Bevacizumab for salvage treatment of metastatic breast cancer: A systemic review and meta-analysis of randomized controlled trials

Summary: Although various new agents have been developed for the treatment of patients with metastatic breast cancer (MBC), overall survival rates have changed little in the last half century. We conducted meta-analysis to verify the clinical efficacy of bevacizumab for the salvage treatment of MBC. Event-based hazard ratios (HR) with 95% confidence intervals (95% CIs) were derived, and a test of heterogeneity was applied. Four studies, with a total of 2,860 patients, met the inclusion criteria for analysis. The pooled results of clinical efficacies were: HR for progression free survival 0.69 (95% CI, 0.58-0.81, z=4.54, P<0.001); HR for overall survival 0.92 (95% CI, 0.82-1.03, z=1.44, P=0.15); and HR for the clinical objective response rate 1.53 (95% CI, 1.37-1.71, z=7.37, P< 0.001). In terms of overall survival, subgroup analysis demonstrated statistically significant improvement for the bevacizumab combination in the initial therapy subgroup (HR, 0.878; 95% CI, 0.771-0.999, z= 1.98, P=0.048). Hypertension and proteinura were more common in the bevacizumab combination arm; however, these toxicities were managed with therapy. In conclusion, meta-analysis suggested benefits of a carefully managed bevacizumab-containing salvage regimen for patients with histologically or cytologically confirmed Her-2 negative MBC who have not received previous cytotoxic therapy. This treatment could improve both progression free survival and overall survival rates.