Effect of MGMT gene methylation status on chemoradiotherapy and prognosis in elderly patients with glioblastoma / 中华放射肿瘤学杂志

ABSTRACT

Objective: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).Methods: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. Results: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). Conclusions: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.