Management of carcinoid syndrome (CS): A systematic review of systemic treatment options.

Abstract

516 Background: CS is a major cause of symptom burden (diarrhea/flushing) in patients (pts) with neuroendocrine tumors and is associated with shortened survival and severe complications such as carcinoid heart disease. We performed a systematic review of clinical evidence for CS systemic treatments. Methods: PubMed, Embase, and Cochrane databases were searched. Large ( > 60 pt) prospective clinical trials investigating the efficacy/safety of systemic treatment options for pts with CS were eligible for inclusion. Data extracted included study design, pt population, interventions, prior treatments, permitted concomitant medications, study endpoints/statistical analyses, and efficacy/safety outcomes. Results: Six large prospective clinical trials (total 953 pts) were identified from 144 search results. Significant heterogeneity existed in pt populations, control groups (placebo vs active comparator), duration of therapy, study endpoints, and efficacy/safety data reporting. Interventions assessed were long-acting and subcutaneous octreotide (OCT & OCT SC), lanreotide (LAN), telotristat ethyl (TE)+somatostatin analogues (SSA), pasireotide (PAS), and everolimus (EVE)+OCT. Symptom response was variably assessed by the frequency of diarrhea/flushing and/or receipt of rescue short-acting SSA in 5/6 studies; a significant improvement in at least one of these measures occurred in 4 studies (OCT and OCT SC; LAN; TE+SSA). Failure to meet symptom response criteria ranged from 29-82% in the studies. Reported reductions in CgA and/or 5-HIAA reached statistical significance in 3 studies (LAN; EVE+OCT; TE+SSA). Interventions were generally well tolerated. Two phase 3 trials focused specifically on management of CS symptoms refractory to SSA; strategies included switching to PAS or an increased dose of OCT (40 mg q28d) for refractory diarrhea/flushing, or receipt of TE with continued SSA for refractory diarrhea. Conclusions: SSA provide substantial symptom relief for pts with CS. For refractory symptoms, TE can be added, SSA dose increased, and metastasis debulking can be used (with surgery, hepatic artery embolization, ablation, and PRRT). The addition of biologic agents to SSA can further improve CS management.