- The Thyroid
- What Is Thyroid Cancer?
- Who Is at Risk for Thyroid Cancer?
- What Are the Signs and Symptoms of Thyroid Cancer
- How Is Thyroid Cancer Diagnosed?
- Treatment for Thyroid Cancer
The thyroid gland, part of the endocrine system, is located at the base of the throat, near the windpipe (trachea), just below the Adam's apple. It's shaped like a butterfly with a left and right lobe. Other glands that are part of the endocrine system are the parathyroid, pituitary and adrenal, as well as the ovaries, testicles and pancreas.
The thyroid controls the amount of calcium in the bloodstream and produces hormones (T3 and T4) that regulate metabolism by controlling heart rate and body temperature. The thyroid gland is regulated by TSH, a hormone produced by the pituitary gland.
Thyroid cancer occurs when the cells of the thyroid gland grow uncontrollably and form tumors that can invade normal tissues of the neck. Tumors also may spread to the lymph nodes, bloodstream or other parts of the body.
Most thyroid cancer forms in glandular tissue called "adenocarcinoma." "Papillary adeno-carcinoma" and "follicular adenocarcinoma" are two of the most common types of thyroid cancer, affected over 90 percent of thyroid cancer patients. Other less common types include "medullary" and "anaplastic" thyroid cancer.
Thyroid cancer is fairly common, more so in women than men. Over 30,000 people per year are diagnosed with the disease. However, death from thyroid cancer is rare since it usually remains locally in the thyroid gland for several years.
Risk factors for thyroid cancer include:
- History of radiation therapy (to treat acne, infected tonsils, thymus and lymph nodes)
- History of goiters (a condition caused from a lack of iodine in the diet)
- Exposure to ionizing radiation to the neck region (patients with Graves' disease, Hodgkin's disease or survivors from atomic blasts)
- Genetic predisposition for multiple endocrine neoplasia (MEN) type 2 syndrome (Sippler’s syndrome)
Thyroid cancer is sporadic and not associated with risk factors that are preventable. Those with any of the risk factors mentioned above should consider careful screening and examination.
The most common symptom of thyroid cancer is a lump near the bottom of the neck (where the thyroid gland is located). Since this a highly visible area, it can be detected early. However, most growths of the thyroid are found to be benign (non-cancerous).
Other symptoms include:
- Symptoms of windpipe (compression, problems or pain with swallowing, neck pain, or shortness of breath or constant "need" for air)
If a lump is found at the base of the neck, testing for TSH, T3, free T4, iodine and calcium are done to determine the functioning of the thyroid gland. Tests that result in an over-functioning thyroid gland usually mean the growth or tumor is benign (non-cancerous).
Nuclear medicine studies also are performed with radioactive iodine, which takes internal pictures of the thyroid gland. Functioning thyroid tissue takes up the iodine. If the growth contains functioning tissue, it also will take up the iodine, meaning it is benign.
Growths that do not take up iodine have non-functioning tissue. If this is the case, a fine-needle aspiration (biopsy) will be done to determine if the growth is benign or malignant (cancerous).
Treatment of thyroid cancer requires a multi-disciplinary approach, involving experts in endocrinology, surgery, pathology, anesthesiology, radiation oncology and otolaryngology. The National Comprehensive Cancer Network (NCCN) provides guidelines for the treatment of thyroid cancer.
Surgery is the primary treatment for thyroid cancer. However, treatment may include a combination of surgery, radiation and radioactive iodine therapy, depending on the type and stage of the disease.
Surgical procedures involved in treating thyroid cancer include:
- Total thyroidectomy
- Partial thyroidectomy
- Lobectomy (removal of a single lobe of the thyroid gland)
**If the thyroid gland is not completely removed during the first surgical procedure, the patient is at an increased risk for thyroid cancer occurring in the portion left behind. Secondary surgeries to remove the remaining portion of the thyroid gland may be performed later.
Radiation therapy may be recommended after surgery, when the patient has a high risk of recurrence.
Normally, chemotherapy is not used when treating thyroid cancer. However, chemotherapy drugs (Adriamycin, Cisplatin or Etopiside) may be recommended for treating anaplastic thyroid cancers that have progressed after radiation therapy.