National Cancer Institute
Last Modified: September 20, 2007
Thyroid cancer is a disease in which cancer (malignant) cells are found in the tissues of the thyroid gland. The thyroid gland is at the base of the throat. It has two lobes, one on the right side and one on the left. The thyroid gland makes important hormones that help the body function normally.
A doctor should be seen if there is a lump or swelling in the front of the neck or in other parts of the neck.
If there are symptoms, a doctor will feel the patient's thyroid and check for lumps in the neck. The doctor may order blood tests and special scans to see whether a lump in the thyroid is making too many hormones. The doctor may want to take a small amount of tissue from the thyroid. This is called a biopsy. To do this, a small needle is inserted into the thyroid at the base of the throat and some tissue is drawn out. The tissue is then looked at under a microscope to see whether it contains cancer.
Some types of thyroid cancer grow faster than others. The chance of recovery (prognosis) depends on the type of thyroid cancer, whether it is in the thyroid only or has spread to other parts of the body (stage), and the patient's age and overall health. The prognosis is better for patients younger than 40 years who have cancer that has not spread beyond the thyroid.
The genes in our cells carry the hereditary information from our parents. An abnormal gene has been found in patients with some forms of thyroid cancer. If medullary thyroid cancer is found, the patient may have been born with a certain abnormal gene which may have led to the cancer. Family members may have also inherited this abnormal gene. Tests have been developed to determine who has the genetic defect long before any cancer appears. It is important that the patient and his or her family members (children, grandchildren, parents, brothers, sisters, nieces and nephews) see a doctor about tests that will show if the abnormal gene is present. These tests are confidential and can help the doctor help patients. Family members, including young children, who don't have cancer, but do have this abnormal gene, may reduce the chance of developing medullary thyroid cancer by having surgery to safely remove the thyroid gland (thyroidectomy).
Once thyroid cancer is found (diagnosed), more tests will be done to find out if cancer cells have spread to other parts of the body. This is called staging. A doctor needs to know the stage of the disease to plan treatment.
The cancer is found in patients aged 45 years or older. The tumor may be any size and has spread to neck tissues near the backbone or around blood vessels in the neck or upper chest. Cancer may have spread to lymph nodes.
Stage 0 (Carcinoma in Situ)
No tumor is found in the thyroid but abnormal cells are found by screening tests. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 is also called carcinoma in situ.
The tumor either:
Anaplastic thyroid cancer is considered to be stage IV thyroid cancer. It grows quickly and has usually spread within the neck when it is found. Anaplastic thyroid cancer develops most often in older people.
Radiation therapy uses high-energy x-rays to kill cancer cells and shrink tumors. Radiation for thyroid cancer may come from a machine outside the body (external radiation therapy) or from drinking a liquid that contains radioactive iodine. Because the thyroid takes up iodine, the radioactive iodine collects in any thyroid tissue remaining in the body and kills the cancer cells.
Hormone therapy uses hormones to stop cancer cells from growing. In treating thyroid cancer, hormones can be used to stop the body from making other hormones that might make cancer cells grow. Hormones are usually given as pills.
Chemotherapy uses drugs to kill cancer cells. Chemotherapy may be taken by pill, or it may be put into the body by a needle in the vein or muscle. Chemotherapy is called a systemic treatment because the drug enters the bloodstream, travels through the body, and can kill cancer cells outside the thyroid.
Treatment of thyroid cancer depends on the type and stage of the disease, and the patient's age and overall health.
Standard treatment may be considered because of its effectiveness in patients in past studies, or participation in a clinical trial may be considered. Not all patients are cured with standard therapy and some standard treatments may have more side effects than are desired. For these reasons, clinical trials are designed to find better ways to treat cancer patients and are based on the most up-to-date information. Clinical trials are ongoing in many parts of the country for some patients with thyroid cancer. To learn more about clinical trials, call the Cancer Information Service at 1-800-4-CANCER (1-800-422-6237); TTY at 1-800-332-8615.
Check for clinical trials from NCI's PDQ® Cancer Clinical Trials Registry that are now accepting patients with stage I papillary thyroid cancer, stage I follicular thyroid cancer, stage II papillary thyroid cancer and stage II follicular thyroid cancer.
Check for clinical trials from NCI's PDQ® Cancer Clinical Trials Registry that are now accepting patients with thyroid gland medullary carcinoma.
Check for clinical trials from NCI's PDQ® Cancer Clinical Trials Registry that are now accepting patients with anaplastic thyroid cancer.
Check for clinical trials from NCI's PDQ® Cancer Clinical Trials Registry that are now accepting patients with recurrent thyroid cancer.
Editorial changes were made to this summary.
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