The impact of histological types on the efficacy of angiogenesis inhibitors in the treatment of advanced NSCLC: a meta-analysis of randomized controlled trials

PURPOSE: We aimed at assessing the overall efficacy of angiogenesis inhibitor (AI)-containing regimens in the treatment of advanced non-small-cell lung cancer (NSCLC) according to histological types. METHODS: Studies from PubMed and Web of Science, and abstracts presented at American Society of Clinical Oncology (ASCO) meeting up to October 31, 2014 were searched to identify relevant studies. Eligible studies included prospective randomized controlled trials (RCTs) evaluating AIs in advanced NSCLC with survival data according to patients’ histologies. The endpoints were overall survival (OS) and progression-free survival (PFS). Statistical analyses were conducted by using either random effects or fixed effect models according to the heterogeneity of included studies. RESULTS: A total of 10,035 patients with advanced NSCLC from 13 RCTs were identified for analysis. The pooled results demonstrated that AI-containing regimens significantly improved the PFS (HR, 0.84, 95% confidence interval (CI): 0.78–0.91, P<0.001) and OS (HR, 0.92, 95% CI: 0.85–0.99, P=0.017) in lung adenocarcinoma when compared to non-AI-containing regimens. Additionally, there was a significantly improved PFS (HR, 0.87, 95% CI: 0.77–0.98, P=0.027) for AI-containing regimens in squamous cell lung carcinoma, but it did not translated into OS benefit (HR, 1.02, 95% CI: 0.92–1.15, P=0.68). For NSCLC patients with other histological types, the use of AIs did not significantly improve PFS (HR, 0.90, 95% CI: 0.75–1.09, P=0.27) and OS (HR, 0.90, 95% CI: 0.76–1.08, P=0.19). CONCLUSION: The findings of this study suggest that the addition of AIs to the treatment therapies for patients with lung adenocarcinoma offers improved survival benefits. Prospective clinical trials investigating the role of AIs in this setting are recommended.