Q. What are the causes and risk factors of thyroid cancer?
A. While doctors can seldom explain why one person gets thyroid cancer and another doesn't, we do know that the disease is not contagious; no one can "catch" thyroid cancer from another person. Scientists do not know exactly what causes this disease, but research does show that some people are more likely to develop it than others.
Some types of thyroid cancer are inherited (run in families) and can be associated with other types of endocrine tumors. People that have a strong family history of thyroid cancer may benefit from discussing this issue with an expert genetic counselor to determine their own risk of developing this disease.
Almost three times as many women develop thyroid cancer as do men. People who have been exposed to radiation or received radiation treatments to the head and neck as an infant or child have a greater chance of developing thyroid cancer, as do those who have had a goiter (enlarged thyroid) or a family history of thyroid disease.
Q. What are the symptoms of thyroid cancer?
A. The most common symptom of thyroid cancer is a lump or swelling in the neck. If you have a lump or swelling in your neck or other symptoms that concern you, you should see your doctor.
Q. How do you diagnose thyroid cancer?
A. The doctor will ask about your medical history and will do a careful physical exam, with special attention to feeling your thyroid and checking for lumps in the neck. You may also be asked to have a blood test or special scans.
The best screening test for a thyroid nodule is a good examination of the neck by your primary care physician. Most internists, family doctors and obstetricians/gynecologists perform examination of the neck during routine checkups, and nodules can often be found in this way.
Sometimes people will notice a lump in their neck when they look at themselves in the mirror, or something will be noted by a spouse or close friend. This may be nothing, but it usually should be checked further – particularly if it is asymmetrical (not even on both sides). The thyroid and most thyroid nodules move easily when you swallow, so if a lump in the neck moves, it most likely involves the thyroid gland. If there is a lump that does not move, this would be concerning and should be evaluated by a physician capable of performing a good neck exam. The combination of a lump and a change in the voice is very concerning and should be evaluated by a specialist right away.
If a lump is thought to involve the thyroid gland, it should be evaluated by a specialist soon, and a needle biopsy done on the nodule. This is an outpatient procedure typically done in the office and causes about the same amount of discomfort as drawing blood from the arm. The doctor removes a small sample of tumor tissue, which is examined under a microscope by a pathologist to determine if cancer cells are present.
If nodules are detected early, even if they are cancer, there is a very good chance for a cure. The larger the nodule, the less likely it is that the entire tumor can be removed before it spreads.
Q. What are the treatment options for thyroid cancer?
A. Because of advances in diagnosis and treatment of thyroid cancer, a longer and better life is possible for patients today. Treatment planning takes into account the type of thyroid cancer and the stage of the disease as well as the general health and age of the patient. Four types of treatments may be used:
Surgery is the most common treatment for thyroid cancer. The goal of the surgery is to completely remove the tumor and a safe margin of the tissue around it. Depending on the outcome of the surgery, the doctor may also recommend other therapy, often including radioiodine, chemotherapy or radiation therapy.
After surgery to remove the thyroid, all patients need to be treated with replacement thyroid hormone (L-thyroxine, sold under the brand names of Synthroid, Levothroid, Levoxyl and others). This treatment is aimed not only at replacing the hormone that would normally be made from the thyroid gland, but also at suppressing the levels of other hormones in the body that would normally stimulate the thyroid gland to grow and produce hormones.
Radioiodine is a radioactive form of the mineral iodine, which is present in many foods, such as iodized salt and shellfish. Because the thyroid is the only gland in the body that stores iodine, cancer of the gland can be treated with radioiodine, which allows the delivery of a killing dose of radioactivity only to the cells that uptake and store this compound. In many cases, this will kill any thyroid cells not removed by surgery, including any normal cells and any cancer cells.
Radiation therapy uses high-energy rays to damage cancer cells and stop their growth. Radiation therapy is generally given in the outpatient department of a hospital or clinic. Most often, patients receive radiation therapy five days a week for five to six weeks.
Chemotherapy is the use of drugs to kill cancer cells. Some drugs are given by mouth; others are injected into a blood vessel or muscle. The drugs travel through the bloodstream to nearly every part of the body. Chemotherapy is usually given in cycles: a treatment period followed by a rest period, then another treatment period, and so on.
Patients may also want to talk with the doctor about taking part in a research study, called a clinical trial, involving new treatment methods.
Q. What are the side effects of treatment?
A. The methods used to treat thyroid cancer are very powerful. That's why treatment often causes side effects. Fortunately, most side effects are temporary.
After radioiodine therapy, some people get swelling of the salivary glands in the cheeks or neck. This is a temporary effect and is usually treated with anti-inflammatory medicines such as ibuprofen (Advil, Motrin) for a few days. Also, sometimes people are taken off the thyroid hormone medication and made hypothyroid (low thyroid) before treatment. This helps the radioiodine treatment to be more effective. In these cases, people will often feel tired, cold and achy. As soon as the treatment dose is given, the thyroid hormone is restarted and the symptoms will go away.
The side effects of chemotherapy and radiation therapy are well known and can be troublesome. However, these treatments are rarely used for thyroid cancer. If your doctor recommends chemotherapy or radiation therapy, you should ask about side effects before beginning.
If you are enrolled in a clinical trial, side effects of the new agents may not be well known. In these cases, if you begin developing strange or unusual symptoms, you should contact your study coordinator or doctor at once to get advice on what steps, if any, need to be taken. This is also important because it helps the manufacturers of the new drugs know if the agents are safe.
Q. What should I ask my doctor when diagnosed with thyroid cancer?
A. Here are some questions you may want to ask your doctor:
- How can this disease be treated? What are my treatment choices?
- How successful is the treatment likely to be?
- Would a clinical trial be appropriate for me?
- What are the expected benefits of treatment?
- What are the risks and possible side effects of treatment?
- Will I have to change my normal activities?
- Can I keep working during treatment?
- How often will I need checkups?
Your doctor is the best person to give advice about working or to answer questions about other activities. Many patients find it also helps to talk with others who are facing similar problems. This kind of help is available through cancer-related support groups. Social services, clergy, nursing personnel or your doctor can offer suggestions as to where to seek assistance with emotional support.