyposis (FAP) — An inherited condition in which numerous polyps (growths that protrude from mucous membranes) form on the inside walls of the colon and rectum. It increases the risk of colorectal cancer. Also called familial polyposis.
Familial Atypical Multiple Mole Melanoma (FAMMM) Syndrome — An inherited condition marked by the following: (1) one or more first- or second-degree relatives (parent, sibling, child, grandparent, grandchild, aunt or uncle) with malignant melanoma; (2) many moles, some of which are atypical (asymmetrical, raised and/or different shades of tan, brown, black or red) and often of different sizes; and (3) moles that have specific features when examined under a microscope. FAMMM syndrome increases the risk of melanoma and may increase the risk of pancreatic cancer.
Familial Isolated Hyperparathyroidism (FIHP) — A rare inherited condition in which one or more tumors form in the parathyroid glands (four pea-sized organs found on the thyroid) and cause them to make too much parathyroid hormone. The increased parathyroid hormone causes a loss of calcium from the bones and too much calcium in the blood.
Familial Platelet Disorder — A disorder in which the person’s bone marrow is not able to make enough platelets and there is family history of the same disorder.
Fanconi Anemia — A rare inherited disorder in which the bone marrow does not make blood cells. It is usually diagnosed in children between 2 and 15 years old. Symptoms include frequent infections, easy bleeding and extreme tiredness. People with Fanconi anemia may have a small skeleton and brown spots on the skin. They also have an increased risk of developing certain types of cancer.
FDA (U.S. Food and Drug Administration) — An agency in the U.S. federal government whose mission is to protect public health by making sure that food, cosmetics and nutritional supplements are safe to use and truthfully labeled. The FDA also makes sure that drugs, medical devices, and medical equipment are safe and effective, and that blood for transfusions and transplant tissue is safe.
Fecal Immunochemical Test (FIT or iFOBT) — A test that checks for occult (hidden) blood in the stool. Small samples of stool are placed on special cards and sent to a doctor or laboratory for testing. An antibody that binds to a blood protein called hemoglobin is used to detect any blood. Blood in the stool may be a sign of colorectal cancer or other problems, such as polyps, ulcers or hemorrhoids. Also called iFOBT, immunoassay fecal occult blood test, immunochemical fecal occult blood test and immunologic fecal occult blood test.
Fibrin Glue — A substance used during surgery to help heal wounds. It contains proteins found in human blood that cause blood to clot. When fibrin glue is placed on a wound, a clot forms. Fibrin glue is being studied as a way to improve healing after lymph node removal in patients with cancer. Also called fibrin sealant.
Fine Needle Aspiration — The removal of tissue or fluid with a thin needle for examination under a microscope. Also called FNA biopsy.
FISH (Fluorescent in Situ Hybridization) — A laboratory technique used to look at genes or chromosomes in cells and tissues. Pieces of DNA that contain a fluorescent dye are made in the laboratory and added to cells or tissues on a glass slide. When these pieces of DNA bind to specific genes or areas of chromosomes on the slide, they light up when viewed under a microscope with a special light.
Flow Cytometry — A technology that uses lasers to determine physical and chemical characteristics of particles in a fluid, in particular to diagnose diseases of the blood, including leukemia.
Fluorescence Staining — A procedure in which a specially treated mouthwash is used as a rinse. The mouthwash will fluoresce under a special light. Abnormal areas that light up may be precancerous.
Folic Acid — A nutrient in the vitamin B complex that the body needs in small amounts to function and stay healthy. Folic acid helps to make red blood cells. It is found in whole-grain breads and cereals, liver, green vegetables, orange juice, lentils, beans and yeast. Folic acid is water soluble (can dissolve in water) and must be taken in every day. Not enough folic acid can cause anemia (a condition in which the number of red blood cells is below normal); diseases of the heart and blood vessels; and defects in the brain and spinal cord in a fetus. Folic acid is being studied with vitamin B12 in the prevention and treatment of cancer. Also called folate.
Follicle-Stimulating Hormone — A hormone released by the pituitary gland. It helps to manage a woman’s cycle and stimulates the ovaries to produce eggs. In men, it stimulates the production of sperm.
Follicular Pituitary Cancer — Cancer that forms in follicular cells in the pituitary gland.
Follicular Thyroid Cancer —The second most frequently diagnosed type of thyroid cancer, this begins in the follicular cells of the thyroid gland and is slow growing and highly treatable. Hürthle cell carcinoma is a form of follicular thyroid cancer.
Free Flap Surgery — A type of surgery used to rebuild the shape of the breast after a mastectomy. A tissue flap, including blood vessels, skin, fat and sometimes muscle, is removed from one area of the body, such as the back or abdomen. It is then reattached to the chest to form a new breast mound. The blood vessels from the tissue are reconnected to blood vessels under the arm or in the chest. A free flap is a type of breast reconstruction.
Gallbladder Cancer — Cancer that forms in tissues of the gallbladder. The gallbladder is a pear-shaped organ below the liver that collects and stores bile (a fluid made by the liver to digest fat). Gallbladder cancer begins in the innermost layer of tissue and spreads through the outer layers as it grows.
Gallstones — Solid material that forms in the gallbladder or common bile duct. Gallstones are made of cholesterol or other substances found in the gallbladder. They may occur as one large stone or as many small ones, and vary from the size of a golf ball to a grain of sand. Also called cholelith.
GAP Flap — A breast reconstruction procedure that uses the gluteal artery perforator blood vessel, which runs through the buttocks, as well as a section of skin and fat to reconstruct the breast. Because no muscle is used, a GAP flap is considered a muscle-sparing type of flap.
Gastrectomy — An operation to remove all or part of the stomach.
Gastric Bypass — A surgical procedure to sew the stomach directly to the small intestine, to bypass a tumor that is blocking the flow of food from the stomach, in order to allow a patient to continue to eat normally.
Gastrinoma — A tumor that causes overproduction of gastric acid. It usually begins in the duodenum (the first part of the small intestine that connects to the stomach) or in the islet cells of the pancreas. Rarely, it may also begin in other organs, including the stomach, liver, jejunum (the middle part of the small intestine), biliary tract (organs and ducts that make and store bile), mesentery or heart. It is a type of neuroendocrine tumor, and it may metastasize (spread) to the liver and the lymph nodes.
Gastritis — Inflammation of the lining of the stomach.
Gastroenterology — The study and treatment of disorders of the digestive system.
Gastroesophageal Reflux Disease (GERD) — The backward flow of stomach acid contents into the esophagus (the tube that connects the mouth to the stomach). Also called esophageal reflux and gastric reflux.
Gastrointestinal Carcinoid Tumor — An indolent (slow-growing) cancer that forms in cells that make hormones in the lining of the gastrointestinal tract (the stomach and intestines). It usually occurs in the appendix (a small finger-like pouch in the large intestine), small intestine or rectum. Having a gastrointestinal carcinoid tumor increases the risk of forming other cancers of the digestive system.
Gastrointestinal (GI) Tract — The stomach and intestines.
Gastrointestinal Stromal Tumor (GIST) — A type of tumor that usually begins in cells in the wall of the gastrointestinal tract. It can be benign or malignant.
Gastrojejunostomy — Surgery to remove the part of the stomach with cancer that is blocking the opening into the small intestine. The stomach is connected to the jejunum (a part of the small intestine) to allow food and medicine to pass from the stomach into the small intestine.
Gene Expression Profiling — The process of analyzing cells for certain types of RNA, the nucleic acid made by cells that relates to making proteins.
Genes — The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein.
Genetic Testing — The study of a sample of DNA to look for mutations (changes) that may increase risk of disease or affect the way a person responds to treatment. Also called genetic analysis.
Genitourinary Cancers — Cancer that involves the prostate, bladder, kidney, testicular, male genital or adrenal glands
Genitourinary System — The parts of the body that play a role in reproduction and getting rid of waste product in the form of urine.
Genome — The complete genetic material of an organism.
Genomic Sequencing and Analysis — A laboratory method that is used to determine the entire genetic makeup of a specific organism or cell type. This method can be used to find changes in areas of the genome that may be important in the development of specific diseases, such as cancer.
Germ Cell — A reproductive cell of the body. Germ cells are egg cells in females and sperm cells in males.
Gland — An organ that makes one or more substances, such as hormones, digestive juices, sweat, tears, saliva or milk. Endocrine glands release the substances directly into the bloodstream. Exocrine glands release the substances into a duct or opening to the inside or outside of the body.
Gleason Score — A system of grading prostate cancer tissue based on how it looks under a microscope. Gleason scores range from 2 to 10 and indicate how likely it is that a tumor will spread. A low Gleason score means the cancer tissue is similar to normal prostate tissue, and the tumor is less likely to spread; a high Gleason score means the cancer tissue is very different from normal, and the tumor is more likely to spread.
Glial Cell — Any of the cells that hold nerve cells in place and help them work the way they should. The types of glial cells include oligodendrocytes, astrocytes, microglia and ependymal cells. Also called neuroglia.
Glioblastoma — A fast-growing type of central nervous system tumor that forms from glial (supportive) tissue of the brain and spinal cord and has cells that look very different from normal cells. Glioblastoma usually occurs in adults and affects the brain more often than the spinal cord. Also called GBM, glioblastoma multiforme and grade IV astrocytoma.
Glioma — A type of tumor that originates in the brain or spine and develops from glial cells.
Glucagon — A hormone produced by the pancreas that increases the level of glucose (sugar) in the blood.
Glucagonoma — A rare pancreatic tumor that produces a hormone called glucagon. Glucagonomas can produce symptoms similar to diabetes.
Gonadotropin-Secreting Adenoma — A type of pituitary tumor that secretes one or more hormones such as Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) blood levels.
Gonioscopy — A procedure in which a gonioscope (special lens) is used to look at the front part of the eye between the cornea (the clear layer) and the iris (the colored part of the eye). Gonioscopy checks for blockages in the area where fluid drains out of the eye.
Granulocyte — A type of immune cell that has granules (small particles) with enzymes that are released during infections, allergic reactions and asthma. A granulocyte is a type of white blood cell. Also called granular leukocyte, polymorphornuclear neutrophil (PMN), and polymorphonuclear leukocyte.
Growth Factor — A substance made by the body that functions to regulate cell division and cell survival. Some growth factors are also produced in the laboratory and used in biological therapy.
Gynecology — The study and treatment of the female reproductive tract, including the cervix, endometrium, fallopian tubes, ovaries, uterus and vagina.
HCL (Hairy-Cell Leukemia) — A rare type of leukemia in which abnormal B lymphocytes (a type of white blood cell) are present in the bone marrow, spleen and peripheral blood. When viewed under a microscope, these cells appear to be covered with tiny, hair-like projections.
Heavy Metals — Chronic exposure of heavy metals has been suggested as causing certain types of cancer. Commonly encountered heavy metals are chromium, cobalt, nickel, copper, zinc, arsenic, selenium, silver, cadmium, antimony, mercury, thallium and lead.
Helicobacter Pylori (H. Pylori) — A type of bacterium that causes inflammation and ulcers in the stomach or small intestine. People with Helicobacter pylori infections may be more likely to develop cancer in the stomach, including MALT (mucosa-associated lymphoid tissue) lymphoma.
Hematology — The study and treatment of blood, bone marrow and the lymphatic system.
Hematuria — Blood in the urine.
Hemilaryngectomy — An operation to remove one side of the larynx (voice box).
Hemochromatosis — A condition in which the body takes up and stores more iron than it needs. The extra iron is stored in the liver, heart and pancreas, which may cause liver disease, heart problems, organ failure and cancer. It may also cause bronze skin, diabetes, pain in the joints and abdomen, tiredness and impotence. Hemochromatosis may be inherited, or it may be caused by blood transfusions. Also called iron overload.
Hemoglobin — A protein inside red blood cells that carries oxygen from the lungs to tissues and organs in the body and carries carbon dioxide back to the lungs. Testing for the amount of hemoglobin in the blood is usually part of a complete blood cell (CBC) test. It is used to check for conditions such as anemia, dehydration and malnutrition.
Hemolytic Anemia — A condition that occurs when red blood cells die sooner than the bone marrow may replace them. Scientific term for the destruction of red blood cells is called hemolysis.
Hemophilia — An inherited rare blood disorder that prevents blood from
Hepatic Artery — The major blood vessel that carries blood to the liver.
Hepatitis B (HBV) — A virus that causes hepatitis (inflammation of the liver). It is carried and passed to others through the blood and other body fluids. Different ways the virus is spread include sharing needles with an infected person and being stuck accidentally by a needle contaminated with the virus. Infants born to infected mothers may also become infected with the virus. Although many patients who are infected with hepatitis B virus may not have symptoms, long-term infection may lead to cirrhosis (scarring of the liver) and liver cancer.
Hepatitis C (HCV) — A virus that causes hepatitis (inflammation of the liver). It is carried and passed to others through the blood and other body fluids. Different ways the virus is spread include sharing needles with an infected person and being stuck accidentally by a needle contaminated with the virus. Infants born to infected mothers may also become infected with the virus. Although patients who are infected with hepatitis C virus may not have symptoms, long-term infection may lead to cirrhosis (scarring of the liver) and liver cancer. These patients may also have an increased risk for certain types of non-Hodgkin lymphoma.
Hepatocellular Carcinoma — A type of adenocarcinoma and the most common type of liver tumor.
Hepatology — Hepatology is a branch of medicine concerned with the study and management of diseases that affect the liver, gallbladder, biliary tree and pancreas.
HER2/neu — A protein involved in normal cell growth. It is found on some types of cancer cells, including breast and ovarian. Cancer cells removed from the body may be tested for the presence of HER2/neu to help decide the best type of treatment. HER2/neu is a type of receptor tyrosine kinase. Also called c-erbB-2, human EGF receptor 2 and human epidermal growth factor receptor 2.
Hereditary Breast and Ovarian Cancer Syndrome — A syndrome caused by a gene mutation in the BRCA1 or BRCA2 gene. It increases the risk for breast cancer, ovarian cancer, prostate cancer and pancreatic cancer.
Hereditary Nonpolyposis Colon Cancer (HNPCC) — An inherited disorder in which affected individuals have a higher than normal chance of developing colorectal cancer and certain other types of cancer, often before the age of 50. Also known as Lynch syndrome.
Histone Deacetylase (HDAC) — An enzyme that removes a small molecule called an acetyl group from histones (proteins found in chromosomes). This changes the way the histones bind to DNA and may affect its activity.
Histone Deacetylase (HDAC) Inhibitor — A substance that causes a chemical change that stops tumor cells from dividing. HDAC inhibitors are being studied in the treatment of cancer.
Human Immunodeficiency Virus (HIV) — A virus that causes acquired immunodeficiency syndrome (AIDS).
Hodgkin’s Lymphoma — A cancer of the immune system that is marked by the presence of a type of cell called the Reed–Sternberg cell. The two major types of Hodgkin's lymphoma are classical Hodgkin's lymphoma and nodular lymphocyte-predominant Hodgkin's lymphoma. Symptoms include the painless enlargement of lymph nodes, spleen or other immune tissue. Other symptoms include fever, weight loss, fatigue or night sweats. Also called Hodgkin lymphoma or Hodgkin disease.
Hormone — One of many substances made by glands in the body. Hormones circulate in the bloodstream and control the actions of certain cells or organs. Some hormones can also be made in the laboratory.
Hormone Receptor — A cell protein that binds a specific hormone. The hormone receptor may be on the surface of the cell or inside the cell. Many changes take place in a cell after a hormone binds to its receptor.
Hormone Replacement Therapy (HRT) — Hormones (estrogen, progesterone or both) given to women after menopause to replace the hormones no longer produced by the ovaries. Also called HRT and menopausal hormone therapy.
Human Papillomavirus (HPV) — A type of virus that can cause abnormal tissue growth (for example, warts) and other changes to cells. Infection for a long time with certain types of HPV can cause cervical cancer. HPV may also play a role in some other types of cancer, such as anal, vaginal, vulvar, penile, oropharyngeal and squamous cell skin cancers.
Human Herpes Virus 8 (HHV8) — A type of virus that causes Kaposi sarcoma (a rare cancer in which lesions grow in the skin, in lymph nodes, in the lining of the mouth, nose and throat, and in other tissues of the body). HHV8 also causes certain types of lymphoma (cancer that begins in cells of the immune system). Also called Kaposi sarcoma–associated herpesvirus and KSHV.
Hürthle Cell Carcinoma — A type of follicular pituitary cancer. If caught early enough, treatment is usually successful.
Hypercalcemia — Higher than normal levels of calcium in the blood. Some types of cancer increase the risk of hypercalcemia.
Hypogammaglobulinemia — A condition in which the level of immunoglobulins (antibodies) in the blood is low and the risk of infection is high.
Hysterectomy — Surgery to remove the uterus and, sometimes, the cervix. When the uterus and the cervix are removed, it is called a total hysterectomy. When only the uterus is removed, it is called a partial hysterectomy.
Ibrutinib — A drug used to treat mantle cell lymphoma and chronic lymphocytic leukemia (CLL). It is used in patients who have already received other treatment. It is also being studied in the treatment of other types of cancer. Ibrutinib blocks a protein called Bruton’s tyrosine kinase (BTK), which may help keep cancer cells from growing. It is a type of tyrosine kinase inhibitor. Also called Imbruvica.
Ifosfamide — A drug that is used with other drugs to treat germ cell testicular cancer that did not respond to previous treatment with other drugs. It is also being studied in the treatment of other types of cancer. Ifosfamide attaches to DNA in cells and may kill cancer cells. It is a type of alkylating agent and a type of antimetabolite. Also called Ifex.
Ileum — The last part of the small intestine. It connects to the cecum (first part of the large intestine). The ileum helps to further digest food coming from the stomach and other parts of the small intestine. It absorbs nutrients (vitamins, minerals, carbohydrates, fats and proteins) and water from food so they can be used by the body.
Image-Guided Radiation Therapy (IGRT) — A procedure that uses a computer to create a picture of a tumor to help guide the radiation beam during radiation therapy. The pictures are made using CT, ultrasound, X-ray or other imaging techniques. Image-guided radiation therapy makes radiation therapy more accurate and causes less damage to healthy tissue.
Imaging Test — A type of test that makes detailed pictures of areas inside the body. Imaging tests use different forms of energy, such as X-rays (high-energy radiation), ultrasound (high-energy sound waves), radio waves and radioactive substances. They may be used to help diagnose disease, plan treatment or find out how well treatment is working. Examples of imaging tests are computed tomography (CT), ultrasonography, magnetic resonance imaging (MRI) and nuclear medicine tests.
Immune System — A complex network of cells, tissues, organs and the substances they make that helps the body fight infections and other diseases. The immune system includes white blood cells and organs and tissues of the lymph system, such as the thymus, spleen, tonsils, lymph nodes, lymph vessels and bone marrow.
Immunocytochemistry — A laboratory test that uses antibodies to test for certain antigens in a sample of cells. The antibody is usually linked to a radioactive substance or a dye that causes the cells to light up under a microscope. Immunocytochemistry is used to help diagnose diseases, such as cancer. It may also be used to help tell the difference between types of cancer.
Immunophenotyping — A process used to identify cells based on the types of antigens or markers on the surface of the cell. This process is used to diagnose specific types of leukemia and lymphoma by comparing the cancer cells to normal cells of the immune system.
Immunotherapy — A type of biological therapy that uses substances to stimulate or suppress the immune system to help the body fight cancer, infection and other diseases. Some types of immunotherapy only target certain cells of the immune system. Others affect the immune system in a general way. Types of immunotherapy include cytokines, vaccines, bacillus Calmette-Guerin (BCG) and some monoclonal antibodies. Also called biologic therapy.
Impotence — In medicine, the inability to have an erection of the penis adequate for sexual intercourse. Also called erectile dysfunction.
In situ — In its original place. For example, in carcinoma in situ, abnormal cells are found only in the place where they first formed. They have not spread.
Incontinence — Inability to control the flow of urine from the bladder (urinary incontinence) or the escape of stool from the rectum (fecal incontinence).
Inflammatory Breast Cancer — Cancer that has spread to the skin of the breast. The breast looks red and swollen and feels warm.
Inguinal Hernia — The bulging of fat or part of the small intestine through weak muscles into the groin.
Inguinal Orchiectomy — An operation in which the testicle is removed through an incision in the groin.
Insulin — A hormone made by the islet cells of the pancreas. Insulin controls the amount of sugar in the blood by moving it into the cells, where it can be used by the body for energy.
Insulinoma — An abnormal mass that grows in the beta cells of the pancreas that make insulin. Insulinomas are usually benign (not cancer). They secrete insulin and are the most common cause of low blood sugar resulting from having too much insulin in the body. Also called beta cell neoplasm, beta cell tumor of the pancreas and pancreatic insulin-producing tumor.
Intensity-Modulated Radiation Therapy (IMRT) — A type of 3-dimensional radiation therapy that uses computer-generated images to show the size and shape of the tumor. Thin beams of radiation of different intensities are aimed at the tumor from many angles. This type of radiation therapy reduces the damage to healthy tissue near the tumor.
Interferon — A biological response modifier (a substance that can improve the body's natural response to infections and other diseases). Interferons interfere with the division of cancer cells and can slow tumor growth. There are several types of interferons, including interferon-alpha, interferon-beta and interferon-gamma. The body normally produces these substances. They are also made in the laboratory to treat cancer and other diseases.
Interferon Therapy — A treatment that stimulates the body’s immune system to work better and lessens flushing and diarrhea. Interferon may also help slow tumor growth.
Intestinal Metaplasia — A condition in which the normal stomach lining is replaced with the cells that line the intestines.
Intrahepatic Ducts — Bile ducts found inside the liver.
Intraoperative Radiation Therapy (IORT) — A treatment method often
recommended for tumors closely positioned next to normal tissues.
Intravenous — Into or within a vein. Usually refers to a way of giving a drug or other substance through a needle or tube inserted into a vein. Also called IV.
Intravenous Pyelogram (IVP) — An X-ray image of the kidneys, ureters and bladder. It is made after a substance that shows up on X-rays is injected into a blood vessel. The substance outlines the kidneys, ureters and bladder as it flows through the system and collects in the urine. An intravenous pyelogram is usually made to look for a blockage in the flow of urine.
Invasive Pituitary Adenoma — A noncancerous tumor that may spread to the skull bones or the sinus cavities.
Iris — The colored area of the eye visible through the cornea.
Isolated Limb Perfusion — A procedure that may be used to deliver anticancer drugs directly to an arm or leg. The flow of blood to and from the limb is temporarily stopped with a tourniquet (a tight band around the limb), and anticancer drugs are put directly into the blood of the limb. This allows the person to receive a high dose of drugs in the area where the cancer occurred. Also called limb perfusion.
Jaundice — A condition in which the skin and the whites of the eyes become yellow, urine darkens and the color of stool becomes lighter than normal. Jaundice occurs when the liver is not working properly or when a bile duct is blocked.
Jejunum — The middle part of the small intestine. It is between the duodenum (the first part of the small intestine) and the ileum (the last part of the small intestine). The jejunum helps to further digest food coming from the stomach. It absorbs nutrients (vitamins, minerals, carbohydrates, fats and proteins) and water from food so they can be used by the body.
Kaposi Sarcoma (KS) — A type of cancer in which lesions (abnormal areas) grow in the skin, in lymph nodes, in the lining of the mouth, nose and throat, and in other tissues of the body. The lesions are usually purple and are made of cancer cells, new blood vessels and blood cells. They may begin in more than one place in the body at the same time. Kaposi’s sarcoma is caused by Kaposi’s sarcoma-associated herpesvirus (KSHV). In the United States, it usually occurs in people who have a weak immune system caused by AIDS or by drugs used in organ transplants. It is also seen in older men of Jewish or Mediterranean descent, or in young men in Africa. Also called Kaposi sarcoma.
Kidney Cancer — Cancer that forms in tissues of the kidneys. Kidney cancer includes renal cell carcinoma (cancer that forms in the lining of very small tubes in the kidney that filter the blood and remove waste products) and renal pelvis carcinoma (cancer that forms in the center of the kidney where urine collects). It also includes Wilms tumor, which is a type of kidney cancer that usually develops in children under the age of 5.
Kinase Inhibitor — A substance that blocks a type of enzyme called a kinase. Human cells have many different kinases, and they help control important functions, such as cell signaling, metabolism, division and survival. Certain kinases are more active in some types of cancer cells and blocking them may help keep the cancer cells from growing. Kinase inhibitors may also block the growth of new blood vessels that tumors need to grow. Some kinase inhibitors are used to treat cancer.
Lactate Dehydrogenase (LDH) — One of a group of enzymes found in the blood and other body tissues and involved in energy production in cells. An increased amount of lactate dehydrogenase in the blood may be a sign of tissue damage and some types of cancer or other diseases. Also called lactic acid dehydrogenase.
Laparoscopy — A procedure that uses a laparoscope, inserted through the abdominal wall, to examine the inside of the abdomen. A laparoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue to be checked under a microscope for signs of disease.
Laparotomy — A surgical incision made in the wall of the abdomen.
Large Intestine — The long, tube-like organ that is connected to the small intestine at one end and the anus at the other. The large intestine has four parts: cecum, colon, rectum and anal canal. Partly digested food moves through the cecum into the colon, where water and some nutrients and electrolytes are removed. The remaining material, solid waste called stool, moves through the colon, is stored in the rectum and leaves the body through the anal canal and anus.
Laryngeal Cancer — Cancer that forms in tissues of the larynx (the area of the throat that contains the vocal cords and is used for breathing, swallowing and talking). Most laryngeal cancers are squamous cell carcinomas (cancers that begin in flat cells lining the larynx).
Laryngoscopy — Examination of the larynx (voice box) with a mirror (indirect laryngoscopy) or with a laryngoscope (direct laryngoscopy).
Larynx — The area of the throat containing the vocal cords and used for breathing, swallowing and talking. Also called voice box.
Laser Surgery — A surgical procedure that uses the cutting power of a laser beam to make bloodless cuts in tissue or to remove a surface lesion such as a tumor.
Latissimus Dorsi Flap — A type of breast reconstruction surgery in which the latissimus dorsi back muscle, along with skin, fat and blood vessels, is moved to the chest via a tunnel under the skin to form either a new breast mound or a pocket for a breast implant.
Lesion — An area of abnormal tissue. A lesion may be benign (not cancer) or malignant (cancer).
Leukemia — Cancer that starts in blood-forming tissue, such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the bloodstream.
Leukopenia — A condition in which there is a lower than normal number of leukocytes (white blood cells) in the blood.
Li–Fraumeni Syndrome — A rare inherited predisposition to multiple cancers, caused by an alteration in the p53 tumor suppressor gene.
Linear Accelerator — A machine that uses electricity to form a stream of fast-moving subatomic particles. This creates high-energy radiation that may be used to treat cancer. Also called linac, mega-voltage linear accelerator, and MeV linear accelerator
Liver Cancer — Primary liver cancer is cancer that forms in the tissues of the liver. Secondary liver cancer is cancer that spreads to the liver from another part of the body.
Liver Function Test (LFT) — A blood test to measure the blood levels of certain substances released by the liver. A high or low level of certain substances can be a sign of liver disease.
Lobe — A portion of an organ, such as the liver, lung, breast, thyroid or brain.
Lobectomy — Surgery to remove a whole lobe (section) of an organ, such as the lungs, liver, brain or thyroid gland.
Lobular Carcinoma — Cancer that begins in the lobules (milk glands) of the breast. Lobular carcinoma may be either lobular carcinoma in situ (LCIS) or invasive lobular carcinoma. LCIS is a noninvasive condition in which abnormal cells are found in the lobules of the breast. LCIS rarely becomes invasive cancer, but having LCIS in one breast increases the risk of developing invasive cancer in either breast. In invasive lobular carcinoma, cancer has spread from the lobules to surrounding normal tissue. It can also spread through the blood and lymph systems to other parts of the body.
Lobule — A small lobe or a subdivision of a lobe.
Local Excision — Surgery to cut out the cancer and some healthy tissue around it.
Loop Electrosurgical Excision Procedure (LEEP) — A technique that uses electric current passed through a thin wire loop to remove abnormal tissue. Also called loop excision.
Lumbar Puncture — A procedure in which a thin needle called a spinal needle is put into the lower part of the spinal column to collect cerebrospinal fluid or to give drugs. Also called spinal tap.
Lumpectomy — Surgery to remove a tumor (lump) in a breast and a small amount of normal tissue around it. It is a type of breast-conserving surgery.
Lung Cancer — Cancer that forms in tissues of the lung, usually in the cells lining air passages. The two main types are small cell lung cancer and non-small cell lung cancer. These types are diagnosed based on how the cells look under a microscope.
Lupus — A chronic inflammatory connective tissue disease that can affect the joints and many organs, including the skin, heart, lungs, kidneys and nervous system. It can cause many different symptoms; however, not everyone with lupus has all of the symptoms. Also called SLE and systemic lupus erythematosus.
Luteinizing Hormone (LH) — A hormone made in the pituitary gland. In females, it acts on the ovaries to make follicles release their eggs and to make hormones that get the uterus ready for a fertilized egg to be implanted. In males, it acts on the testes to cause cells to grow and make testosterone. Also called interstitial cell-stimulating hormone and lutropin.
Luteinizing Hormone-Releasing Hormone Agonist — A substance that blocks the pituitary gland from making follicle-stimulating hormone (FSH) and luteinizing hormone (LH). In men, this causes the testicles to stop making testosterone. In women, this causes the ovaries to stop making estrogen and progesterone. Some luteinizing hormone-releasing hormone antagonists are used to treat advanced prostate cancer. They are also used to treat certain gynecologic conditions and are being studied in the treatment of hormone-sensitive breast cancer. Also called GnRH antagonist, gonadotropin-releasing hormone antagonist and LHRH antagonist.
Lymph Node — A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Lymph nodes filter lymph (lymphatic fluid), and they store lymphocytes (white blood cells). They are located along lymphatic vessels. Also called lymph gland.
Lymph Vessel — A thin tube that carries lymph (lymphatic fluid) and white blood cells through the lymphatic system. Also called lymphatic vessel.
Lymphadenectomy — A surgical procedure in which the lymph nodes are removed and a sample of tissue is checked under a microscope for signs of cancer. For a regional lymphadenectomy, some of the lymph nodes in the tumor area are removed; for a radical lymphadenectomy, most or all of the lymph nodes in the tumor area are removed. Also called lymph node dissection.
Lymphedema — A condition in which extra lymph fluid builds up in tissues and causes swelling. It may occur in an arm or leg if lymph vessels are blocked, damaged or removed by surgery.
Lymphocyte — A type of immune cell that is made in the bone marrow and is found in the blood and in lymph tissue. The two main types of lymphocytes are B lymphocytes and T lymphocytes. B lymphocytes make antibodies, and T lymphocytes help kill tumor cells and help control immune responses. A lymphocyte is a type of white blood cell.
Lymphoma — Cancer that begins in cells of the immune system. There are two basic categories of lymphomas. One kind is Hodgkin lymphoma, which is marked by the presence of a type of cell called the Reed–Sternberg cell. The other category is non-Hodgkin lymphomas, a large, diverse group of cancers of immune system cells. Non-Hodgkin lymphomas can be further divided into cancers that have an indolent (slow-growing) course and those that have an aggressive (fast-growing) course. These subtypes behave and respond to treatment differently. Both Hodgkin and non-Hodgkin lymphomas can occur in children and adults, and prognosis and treatment depend on the stage and the type of cancer.
Lynch Syndrome — An inherited disorder in which affected individuals have a higher than normal chance of developing colorectal cancer and certain other types of cancer, often before the age of 50. Also called hereditary nonpolyposis colon cancer and HNPCC.
Magnetic Resonance Imaging (MRI) — A procedure in which radio waves and a powerful magnet linked to a computer are used to create detailed pictures of areas inside the body. These pictures can show the difference between normal and diseased tissue. Magnetic resonance imaging makes better images of organs and soft tissue than other scanning techniques, such as computed tomography (CT) or X-ray. Magnetic resonance imaging is especially useful for imaging the brain, the spine, the soft tissue of joints and the inside of bones. Also called NMRI and nuclear magnetic resonance imaging.
Maintenance Therapy — Treatment that is given to help keep cancer from coming back after it has disappeared following the initial therapy. It may include treatment with drugs, vaccines, or antibodies that kill cancer cells, and it may be given for a long time.
Malignant — Cancerous. Malignant cells can invade and destroy nearby tissue and spread to other parts of the body.
Mammogram — An X-ray of the breast.
Mastectomy — Surgery to remove part or all of the breast. There are different types of mastectomy that call for varying amounts of tissue and lymph nodes to be removed.
Mediastinoscopy — A procedure in which a mediastinoscope is used to examine the organs in the area between the lungs and nearby lymph nodes. A mediastinoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue to be checked under a microscope for signs of disease. The mediastinoscope is inserted into the chest through an incision above the breastbone. This procedure is usually done to get a tissue sample from the lymph nodes on the right side of the chest.
Mediastinotomy — A procedure in which a tube is inserted into the chest to view the tissues and organs in the area between the lungs and between the breastbone and heart. The tube is inserted through an incision next to the breastbone. This procedure is usually done to get a tissue sample from the lymph nodes on the left side of the chest. Also called Chamberlain procedure.
Medullary Breast Cancer — A rare type of breast cancer that often can be treated successfully. It is marked by lymphocytes (a type of white blood cell) in and around the tumor that can be seen when viewed under a microscope.
Medullary Thyroid Cancer — Cancer that develops in C cells of the thyroid. The C cells make a hormone (calcitonin) that helps maintain a healthy level of calcium in the blood.
Melanocytes — Cells that create the pigment melanin in skin and eyes.
Melanoma — A form of cancer that begins in melanocytes (cells that make the pigment melanin). It may begin in a mole (skin melanoma), but can also begin in other pigmented tissues, such as in the eye or in the intestines.
Meningioma — A type of slow-growing tumor that forms in the meninges (thin layers of tissue that cover and protect the brain and spinal cord). Meningiomas usually occur in adults.
Menopausal Hormone Therapy — Hormones (estrogen, progesterone or both) given to women after menopause to replace the hormones no longer produced by the ovaries. Also called hormone replacement therapy and HRT.
Menopause — The time of life when a woman’s ovaries stop producing hormones and menstrual periods stop. Natural menopause usually occurs around age 50. A woman is said to be in menopause when she hasn’t had a period for 12 months in a row. Symptoms of menopause include hot flashes, mood swings, night sweats, vaginal dryness, trouble concentrating and infertility.
Menstruation — Periodic discharge of blood and tissue from the uterus. From puberty until menopause, menstruation occurs about every 28 days when a woman is not pregnant.
Merkel Cell Carcinoma — A rare type of cancer that forms on or just beneath the skin, usually in parts of the body that have been exposed to the sun. It is most common in older people and in people with weakened immune systems. Also called Merkel cell cancer, neuroendocrine carcinoma of the skin, neuroendocrine cancer of the skin and trabecular cancer.
Metastasectomy — Surgery to remove one or more metastases (tumors formed from cells that have spread from the primary tumor). When all metastases are removed, it is called a complete metastasectomy.
Metastasis — The spread of cancer from one part of the body to another. A tumor formed by cells that have spread is called a metastatic tumor or a metastasis. The metastatic tumor contains cells that are like those in the original (primary) tumor.
Metastatic — Having to do with metastasis, which is the spread of cancer from the primary site (place where it started) to other places in the body.
MIBG (Metaiodobenzylguanidine) Scan — A procedure used to find neuroendocrine tumors, such as neuroblastomas and pheochromocytomas. A small amount of a substance called radioactive MIBG is injected into a vein and travels through the bloodstream. Neuroendocrine tumor cells take up the radioactive MIBG and are detected by a scanner. Also called an iobenguane scan.
MicroRNA — A type of RNA found in cells and in blood. MicroRNAs are smaller than many other types of RNA and can bind to messenger RNAs (mRNAs) to block them from making proteins. MicroRNAs are being studied in the diagnosis and treatment of cancer. Also called miRNA.
Microsurgery — A general term for surgery requiring an operating microscope.
Microwave Therapy — A type of treatment in which body tissue is exposed to high temperatures to damage and kill cancer cells or to make cancer cells more sensitive to the effects of radiation and certain anticancer drugs. Also called microwave thermotherapy.
Mohs Microsurgery — A surgical procedure used to treat skin cancer. Individual layers of cancer tissue are removed and examined under a microscope one at a time until all cancer tissue has been removed. Also called Mohs micrographic surgery.
Molecular Diagnosis — Refers to the detection or diagnosis of a disease by analyzing DNA or RNA. The process of identifying a disease by studying molecules, such as proteins, DNA, and RNA, in a tissue or fluid
Monoclonal Antibody — A type of protein made in the laboratory that can bind to substances in the body, including cancer cells. There are many kinds of monoclonal antibodies. A monoclonal antibody is made so that it binds to only one substance. Monoclonal antibodies are being used to treat some types of cancer. They can be used alone or to carry drugs, toxins or radioactive substances directly to cancer cells.
Monoclonal Antibody Therapy — A cancer treatment that uses antibodies made in the laboratory from a single type of immune system cell. These antibodies can identify substances on cancer cells or normal substances that may help cancer cells grow. The antibodies attach to the substances and kill the cancer cells, block their growth or keep them from spreading.
Monoclonal Gammopathy of Unknown Significance (MGUS) — A benign condition in which there is a higher than normal level of a protein called M protein in the blood. Patients with MGUS are at an increased risk of developing cancer.
Monocyte — A type of immune cell that is made in the bone marrow and travels through the blood to tissues in the body where it becomes a macrophage. Macrophages surround and kill microorganisms, ingest foreign material, remove dead cells and boost immune responses. A monocyte is a type of white blood cell and a type of phagocyte.
Mucous Membrane Melanoma — A type of skin cancer that develops in the moist, thin layers that cover organs and cavities, such as the lips.
Multilineage Dysplasia — Abnormal cells that are in multiple types of blood cells such as white cells, platelets and red cells. This term is commonly used in patients with myelodysplastic disease which can be a precursor to acute myelogenous leukemia (AML).
Multiple Endocrine Neoplasia Type 1 (MEN1) Syndrome — A rare inherited disorder that affects the endocrine glands and can cause tumors in the parathyroid and pituitary glands and the pancreas. These tumors are usually benign (not cancer). They cause the glands to secrete high levels of hormones, which can lead to other medical problems, such as kidney stones, fertility problems and severe ulcers. In some cases, tumors inside the pancreas can become malignant (cancer). Also called multiple endocrine adenomatosis and Wermer syndrome.
Multiple Endocrine Neoplasia Type 2A (MEN2A) Syndrome — A rare genetic disorder that affects the endocrine glands and causes a type of thyroid cancer called medullary thyroid cancer, as well as pheochromocytoma and parathyroid gland cancer. It may also cause benign (noncancerous) tumors in the parathyroid glands and adrenal glands. The affected endocrine glands may make high levels of hormones, which can lead to other medical problems such as high blood pressure and kidney stones. An itchy skin condition may also occur. Multiple endocrine neoplasia type 2A syndrome is caused by a mutation (change) in a gene called RET. Also called multiple endocrine adenomatosis type 2A, and Sipple syndrome.
Multiple Endocrine Neoplasia Type 2B (MEN2B) Syndrome — A rare genetic disorder that affects the endocrine glands and causes a type of thyroid cancer called medullary thyroid cancer, as well as pheochromocytoma and parathyroid gland cancer. It may also cause benign (noncancerous) tumors in the adrenal glands and growths around the nerves in the lips, tongue, lining of the mouth, and eyelids. Gastrointestinal symptoms and trouble with the spine or bones in the feet and thighs may also occur. Multiple endocrine neoplasia type 2B syndrome is caused by a mutation (change) in a gene called RET. Also called multiple endocrine adenomatosis type 2B.
Multiple Myeloma — A type of cancer that begins in plasma cells (white blood cells that produce antibodies). Also called Kahler disease, myelomatosis and plasma cell myeloma.
MYH-Associated Polyposis (MAP) — A hereditary condition caused by mutations in the MUTYH gene that increases the risk of colorectal cancer.
Myeloblast — A type of immature white blood cell that forms in the bone marrow. Myeloblasts become mature white blood cells called granulocytes (neutrophils, basophils and eosinophils).
Myelodysplastic Syndrome (MDS) — A type of cancer in which the bone marrow does not make enough healthy blood cells (white blood cells, red blood cells and platelets), and there are abnormal cells in the blood and/or bone marrow. When there are fewer healthy blood cells, infection, anemia or bleeding may occur. Sometimes MDS becomes acute myeloid leukemia (AML).
Myeloproliferative Disease (MPD) — A type of disease in which the bone marrow makes too many red blood cells, platelets or certain white blood cells.
Nasal Polyps — Noncancerous and usually painless growths on the lining of nasal tissue.
Nasopharyngeal Cancer — Cancer that forms in tissues of the nasopharynx (upper part of the throat behind the nose). Most nasopharyngeal cancers are squamous cell carcinomas (cancers that begin in flat cells lining the nasopharynx).
National Cancer Institute (NCI) — The National Cancer Institute, part of the National Institutes of Health of the U.S. Department of Health and Human Services, is the federal government's principal agency for cancer research. It conducts, coordinates and funds cancer research, training, health information dissemination and other programs with respect to the cause, diagnosis, prevention and treatment of cancer.
Neck Dissection — Surgery to remove lymph nodes and other tissues in the neck.
Neoadjuvant Therapy — Treatment given as a first step to shrink a tumor before the main treatment, which is usually surgery, is given. Examples of neoadjuvant therapy include chemotherapy, radiation therapy and hormone therapy. It is a type of induction therapy.
Nephrectomy — Surgery to remove a kidney or part of a kidney. In a partial nephrectomy, part of one kidney or a tumor is removed, but not an entire kidney. In a simple nephrectomy, one kidney is removed. In a radical nephrectomy, an entire kidney, nearby adrenal gland and lymph nodes, and other surrounding tissue are removed. In a bilateral nephrectomy, both kidneys are removed.
Neuroendocrine Tumor (NET) — A tumor that forms from cells that release hormones into the blood in response to a signal from the nervous system. Neuroendocrine tumors may make higher than normal amounts of hormones, which can cause many different symptoms. These tumors may be benign (not cancer) or malignant (cancer). Some examples of neuroendocrine tumors are carcinoid tumors, islet cell tumors, medullary thyroid cancer, pheochromocytomas, neuroendocrine carcinoma of the skin (Merkel cell cancer), small cell lung cancer and large cell neuroendocrine carcinoma (a rare type of lung cancer). Also called neurofibromatosis type 1 or von Recklinghausen disease.
Neurofibromatosis Type 1 (NF1) — A rare genetic condition that causes brown spots and tumors on the skin, freckling in skin areas not exposed to the sun, tumors on the nerves and developmental changes in the nervous system, muscles, bone and skin.
Neurology — The branch of medicine or biology that deals with the anatomy, functions, and organic disorders of nerves and the nervous system.
Neurosurgery — S branch of medicine that deals with the surgical treatment of
problems affecting the: brain, spine, peripheral nerves, arteries of the neck.
Neutropenia — A condition in which there is a lower than normal number of neutrophils (a type of white blood cell).
Neutrophil — A type of immune cell that is one of the first cell types to travel to the site of an infection. Neutrophils help fight infection by ingesting microorganisms and releasing enzymes that kill the microorganisms. A neutrophil is a type of white blood cell, a type of granulocyte and a type of phagocyte.
Nevoid Basal Cell Carcinoma Syndrome (Gorlin Syndrome) — A genetic condition that causes unusual facial features and disorders of the skin, bones, nervous system, eyes and endocrine glands. People with this syndrome have a higher risk of basal cell carcinoma. Also called basal cell nevus syndrome.
Nipple Areola Reconstruction — A breast reconstruction procedure in which a nipple mound is created on the reconstructed breast. The areola can then be either tattooed or reconstructed with a skin graft taken from elsewhere on the body.
Non-Hodgkin’s Lymphoma (NHL; B-Cell, T-Cell) — Any of a large group of cancers of lymphocytes (white blood cells). NHLs can occur at any age and are often marked by lymph nodes that are larger than normal, and by fever and weight loss. There are aggressive (fast-growing) and indolent (slow-growing) types, and they can be formed from either B cells or T cells. B-cell NHLs include Burkitt lymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), diffuse large B-cell lymphoma, follicular lymphoma, immunoblastic large cell lymphoma, precursor B-lymphoblastic lymphoma and mantle cell lymphoma. T-cell NHLs include mycosis fungoides, anaplastic large cell lymphoma and precursor T-lymphoblastic lymphoma. Lymphomas that occur after bone marrow or stem cell transplantation are usually B-cell NHLs. Prognosis and treatment depend on the stage and type of disease.
Non-Small Cell Lung Cancers (NSCLC) — A group of lung cancers that are named for the kinds of cells found in the cancer and how the cells look under a microscope. The three main types of non-small cell lung cancer are squamous cell carcinoma, large cell carcinoma and adenocarcinoma. Non-small cell lung cancer is the most common kind of lung cancer.
Nuclear Medicine Scan — A method that uses radioactive substances to make pictures of areas inside the body. The radioactive substance is injected into the body, and locates and binds to specific cells or tissues, including cancer cells. Images are made using a special machine that detects the radioactive substance. Also called radioimaging.
Nutrition Therapy — Treatment based on nutrition. It includes checking a person’s nutrition status and giving the right foods or nutrients to treat conditions such as those caused by diabetes, heart disease and cancer. It may involve simple changes in a person’s diet, or intravenous or tube feeding. Nutrition therapy may help patients recover more quickly and spend less time in the hospital. Also called medical nutrition therapy.
Ocular Melanoma — A rare cancer of melanocytes (cells that produce the pigment melanin) found in the eye. Also called intraocular melanoma.
Olfactory Neuroblastoma — A rare cancer that develops in the nose. Also called esthesioneuroblastoma.
Oligodendroglioma — A rare, slow-growing tumor that begins in oligodendrocytes (cells that cover and protect nerve cells in the brain and spinal cord). Also called oligodendroglial tumor.
Omentectomy — Surgery to remove part or all of the omentum, a fold of the thin tissue that lines the abdomen. The omentum surrounds the stomach and other organs in the abdomen.
Oncology — A branch of medicine that specializes in the diagnosis and treatment of cancer. It includes medical oncology (the use of chemotherapy, hormone therapy and other drugs to treat cancer), radiation oncology (the use of radiation therapy to treat cancer) and surgical oncology (the use of surgery and other procedures to treat cancer).
Oncolytic Virus Therapy — Treatment using an oncolytic virus (a virus that infects and breaks down cancer cells but not normal cells). Oncolytic virus therapy may simplify the process of killing a tumor cell with chemotherapy and radiation therapy. Also called oncolytic virotherapy, viral therapy and virotherapy.
Ophthalmoscopy — An exam that uses a magnifying lens and a light to check the fundus of the eye (the back of the inside of the eye, including the retina and optic nerve). The pupils may be dilated (enlarged) with medicated eyedrops so the doctor can see through the pupil to the back of the eye. Ophthalmoscopy may be used to check for eye problems, such as glaucoma, macular degeneration, eye cancer, optic nerve problems or eye injury. Also called fundoscopy and funduscopy.
Oral Cavity — Refers to the mouth. It includes the lips, the lining inside the cheeks and lips, the front two-thirds of the tongue, the upper and lower gums, the floor of the mouth under the tongue, the bony roof of the mouth and the small area behind the wisdom teeth.
Orchiectomy — Surgery to remove one or both testicles. Also called orchidectomy.
Oropharyngeal Cancer — Cancer that forms in tissues of the oropharynx (the part of the throat at the back of the mouth, including the soft palate, the base of the tongue, and the tonsils). Most oropharyngeal cancers are squamous cell carcinomas (cancers that begin in flat cells lining the oropharynx).
Oropharynx — The part of the throat at the back of the mouth behind the oral cavity. It includes the back third of the tongue, the soft palate, the side and back walls of the throat, and the tonsils.
Orthopedics — A field of surgery that concerns conditions involving the body’s musculoskeletal system.
Osteosarcoma — A cancer of the bone that usually affects the large bones of the arm or leg. It occurs most commonly in young people and affects more males than females. Also called osteogenic sarcoma.
Otolaryngology — The branch of medicine concerning the ear, nose and throat (ENT).
Ovarian Cancer — Cancer that forms in tissues of the ovary (one of a pair of female reproductive glands in which the ova, or eggs, are formed). Most ovarian cancers are either ovarian epithelial carcinomas (cancers that begin in the cells on the surface of the ovary) or malignant germ cell tumors (cancers that begin in egg cells).
Ovaries — The pair of female reproductive glands in which the ova, or eggs, are formed. The ovaries are located in the pelvis, one on each side of the uterus.
Paget Disease of the Bone — A chronic condition in which both the breakdown and regrowth of bone are increased. It occurs most frequently in the pelvic and leg bones, skull and lower spine. It is most common in older individuals and may lead to bone pain, deformities and fractures. Also called osteitis deformans.
Palliative Care — Care given to improve the quality of life of patients who have a serious or life-threatening disease. The goal of palliative care is to prevent or treat as early as possible the symptoms of a disease, the side effects caused by treatment of a disease, and the psychological, social and spiritual problems related to a disease or its treatment. Also called comfort care, supportive care and symptom management.
Palliative Surgery — Surgery used to treat discomfort, disability or other problems caused by advanced cancer. An example would be a case of abdominal cancer in which the tumor has grown to obstruct the intestine, and surgery is used to remove the blockage. Palliative surgery is not used to cure cancer, but to help manage pain and other related issues.
Pancreas — A glandular organ located in the abdomen. It makes pancreatic juices, which contain enzymes that aid in digestion, and it produces several hormones, including insulin. The pancreas is surrounded by the stomach, intestines and other organs.
Pancreatic Cancer — A disease in which malignant (cancer) cells are found in the tissues of the pancreas. Also called exocrine cancer.
Pancytopenia — An abnormal reduction in the number of red blood cells, white blood cells and platelets.
Pap Test — A procedure in which a small brush or spatula is used to gently remove cells from the cervix so they can be checked under a microscope for cervical cancer or cell changes that may lead to cervical cancer. A Pap test may also help find other conditions, such as infections or inflammation. It is sometimes done at the same time as a pelvic exam and may also be done at the same time as a test for certain types of human papillomavirus (HPV). Also called Pap smear.
Papillary Thyroid Cancer — Cancer that forms in follicular cells in the thyroid and grows in small finger-like shapes. It grows slowly, is more common in women than in men, and often occurs before age 45. It is the most common type of thyroid cancer.
Parathyroid Cancer — A rare cancer that forms in tissues of one or more of the parathyroid glands (four pea-sized glands in the neck that make parathyroid hormone, which helps the body store and use calcium).
Parathyroid Glands — Four pea-sized glands found on the surface of the thyroid. The parathyroid hormone made by these glands increases the calcium level in the blood.
Parietal Cell Vagotomy — Surgery to cut the parts of the vagus nerve that cause gastric acid to be made in the stomach. It is done to treat stomach ulcers or other conditions in which the stomach makes too much acid.
PARP Inhibitor — A substance that blocks an enzyme involved in many functions of the cell, including the repair of DNA damage. DNA damage may be caused by normal cell actions, UV light, some anticancer drugs and radiation used to treat cancer. A PARP inhibitor may cause cancer cells to die. It is a type of targeted therapy. Also called poly (ADP-ribose) polymerase inhibitor.
Partial Hepatectomy — Removal of the part of the liver where cancer is found.
Partial Laryngectomy — An operation to remove part of the larynx (voice box).
Pathology — A branch of medicine that deals with the laboratory examination of samples of body tissue for diagnostic purpose.
Pathologist — A doctor who identifies diseases by studying cells and tissues under a microscope.
Pelvic Exenteration — Surgery to remove the lower colon, rectum and bladder, and create stomata (openings) through which urine and stool are passed out of the body. In women, the cervix, vagina, ovaries and nearby lymph nodes are also removed.
Pelvic Lymphadenectomy — Surgery to remove lymph nodes in the pelvis for examination under a microscope to see if they contain cancer.
Pelvis — The area of the body below the abdomen that contains the hip bones, bladder and rectum. In females, it also contains the vagina, uterus, fallopian tubes and ovaries. In males, it also contains the prostate.
Percutaneous Ethanol Ablation (PEI) — An injection of ethanol (alcohol) through the skin directly into a tumor to kill cancer cells. Also called alcohol ablation and PEI.
Percutaneous Transhepatic Biliary Drainage (PTCD) — A procedure to drain bile to relieve pressure in the bile ducts caused by a blockage. This procedure may relieve jaundice before surgery. Also called percutaneous transhepatic cholangiodrainage and PTCD.
Percutaneous Transhepatic Cholangiography — A procedure to X-ray the hepatic and common bile ducts.
Perineal Prostatectomy — Surgery to remove the prostate through an incision made between the scrotum and the anus.
Peripheral Blood Smear — A procedure in which a sample of blood is viewed under a microscope to count different circulating blood cells (red blood cells, white blood cells, platelets and so on) and see whether the cells look normal.
Peripheral Nerve Tumors — Tumors that develop from the cells and tissues that cover nerves.
Pernicious Anemia — A type of anemia (low red blood cell count) caused by the body's inability to absorb vitamin B12.
Positron Emission Tomography (PET) Scan — A procedure in which a small amount of radioactive glucose (sugar) is injected into a vein, and a scanner is used to make detailed, computerized pictures of areas inside the body where the glucose is taken up. Because cancer cells often take up more glucose than normal cells, the pictures can be used to find cancer cells in the body.
Peutz–Jeghers Syndrome (PJS) — A genetic disorder in which polyps form in the intestine and dark spots appear on the mouth and fingers. Having Peutz–Jeghers syndrome increases the risk of developing gastrointestinal and many other types of cancer.
Pheochromocytoma — A tumor that forms in the center of the adrenal gland (gland located above the kidney) that causes it to make too much adrenaline. Pheochromocytomas are usually benign (not cancer) but can cause high blood pressure, pounding headaches, heart palpitations, flushing of the face, nausea and vomiting.
Philadelphia Chromosome — An abnormality of chromosome 22 in which part of chromosome 9 is transferred to it. Bone marrow cells that contain the Philadelphia chromosome are often found in chronic myelogenous leukemia and sometimes found in acute lymphocytic leukemia.
Photocoagulation — A procedure that uses lasers to destroy the blood vessels that supply a tumor with nutrients.
Photodynamic Therapy — Treatment with drugs that become active when exposed to light. These activated drugs may kill cancer cells.
Phyllodes Tumor — A type of tumor found in breast or prostate tissue. It is often large and bulky and grows quickly. It may be benign (not cancer) or malignant (cancer) and may spread to other parts of the body. Also called CSP and cystosarcoma phyllodes.
Pituitary Cancer — A cancer of the pituitary gland that is rare.
Pituitary Carcinoma — A rare, cancerous tumor that can spread to the brain and spinal cord or to other parts of the central nervous system.
Pituitary Gland — A pea-sized organ located in the bottom center of the brain, just above the back of the nose.
Pituitary Gland Tumor — A tumor that forms in the pituitary gland. The pituitary gland is a pea-sized organ at the base of the brain. It makes hormones that affect other glands and many of the body’s functions, including growth. Symptoms depend on the hormones affected by the tumor. Most pituitary tumors are benign (not cancer), and many do not cause any symptoms.
Plasma — The clear, yellowish, fluid part of the blood that carries the blood cells. The proteins that form blood clots are in plasma.
Plasma Exchange (Plasmapheresis) — The process of separating certain cells from the plasma in the blood by a machine; only the cells are returned to the person. Plasmapheresis can be used to remove excess antibodies from the blood.
Plasmacytoma — A type of cancer that begins in plasma cells (white blood cells that produce antibodies). A plasmacytoma may turn into multiple myeloma.
Platelets — Small pieces of cell that are made by the breaking off of a large cell in the bone marrow. Platelets are found in the blood and spleen. They help form blood clots to slow or stop bleeding, and to help wounds heal. Also called thrombocyte.
Pneumonectomy — Surgery to remove all of one lung. In a partial pneumonectomy, one or more lobes of a lung are removed.
Polymerase Chain Reaction (PCR) — A laboratory method used to make many copies of a specific DNA sequence.
Polyps — Growths that protrude from a mucous membrane.
Preventive Surgery — Surgery that involves removing organs or body tissues that may currently appear healthy but are likely to become cancerous in the near future. Examples might include removing the breast when a patient shows early signs or a genetic history of breast cancer, or removing polyps from the colon. Also known as prophylactic surgery.
Primary Sclerosing Cholangitis — A bile-duct disease characterized by inflammation and subsequent obstruction of bile ducts.
Proctoscopy — A procedure that uses a proctoscope to look inside the anus and rectum. A proctoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue to be checked under a microscope for signs of disease.
Progestin — Any natural or laboratory-made substance that has some or all of the biologic effects of progesterone, a female hormone.
Prolactin — A hormone that is made by the pituitary gland, a pea-sized organ in the center of the brain. Prolactin causes a woman’s breasts to make milk during and after pregnancy, and has many other effects in the body.
Prostate Cancer — Cancer that forms in tissues of the prostate (a gland in the male reproductive system found below the bladder and in front of the rectum). Prostate cancer usually occurs in older men.
Prostate-Specific Antigen (PSA) — A protein made by the prostate gland and found in the blood. Prostate-specific antigen blood levels may be higher than normal in men who have prostate cancer, benign prostatic hyperplasia (BPH), or infection or inflammation of the prostate gland.
Prostatic Acid Phosphatase (PAP) — An enzyme produced by the prostate. It may be found in increased amounts in men who have prostate cancer.
Prostatitis — Inflammation of the prostate gland.
Prosthesis — A device, such as an artificial leg, that replaces a part of the body
Prostatocystectomy — Surgery to remove the bladder (the organ that holds urine) and the prostate. In a radical prostatocystectomy, the seminal vesicles are also removed. The prostate and seminal vesicles are glands in the male reproductive system that help make semen. Also called cystoprostatectomy.
Percutaneous Transhepatic Cholangiography (PTC) — A procedure to X-ray the hepatic and common bile ducts. A contrasting agent is injected through the skin into the liver or bile duct, and the ducts are then X-rayed to find the point of obstruction.
Pulmonary Function Test (PFT) — A test used to measure how well the lungs work. It measures how much air the lungs can hold and how quickly air is moved into and out of the lungs. It also measures how much oxygen is used and how much carbon dioxide is given off during breathing. A pulmonary function test can be used to diagnose a lung disease and to see how well treatment for the disease is working. Also called lung function test.
Pulmonologist — Medical specialty dealing with disease involving the respiratory tract.
Punch Biopsy — A procedure in which a small round piece of tissue about the size of a pencil eraser is removed using a sharp, hollow, circular instrument. The tissue is then checked under a microscope for signs of disease. A punch biopsy may be used to check for certain types of cancer, including skin, vulvar and cervical cancer. It may also be used to check for certain skin conditions and changes that may lead to cancer.
Radiation Therapy — The use of high-energy radiation from X-rays, gamma rays, neutrons, protons and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy). Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called irradiation and radiotherapy.
Radical Prostatectomy — Surgery to remove the entire prostate and some of the tissue around it. Nearby lymph nodes may also be removed. In a radical retropubic prostatectomy, an incision (cut) is made in the wall of the lower abdomen. In a radical perineal prostatectomy, an incision is made in the perineum (the area between the anus and scrotum). In a laparoscopic radical prostatectomy, several small incisions are made in the wall of the abdomen. A laparoscope (a thin, tube-like instrument with a light and lens for viewing) is inserted through one opening to guide the surgery. Surgical instruments are inserted through the other openings to do the surgery.
Radioembolization — A type of radiation therapy used to treat liver cancer that is advanced or has come back. Tiny beads that hold the radioisotope yttrium Y 90 are injected into the hepatic artery (the main blood vessel that carries blood to the liver). The beads collect in the tumor and the yttrium Y 90 gives off radiation. This destroys the blood vessels that the tumor needs to grow and kills the cancer cells. Radioembolization is a type of selective internal radiation therapy (SIRT). Also called intra-arterial brachytherapy.
Radiofrequency Ablation (RFA) — A procedure that uses radio waves to heat and destroy abnormal cells. The radio waves travel through electrodes (small devices that carry electricity). Radiofrequency ablation may be used to treat cancer and other conditions.
Radiology — The use of radiation (such as X-rays) or other imaging technologies (such as ultrasound and magnetic resonance imaging) to diagnose or treat disease.
Radon — A radioactive gas that is released by uranium, a substance found in soil and rock. Breathing in too much radon can damage lung cells and may lead to lung cancer.
Rathke Cleft Cyst — A benign growth on the pituitary gland in the brain. Rathke cleft is the area between the two sections or lobes of the pituitary gland.
Receptor — A protein molecule on the surface of or inside a cell that receives chemical signals from outside the cell and binds a specific substance.
Reconstructive Surgery — Surgery that is done to reshape or rebuild (reconstruct) a part of the body changed by previous surgery. Examples would include breast reconstruction after a mastectomy, or the use of tissue flaps, bone grafts or other prosthetics after surgery for head and neck cancers. Prostheses may be used as a part of the reconstructive process.
Rectal Cancer — Cancer that forms in the tissues of the rectum (the last several inches of the large intestine closest to the anus).
Rectum — The last several inches of the large intestine closest to the anus.
Red Blood Cell (RBC) — A type of blood cell that is made in the bone marrow and found in the blood. Red blood cells contain a protein called hemoglobin, which carries oxygen from the lungs to all parts of the body. Checking the number of red blood cells in the blood is usually part of a complete blood cell (CBC) test. It may be used to look for conditions such as anemia, dehydration, malnutrition and leukemia. Also called erythrocyte.
Reed–Sternberg Cell — A type of cell that appears in people with Hodgkin disease. The number of these cells increases as the disease advances.
Refractory Anemia — A condition in which there are too few red blood cells in the blood and the patient has anemia. The number of white blood cells and platelets is normal. Refractory anemia is one of the types of myelodysplastic syndromes.
Regional Hyperthermia Therapy — A treatment in which tissue around the tumor is exposed to high temperatures to damage and kill cancer cells or to make cancer cells more sensitive to chemotherapy.
Remission — A decrease in or disappearance of signs and symptoms of cancer. In partial remission, some, but not all, signs and symptoms of cancer have disappeared. In complete remission, all signs and symptoms of cancer have disappeared, although cancer still may be in the body.
Resection — Surgery to remove tissue or part or all of an organ.
Retinoblastoma — Cancer that forms in the tissues of the retina (the light-sensitive layers of nerve tissue at the back of the eye). Retinoblastoma usually occurs in children younger than 5 years. It may be hereditary or nonhereditary (sporadic).
Retropubic Prostatectomy — Surgery to remove part or all of the prostate and some of the tissue around it. Nearby lymph nodes may also be removed. A retropubic prostatectomy may be done through an incision (cut) made in the wall of the lower abdomen, or it may be done using a laparoscope. A laparoscope is a thin, tube-like instrument with a light and lens for viewing. Several small incisions are made in the wall of the abdomen, and the laparoscope is inserted through one opening to guide the surgery. Surgical instruments are inserted through the other openings to do the surgery.
Rhabdomyosarcoma — Cancer that forms in the soft tissues in a type of muscle called striated muscle. This cancer can occur anywhere in the body
Risk Factor — Something that increases the chance of developing a disease. Some examples of risk factors for cancer are age, a family history of certain cancers, use of tobacco products, being exposed to radiation or certain chemicals, infection with certain viruses or bacteria, and certain genetic changes.
Ribonucleic Acid (RNA) — One of two types of nucleic acid made by cells. Ribonucleic acid contains information that has been copied from DNA (the other type of nucleic acid). Cells make several different forms of ribonucleic acid, and each form has a specific job in the cell. Many forms of ribonucleic acid have functions related to making proteins. Ribonucleic acid is also the genetic material of some viruses instead of DNA. Ribonucleic acid can be made in the laboratory and used in research studies.
Robotic-Assisted Laparoscopic Radical Prostatectomy — A minimally invasive surgery to remove the entire prostate and some of the tissue around it. Nearby lymph nodes may also be removed. In a radical retropubic prostatectomy, an incision (cut) is made in the wall of the lower abdomen. In a radical perineal prostatectomy, an incision is made in the perineum (the area between the anus and scrotum). In a laparoscopic radical prostatectomy, several small incisions are made in the wall of the abdomen. A laparoscope (a thin, tube-like instrument with a light and lens for viewing) is inserted through one opening to guide the surgery. Surgical instruments are inserted through the other openings to do the surgery.
Robotic-Assisted Surgery — An advanced surgical method using small incisions using a robotic system. The surgeon manipulates surgical instrumentation with the use of a robot.
Rothmund–Thomson Syndrome (RTS) — A rare inherited disorder that affects the skin and many other parts of the body, including the bones, eyes, nose, hair, nails, teeth, testes and ovaries. People with Rothmund–Thomson syndrome have an increased risk of osteosarcoma (bone cancer).
Salpingo-oophorectomy — Surgical removal of the fallopian tubes and ovaries.
Samarium — A radioactive substance used in the treatment of bone cancer and bone metastases (cancers that have spread from the original tumor to the bone). Samarium 153 is a radioactive form of the element samarium. It collects in bone, where it releases radiation that may kill cancer cells. It is a type of radioisotope.
Sarcoma — A type of cancer that begins in bone or in the soft tissues of the body, including cartilage, fat, muscle, blood vessels, fibrous tissue and other connective or supportive tissue. Different types of sarcoma are based on where the cancer forms. For example, osteosarcoma forms in bone, liposarcoma forms in fat and rhabdomyosarcoma forms in muscle.
Schistosome — A parasitic worm that can cause diseases of the liver, bladder and gastrointestinal tract.
Schwannoma — An almost always benign tumor that begins in Schwann cells, which produce the myelin that protects the acoustic nerve (the nerve of hearing). It occurs mainly in adults and affects women twice as often as men.
Screening Exam — A series of tests that look for diseases before symptoms arise. Screening tests can find diseases early, when they're easier to treat.
Segmental Resection — Surgery to remove part of an organ or gland. It may also be used to remove a tumor and normal tissue around it. In lung cancer surgery, segmental resection refers to removing a section of a lobe of the lung. Also called segmentectomy.
Semen — The fluid that is released through the penis during orgasm. Semen is made up of sperm from the testicles and fluid from the prostate and other sex glands.
Seminoma — A type of cancer that begins in cells that make sperm or eggs. Seminomas occur most often in the testicles or the ovaries. They may also occur in other areas, such as the brain, chest or abdomen. This happens when cells that have the ability to form sperm or eggs are found in other parts of the body. Seminomas grow and spread slowly.
Sentinel Lymph Node — The first lymph node to which cancer is likely to spread from the primary tumor before spreading to other lymph nodes.
Sestamibi Scan — An imaging test used to find overactive parathyroid glands (four pea-sized glands found on the thyroid) and breast cancer cells, and to diagnose heart disease. The patient receives an injection of a small amount of a radioactive substance called technetium, which is bound to another substance called sestamibi. This substance collects in overactive glands, cancer cells, heart muscle or other tissues, and a picture is taken by a gamma camera (a special camera that detects radioactivity).
Shave Biopsy — A procedure in which a skin abnormality and a thin layer of surrounding skin are removed with a small blade for examination under a microscope. Stitches are not needed with this procedure.
Shwachman–Diamond Syndrome (SDS) — A rare inherited disorder in which the pancreas and bone marrow do not work the way they should. Symptoms include problems digesting food, a low number of neutrophils (a type of white blood cell), bone problems and short stature. Infants with the disorder get bacterial infections and are at an increased risk of aplastic anemia, myelodysplastic syndrome and leukemia. Also called Shwachman syndrome.
Sickle Cell Anemia — An inherited disease in which the red blood cells have an abnormal crescent shape, block small blood vessels and do not last as long as normal red blood cells. Sickle cell anemia is caused by a mutation (change) in one of the genes for hemoglobin (the substance inside red blood cells that binds to oxygen and carries it from the lungs to the tissues). It is most common in people of West and Central African descent. Also called sickle cell disease, sickling disorder, HbS disease and hemoglobin S disease.
Sigmoidoscopy — Examination of the lower colon using a sigmoidoscope inserted into the rectum. A sigmoidoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue to be checked under a microscope for signs of disease. Also called proctosigmoidoscopy.
Signal Transduction Inhibitor — A substance that blocks signals passed from one molecule to another inside a cell. Blocking these signals can affect many functions of the cell, including cell division and cell death, and may kill cancer cells. Certain signal transduction inhibitors are being studied in the treatment of cancer.
Signet Ring Cell Carcinoma — A highly malignant type of cancer typically found in glandular cells that line the digestive organs. The cells resemble signet rings when examined under a microscope. Also called signet ring carcinoma.
Sinus — A cavity, space or channel in the body. Examples include hollow spaces in the bones at the front of the skull, and channels for blood and lymph. Sinuses may also be found in the heart, brain and other organs.
Sjögren Syndrome — An autoimmune disease that affects the tear glands and salivary glands and may affect glands in the stomach, pancreas and intestines. The disease causes dry eyes and mouth and may cause dryness in the nose, throat, air passages, skin and vagina. It may also cause inflammation in the joints, muscles and skin; pneumonia; tingling in the fingers and toes; and fatigue. It often occurs with rheumatoid arthritis or other connective tissue diseases.
Skull Base Tumors —Tumors that form in the bottom of the head behind the eyes.
Sleeve Resection — Surgery to remove a tumor in a lobe of the lung and a part of the main bronchus (airway). The ends of the bronchus are rejoined and any remaining lobes are reattached to the bronchus. This surgery is done to save part of the lung. Also called sleeve lobectomy.
Slit-Lamp Biomicroscopy — An eye exam using an instrument that combines a low-power microscope with a light source that makes a narrow beam of light. The instrument may be used to examine the retina, optic nerve and other parts of the eye. Also called slit-lamp eye exam.
Small Cell Lung Cancer — An aggressive (fast-growing) cancer that forms in tissues of the lung and can spread to other parts of the body. The cancer cells look small and oval-shaped when looked at under a microscope.
Small Intestine — A long, tube-like organ that connects the stomach and the large intestine. It is about 20 feet long and folds many times to fit inside the abdomen. The small intestine has three parts: the duodenum, the jejunum and the ileum. It helps to further digest food coming from the stomach. It absorbs nutrients (vitamins, minerals, carbohydrates, fats and proteins) and water from food so they can be used by the body. The small intestine is part of the digestive system.
Small Intestine Cancer — A rare cancer that forms in tissues of the small intestine (the part of the digestive tract between the stomach and the large intestine). The most common type is adenocarcinoma (cancer that begins in cells that make and release mucus and other fluids). Other types of small intestine cancer include sarcoma (cancer that begins in connective or supportive tissue), carcinoid tumor (a slow-growing type of cancer), gastrointestinal stromal tumor (a type of soft tissue sarcoma) and lymphoma (cancer that begins in immune system cells).
Soft Tissue Sarcoma — A cancer that begins in the muscle, fat, fibrous tissue, blood vessels or other supporting tissue of the body.
Somatotropin — A protein made by the pituitary gland that helps control body growth and the use of glucose and fat in the body. Also called growth hormone.
Sphincter — A ring-shaped muscle that relaxes or tightens to open or close a passage or opening in the body. Examples are the anal sphincter (around the opening of the anus) and the pyloric sphincter (at the lower opening of the stomach).
Spindle Cell Tumor — A type of tumor that contains cells called spindle cells based on their shape. Under microscope spindle cells look long and slender. Spindle cell tumors may be sarcomas or carcinomas.
Spine Sarcoma — A type of cancer that begins in bone or in the soft tissues of the spine.
Sputum Cytology — Examination under a microscope of cells found in sputum (mucus and other matter brought up from the lungs by coughing). The test checks for abnormal cells, such as lung cancer cells.
Squamous Cell Carcinoma — Cancer that begins in squamous cells. Squamous cells are thin, flat cells that look like fish scales and are found in the tissues that form the surface of the skin, the lining of the hollow organs of the body and the lining of the respiratory and digestive tracts. Most cancers of the anus, cervix, head and neck, and vagina are squamous cell carcinomas. Also called epidermoid carcinoma.
Squamous Cells — Flat cells that look like fish scales under a microscope. These cells are found in the tissues that form the surface of the skin, the passages of the respiratory and digestive tracts, and the lining of the hollow organs of the body (such as the bladder, kidney and uterus, including the cervix).
Staging — The process of determining the extent of a cancer in the body. Staging is usually based on the size of the tumor, whether lymph nodes contain cancer and whether the cancer has spread from the original site to other parts of the body.
Staging Surgery — Surgery to determine how far and in what areas cancer may have spread within the body. Procedures frequently used for these purposes include laparotomy (an abdominal incision) and laparoscopy (the insertion of a fiber-optic instrument through the abdominal wall to view the organs).
Stem Cell — A cell from which other types of cells develop. For example, blood cells develop from blood-forming stem cells.
Stem Cell Transplant — A method of replacing immature blood-forming cells in the bone marrow that have been destroyed by drugs, radiation or disease. Stem cells are injected into the patient and make healthy blood cells. A stem cell transplant may be autologous (using a patient’s own stem cells that were saved before treatment), allogeneic (using stem cells donated by someone who is not an identical twin) or syngeneic (using stem cells donated by an identical twin).
Stent — A device placed in a body structure (such as a blood vessel or the gastrointestinal tract) to keep the structure open.
Stereotactic Ablative Radiation Therapy — A type of external radiation therapy that uses special equipment to position the patient and precisely deliver radiation to a tumor. The total dose of radiation is divided into several smaller doses given over several days. Stereotactic radiation therapy is used to treat brain tumors and other brain disorders. It is also being studied in the treatment of other types of cancer, such as lung cancer. Also called stereotactic radiation therapy, stereotactic external-beam radiation therapy and stereotaxic radiation therapy.
Stereotactic Body Radiation Therapy (SBRT) — An image-guided radiation therapy that allows higher dose delivery to select body sites, with fewer treatments.
Stereotactic Radiosurgery (SRS) — A type of external radiation therapy that uses special equipment to position the patient and precisely give a single large dose of radiation to a tumor. It is used to treat brain tumors and other brain disorders that cannot be treated by regular surgery. It is also being studied in the treatment of other types of cancer. Also called radiation surgery, radiosurgery and stereotaxic radiosurgery.
Stomach Cancer — Cancer that forms in tissues lining the stomach. Also called gastric cancer.
Stroma — The connective and supportive framework of a biological cell, tissue or organ.
Stromal Cell — A type of cell that makes up certain types of connective tissue (supporting tissue that surrounds other tissues and organs).
Strontium 89 — A radioactive form of the metal strontium that is taken up by a part of growing bone. It is being studied in the treatment of bone pain caused by some types of cancer.
Supportive Surgery — Surgery to support other types of treatment, such as the insertion of a catheter or infusion port in a large vein.
Supraglottic Laryngectomy — An operation to remove the supraglottis, which is part of the larynx (voice box) above the vocal cords.
Surgical Oncology — The branch of surgery that focuses on the surgical management of tumors, in particular cancerous tumors.
Syngeneic Transplant — A procedure in which patients receive stem cells from an identical twin.
Tamoxifen — A drug used to treat certain types of breast cancer in women and men. It is also used to prevent breast cancer in women who have had ductal carcinoma in situ (abnormal cells in the ducts of the breast) and in women who are at a high risk of developing breast cancer. Tamoxifen is also being studied in the treatment of other types of cancer. It blocks the effects of the hormone estrogen in the breast. Tamoxifen is a type of antiestrogen. Also called tamoxifen citrate.
Targeted Therapy — A type of treatment that uses drugs or other substances to identify and attack specific types of cancer cells with less harm to normal cells. Some targeted therapies block the action of certain enzymes, proteins or other molecules involved in the growth and spread of cancer cells. Other types of targeted therapies help the immune system kill cancer cells or deliver toxic substances directly to cancer cells and kill them. Targeted therapy may have fewer side effects than other types of cancer treatment. Most targeted therapies are either small molecule drugs or monoclonal antibodies.
Taxol — A drug used to treat breast cancer, ovarian cancer and AIDS-related Kaposi sarcoma. It is also used together with another drug to treat non-small cell lung cancer. Taxol is being studied in the treatment of other types of cancer. It blocks cell growth by stopping cell division and may kill cancer cells. It is a type of antimitotic agent. Also called paclitaxel.
Teratoma — A type of germ cell tumor that may contain several different types of tissue, such as hair, muscle and bone. Teratomas occur most often in the ovaries in women, the testicles in men and the tailbone in children. Not all teratomas are malignant.
Testicles (Testes) — Two egg-shaped glands inside the scrotum that produce sperm and male hormones. One of these glands is called a testis.
Testicular Cancer — Cancer that forms in tissues of one or both testicles. Testicular cancer is most common in young or middle-aged men. Most testicular cancers begin in germ cells (cells that make sperm) and are called testicular germ cell tumors.
Testosterone — A hormone made mainly in the testes (part of the male reproductive system). It is needed to develop and maintain male sex characteristics, such as facial hair, deep voice and muscle growth. Testosterone may also be made in the laboratory and is used to treat certain medical conditions.
Thermotherapy — A treatment that uses heat from a laser to destroy cancer cells and shrink a tumor.
Thoracentesis — Removal of fluid from the pleural cavity through a needle inserted between the ribs.
Thoracic Surgery — A field of medicine that involves surgical treatment of conditions affecting the organs inside the thorax such as the heart and lung.
Thoracoscopy — Examination of the inside of the chest using a thoracoscope. A thoracoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue to be checked under a microscope for signs of disease.
Thrombocytopenia — A condition in which there is a lower than normal number of platelets in the blood. It may result in easy bruising and excessive bleeding from wounds or bleeding in mucous membranes and other tissues.
Thyroid Cancer — Cancer that forms in the thyroid gland (an organ at the base of the throat that makes hormones that help control heart rate, blood pressure, body temperature and weight). Four main types of thyroid cancer are papillary, follicular, medullary and anaplastic thyroid cancer. The four types are distinguished by how the cancer cells look under a microscope.
Thyroid Gland — A gland located beneath the larynx (voice box) that makes thyroid hormone and calcitonin. The thyroid gland helps regulate growth and metabolism. Also called thyroid.
Thyroid-Stimulating Hormone (TSH) — A hormone produced by the pituitary gland. Thyroid-stimulating hormone stimulates the release of thyroid hormone from thyroglobulin. It also stimulates the growth of thyroid follicular cells. An abnormal thyroid-stimulating hormone level may mean that the thyroid hormonal regulation system is out of control, usually as a result of a benign condition (hyperthyroidism or hypothyroidism).
Thyroidectomy — A procedure in which all or some of the thyroid gland is removed.
Thyrotropin — A form of thyroid-stimulating hormone (TSH) that is made in the laboratory. It is used to test for remaining or recurring cancer cells in patients who have been treated for thyroid cancer. Also called thyrotropin alfa.
Toluidine Blue Stain — A procedure in which a blue dye is used to coat
suspicious lesions in the mouth. Areas that take on more of the dye produce
a darker stain and are more likely to be precancerous.
Topical Chemotherapy — The use of anticancer drugs in cream or lotion applied to the skin.
Total Laryngectomy — An operation to remove the larynx (voice box).
Trachea — The airway that leads from the larynx (voice box) to the bronchi (large airways that lead to the lungs). Also called windpipe.
TRAM Flap — A type of breast reconstruction surgery in which a portion of
the lower abdomen, along with skin, fat and blood vessels, is moved to the chest via a tunnel under the skin. A TRAM flap forms a natural-looking breast, so the patient usually does not need a breast implant. Also called transverse rectus abdominis myocutaneous flap.
Transitional Cell Carcinoma — A type of cancer that typically occurs in the urinary system (kidneys, bladder and other renal organs).
Transrectal Biopsy — A procedure in which a sample of tissue is removed from the prostate using a thin needle that is inserted through the rectum and into the prostate. Transrectal ultrasound (TRUS) is usually used to guide the needle. The sample is examined under a microscope to see if it contains cancer.
Transsphenoidal Surgery — A type of surgery in which instruments are inserted through the nose and sphenoid sinus (a hollow space in a bone in the nose) to remove tumors that are in or near the pituitary gland. The pituitary gland is a pea-sized organ that lies at the base of the brain above the back of the nose.
Transurethral Resection of the Prostate — Surgery to remove tissue from the prostate using an instrument inserted through the urethra. Also called TURP.
Transvaginal Ultrasound Exam — A procedure used to examine the vagina, uterus, fallopian tubes, ovaries and bladder. An instrument is inserted into the vagina that causes sound waves to bounce off organs inside the pelvis. These sound waves create echoes that are sent to a computer, which creates a picture called a sonogram. Also called transvaginal sonography and TVS.
Trigeminal Neuralgia — A chronic pain condition that affects the 5th cranial nerve which is the most widely distributed nerve in the head. Pain may be experienced as stabbing or severe convulsive pain in parts of the face.
Triple-Negative Breast Cancer — Breast cancer cells that do not have estrogen receptors, progesterone receptors or large amounts of HER2/neu protein. Also called ER-negative PR-negative HER2/neu-negative breast cancer.
Thrombotic Thrombocytopenic Purpura (TTP) — A rare blood disorder that causes clots to form in small blood vessels, which can block the flow of blood and oxygen to organs.
Tuberous Sclerosis — A genetic disorder in which benign (not cancer) tumors form in the kidneys, brain, eyes, heart, lungs and skin. This disease can cause seizures, mental disabilities and different types of skin lesions. Also called Bourneville disease.
TUG Flap — A breast reconstruction procedure that uses the transverse upper gracilis blood vessel, which runs through the upper thigh area, which reduces visible scarring.
Tumor — An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancer), or malignant (cancer). Also called neoplasm.
Tumor Debulking — The process by which a surgeon removes as much of the tumor as possible. Tumor debulking may increase the chance that chemotherapy or radiation therapy will kill all the tumor cells. It may also be done to relieve symptoms or help the patient live longer.
Tumor Marker — A substance found in tissue, blood or other body fluids that may be a sign of cancer or certain benign (noncancerous) conditions. Most tumor markers are made by both normal cells and cancer cells, but they are made in larger amounts by cancer cells. A tumor marker may help to diagnose cancer, plan treatment or find out how well treatment is working or if cancer has come back. Examples of tumor markers include CA-125 (in ovarian cancer), CA 15-3 (in breast cancer), CEA (in colon cancer) and PSA (in prostate cancer).
Tumor Marker Test — A test that measures the amount of substances called tumor markers in tissue, blood, urine or other body fluids. Most tumor markers are made by both normal cells and cancer cells, but they are made in higher amounts by cancer cells. A high level of a tumor marker may be a sign of cancer or certain benign (noncancerous) conditions. A tumor marker test is usually done with other tests, such as biopsies, to help diagnose some types of cancer. It may also be used to help plan treatment or find out how well treatment is working or if cancer has come back.
Tumor Sequencing — The study of the sequence of DNA and how each string of letters passes information to help each cell in the body work properly. Also called cancer genome sequencing.
Turcot Syndrome — A rare inherited disorder in which polyps (abnormal growths of tissue) form on the inside walls of the colon and rectum, and tumors form in the brain. There are two types of Turcot syndrome, which are caused by mutations (changes) in different genes. People with Turcot syndrome have a higher than normal risk of colorectal cancer and brain cancer, especially glioblastoma and medulloblastoma.
Type 2 Diabetes — When your body does not use insulin properyl. The most common form of diabetes.
Ulcer — A break on the skin, in the lining of an organ or on the surface of a tissue. An ulcer forms when the surface cells become inflamed, die and are shed. Ulcers may be linked to cancer and other diseases.
Ulcerative Colitis — A chronic inflammation of the colon that produces ulcers in its lining. This condition is marked by abdominal pain, cramps and loose discharges of pus, blood and mucus from the bowel.
Ultrasound — A procedure that uses high-energy sound waves to look at tissues and organs inside the body. The sound waves make echoes that form pictures of the tissues and organs on a computer screen (sonogram). Ultrasound may be used to help diagnose diseases, such as cancer. It may also be used during pregnancy to check the fetus (unborn baby) and during medical procedures, such as biopsies. Also called ultrasonography.
Ultraviolet A Therapy — A type of photodynamic therapy used to treat skin conditions such as psoriasis, vitiligo and skin nodules of cutaneous T-cell lymphoma.
Unclassifiable Myelodysplastic Syndrome — Myelodysplastic syndromes that do not meet criteria of a specific World Health Organization entity.
Urinalysis — A test that determines the content of the urine.
Urinary Diversion — A surgical procedure to make a new way for urine to leave the body. It may involve redirecting urine into the colon, using catheters to drain the bladder or making an opening in the abdomen and collecting urine in a bag outside the body.
Urine Cytology — Tests performed on cells in urine to detect disease.
Urology — A surgical specialty that deals with diseases of the male and female urinary tract and the male reproductive organs.
Uteroscopy — Examination of the inside of the kidney and ureter, using a ureteroscope. A ureteroscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue to be checked under a microscope for signs of disease. The ureteroscope is passed through the urethra into the bladder, ureter and renal pelvis (part of the kidney that collects, holds and drains urine).
Uterus — The hollow, pear-shaped organ in a woman's pelvis. The uterus is where a fetus (unborn baby) develops and grows. Also called womb.
Vagina — The muscular canal that goes from the uterus to the outside of the body. During birth, the baby passes through the vagina. Also called birth canal.
Vaginal Cancer — Cancer that forms in the tissues of the vagina (birth canal). The vagina leads from the cervix (the opening of the uterus) to the outside of the body. The most common type of vaginal cancer is squamous cell carcinoma, which starts in the thin, flat cells lining the vagina. Another type of vaginal cancer is adenocarcinoma, cancer that begins in glandular cells in the lining of the vagina.
Vaginectomy — Surgery to remove part or all of the vagina (the birth canal).
Vascular Malformations — Blood vessel abnormalities.
Vascular Tumor — A benign or cancerous growth formed by blood vessels.
Ventricle — A fluid-filled cavity in the heart or brain.
Vinyl Chloride — A substance used to make plastics. Exposure to vinyl chloride may increase the risk of developing liver, brain and lung cancers; lymphoma; and leukemia.
Vitamin E — A nutrient and antioxidant that the body needs in small amounts to stay healthy and work the way it should. It is fat soluble (can dissolve in fats and oils) and is found in seeds, nuts, leafy green vegetables and vegetable oils. Vitamin E boosts the immune system and helps keep blood clots from forming. It also helps prevent cell damage caused by free radicals (highly reactive chemicals). Vitamin E is being studied in the prevention and treatment of some types of cancer. Also called alpha-tocopherol.
Von Hippel–Lindau Syndrome — A rare inherited disorder in which blood vessels grow abnormally in the eyes, brain, spinal cord, adrenal glands or other parts of the body. People with von Hippel–Lindau syndrome have a higher risk of developing some types of cancer. Also called VHL syndrome.
Von Willebrand Disease (VWD) — A bleeding disorder that inhibits the blood’s ability to clot. People who have VWD have low levels of a protein called von Willebrand factor in their blood.
Vulva — The external female genital organs, including the clitoris, vaginal lips and the opening to the vagina.
Vulvar Cancer — Cancer of the vulva (the external female genital organs, including the clitoris, vaginal lips and the opening to the vagina).
Vulvectomy — Surgery to remove the entire vulva (the external female genital organs, including the clitoris, vaginal lips and the opening to the vagina).
Watchful Waiting — Closely watching a patient’s condition but not giving treatment unless symptoms appear or change. Watchful waiting is sometimes used in conditions that progress slowly. It is also used when the risks of treatment are greater than the possible benefits. During watchful waiting, patients may be given certain tests and exams. Watchful waiting is sometimes used in prostate cancer. It is a type of expectant management.
Wedge Resection — Surgery to remove a triangle-shaped slice of tissue. It may be used to remove a tumor and a small amount of normal tissue around it.
Werner Syndrome — An inherited disorder marked by rapid aging that begins in early adolescence. Patients may be shorter than average and may have health problems such as loss and graying of hair, hardening of the arteries, thinning of the bones, diabetes and thin, hardened skin. They also have an increased risk of cancer, especially osteosarcoma (a type of bone cancer). Werner syndrome is caused by a mutation (change) in a gene involved in cell division. It is a type of autosomal recessive gene disease. Also called adult progeria.
Whipple Procedure — A type of surgery used to treat pancreatic cancer. The head of the pancreas, the duodenum, a portion of the stomach, and other nearby tissues are removed. Also called pancreatoduodenectomy.
White Blood Cell (WBC) — A type of blood cell that is made in the bone marrow and found in the blood and lymph tissue. White blood cells are part of the body’s immune system. They help the body fight infection and other diseases. Types of white blood cells are granulocytes (neutrophils, eosinophils and basophils), monocytes and lymphocytes (T cells and B cells). Checking the number of white blood cells in the blood is usually part of a complete blood cell (CBC) test. It may be used to look for conditions such as infection, inflammation, allergies and leukemia. Also called leukocyte.
Wiskott–Aldrich Syndrome — An inherited immune disorder that occurs in young boys. It causes eczema (a type of skin inflammation), a decrease in the number of platelets (blood cells that help prevent bleeding), and frequent bacterial infections. People with Wiskott–Aldrich syndrome are at increased risk of developing leukemia and lymphoma. Also called Aldrich syndrome.
X-ray — A type of radiation used in the diagnosis and treatment of cancer and other diseases. In low doses, X-rays are used to diagnose diseases by making pictures of the inside of the body. In high doses, X-rays are used to treat cancer.
X-ray Therapy — A type of radiation therapy that uses high-energy radiation from X-rays to kill cancer cells and shrink tumors.
Yolk Sac Carcinoma — A type of cancer that begins in cells that form sperm or eggs.
Zollinger–Ellison Syndrome — A disorder in which tumors of the pancreatic islet cells produce large amounts of gastrin (a hormone), leading to excess acid in the stomach and, possibly, a peptic ulcer (ulcer of the stomach or the upper part of the small intestine).