Abstract TP490: Long Term Clinical Results of Linear Accelerator Stereotactic Radiosurgery for Cerebral Arteriovenous Malformations: A Single Institution Experience of 18 Years

Abstract

Introduction: Cerebral arteriovenous malformation (AVM) is an intracranial pial vascular lesion which is treated with microsurgery, endovascular treatment or stereotactic radiosurgery (SRS). We introduce the long-term clinical results of linear accelerator (LINAC) stereotactic radiosurgery for cerebral AVM which is treated in single institution for 18 years period. Methods: Retrospective chart review was held in cerebral AVM patients treated with Novalis (BrainLAB AG, Heimstetten, Germany) stereotactic radiotherapy from 2001 to 2018. Clinical results such as obliteration rate, hemorrhage rate after SRS, and radiosurgery related adverse event was analyzed. Furthermore, predictors for obliteration and symptomatic radiosurgery induced adverse event was analyzed with multivariate logistic regression test. Results: Among 117 patients with cerebral AVMs treated with LINAC-based SRS, 72 were included in study. Total obliteration rate was 80.6% (58/72) for mean 57.0±48.3 months follow up period. Post-SRS hemorrhage and mortality rate was 6.9% (4/72) and 1.4% (1/72), respectively. Mean radiation dose and volume was 22.8Gy and 3.7cc, respectively. Independent predictive factors for nidus obliteration was: (1) radiation dose (OR 1.43, 95% CI 1.04-2.08, p=0.0374), (2) Ruptured AVM (OR 12.18, 95% CI 2.38-86.47, p=0.0054), (3) Virginia AVM score (OR 0.21, 95% CI 0.07-0.53, p=0.0028), and (4) follow up period months (OR 1.03, 95% CI 1.01-1.06, p=0.0261). Independent risk factors for symptomatic radiosurgery related adverse event was radiation volume (OR 1.61, 95% CI 1.09-2.65, p=0.0326). Conclusion: LINAC-based SRS is effective and relatively safe method for treatment of cerebral AVMs. Independent predictive factors for obliteration was high radiation dosage, ruptured status, low Virginia AVM score, and long follow up period. High radiation volume was related to symptomatic radiation induced adverse event.