Author(s): HattangadiGluth JA, Chapman PH, Kim D, Niemierko A, Bussire MR,
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Abstract PURPOSE/OBJECTIVE(S): To evaluate the obliteration rate and potential adverse effects of single-fraction proton beam stereotactic radiosurgery (PSRS) in patients with cerebral arteriovenous malformations (AVMs). METHODS AND MATERIALS: From 1991 to 2010, 248 consecutive patients with 254 cerebral AVMs received single-fraction PSRS at our institution. The median AVM nidus volume was 3.5 cc (range, 0.1-28.1 cc), 23\% of AVMs were in critical/deep locations (basal ganglia, thalamus, or brainstem), and the most common prescription dose was 15 Gy(relative biological effectiveness [RBE]). Univariable and multivariable analyses were performed to assess factors associated with obliteration and hemorrhage. RESULTS: At a median follow-up time of 35 months (range, 6-198 months), 64.6\% of AVMs were obliterated. The median time to total obliteration was 31 months (range, 6-127 months), and the 5-year and 10-year cumulative incidence of total obliteration was 70\% and 91\%, respectively. On univariable analysis, smaller target volume (hazard ratio [HR] 0.78, 95\% confidence interval [CI] 0.86-0.93, P<.0001), smaller treatment volume (HR 0.93, 95\% CI 0.90-0.96, P<.0001), higher prescription dose (HR 1.16, 95\% CI 1.07-1.26, P=.001), and higher maximum dose (HR 1.14, 95\% CI 1.05-1.23, P=.002) were associated with total obliteration. Deep/critical location was also associated with decreased likelihood of obliteration (HR 0.68, 95\% CI 0.47-0.98, P=.04). On multivariable analysis, critical location (adjusted HR [AHR] 0.42, 95\% CI 0.27-0.65, P<.001) and smaller target volume (AHR 0.81, 95\% CI 0.68-0.97, P=.02) remained associated with total obliteration. Posttreatment hemorrhage occurred in 13 cases (5-year cumulative incidence of 7\%), all among patients with less than total obliteration, and 3 of these events were fatal. The most common complication was seizure, controlled with medications, both acutely (8\%) and in the long term (9.1\%). CONCLUSIONS: The current series is the largest modern series of PSRS for cerebral AVMs. PSRS can achieve a high obliteration rate with minimal morbidity. Post-treatment hemorrhage remains a potentially fatal risk among patients who have not yet responded to treatment. Copyright © 2014 Elsevier Inc. All rights reserved.
This article was published in Int J Radiat Oncol Biol Phys
and referenced in International Journal of Neurorehabilitation