Introduction: We assessed the clinical and radiological outcome after repeated radiosurgery for brain arteriovenous malformations (bAVMs) after failure of initial radiosurgery. Materials and methods: Fifteen patients underwent repeated radiosurgery. The mean bAVM volume at first radiosurgery (Si) was 4.6 +/- 4.3 ml and that at second radiosurgery (52) was 2.1 +/- 2.5 ml. The median marginal dose was 18 Gy at S1, and 21 Gy at S2. Modified Rankin Scale (MRS) score was determined in all patients at last follow-up (FU). Results: Complete obliteration was reached in nine patients (60%). Median time to obliteration was 50 months after S2. An excellent outcome (no new neurologic deficiencies, complete obliteration) was reached in seven patients (47%). Eleven patients (73%) showed a MRS <= 1. Radiation-induced complications occurred in 20%, of which 13% occurred after S2. Radiological complications included cyst formation (n = 1), radiation-related edema (n = 4), and radiation necrosis (n = 1), resulting in an increasing mean MRS of 0.5 at S1, 0.6 at S2, to 0.8 at FU. No (re-)bleedings were encountered during 137-patient years at risk. Discussion: Repeated radiosurgery is a viable option for the treatment of small remnant bAVMs. We report 20% permanent radiation-induced complications. Such complications were mainly seen in relatively large, and therefore difficult to treat, bAVMs. (C) 2010 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and Oncology 95 (2010) 250-25
