Colon Cancer Screening
Cancer screenings can help find colon cancer at its earliest stage, when the chances for successful treatment are greatest. These tests are usually done when the patient is healthy and has no specific symptoms.
Adults who are not at high risk for colon cancer should begin having screening exams at age 50. People who are at higher risk because of a personal or family history of colon or rectal cancer, colorectal polyps or inflammatory bowel disease should be screened before they turn 50.
Family members of newly diagnosed colon cancer patients should also be screened for Lynch syndrome, a gene mutation discovered at the OSUCCC – James and the most diagnosed inherited form of colorectal cancer. This screening can actually prevent colon cancer in those family members by identifying precancerous conditions and treating them before cancer can ever occur.
Screening Tests for Colon Cancer
Cancer screening exams can help find colon cancer at its earliest stage, when the chances for successful treatment, optimal outcomes and fewer side effects are greatest. These tests are usually done when a patient is healthy and has no specific symptoms.
Not only are expert cancer researchers at the OSUCCC – James continually working to detect and diagnose colon cancer early, but they are also developing additional tests to detect and diagnose cancer even earlier, leading to improved outcomes, faster responses and fewer side effects.
At the OSUCCC – James, colon cancer screening for patients with no symptoms and for patients with risk factors can include:
Fecal Occult Blood Test
A stool sample is analyzed for blood that can be seen only with a microscope.
Fecal Immunochemical Test
This newer test can identify blood in stool using a special chemical that reacts to a protein in red blood cells. The exam can be completed without the dietary restrictions usually required for a fecal occult blood test.
A radiologist takes a series of X-ray images of the lower digestive tract after placing a special barium-infused liquid into the rectum to highlight the lining of the intestine.
Colonoscopy is the most reliable and preferred screening method for identifying abnormal precancerous growths, called polyps. Using a tube that is slightly longer than a sigmoidoscope, a specially trained doctor examines the inside of the colon and rectum to identify polyps or other abnormal tissue and remove polyps to prevent future cancer and possibly for biopsy. Patients must prepare for colonoscopies for a day to several days in advance to make sure that their colons are clear for the exam.
A doctor analyzes the colon and rectum using a thin, flexible tube with a lighted end called a sigmoidoscope. A camera on the end of the scope can display images of the inside of the colon, and a special tool on the scope can assist in polyp or tissue removal.
Also called CT colonoscopy, this exam uses a special scanner that rotates around the patient to take X-ray images of the colon and rectum to detect polyps or signs of cancer. Preparation for this test is similar to colonoscopy.
Tissue samples can be analyzed to look for changes in genes that indicate colorectal cancer or patients with increased risk for colon cancer.
Diagnosing Colon Cancer
Your physician will use several exams to diagnose colon cancer if you show any signs or symptoms of the disease or following screening tests for colon cancer. The physician asks questions about your medical and personal history and your family history. The physician also conducts a physical exam, which may include a rectal exam.
Many of the exams used to screen for colon cancer such as an occult blood test, a colonoscopy, a barium enema exam or a sigmoidoscopy are also used in diagnosing the disease.
Colonoscopy is the most important imaging exam used to analyze the colon and to diagnose polyps and colon cancer.
Blood tests that analyze samples of blood drawn from a patient can identify signs that indicate colorectal cancer. A complete blood count measures various blood cells and can show that a patient has anemia. Anemia can occur as the result of a tumor bleeding over a long time period.
A biopsy confirms a colon cancer diagnosis. Sample tissue from the colon is analyzed under a microscope by a specially trained pathologist. A doctor can obtain the tissue during a sigmoidoscopy or colonoscopy.
Analyzing genes of certain cancer cells from a colon tumor biopsy can assist in planning targeted treatment for patients with colon cancer.
Tests Used for Staging Colon Cancer
Once a patient receives a colon cancer diagnosis, a physician may order tests to determine whether the cancer has spread to other parts of the body and to help stage the cancer. These tests include:
Computed Tomography (CT) Scan
The X-ray examination makes a series of detailed images using an X-ray machine that revolves around the patient’s body to create multidimensional images.
Positron Emission Tomography (PET) Scan
A PET scan is an imaging exam used to find malignant tumor cells in the body. A small amount of radioactive sugar is injected into a vein. The PET scanner identifies areas where the radioactivity concentrates. These areas are more active and may indicate cancerous cells. These images can then be combined with CT images (known as PET/CT) to better locate the radioactivity.
Magnetic Resonance Imaging (MRI)
An MRI uses a high-powered magnet and radio waves to produce detailed images of the body.
Ultrasound uses sound waves to evaluate the organs and spaces inside the abdomen to determine if colon cancer has spread.
X-rays produce images of the tissues and organs inside the chest, especially the lungs.
Lymph Node Biopsy
Lymph nodes near the colon cancer are typically removed at the time of colon cancer surgery for analysis under a microscope. This is part of the staging for colon cancer and helps to determine future therapy.
During surgery, a physician removes the segment of the colon containing the tumor and analyzes how far the cancer has spread within the colon.
Tumor Marker Analysis
A sample of blood is analyzed for substances made by organs, tissues or tumor cells in the body that are linked to specific types of cancer. These are called tumor markers. Carcinoembryonic antigen (CEA) and CA 19-9 are associated with colon cancer and other diseases.
Staging Colon Cancer
If colon cancer is diagnosed, your doctor will determine the stage of the disease.
Stage 0 is called carcinoma in situ. Abnormal cells are found in the mucosa, or innermost layer, of the colon wall but have not yet invaded the colon. These abnormal cells may become cancer and spread.
Cancer has formed in the mucosa of the colon wall and has spread to the submucosa (layer of tissue beneath the mucosa). Cancer may have spread to the colon wall’s muscle layer but has not spread to lymph nodes or other organs.
Cancer has spread through the colon wall’s muscle layer to the serosa (outermost layer) of the colon wall, through the serosa, or directly into nearby organs but has not spread to lymph nodes or to faraway organs.
Cancer has spread through the colon wall’s muscle layer to the serosa (outermost layer) of the colon wall, through the serosa, or directly into nearby organs and has spread to lymph nodes but not to faraway organs.
Cancer has spread to faraway organs such as the lung, liver, ovary or inner lining of the abdomen, called the peritoneum.
(Source: National Cancer Institute)
If you’ve been diagnosed with colon cancer, would like a second opinion or would like to speak with a colon cancer specialist, please call The James Line at 800-293-5066 or 614-293-5066 to make an appointment.