Head & Neck Oncology Program

Thyroid Cancer

Risk Factors

The American Cancer Society estimates that about 37,340 cases of thyroid cancer will be diagnosed in the United States in 2008. About three-quarters of the cases will be found in women. Thyroid cancer is most commonly found in people between the ages of 30 and 50.

With the exception of age and gender, there are only a few suspected risk factors for cancer of the thyroid. People with a few inherited medical conditions (Garder’s syndrome, familial polyposis, and Cowden’s disease) are more likely to develop thyroid cancer.

In addition, the disease is more likely to affect people who have a diet low in iodine and people who have been exposed to large amounts of environmental radiation or who have had radiation treatment for medical problems in the head and neck. Cancer may not develop until 20 years or longer after radiation treatment.

The majority of people with thyroid cancer have no known factors, so most cases are not preventable. However, developments in the scientific understanding of the hereditary type of medullary thyroid carcinoma have made it possible to prevent that type in people who carry the gene.

This page was last updated on: April 2, 2009.