The standard of care for glioblastoma is concomitant chemoradiotherapy and adjuvant chemotherapy with Temozolomide. In this trial, we investigated the impact of MGMT promoter methylation on prognosis and the benefit from Temozolomide based chemotherapy in a group of patients with glioblastoma in our region.
In this retrospective study, glioblastoma cases who were treated in our institute between 2006 and 2011 were included. We used Methylation Specific PCR (MSP) to detect methylation in the promoter region of MGMT gene. Kaplan-Meier technique was used to calculate overall survival from the time of diagnosis to the time of death. We utilized Log-rank test and Cox-regression model to univariate and multivariate analysis of potential prognostic factors.
68 patients with a median age of 50 (range; 20 to 75) and a male to female ratio of 56/22 were included. All patients had received adjuvant radiotherapy with a median dose of 60 Gy (54-60 Gy). 25 patients had received concomitant and adjuvant chemotherapy with Temozolomide. MGMT promoter methylation was found in 19 (24.4%) cases. MGMT promoter methylation was significantly more frequent in men than women (p=). MGMT promoter methylation was associated with significantly higher 2- year survival (57.2% vs. 16.8% p < 0.001). In multivariate analysis male sex and MGMT promoter methylation were independent prognostic factor. In contrast to patients with tumors not containing MGMT methylation, in cases with this genetic change, administering concomitant and adjuvant chemotherapy was associated with more favorable outcome.
In our series, MGMT promoter methylation was a significant independent prognostic factor. The finding of more favorable survival in men than women needs further validation. Concurrent and adjuvant chemotherapy improved outcome only in patients with MGMT methylation. Treatment stratification based on MGMT methylation test can be recommended especially in patients who are high risk for concomitant treatment side effects.
Clinical trial identification
All authors have declared no conflicts of interest.