Nearly 63,000 new cases of thyroid cancer will be diagnosed in 2015, according to National Cancer Institute estimates – that’s nearly 13 men and women in every 100,000 people in the United States. Thyroid cancer is often detected early, resulting in impressive survival rates: Almost 98% of those diagnosed are still surviving 5 years later or longer.
The thyroid is a butterfly-shaped gland at the base of the throat that produces hormones that help regulate the body’s temperature, metabolism, and growth and development.
Thyroid cancer occurs three times more frequently in women than in men, twice as often in Caucasians compared with other races, and is most often diagnosed in people between age 25 and age 65. Rates of thyroid cancer have been on the rise since 1990, which can only partly be explained by improved ways of detecting the disease. People who have been exposed to radiation fallout or radiation for problems in the head and neck (excluding dental x-rays), have a personal history of goiter or a family history of thyroid disease have a greater risk for thyroid cancer.
Symptoms of thyroid cancer include a lump or swelling in the neck, pain in the neck or ears, difficulty swallowing, wheezing, hoarseness, or a persistent cough. Thyroid cancer may be first found as a lump in the neck during a routine physical exam before worrisome symptoms manifest.
There are four main types of thyroid cancer: papillary, follicular, medullary, and anaplastic. Papillary and follicular are the most common types of thyroid cancer in the United States. These cancers begin in follicular cells and grow slowly. Medullary thyroid cancer begins in C cells and can create abnormally high levels of calcitonin. It has been associated with mutations in the RET gene which can be inherited and can usually be found with genetic testing. Anaplastic thyroid cancer occurs only in 1 of every 100 people with thyroid cancer, usually in people older than age 60. It, too, begins in follicular cells, but spreads very quickly and can be more difficult to treat.
A biopsy of the thyroid gland takes a tissue sample for study under a microscope by a trained pathologist and can usually confirm or rule out the presence of cancer cells. Blood tests cannot confirm thyroid cancer, but they can help diagnose the disease by showing high levels or proteins or hormones associated with thyroid cancer.
An ultrasound, radioiodine scan, chest x-ray, computed tomography (CT) scan, magnetic resonance imaging (MRI), positron emission tomography (PET) scan, or combined PET/CT scan can help detail suspicious areas, learn how far cancer may have spread, or determine how well a treatment approach is working.
Treatment for thyroid cancer depends on the type and stage found. In many cases, surgically removing the thyroid (total thyroidectomy) may be necessary. Removing part of the thyroid containing the cancer (lobectomy) or most of the thyroid (subtotal thyroidectomy) may be an appropriate option for certain patients. Patients must take daily thyroid hormone pills (levothyroxine) after thyroidectomy to maintain normal body functions formerly regulated by the thyroid and to keep levels of the hormone TSH low and reduce the risk of recurrent thyroid cancer.
After surgery, radioactive iodine (sodium iodide I 131) may be administered orally, where it is trapped within the thyroid gland to reduce the production and release of thyroid hormones. External radiation therapy is usually only indicated if patients cannot tolerate surgery, because of the potential damage to surrounding tissues needed for breathing, speaking and swallowing.
Hormone therapy, targeted therapy -- drugs that stop or slow cancer growth by “starving” the tumor by stopping angiogenesis, the creation of new blood vessels -- and newer approaches using drugs created for other uses, such as valproic acid for seizures, are showing tremendous promise in thyroid cancer treatment. Results from a study published in the February 2015 New England Journal of Medicine showed that patients who were resistant to radioactive iodine showed a strong positive response to the oral anti-angiogenesis drug lenvatinib, the first new treatment for such patients since the 1940s.
The American Thyroid Association provides expert research, news, and access to clinical trials for patients with thyroid disease. The Thyroid Cancer Survivors’ Association provides information and support in several languages.