Treatment outcome after linac-based radiosurgery in cerebral arteriovenous malformations: Retrospective analysis of factors affecting obliteration

Abstract

Purpose We investigated patient outcome and factors affecting obliteration rate after radiosurgery in cerebral arteriovenous malformations (AVM). Material and Methods We have treated 110 patients with cerebral AVM with linac-based radiosurgery (RS). AVM classification according Spetzler–Martin was 17 patients grade I (15%), 39 grade II (36%), 41 grade III (37%), 12 grade IV (11%) and 1 grade V (1%). Median single dose was 18 Gy. Mean treatment volume was 4.7 cc (range, 0.1–24.0 cc). Fifty-two patients experienced hemorrhage prior to RS. Median follow-up was 2.5 years. Results Actuarial complete obliteration rate (CO) was 51% after 3 years and 67% after 4 years. CO rate was significantly higher in AVM <3 cm (64% vs. 43%, P<0.04) and in patients with grade I/II vs. III–V (71% vs. 33%, P<0.001). CO was significantly improved after doses >18 Gy ( P<0.02) and in male gender ( P<0.04). In multivariate analysis Spetzler–Martin grade remained significant. Intracranial hemorrhage after RS occurred in 9 patients 13.9 months median after RS. Neurological dysfunction improved/completely dissolved or remained stable in 95% of patients. No new onset of neurological dysfunction was seen. No significant adverse effects after RS were seen. Conclusions The rate of obliteration after RS in AVM depends on applied single dose as well as size and Spetzler–Martin grade. RS is an alternative to neurosurgery, especially in patients with small or surgically inaccesible AVM.