Dynamic conformal arc radiosurgery for arteriovenous malformations: Outcome and influence of clinical and dosimetrical data.

PURPOSE: To assess efficacy, toxicity, and their predictive factors for dynamic conformal arc arteriovenous malformations (AVM) stereotactic radiosurgery. METHOD: Data concerning 90 consecutive patients were retrospectively studied. Clinical, radiological, dosimetrical data and quality indexes were computed. RESULTS: AVM median volume was 1.06cc. Median prescribed dose was 22Gy. Total occlusion was obtained for 69% of patients. Post-radiosurgery annual hemorrhage rate was 2.2%. Predictive factor for total occlusion was delivered dose. Undesirable events occurred for 28% of patients. Predictive factors for adverse events were AVM revealing mode with seizure or headache, age≤28, AVM diameter≥3cm Spetzler-Martin score≥4, V12Gy≥2cc, large target volume and low homogeneity index (p<0.05). Brain parenchymal radiological reactions concerned 23% of patients, and their predictive factors were AVM revelation by seizure, deep localization, AVM diameter≥3cm, Spetzler-Martin score≥4, previous radiosurgery, numerous embolization, target volume, V12Gy and low homogeneity index (p<0.05). CONCLUSION: Occlusion rate and toxicities are comparable to other series. Specific attention must be paid on pre-treatment clinical data, and target volume should be as small as possible, without reducing the delivered dose.