What Increases the Risk of Thyroid Cancer?

Thyroid cancer is a type of cancer that occurs in the thyroid gland, a butterfly-shaped organ located at the base of the neck just below the Adam's apple. The exact cause of thyroid cancer is unknown, but certain factors can increase a person's risk. These include radiation exposure, age, noncancerous thyroid conditions, and a family history of thyroid cancer. Radiation exposure is a proven risk factor for thyroid cancer.

Sources of such radiation include certain medical treatments and fallout from accidents involving power plants or nuclear weapons. A person's risk of developing thyroid cancer may also be higher if their mother, father, brother, sister, or child has had it. The association between exposure to medical radiation and the risk of thyroid cancer can be complicated by factors such as individual susceptibility, nutritional status of iodine, and bias in patient selection. It is not clear how these factors can mediate or influence the risk of radiation exposure in relation to thyroid cancer.

In addition, having a hysterectomy may increase the risk of developing thyroid cancer, particularly if combined with hormone replacement therapy (HRT). Adults and children with an inherited genetic mutation that increases the risk of medullary thyroid cancer may consider having thyroid surgery to prevent cancer (prophylactic thyroidectomy). It's important to note that almost all thyroid cancers have few or no symptoms, and laboratory tests for thyroid cancer are often negative (even when cancer is present). Therefore, it is important to talk to your family doctor if you are concerned about your family history of thyroid cancer.

Doctors aren't sure what causes most cases of thyroid cancer, so there's no way to prevent it in people who are at average risk of getting the disease. However, regular blood tests or thyroid scans may help detect signs of recurrence of thyroid cancer. With further research into modifiable risk factors, we could begin to see reductions in the number of thyroid operations and perhaps in the incidence of thyroid cancer.