SURG-47. SUPRAMAXIMAL RESECTION IMPROVES OVERALL SURVIVAL IN PATIENTS WITH MGMT-UNMETHYLATED GLIOBLASTOMA

Abstract INTRODUCTION Glioblastoma is highly resistant to radio- and chemotherapy and its heterogeneity is a therapeutic challenge. O6-methylguanine–DNA methyltransferase (MGMT) promotor methylation is an established biomarker for favorable effect of chemotherapy. Supramaximal resection has proven predict the best overall survival (OS), but whether this benefit applies equally to patients with different MGMT-promotor methylation status is still to be debated. MATERIAL AND METHODS Population based retrospective study that examined all adult patients in South-Eastern Norway that underwent resection for IDH wildtype glioblastoma between January 2019 and December 2021. Extent of resection (EOR) was classified according to RANO resect classification and MGMT-promotor methylation status by pyrosequencing-qPCR. RESULTS The study included 281 patients. MGMT-promotor methylated patients (MGMT+) had a median OS of 18.4 months compared to 13.1 months in MGMT-unmethylated (MGMT-) patients (p