Stereotactic Radiosurgery for Pediatric Brain Arteriovenous Malformations: Long-Term Outcomes

Abstract

Abstract INTRODUCTION Contrary to the better described obliteration and hemorrhage data after stereotactic radiosurgery (SRS) treatment of brain arteriovenous malformations (AVMs) in pediatric patients, estimates of the rarer complications including cyst and tumor formation are limited in the literature. The aim of the study was to assess the long-term outcomes and risks of SRS for AVMs in pediatric (age < 18 yr) patients. METHODS We retrospectively analyzed the International Radiosurgery Research Foundation pediatric AVM database from 1987 to 2018. AVM obliteration, post-SRS hemorrhage, cyst formation, and tumor formation were assessed. Cumulative probabilities, adjusted for competing risk of death, were calculated. RESULTS The study cohort comprised 539 pediatric AVM patients (mean follow-up: 85.8 mo). AVM obliteration was observed in 64.3% of patients, with cumulative probabilities of 63.6% (95% CI: 58.8%-68.0%), 77.1% (95% CI: 72.1%-81.3%), and 88.1% (95% CI: 82.5%-92.0%) over 5, 10, and 15 yr, respectively. Post-SRS hemorrhage was observed in 8.4% of patients, with cumulative probabilities of 4.9% (95% CI: 3.1%-7.2%), 9.7% (95% CI: 6.4%-13.7%), and 14.5% (95% CI: 9.5%-20.5%) over 5, 10, and 15 yr, respectively. Cyst formation was observed in 2.1% of patients, with cumulative probabilities of 5.5% (95% CI: 2.3%-10.7%) and 6.9% (95% CI: 3.1%-12.9%) over 10 and 15 yr, respectively. Meningioma was observed in 2 patients (0.4%) at 10 and 12 yr after SRS, with cumulative probability of 3.1% (95% CI: 0.6%-9.7%) over 15 yr. CONCLUSION AVM obliteration can be expected after SRS in the majority of the pediatric population, with a relatively low risk of hemorrhage during the latency period. Cyst and benign tumor formation after SRS can be observed in 7% and 3% of patients over 15 yr, respectively. Longitudinal surveillance for delayed neoplasia is prudent despite its low incidence.