CNSC-35. PERIOPERATIVE OUTCOMES AND HISTOPATHOLOGICAL CHANGES FOLLOWING HYPOFRACTIONATED RADIOTHERAPY COMBINED WITH SUPERSELECTIVE INTRA-ARTERIAL CHEMOTHERAPY IN RECURRENT HIGH-GRADE GLIOMA: A PROSPECTIVE CASE SERIES

Abstract BACKGROUND While hypofractionated radiotherapy (HFRT) and superselective intra-arterial chemotherapy (SIAC) have shown promise for recurrent high-grade glioma (rHGG), the perioperative safety profile and histopathological effects of salvage surgery following this combined modality approach remain poorly characterized. METHODS We prospectively evaluated 5 consecutive rHGG patients (4 glioblastoma, 1 anaplastic astrocytoma) who underwent HFRT (30Gy/10 fractions) followed by SIAC (teniposide 50mg/m²) as a bridge to salvage surgery at our institution between January 2025 and May 2025. Comprehensive perioperative metrics included: (1) treatment-related toxicity (CTCAE v5.0), (2) surgical timing and technical parameters, (3) 90-day postoperative complications, and (4) systematic histopathological assessment of treatment effects using the RANO-PATH criteria. RESULTS Treatment tolerance: All patients completed HFRT-SIAC with only grade 1-2 toxicities (transient blurred vision 20%, headache 40%);Surgical outcomes: Median SIAC-to-surgery interval 26 days (IQR 21-30); mean operative time 4.2±0.8 hours; median blood loss 300mL (200-500) Safety profile: No 30-day mortality; No asymptomatic deep vein thrombosisHistopathological findings: 3 specimens (60%) showed >50% tumor necrosis with prominent vascular hyalinization; 2 demonstrated marked reduction in mitotic figures CONCLUSION This prospective analysis demonstrates that salvage surgery following HFRT-SIAC is feasible with acceptable perioperative risks in selected rHGG patients. The significant histopathological treatment effects observed support the biological activity of this approach.