New cases of thyroid cancer were diagnosed in approximately 37,200 people in the United States in 2009, according to the American Cancer Society. The thyroid gland is a butterfly-shaped gland that produces hormones that help to regulate various bodily processes, including heart rate, body temperature and weight, and it sits at the base of your neck. There are some factors that can increase your risk of developing thyroid cancer; however, having one or more of these factors does not mean you will definitively get thyroid cancer.
Radiation
The American Cancer Society lists exposure to radiation as a known risk factor for developing thyroid cancer. Exposure can mean past medical treatments involving radiation, especially radiation for cancers of the head or neck, or events such as power plant accidents. Despite prior radiation exposure being a risk factor, thyroid cancer that develops as a result is not more aggressive than other thyroid cancers.
Iodine in the Diet
Low levels of dietary iodine have also been shown to increase the risk of developing follicular thyroid cancer, according to the National Cancer Institute and the American Cancer Society. Because of the addition of iodine in the United States to foods such as salt, this is less of a concern here. The National Cancer Institute mentions that some studies have shown that too much iodine can increase the risk of papillary thyroid cancer, but more research is needed to definitively label it a risk factor.
Demographic Factors
Women are three times more likely than men to be diagnosed with thyroid cancer, according to the American Cancer Society. While these cancers can be diagnosed at any age, nearly two out of three papillary and follicular thyroid cancers are diagnosed in individuals who are between 20 and 60 years old.
Hereditary Factors
The American Cancer Society estimates that one in five medullary thyroid cancers are caused by hereditary factors. These cancers occur due to a mutation in a gene called RET. This can be called familial medullary thyroid carcinoma or multiple endocrine neoplasia type 2, if the thyroid cancer is diagnosed along with other endocrine cancers. The Mayo Clinic and the National Cancer Institute also list familial adenomatosis polyposis, a condition in which polyps form in the colon or rectum, as a risk factor.
