What is thyroid cancer?
The thyroid is a small, butterfly-shaped organ that is located in the neck below the voice box. It is responsible for secreting a hormone that regulates the body's energy production. The thyroid gland contains two types of cells: follicular cells, which produce and store thyroxine and the protein thyroglobulin; and C-cells (parafollicular cells), which produce calcitonin, a hormone that regulates body levels of calcium and phosphate.
There are four types of thyroid cancers: papillary carcinoma, follicular carcinoma, anaplastic carcinoma and medullary thyroid carcinoma (MTC).
Follicular carcinoma (follicular adenocarcinoma) is the second most common type of thyroid cancer, and it originates in follicular cells. Although follicular carcinoma usually involves only the thyroid gland, it can sometimes spread to other parts of the body, such as the lungs and the bones.
Anaplastic carcinoma (undifferentiated thyroid cancer) is the rarest form of thyroid cancer, and scientists theorize that it develops from existing papillary or follicular carcinoma. Anaplastic carcinoma spreads quickly and aggressively to the neck and other parts of the body.
Medullary thyroid carcinoma (MTC) is the only type of thyroid cancer to develop from the thyroid's C-cells. It can spread to the lymph nodes, the lungs and the liver, even before an abnormal lump in the thyroid has been detected. It can be a familial cancer in which case genetic susceptibility studies can be informative.
What causes thyroid cancer?
The exact cause of thyroid cancer is still not known, but many studies have shown that people exposed to nuclear fallout or power plant accidents such as the incident that occured in Chernobyl in 1986 are at a higher risk of developing thyroid cancer than the general population. In countries where people's diets are low in iodine, there has been an increased number of people with thyroid cancer.
What are the symptoms of thyroid cancer?
Although many of the following symptoms may be present in non-cancerous conditions, they are also consistent in people with thyroid cancer. They are: difficulty swallowing, a lump in the neck that may or may not grow rapidly, a pain in the neck that may shoot up into the ears, difficulty breathing, a persistant cough and hoarseness.
What is the treatment for thyroid cancer?
The treatment of this type of cancer depends greatly on the pathologically-determined subtype. Surgery is very common in the treatment of thyriod cancer. All or part of the noncancerous thyroid and nearby lymph nodes are removed. When the thyroid gland is removed in its entirety, thyroid hormones must be taken in pill form (replacement therapy) to help restore normal metabolism to the body. A treatment known as radioactive iodine is sometimes used to kill any cancerous thyroid tissue not removed during surgery. Finally, chemotherapy and external beam radiation therapy may also be used to kill any cancerous cells.