Intraoperative neurophysiological monitoring and survival outcomes in patients with IDH–wildtype glioblastoma
Giorgio Fiore, Giulio Andrea Bertani, Giorgio Giovanni Carrabba, Mauro Pluderi, Stefano Borsa, Giorgio Conte, Maurizio Vergari, Stefania Navone, Laura Guarnaccia, Filippo Cogiamanian, Giovanni Marfia, Manuela Caroli, Marco LocatelliAbstract
Background
Intraoperative neurophysiological monitoring (IONM) facilitates safe glioma resection in eloquent regions. Its effect on survival in molecularly defined IDH–wildtype glioblastoma remains uncertain. We assessed the association between IONM-supported surgery and survival outcomes in this high-risk population and explored subgroups deriving the greatest benefit.
Methods
We retrospectively analyzed 200 adults who underwent first-time resection for IDH–wildtype glioblastoma between 2012 and 2021. Co-primary outcomes were progression-free survival (PFS) and overall survival (OS), evaluated through Kaplan–Meier estimates and multivariable Cox models. Secondary 1:1 propensity score-matched analyses were performed based on age, preoperative KPS, MGMT methylation status, preoperative tumor volumes and localization. Volumetric analysis included contrast-enhancing (CE) and non–CE tumor components. Subgroup analyses were stratified by tumor location.
Results
In the unmatched cohort, IONM was independently associated with prolonged PFS (HR 0.60, 95% CI 0.45–0.84) and OS (HR 0.60, 95% CI 0.43–0.83), along with younger age, MGMT methylation, higher KPS, and smaller postoperative volumes. IONM patients had higher complete CE resection rates (64.2% vs 40.4%, P = 0.0005) and improved functional preservation (postoperative KPS 80 vs. 70, P = 0.008), despite more early deficits. In the location-matched cohort (n = 104), median PFS was 12 months with IONM vs 7 months without (P = 0.0007), and OS was 17 vs 11 months (P = 0.0018). Supramaximal resections occurred exclusively in the IONM group. The benefit was most evident in frontal, parietal, and insular tumors.
Conclusions
IONM-supported surgery was associated with more extensive resection, functional preservation, and longer survival in IDH–wildtype glioblastoma. IONM was more frequently used in tumors located in frontal, parietal, and insular regions, consistent with the functional complexity of these areas.