The Impact of Volume Factor on the Long-Term Outcome of Gamma Knife Radiosurgery for Sporadic Cerebral Cavernous Malformations

OBJECTIVE: We aimed to evaluate the long-term outcome of gamma knife radiosurgery (GKRS) for the treatment of sporadic cerebral cavernous malformation (CCM), especially the influence of lesion volume on annual hemorrhage rate (AHR) of patients with CCM after GKRS. METHODS: Fifty-one single-lesion patients with a history of hemorrhage who underwent radiosurgery at our institution were included and divided into 2 groups (A and B), based on their lesion volume. Group A included 25 patients with lesion volumes >1 cm(3), whereas group B included 26 patients with lesion volumes <= 1 cm(3). The clinical data of the patients were retrospectively analyzed. RESULTS: All patients were followed up for more than 4 years after GKRS. The calculated AHR before GKRS was 18.49% in group A and 10.16% in group B. The calculated AHR after GKRS was 5.43% and 0.99% for groups A and B, respectively. Significant differences in AHR after GKRS were identified between group A and group B (P = 0.011). Thirty-seven patients with sporadic CCM (14 in group A, 23 in group B) experienced symptom improvement, and significant differences in symptom improvement were observed between group A and group B (P = 0.009). CONCLUSIONS: GKRS decreased the risk of hemorrhage and was beneficial for symptomatic improvement in patients with sporadic CCM with a history of hemorrhage. The longterm clinical outcomes for patients with sporadic CCM with small lesion volumes (<= 1 cm(3) ) were better than those of patients with sporadic CCM with large lesion volumes (>1 cm(3)).