Thyroid nodules, or lumps, are quite common, occurring in more than 50% of the world's population. Moreover, the likelihood of developing a thyroid nodule increases with age and in part represents the aging process of the thyroid gland.
Although most nodules are harmless and do not require any treatment at all, approximately 5% of all nodules are cancerous.
Thyroid nodules occur more frequently in women than in men, however the incidence of cancerous nodules is greatest in men. Despite the low incidence of cancer, all nodules should be evaluated to determine their status.
Although the cause of most thyroid nodules is unknown, some risk factors for developing nodules include a lack of iodine in the diet, which can cause thyroid enlargement, family history of benign thyroid nodules, and pre-existing thyroid disease.