MGMT promoter methylation and glioblastoma prognosis: a systematic review and meta-analysis.

Background And Aims: We undertook this study to comprehensively summarize the associations between MGMT promoter methylation and prognosis of glioblastoma (GBM).

Methods: We searched PubMed, EMBASE and Cochrane databases (from January 2003 to November 1, 2011) and the references of the relevant articles in English with hazard ratios (HRs) and 95% confidence intervals (95% CIs). Two reviewers independently extracted data using a standardized form. Discrepancies were adjudicated by discussion.

Results: Twenty four studies met the inclusion criteria. There were 22 studies reporting on the relationship between MGMT methylation and overall survival (OS) of GBM and 12 studies on the association between MGMT methylation and progression-free survival (PFS) of GBM. Patients with a methylated status of MGMT had significant OS and PFS advantage (HR = 0.48, 95% CI: 0.35-0.65; I² = 79.78 for OS; HR = 0.43, 95% CI: 0.32-0.56; I² = 50.38 for PFS). Pooled HRs remained significant in further subgroup analysis based on the year of publication and continents of studies.

Conclusions: Patients with MGMT promoter methylation had significant OS and PFS advantage than those without methylated status.