Management of advanced and/or metastatic carcinoid tumors: historical perspectives and emerging therapies.

INTRODUCTION: Carcinoid tumors are uncommon neoplasms that offer unique therapeutic challenges to practicing physicians. Several chemotherapy combinations and IFN-α have been used for the treatment of unresectable carcinoid tumors over the last decades, but they have shown variable clinical results. Given the heterogeneity of these tumors, there is no clear therapeutic agent or combination that confers a significant advantage over others.

AREAS COVERED: The authors provide a comprehensive evaluation of the existing therapies for advanced carcinoid tumors such as traditional agents, combination therapies and newer drugs.

EXPERT OPINION: Somatostatin analogs are known to provide symptomatic relief in patients with carcinoid syndrome, but their antiproliferative effect has not been proven beyond the reasonable doubt. Traditional streptozocin-based regimens may offer a survival benefit in patients with advanced carcinoids, yet their toxicity is not negligible. Temozolomide has shown efficacy alone and in combination with other agents, and its further testing in advanced carcinoid tumors appears warranted. Efficacy of various tyrosine kinase inhibitors, VEGF inhibitors and mTOR inhibitors appears promising, and should be explored in patients with metastatic carcinoid tumors. In addition, use of these agents in combination with traditional chemotherapeutic agents should also be investigated.