To investigate the effect of O-6-methylguananine-DNA methyltransferase (MGMT) gene promoter methylation status on the treatment and prognosis of elderly patients newly-diagnosed with glioblastoma (GBM).

Clinical data of 65 newly-diagnosed GBM patients admitted to Tianjin Huanhu Hospital from January 2012 to December 2018 were retrospectively analyzed. All patients received intensity-modulated radiotherapy after surgery and 49 patients received temozolomide (TMZ) monotherapy. All patients were divided into the MGMT(+ ) group and MGMT(-) group according to the methylation status of MGMT promoter. Kaplan-Meier method and log-rank test were used for univariate survival analysis, and Cox regression model was used for multivariate prognostic analysis.

The median overall survival (OS) for all patients was 18.0 months. The median OS was 27.0 months and 15.3 months in the MGMT(+ ) group and MGMT(-) group, respectively. Univariate analysis revealed that tumor number, MGMT promoter methylation, postoperative concurrent chemoradiotherapy were significantly related to clinical prognosis (P=0.029, P=0.001 and P<0.001). In multivariate analysis, tumor number and postoperative concurrent chemoradiotherapy were identified as significant prognostic factors for OS (P=0.037, P=0.004). In the MGMT(+ ) group, the median OS was 27.0 months for patients receiving concurrent chemoradiotherapy and 12.0 months for radiotherapy alone (P=0.040). In the MGMT(-) group, the median OS was 17.0 months for concurrent chemoradiotherapy patients and 10.0 months for radiotherapy alone (P=0.122).

MGMT promoter methylation status is significantly associated with longer OS in elderly GBM patients. Conventional fractional radiotherapy combined with concurrent and sequential TMZ chemotherapy probably yields better survival benefits.

O-6-methylguananine-DNA methyltransferase; Glioblastoma/radiotherapy; Glioblastoma/targeted therapy; Temozolomide; Elderly