Targeted therapy in advanced well-differentiated neuroendocrine tumors.

Treatments for advanced neuroendocrine tumors were, until recently, rather limited. Salvage surgery and liver-directed therapy both have relatively limited impact, and systemic cytotoxic chemotherapy has minimal efficacy. In the absence of other effective treatments, somatostatin analogs have been used for years to control disease and neuroendocrine symptoms, without cytotoxic intent. Advances in targeted therapy for neuroendocrine tumors have opened several potentially new treatment paradigms in the management of these otherwise relatively drug-resistant neoplasms. Promising results have emerged from studies evaluating radiolabeled somatostatin analogs and inhibitors of the vascular endothelial growth factor and mammalian target of rapamycin pathways. This article reviews several of the more encouraging developments in this field.