Risk Factors

For the vast majority of individual patients, the cause of thyroid cancer is unknown (1). As this is the case, there is no way of preventing thyroid cancer in people who have an average risk of developing this disease. Despite the fact that the death rate of thyroid cancer is one of the lowest among all cancers, it is still important to be aware of inherent risk factors and possible risk factors.

Known risk factors for thyroid cancer include:

  • Exposure to ionizing radiation
    • This is the strongest risk factor for thyroid cancer. The younger you were when exposed, the higher your risk of developing thyroid cancer. Possible sources include radiation therapy, which is often used to treat childhood cancers, nuclear accidents and weapons, and diagnostic imaging tests, such as X-Ray and MRI scans.
  • Non-cancerous thyroid conditions
    • A history of benign thyroid conditions, such as nodules, goiter, or thyroiditis, is linked to an increased risk of thyroid cancer.
  • Family history of thyroid cancer
    • If there is a history of thyroid cancer in your immediate family, this puts you at higher risk of developing it.
  • Hereditary conditions
    • Some rare hereditary conditions are linked to an increased risk of thyroid cancer, including MEN2 (as mentioned in About Thyroid Cancer), Cowden syndrome, and Werner syndrome.
  • Acromegaly
    • Acromegaly is a condition in which the body produces too much growth hormone. The increase in this hormone leads to uncontrolled thyroid growth, and an increased risk of thyroid cancer.
  • Obesity
    • This association has been confirmed by multiple studies, but the exact reason for this link is not entirely clear.
  • Tall height
    • Once again, there is no clear explanation for this link. It is thought to be linked to childhood hormone levels.
  • Increased thyroid-stimulating hormone (TSH) secretion
    • Though this link is not directly understood, there are many theories estimating their relationship. One theory hypothesizes that high levels of TSH causes a rapid increase in the growth rate of thyroid cells, and this increased number of cells can result in mutation, thus increasing the risk of thyroid cancer.


Information taken from Canadian Cancer Society unless otherwise indicated.

(1) “Thyroid Cancer – Who Gets It and Risk Factors”, Thyroid Cancer Canada. https://www.thyroidcancercanada.org/en/thyroid-cancer/who-gets-it-and-risk-factors