Thyroid cancer occurs in the cells of the thyroid, a butterfly-shaped gland located at the base of the neck, just below the Adam’s apple. The thyroid produces hormones that regulate heart rate, blood pressure, body temperature and weight. Nearly 54,000 cases of thyroid cancer will be diagnosed in the United States this year, with 3 out of 4 cases being in women. The chance of being diagnosed with thyroid cancer has risen in recent years, and much of this rise appears to be the result of the increased use of thyroid ultrasounds, which can detect small thyroid nodules that might not otherwise have been found in the past.
Thyroid cancer typically doesn’t cause any signs or symptoms early in the disease. As thyroid cancer grows, it may cause a lump that can be felt through the skin on the neck; changes to voice, including increasing hoarseness; difficulty swallowing; pain in the neck and throat; or swollen lymph nodes in the neck.
If thyroid cancer is suspected, as series of tests may be performed starting with a physical exam and blood tests. One or more imaging tests may be used, such as CT scans, PET or ultrasound, to determine if the cancer has spread beyond the thyroid. A fine-needle biopsy may also be required to remove a sample of the thyroid tissue to be analyzed in the laboratory to look for cancer cells.
Detecting the correct type of thyroid cancer may determine what treatment plan is used. Types of thyroid cancer include:
- Papillary thyroid cancer: the most common form of thyroid cancer, arises from follicular cells, which produce and store thyroid hormones, and most often affects people ages 30 to 50.
- Follicular thyroid cancer: also arises from the follicular cells of the thyroid, usually affecting people older than age 50.
- Medullary thyroid cancer: begins in thyroid cells called “C cells”, which produce the hormone calcitonin. Elevated levels of calcitonin in the blood can indicate this cancer at a very early stage.
- Anaplastic thyroid cancer: a rare and rapidly growing cancer that is very difficult to treat, typically occurring in adults age 60 and older.
- Thyroid lymphoma: a rare form of thyroid cancer that begins in the immune system cells in the thyroid and grows very quickly, typically occurring in older adults.
Most people with thyroid cancer undergo surgery to remove all or most of the thyroid. Operations used to treat thyroid cancer usually involve removing all or most of the thyroid (thyroidectomy) or removing a portion of the thyroid (thyroid lobectomy). In certain situations where the thyroid cancer is very small, it may be recommended to remove only one side (lobe) of the thyroid. Lymph nodes in the neck may also be removed during one of these procedures. Radiation and chemotherapy are not necessary in most cases of thyroid cancer, unless a patient cannot undergo surgery or has failed other courses of treatment.
There are no known preventative measures for thyroid cancer, but known risk factors including being female, exposure to high levels of radiation and certain inherited genetic syndromes.