Effect of Bevacizumab Plus Temozolomide-Radiotherapy for Newly Diagnosed Glioblastoma with Different MGMT Methylation Status: A Meta-Analysis of Clinical Trials

BACKGROUND: MGMT methylation status can influence the therapeutic effect and prognosis of glioblastoma (GBM). There are conflicting results from studies evaluating the efficacy of bevacizumab (BV) when it is combined with temozolomide (TMZ) and radiotherapy (RT) in patients diagnosed with GBM with different MGMT methylation status. MATERIAL/METHODS: Data were extracted from publications in PubMed, Embase, and The Cochrane Library, with the last search performed March 23, 2016. Data on overall survival (OS), progression-free survival (PFS), and MGMT methylation status were obtained. RESULTS: Data from 3 clinical trials for a total of 1443 subjects were used for this meta-analysis. MGMT methylated and unmethylated patients showed improved PFS in the BV group (pooled HRs, 0.769, 95% CIs 0.604–0.978, P=0.032; 0.675, 95%CIs 0.466–0.979, P=0.038). For patients with either type of GBM, BV did not improve the OS based on the pooled HRs 1.132 (95% CIs 0.876–1.462; P=0.345) for methylated and 1.018 (95% CIs 0.879–1.179; P=0.345) for unmethylated. CONCLUSIONS: Bevacizumab combined with temozolomide-radiotherapy correlated with improved PFS for treatment of patients with different MGMT methylation status of newly diagnosed GBM. There was insufficient evidence to determine the synergistic effects of combining BV with TMZ and RT on improving survival in patients with different MGMT methylation status.