Biologically Effective Dose (BED) Predicts Obliteration of Unruptured Arteriovenous Malformations Treated by First Intention Gamma Knife Radiosurgery. (16th November 2020)

• Record Type: Journal Article
• Authors: Tuleasca, Constantin; Peciu-Florianu, Iulia; Leroy, Henri-Arthur; Vermandel, Maximilien; Faouzi, Mohamed; Reyns, Nicolas
• Is Part Of: Neurosurgery. Volume 67(2010)Supplement 1
• Publication Date: 2020-11-16
• Subjects: Nervous system -- Surgery -- Periodicals; 617.48005
• DOI: 10.1093/neuros/nyaa447_647
• Languages: English
• ISSNs: 0148-396X

Abstract

Abstract: INTRODUCTION: Arteriovenous malformations (AVMs) present no pathological tissue and radiation dose is confined in a clear-targeted volume. METHODS: Were enrolled 149 consecutive cases ofunruptured AVMs treated by first intention GKR in Lille University Hospital, France. Mean follow-up was 52.9 months (median 48, 12–154). Primary outcome was obliteration and secondary outcome was complication appearance. Marginal dose was 24 Gy in vast majority of cases (n = 115, 77.2%; 18–25 Gy).Mean BED was 220.1 Gy2.45 (median 229.9, 106.7-246.8). Mean beam on time was 32.3 min (median 30.8, 9–138.7). Virginia score was 0 in 29 (19.5%), 1 in 62 (41.6%), 2 in 41 (29.5%), 3 in 18 (12.1%), 4 in 0 (0%) patients, respectively. Mean Pollock-Flickinger score was 1.11 (median 1.52, 0.4-2.9).Uni- (obliteration, complication) and multivariate (obliteration) analysis was performed. RESULTS: 104 (69.8%) AVMs were obliterated at last follow-up. Strongest predictor for obliteration was BED ( P = .03). The area under the ROC curve was 56% for dose and obliteration and 60.9% for BED and obliteration. A radiosurgical obliteration score is proposed, derived from a fitted multivariable model: (0.018*BED) + (1.58*V12) + (-0.013689* beam on time) + (0.021*age) -4.38. The area under the ROC curve for this score was 74.38 and after internal validation using bootstrap methods was 70.88. Twenty-eight (18.8%) patients developed complications after GKR (transient radiological in 20, 13.4%). Predictors for complication appearance were: higher prescription isodose volume ( P = .0005) and 12 Gy isodose line volume (V12, P = .001), higher Pollock-Flickinger ( P = .001) and Viginia scores ( P = .003), lower beam-on time ( P = .03). CONCLUSION: Biologically effective dose was strongest predictor of obliteration of unruptured AVMs after first intention GKR. A radiosurgical score comprising the BED is proposed. V12 appears as a predictor for both efficacy and toxicity. Beam-on time was statistically significant for both obliteration and complication appearance. The exact threshold remains to be established by further studies.