Evolving treatment strategies for management of carcinoid tumors

Carcinoid tumors of the digestive tract and lungs are neuroendocrine neoplasms with diverse biological features, which vary based on primary tumor location and histological differentiation. Recent years have seen a surge of research on treatments for advanced neuroendocrine tumors. The role of somatostatin analogs has expanded from treatment of the carcinoid syndrome to inhibition of tumor growth. Radiolabeled somatostatin analogs allow for targeted delivery of radiation to somatostatin receptor-expressing tumor cells. A number of biologic agents targeting the VEGF and mTOR pathways have shown promise in randomized clinical trials; however, their role in the treatment of carcinoid tumors remains controversial. This article reviews the evolving treatment strategies for metastatic carcinoid tumors of the aerodigestive tract, with a focus on new systemic targeted agents and liver-directed therapies.