ABSTRACT
Papillary and follicular thyroid cancer, together termed differentiated thyroid cancer (DTC), is usually curable when it is discovered at an early stage and is treated appropriately. Derived from follicular epithelial cells that normally trap iodine and secrete thyroid hormone, these tumors usually have receptors for and grow in response to thyrotropin (TSH). They are the only malignant tumors that respond to a combination of thyroid surgery, radioiodine (131I), and thyroxine (T4) suppression of TSH and that synthesize and secrete thyroglobulin (Tg), a senistive marker that is elevated by small amounts of tumor. Indeed, in the absence of normal thyroid tissue, early detection of persistent tumor is made possible by an elevation of the serum Tg level. Papillary cancer comprises the majority of thyroid malignancies (90%) and has the best 10-year relative survival rate (93%), responding better to treatment than other thyroid tumors. Nonetheless, it accounts for over half the deaths from thyroid cancer (Table 1) (1), killing more patients than all other forms of thyroid cancer.
