SURG-29. EXTENDED RESECTION IMPROVES PATIENT SURVIVAL OUTCOMES AFTER GROSS-TOTAL RESECTION OF GLIOBLASTOMA

Abstract In recent years, the effectiveness of extended resection (ER) beyond the contrast-enhanced (CE) lesion has been reported as a surgical strategy for glioblastoma. This study was to determine whether ER of FLAIR-hyperintense area beyond the CE tumor affected the overall survival (OS) and progression-free survival (PFS) of patients with glioblastoma after gross-total resection (GTR). From October 2019 to March 2022, a total of 62 patients who underwent resection of glioblastoma (GBM) at Kobe University Hospital were retrospectively examined. Volumetric measurements of the CE area and surrounding FLAIR-hyperintense area were performed, and clinical variables related with OS and PFS were analyzed. In total, 33 patients with GBM who underwent GTR of the CE tumor met the inclusion criteria. The mean volume of CE tumor and FLAIR hyperintensity area before resection was 36.5 cm3 and 77.2 cm3 respectively. The mean excision rate of FLAIR-hyperintense area was 18.2%. Removal rates of 20% or more in the FLAIR-hyperintense region significantly increased OS and PFS (p=0.040 and 0.026, respectively). In multivariate analysis, age ≥ 65 years (HR 2.73; 95% CI 1.09–7.22; p=0.032) were associated with shorter OS, but ER ≥ 20% (HR 0.41; 95% CI 0.17–0.99; p=0.049) and MGMT promotor methylation (HR 0.36; 95% CI 0.15–0.85; p=0.020) were associated with longer OS. ER of FLAIR-hyperintense lesions of 20% or more in glioblastoma contributed to prolonging patient survival. It is necessary to validate the effect of ER in prospective clinical trials.