Management of Patients with Metastatic Medullary Thyroid Carcinoma: The Role for Systemic Therapy

Medullary thyroid carcinoma (MTC) is an uncommon neuroendocrine malignancy that arises from the parafollicular C-cells of the thyroid gland and which frequency metastasizes to local and distant sites. Although often slowly growing, progressive metastatic disease is the cause of death in most patients with advanced MTC and the prognosis typically falls between that of differentiated follicular epithelial and anaplastic forms of thyroid cancer. In the past, effective treatment options were lacking for patients with advanced MTC, since only minimal response rates were seen with the use of traditional cytotoxic agents. However, recent elucidation of key intracellular signaling cascades that contribute to tumorigenesis has fostered development of small molecule kinase inhibitors that offer effective therapeutic options for patients with progressive disease. While these novel agents have had a profound effect on the management of advanced MTC, standardization of practice is challenged by the relative rarity of this tumor and the infrequent need for systemic therapy . This chapter outlines a suggested approach to the use of systemic therapy in progressive metastatic MTC.