Anti-vascular endothelial growth factor in glioblastoma: a systematic review and meta-analysis

Glioblastoma is one of the most common primary brain tumors in adults. The current treatment strategies failed to achieve satisfactory outcomes. Anti-vascular endothelial growth factor (anti-VEGF) agents have been proposed to enhance the survival and quality of life in these patients. To investigate this, different databases were searched in addition to hand searching. Relevant studies were screened and only ten randomized controlled trials (RCTs) met the eligibility criteria; six of them were considered for meta-analysis. Eligible RCTs were assessed regarding risk of bias using the Cochrane tool. Relevant data were extracted and meta-analysis was conducted using the random effects model analysis on RevMan software. One thousand seventy-eight patients in the anti-VEGF group and 946 patients in the control group were available for analysis. No statistically significant improvement in the overall survival (OS) was detected for anti-VEGF (OR 0.87, 95% CI 0.7-1.09, p=0.23) or bevacizumab subgroup (OR 0.84, 95% CI 0.65-1.08, p=0.17) compared to standard therapy alone. However, the progression-free survival (PFS) showed a significant improvement with both anti-VEGF (OR 0.76, 95% CI 0.65-0.89, p=0.0007) and bevacizumab subgroup (OR 0.75, 95% CI 0.65-0.87, p=0.0001). In conclusion, anti-VEGF agents can improve the PFS but not OS in glioblastoma patients. The current evidence is not satisfactory to declare a new therapeutic line. Further RCTs with sharply determined outcomes and assessment methods are required.