Extent of resection and perioperative neurological status as prognostic markers in glioblastoma: a population-based study

Maximal safe resection is the suggested standard for surgical treatment for patients with IDH-wildtype glioblastoma. Surgical safety is prioritized over radical extent of resection (EOR) because new neurological deficits are considered detrimental for survival. The aim of this study was to explore the combined impact of extent of resection and neurological status on survival in glioblastoma patients, using standardized tools for neurological function (neurological assessment in neuro-oncology (NANO scale) and extent of resection (RANO resect classification). Population-based study of all adult patients who underwent resection for newly diagnosed glioblastoma from 2019 to 2022 in a geographically defined region. EOR was evaluated according to the RANO resect classification. Neurological function was assessed using the NANO scale preoperatively, immediately after surgery, and before start of radiotherapy. Kaplan Meier survival analysis, chi-square and log-rank tests were used to compare groups. The median overall survival (mOS) for 503 patients was 12.9 months. RANO resect class 1 was associated with significantly longer mOS compared to patients with RANO classes 2, 3, and 4 (21.0 vs. 14.8, 8.3, and 4.5 months, respectively; p < 0.01). Preoperatively neurologically intact patients (NANO-score 0) had a longer mOS, than patients with neurological deficits. Neither the postoperative NANO-score nor the change in the score impacted survival. Being neurologically intact before surgery and supramaximal resection were independent, strong predictors of longer survival. Mild to moderate new postoperative neurological deficits did not impact mOS, suggesting that supramaximal resection may confer a survival benefit even when such deficits are induced.