ESTRO 2025 - Abstract Book

S665

Clinical - CNS

ESTRO 2025

723

Digital Poster Clinical outcomes of C-arm linear accelerator-based stereotactic radiosurgery for cerebral arteriovenous malformation Komsan Thamronganantasakul 1 , Siriwan Lulitanond 1 , Mix Wannasarnmetha 2 , Waranon Munkong 2 , Narudom Supakalin 1 , Chunsri Supaadirek 1 , Srichai Krusun 1 , Montien Pesee 1 , Yotdanai Namuangchan 1 1 Division of Radiation Oncology, Department of Radiology, Khon Kaen University, Khon Kaen, Thailand. 2 Division of Diagnostic Radiology, Department of Radiology, Khon Kaen University, Khon Kaen, Thailand Purpose/Objective: Stereotactic radiosurgery (SRS) is an alternative treatment suitable for cerebral arteriovenous malformation (AVM), especially for lesions located in deep and eloquent areas where surgery is limited. However, the outcomes of C-arm linear accelerator (LINAC)-based SRS remain not well established. This study aimed to evaluate the clinical outcomes of AVM patients treated with C-arm LINAC-based SRS. Material/Methods: A retrospective evaluation was conducted on the electronic medical records of 43 patients with unresectable cerebral AVM who underwent first-line SRS with C-arm LINAC at Division of Radiation Oncology, Srinagarind Hospital, Khon Kaen University, Thailand between January 2013 and December 2018. The primary outcome was AVM obliteration rates, as assessed by magnetic resonance angiography (MRA) and digital subtraction angiography (DSA) of the brain. The secondary outcomes were predictors of AVM obliteration, adverse effects of SRS, and the incidence of post-SRS hemorrhage. Statistical analysis was performed with Kaplan-Meier method to determine AVM obliteration rates and bivariate analysis to identify predictors of AVM obliteration. A p -value of ≤ 0.05 was considered as statistically significant. Results: Of the 43 patients identified, 39 were eligible for inclusion and analysis. The median follow-up time was 30 months (range: 12 - 64 months). The median size and volume of AVM nidus was 1.68 cm (range: 0.5 - 3.7 cm) and 2.19 cm 3 (range: 0.17 - 16.76 cm 3 ), respectively. C-arm LINAC-based SRS achieved AVM obliteration rates of 26.67% at 3 years, 48.93% at 4 years, and 78.11% at 5 years of follow-up. Statistical analysis did not identify any predictive factors that were significantly associated with achievement of AVM obliteration following C-arm LINAC-based SRS. The most common complication was radiation necrosis, observed in 5 patients (12.82%). There were no new neurological deficits or evidence of post-SRS hemorrhage in any of the patients. Conclusion: This study provides evidence that C-arm LINAC-based SRS is a safe and effective treatment option for patients with unresectable cerebral AVM, considering the fair obliteration rate and acceptable complication profile compared to Gamma Knife and dedicated LINAC-based SRS.

Keywords: AVM, SRS, Conventional LINAC

802

Digital Poster Treatment outcomes and predictive value of planning metrics after Gamma Knife stereotactic radiosurgery for intracranial chordoma and chondrosarcoma Joseph A Adedigba, Sean A Roles, Guillermo O Rangel Rivera, Osagie S Igiebor, Charlotte I Rivers Radiation Medicine, Medical University of South Carolina, Charleston, USA