Causes of Thyroid Cancer

There is often no definitive cause of thyroid cancer. It’s a combination of genetics and environmental factors. However, listed below are a few known risk factors for developing thyroid cancer:


Radiation exposure—from previous medical treatments or from environmental disasters like power plant accidents or nuclear explosions—is a known risk factor for developing thyroid cancer. Head and neck radiation treatments during childhood have been associated with an increased risk of thyroid cancer; this risk is higher for larger doses and younger ages of a patient at the time of radiation treatment.

Family History

People with at least 2 first-degree relatives diagnosed with thyroid cancer are at an increased risk of developing thyroid cancer themselves. This risk factor applies to people regardless of whether or not they have a known genetic syndrome associated with thyroid cancer.

Inherited Medical Conditions

Patients with familial adenomatous polyposis (FAP), Cowden disease, or Carney complex type I may be at an increased risk of developing papillary or follicular thyroid cancer.

Low-Iodine Diet

Although most people in Australia obtain enough iodine in their diet due to iodised table salt and other food products that contain iodine, low-iodine diets are common in other parts of the world. Diets low in iodine may increase the risk of follicular and papillary thyroid cancer, especially if a person has also experienced some radiation exposure.