SURG-03. SURVIVAL STRATIFICATION OF IDH-WILDTYPE GLIOBLASTOMA IN THE MOLECULAR ERA: A RECURSIVE PARTITIONING ANALYSIS INCORPORATING EXTENT OF RESECTION OF CONTRAST-ENHANCING AND NON-ENHANCING TUMORS

Abstract

Abstract METHODS This multicenter cohort study included a development cohort of 622 IDH-wildtype glioblastoma patients from a single institution (diagnosed between 2001 and 2021) and 445 patients as validation cohorts from two institutions. All patients completed radiotherapy plus concurrent temozolomide and had complete information on IDH mutation and MGMT promoter methylation status. EOR of CE and NE tumors were evaluated. A RPA analysis was performed on behalf of results of the Cox proportional hazards model. The RPA model was compared with a previous RTOG RPA model. RESULTS In the developmental cohort, older age (hazard ratio [HR] = 1.02, P < 0.001), MGMT methylation (HR = 0.51, P < 0.001), KPS (HR = 0.98, P < 0.001), and EOR of CE and NE tumors (GTR of CE tumor and non-GTR of NE tumor, HR = 1.82, P < 0.001; non-GTR of both CE and NE tumor, HR = 2.05, P < 0.001; reference group as GTR of both CE and NE tumor) were independent prognostic factors on multivariable analysis. The novel RPA consisting of age, MGMT methylation, KPS, and EOR of CE and NE tumors revealed greater separation of prognostic classes compared with the previous RTOG RPA model. The prognostic significance of the novel RPA model was subsequently confirmed in the validation cohorts. CONCLUSION The RPA model in IDH-wildtype glioblastoma patients incorporating EOR of CE and NE tumors is a valid model. This simple RPA model has the potential to contribute to improving the accurate assessment of prognostic groups in IDH-wildtype glioblastoma patients and to influence clinical decision-making.