SURG-71. Impact of Surgical Ventricular Entry on Outcomes in Gliomas: A Single Center Experience of 731 patients

INTRODUCTION Ventricular entry (VE) during glioma resection is often unavoidable in tumors adjacent to the ventricular system, yet its prognostic significance remains poorly understood. This study aims to investigate the impact of VE on clinical outcomes in patients with gliomas. METHODS A retrospective analysis was performed on patients with supratentorial gliomas treated between 2006–2024 at the University of Pittsburgh Medical Center, all without prior surgical VE. SVZ involvement, VE, tumor size, and extent of resection were assessed via imaging. Multivariable Cox and logistic regressions adjusted for age, preoperative KPS, recurrence status, tumor size, EOR, adjuvant therapy, IDH mutation, 1p/19q codeletion, MGMT methylation, and SVZ contact. RESULTS Among 731 patients, 532 (72.8%) had IDH-wildtype gliomas, 126 (17.2%) had IDH-mutant non-codeleted gliomas, and 73 (10%) had codeleted gliomas. SVZ involvement was present in 65.7% (n=480). VE occurred in 40.4% (n=295) and was associated with shorter progression-free survival (PFS; 9 months [7–10] vs. 14 [11–17], p<0.001) and overall survival (OS; 17 [15–21] vs. 25 [23–29], p<0.001), independent of IDH status and SVZ involvement (Figures 1, 2, 3). Among patients with GTR, VE was associated with shorter OS (21 [17–27] vs. 34 [27–51], p=0.0001), regardless of IDH status (Figure 4). VE remained an independent predictor of worse PFS (HR: 1.6 [1.3–1.9], p<0.0001) and OS (1.4 [1.2–1.7], p=0.001) in multivariable analysis. Distant recurrence (DR) and leptomeningeal disease (LMD) were more frequent in the VE group (DR: 51.4% vs. 20.2%, p<0.001; and LMD: 6.8% vs. 1.1%, p<0.001), with VE independently linked to both (DR: OR: 4.1 [2.8–6.1], p<0.0001; LMD: 5.6 [1.97–18.7], p=0.002). CONCLUSION VE independently predicted reduced survival and higher risk of distant recurrence and LMD. While maximal resection is essential, the risks associated with VE should be considered during surgical planning.