Effect of Prior Embolization on Outcomes After Stereotactic Radiosurgery for Pediatric Brain Arteriovenous Malformations: An International Multicenter Study.

Abstract

Pediatric brain arteriovenous malformations (AVMs) are a significant cause of morbidity but the role of multimodal therapy in the treatment of these lesions is not well understood. To compare the outcomes of stereotactic radiosurgery (SRS) with and without prior embolization for pediatric AVMs. We retrospectively evaluated the International Radiosurgery Research Foundation pediatric AVM database. AVMs were categorized, based on use of pre-embolization (E + SRS) or lack thereof (SRS-only). Outcomes were compared in unadjusted and inverse probability weight (IPW)-adjusted models. Favorable outcome was defined as obliteration without post-SRS hemorrhage or permanent radiation-induced changes (RIC). The E + SRS and SRS-only cohorts comprised 91 and 448 patients, respectively. In unadjusted models, the SRS-only cohort had higher rates of obliteration (68.5% vs 43.3%,  < .001) and favorable outcome (61.2% vs 36.3%, P < .001) but a lower rate of symptomatic RIC (9.0% vs 16.7%, P = .031). The IPW-adjusted rates of every outcome were similar between the 2 cohorts. However, cumulative obliteration rates at 3, 5, 8, and 10 yr remained higher in the absence of prior embolization (46.3%, 64.6%, 72.6%, and 77.4% for SRS-only vs 24.4%, 37.2%, 44.1%, and 48.7% for E + SRS cohorts, respectively; SHR = 0.449 [0.238-0.846], P = .013). Embolization appears to decrease cumulative obliteration rates after SRS for pediatric AVMs without affecting the risk of post-treatment hemorrhage or adverse radiation effects arguing against the routine use of pre-SRS embolization. While endovascular therapy can be considered for occlusion of high-risk angioarchitectural features prior to SRS, future studies are necessary to clarify its role.