Bevacizumab treatment for newly diagnosed glioblastoma: Systematic review and meta-analysis of clinical trials

High-grade glioma is a richly neovascularized brain solid tumor with a poor prognosis. Bevacizumab is a recombinant humanized monoclonal antibody that inhibits vascular endothelial cell proliferation and angiogenesis, which has shown clinical efficacy in recurrent glioblastoma. MEDLINE/PubMed, EMBASE and Web of Science databases were searched for relevant studies that compared bevacizumab plus combined radiotherapy/temozolomide (RT/TMZ) with RT/TMZ alone in newly diagnosed glioblastoma (GBM). Of all the studies identified, three comparative trials were included in the systematic review. All three enrolling trials, including a total of 1,738 patients, investigated bevacizumab or placebo plus combined RT/TMZ treatment in glioblastoma. The result showed no increased overall survival (OS) (pooled hazard ratio (HR), 1.04; 95% confidence interval (CI), 0.84-1.29; P=0.71) but increased progression-free survival (HR, 0.74; 95% CI, 0.62-0.88; P=0.0009). However, the two randomized double-blind placebo-control trials exemplified a high rate of adverse events of the bevacizumab compared with the placebo group while discrepant points were noted in term of quality-of-life outcome. Additionally, bevacizumab plus RT/TMZ did not increase the 6-month survival rate [odd ratios (ORs), 0.65; 95% CI, 0.37-1.13; P=0.13). Overall, addition of bevacizumab to radiotherapy-temozolomide treatment may be an effective therapy strategy for improving progression-free survival. OS and the 6-month survival rate was not prolonged and there was questionable efficacy of bevacizumab on the quality-of-life of glioblastoma patients, thus further clinical trials should be performed.