A disease of follicular or parafollicular cells found in the thyroid gland. Thyroid cancer is a relatively rare condition and is more common in women than men. Known causes of thyroid cancer include exposure to radiation (especially to the head and neck region) or radioactive iodine, diet low in iodine, and a mutation in the RET gene.
The stage of thyroid cancer can vary at diagnosis and throughout treatment. Stages of thyroid cancer include stages I, II, III, IV, and I. The effectiveness of the treatment may depend upon the stage at diagnosis.