What Is Thyroid Cancer?

Thyroid cancer is a solid tumor cancer that usually shows up as a nodule, or mass, in the thyroid gland, which is located at the front base of your throat. It occurs when rogue cells reproduce too rapidly for the immune system to control. There are several types of thyroid cancer, but two types — papillary thyroid cancer and follicular thyroid cancer — are by far the most common, accounting for some 95 percent of cases. Between 1% and 2% of people will get thyroid cancer at some point during their lifetime. It affects three times as many women as men and is most common after age 30, though it can occur in any age group. Thyroid cancer is more likely to be aggressive in older adults.

What Causes Thyroid Cancer?

It’s not clear exactly what causes thyroid cancer to develop. However, there are a number of known potential risk factors, some of which can be modified and others (like your age and sex) that can’t.