Thyroid Cancer

Located in the neck just beneath the voice box, the thyroid is a gland which has two types of cells that make hormones. Follicular cells make thyroid hormone, which regulates body temperature, heart rate and energy levels. C cells make calcitonin hormone, which helps control calcium levels in the blood. There are three major forms of thyroid cancer:

Papillary and follicular – account for 80 percent to 90 percent of all thyroid cancer. If detected early, these can be treated successfully.
Medullary thyroid carcinoma (MTC) – account for 5 percent to 10 percent of thyroid cancer. This type forms in the C cells and is easier to control if found early before spreading to other parts of the body. MTC in 80 percent of the cases occurs without a family history. An inherited type or familial MTC can be tested for in families with a history of the genetic changes.
Anaplastic thyroid carcinoma – is the least common type, accounting for only 1 percent to 2 percent of cases. Starting in the follicular cells, this type grows cancer cells that spread quickly making treatment more difficult.

The exact cause of thyroid cancer is unknown. Thyroid cancer occurs more often in women than men, and affects Hispanics and Asian Island Pacific Islanders more often than whites or blacks.
A diet lacking iodine is common in follicular thyroid cancers. Iodine is added to table salt and other foods in the United States. In combination with a diet low in iodine, exposure to radiation increases the chances of developing papillary thyroid cancer.

People, who were exposed to high doses of radiation during the 1920s and 1950s as treatment for childhood illnesses, may be at an increased risk of thyroid cancer. Radioactive fallout (survivors of the Chernobyl accident in 1986, and living near nuclear weapons production plants) is another possible cause of thyroid cancer.

Most cases of papillary and follicular thyroid cancer are found in people between the ages of 20 and 60. Primarily, thyroid cancer affects younger people between the ages of 20 and 55. This is atypical since most cancer rates increase with age.

Benign thyroid nodules and thyroid cancers can occur in people of all ages. The five-year survival rate for thyroid cancer is nearly 97 percent.

Early thyroid cancer produces no symptoms, but as the cancer grows, symptoms may include:

• pain in the neck or throat
• breathing problems
• hoarseness or trouble swallowing
• lump in the front of the neck below the Adam’s apple; and/or
• swollen lymph nodes, especially in the neck.

Be sure to consult with your physician if you experience any of these symptoms. Thyroid cancer can be found early and treated successfully. Detecting a lump and making an appointment with a doctor as soon as possible assures the best way to find the cancer early.

Although exposure to radiation may be a cause of thyroid cancer, radioactive iodine-131 is used to treat thyroid cancer. I-131 can be used to kill the cancerous cells in the thyroid. 

There is no definite way to prevent thyroid cancer because most people with thyroid cancer have no association with the possible risk factors. Genetic testing of familial MTC can be used in families with a history. Families can be screened for the disease and removal of the thyroid can help prevent the development of MTC.

Eating a healthy diet high in fruits and vegetables and low in animal fat, and maintaining a healthy weight can help to prevent many cancers. 

• American Cancer Society
• American Thyroid Association
• National Cancer Institute
• Thyroid Cancer Survivors’ Association