Treatment of Aggressive Thyroid Cancer.

Although thyroid cancer generally has a good prognosis, there is a subset of patients for whom standard care (ie, treatment limited to surgery or surgery plus radioactive iodine) is either not appropriate because of the aggressive nature of their disease or not sufficient because of disease progression through standard treatment. Most of these tumors are in 3 groups: radioactive iodine-refractory differentiated thyroid carcinoma including poorly differentiated thyroid carcinoma anaplastic thyroid carcinoma, and progressive medullary thyroid carcinoma. Major classes of treatments in clinical development for these aggressive thyroid tumors include tyrosine kinase inhibitors, mammalian target of rapamycin inhibitors, and mitogen-activated protein kinase kinase inhibitors.