Meta-analysis of the role of bevacizumab in extensive stage small cell lung cancer

Progress in the treatment options for small cell lung cancer (SCLC) remains poor. Concerns exist regarding the efficacy of bevacizumab in SCLC. The present study aimed to evaluate the efficacy of bevacizumab in extensive stage (ES)-SCLC. A meta-analysis on studies conducted and listed on the Medline, Cochrane Trials, ASCO, ESMO and ClinicalTrial databases, and Chinese databases prior to April 2015 was performed. All clinical trials in which patients with ES-SCLC were treated with bevacizumab were considered. Survival rates at specific time points were extracted from the reported survival curves. Hazard ratios (HR) for progression-free survival (PFS) and overall survival (OS), rates for PFS, OS, overall response rate (ORR), and side-effects were synthesized using random-effects or fixed-effects model. Two randomized control trials (RCT) (176 patients) and six single-arm trials (292 patients) were identified. In RCTs, no statistically significant differences were observed in PFS [HR, 0.70; 95% confidence interval (CI), 0.41-1.19; P=0.19] or OS (HR, 1.21; 95% CI, 0.84-1.75; P=0.31). In the first-line trials, pooled 6-month and 1-year PFS rates were 57% (95% CI, 39-76%) and 10% (95% CI, 4-16%), respectively. Synthesized 1-year and 2-year OS rates were 45% (95% CI, 36-54%) and 10% (95% CI, 6-14%), respectively. Reported median PFS and OS times for pretreated patients were 2.7-4.0 months and 6.3-7.4 months, respectively. Pooled ORRs were 71% (95% CI, 59-82%) in the first-line trials and 18% (95% CI, 11-25%) in the second-line trials. The most common types of reported toxicities were chemotherapy-associated, including neutropenia, leukopenia, fatigue and thrombocytopenia. According to the RCTs, bevacizumab did not appear to improve the PFS or OS for patients with ES-SCLC, with low quality of evidence. Due to the disappointing pooled efficacy in the single-arm trials, more clinical studies on bevacizumab in SCLC may not be valuable, although the evidence was with low quality.