Thyroid cancer cannot be prevented. Most people who have thyroid cancer do not have any known risk factors for the disease.

One type of thyroid cancer, called medullary thyroid cancer (MTC), is much more likely if you have a gene change called an RET mutation. This can run in families. If there is a history of conditions called MEN 2a, MEN 2b, or FMTC (familial medullary thyroid carcinoma) in your family, a genetic test can determine whether you have an increased risk for medullary thyroid cancer (MTC). If genetic testing shows that you have an increased risk for MTC, you can have your thyroid gland removed to prevent the development of thyroid cancer later in life. If this gene change is present, even very young children can have their thyroid removed to help prevent future MTC.