No abstract

Background The impact of extent of resection (EOR), residual tumor volume (RTV), and gross-total resection (GTR) in glioblastoma subgroups is currently unknown. This study aimed to analyze their impact in patient subgroups in relation to neurological and functional outcomes. Methods Patients with tumor resection for eloquent glioblastoma between 2010 and 2020 at four tertiary centers were recruited from a cohort of 3919 patients. Results One thousand and forty-seven (1047) patients were included. Higher EOR and lower RTV were significantly associated with improved OS and PFS across all subgroups, but RTV was a stronger prognostic factor. GTR based on RTV improved median OS in the overall cohort (19.0 months, p<0.0001), and in the subgroups with IDH wildtype tumors (18.5 months, p=0.00055), MGMT methylated tumors (35.0 months, p<0.0001), aged <70 (20.0 months, p<0.0001), NIHSS 0-1 (19.0 months, p=0.0038), KPS 90-100 (19.5 months, p=0.0012), and KPS ≤ 80 (17.0 months, p=0.036). GTR was significantly associated with improved OS in the overall cohort (HR 0.58, p=0.0070) and improved PFS in the NIHSS 0-1 subgroup (HR 0.47, p=0.012). GTR combined with preservation of neurological function (OFO 1 grade) yielded the longest survival times (median OS 22.0 months, p <0.0001), which was significantly more frequently achieved in the awake mapping group (50.0%) than in the asleep group (21.8%) (p<0.0001). Conclusions Maximum resection was especially beneficial in the subgroups aged <70, NIHSS 0-1, and KPS 90-100 without increasing the risk of postoperative NIHSS or KPS worsening. These findings may assist surgical decision making in individual glioblastoma patients.