SURG-20. PREOPERATIVE QUANTITATION OF UNRESECTABLE TUMOR VOLUME USING WHOLE-BRAIN TRACTOGRAPHY TO IMPROVE OUTCOME PREDICTION AFTER SURGERY FOR HIGH-GRADE DIFFUSE GLIOMAS

Abstract BACKGROUND Because minimizing injury to critical brain regions during high-grade glioma (HGG) surgery is essential, the optimal extent of resection (EOR) for any given patient often less than 100% tumor bulk. However, there are no accepted methods assessing upper limit EOR. Advances in whole-brain tractography (WBT) present an opportunity address this problem. Here, we develop a predictive model surgical outcomes HGG as classified by WHO CNS5, and leverage it determine added utility WBT-based volumetric resectability metric. METHODS We included patients who underwent biopsy or new recurrent senior author from 2013 2020. A analysis method incorporating WBT was developed calculate EOR unresectable volume (UTV). Using perioperative clinical data, multiple linear Cox regression models were used identify independent predictors progression-free survival (PFS). RESULTS total 151 HGGs included. Median PFS 97.0% 5.0 months, respectively. Greater strongly predicted longer overall (hazard ratio [HR]=0.21, 95% confidence interval [CI] 0.07-0.72), with largest benefit observed at > 85% When controlling EOR, higher residual (RTV) (HR=0.97, CI 0.94-0.99), suggesting existence RTV threshold below which decreases. Involvement eloquent (p=0.0086) brainstem (p=0.0006) categorical variables lower but failed predict shorter PFS. Calculation UTV based on actual imputed data feasible reliably CONCLUSION Existing measuring poorly reproducible do not independently survival. Preoperative measurement UTV, substituting may simplify improve outcome prediction, allowing neurosurgeons better assess candidacy individual patients.