RADT-07. HYPOFRACTIONATED RADIOTHERAPY IN BRAINSTEM GLIOMAS- EXPERIENCE FROM A TERTIARY CARE CENTRE IN INDIA

Abstract Brainstem Gliomas have limited therapeutic options and poor outcomes. Radiation forms the cornerstone of management but data is lacking. We performed an audit of brainstem glioma patients treated with hypofractionated radiation between July 2021 to May 2024. Diagnostic MRI was co-registered with planning CT to delineate GTV with an isotropic 5 mm margin for CTV and 3mm for PTV. Baseline clinical and imaging details, radiation details, acute toxicities, steroid usage, progression, and overall survival data were recorded. PFS and OS were defined from the date of diagnosis to progression and death respectively. This study included 31 Brainstem glioma patients. The median age at presentation was 14 years (2–80 years). Majority of patients were male (67.7%). The baseline performance status assessed by ECOG/Lansky was 0-2 in 83.9%. The most common presenting complaint was motor weakness in 51.6% followed by cerebellar symptoms in 29%. Baseline neurological deficit was seen in 90.3%. The most common epicenter of the disease was pons (67.7%). Biopsy was available in only 9.7% (2 patients: Diffuse Midline Glioma H3k27 altered,1: High-Grade Glioma). VP shunting was done in 29%. All patients were planned via VMAT technique. Median GTV volume 34.3cc (4.9-109.5cc). Median PTV volume was 95.1 cc (7.9-363.1 cc). Most frequently used regimen was 40Gy/15#/3 weeks in 74.3% of patients. Median PTV coverage D95% was 98.7% (90.5-99%). Only one patient received concurrent Temozolamide. Median Radiation treatment time was 22.5 days (-46 days). Steroid usage during radiation was seen in 41.9% of the patients. Naso-gastric tube was required in 12.9% patients. During radiation, aspiration and raised ICT were seen in in 12.9% each. At a median follow-up of 6.42 months, the median PFS was 6.42 months (3-9.83 months) and OS was 7.18 months (3-11.37 months). Hypofractionation seems a feasible approach in brainstem gliomas. International collaborative efforts are required.