Linac-based stereotactic radiosurgery for brain arteriovenous malformations

PURPOSE: Linac stereotactic radiosurgery (SRS) is gaining popularity as a form of radiation treatment for cerebral arteriovenous malformations (AVMs) since the theory of combined radiosurgical and endovascular treatment poses much uncertainty and due to significant technical progress for SRS. This study focuses on how to evaluate obliteration and re-bleeding rates, and to determine factors and adverse effects influencing obliteration after linac-based SRS for cerebral AVMs. MATERIAL AND METHODS: From a statistical record of 71 patients, 31 had partial embolisation, five surgery and 29 had no prior treatment. Using Kaplan–Meier survival and life table analyses, actuarial obliteration and annual bleeding hazard rates were calculated after SRS. RESULTS: After a follow up of 1, 2 and 3 years the actual obliteration rates were 22, 59 and 66%, respectively whereby it was noted that prior embolization had no effect on the obliteration rate. Annual bleeding hazard rates were further analyzed after stereotactic radiosurgery to be 2.1% and 1.4% for the first and second year respectively. Asymptomatic abnormalities were detected after imaging in 33.9% of patients. A dose of less than 18 Gy significantly reduced the obliteration probability. CONCLUSION: SRS is a therapeutic option for intracerebral AVM. In general, there is a low rate of morbidity and a high probability of nidus obliteration.