NCOG-11. EXTENT OF RESECTION OF CONTRAST-ENHANCING AND NON-ENHANCING TUMOR: DIFFERENT IMPACTS ON SURVIVAL ACCORDING TO TYPES OF ADULT-TYPE DIFFUSE GLIOMAS IN 2021 WHO CLASSIFICATION

Abstract

Abstract BACKGROUND To evaluate the impact of extent of resection (EOR) of contrast-enhancing (CE) and nonenhancing (NE) tumors in the types of adult-type diffuse gliomas according to the 2021 WHO classification. METHODS Total 1,196 adult-type diffuse glioma patients diagnosed between 2001 and 2021 from a single institution were enrolled (183 patients with isocitrate dehydrogenase [IDH]-mutant and 1p/19q codeleted oligodendroglioma [herein oligodendroglioma], 211 patients with IDH-mutant astrocytoma, and 802 patients with IDH-wildtype glioblastoma). Analyses were performed within each type to assess predictors of overall survival, including clinical, imaging data, histological grade, O6-methylguanine-methyltransferase (MGMT) promoter methylation status, adjuvant treatment, and EOR of CE and NE tumors. Subgroup analyses were performed in patients with CE tumor. RESULTS Among 1,196 patients, 926 (77.4%) patients had CE tumors. In oligodendrogliomas, gross total removal (GTR) of CE tumor was associated with survival (hazard ratio [HR]=0.09, P< 0.001), whereas GTR of NE tumor was not associated with survival (HR=0.41, P=0.088). In 81 (43.3%) oligodendroglioma patients with CE tumor, GTR of CE tumor was the only independent predictor of survival (HR=0.20, P=0.092) in multivariable analysis. GTR of CE and NE tumors was independently associated with better survival in IDH-mutant astrocytoma and IDH-wildtype glioblastoma (all Ps< 0.05). CONCLUSIONS GTR of both CE and NE tumors may significantly improve survival within all types of adult-type diffuse gliomas except oligodendrogliomas. In oligodendrogliomas, the EOR of CE tumor may be crucial in survival; aggressive GTR of NE tumor may be unnecessary, whereas GTR of the CE tumor is recommended.