Long-term Results after Stereotactic Radiosurgery for Patients with Cavernous Malformations

OBJECTIVE Stereotactic radiosurgery has been used for patients with high-risk cavernous malformations of the brain. We performed radiosurgery for patients with symptomatic, imaging-confirmed hemorrhages for which resection was believed to be associated with high risk. This study examines the long-term hemorrhage rate after radiosurgery. METHODS We reviewed data obtained before and after gamma knife radiosurgery on 82 patients treated between 1987 and 2000. Most patients had multiple hemorrhages from brainstem or diencephalic cavernous malformations. Follow-up data were examined to identify hemorrhages, and an overall hemorrhage rate was calculated. RESULTS Observation before treatment averaged 4.33 years (range, 0.17–18 yr) for a total of 354 patient-years. During this period, 202 hemorrhages were observed, for an annual hemorrhage rate of 33.9%, excluding the first hemorrhage. Temporal clustering of hemorrhages was not significant. After radiosurgery, patient follow-up averaged 5 years (range, 0.42–12.08 yr), for a total of 401 patient-years. During this period, 19 hemorrhages were identified, 17 in the first 2 years posttreatment and 2 after 2 years. The annual hemorrhage rate was 12.3% per year for the first 2 years after radiosurgery, followed by 0.76% per year from Years 2 to 12. Eleven patients had new neurological symptoms without hemorrhage after radiosurgery (13.4%). The symptoms were minor in six of these patients and temporary in five. CONCLUSION Radiosurgery confers a reduction in the risk of hemorrhage for high-risk cavernous malformations. Risk reduction, although in evidence during initial follow-up, is most pronounced after 2 years. Given the difficulty of identifying high-risk patients, treatment after one major hemorrhage should be considered in selected younger patients. Such a strategy warrants further investigation.