Stereotactic Radiosurgery for Brainstem Cavernous Malformations: An Updated Systematic Review and Meta-Analysis

Objective: This study was conducted to achieve more conclusive evidence for the efficacy of stereotactic radiosurgery (SRS) for brainstem cavernous malformations (BSCMs). Methods: A literature search of PubMed, EMBASE, and Web of Science was performed and studies reporting the outcomes of SRS for BSCMs were included. The primary outcome was the pre-SRS and post-SRS hemorrhage rates; the pooled incidence rate ratio (IRR) with 95% confidence interval was chosen as effect size. Lesion control, symptom change, and radiation-related complications were evaluated. Results: A total of 576 patients across 14 studies were included in this meta-analysis. The post-SRS hemorrhage rate was significantly decreased compared with the pre-SRS rate (IRR, 0.123; P < 0.001), and the hemorrhage rate 2 years after SRS was significantly lower than that within 2 years after SRS (IRR, 0.317; P < 0.001). Ten among 14 studies have shown that the symptoms were improved or stationary after SRS. Lesion volume was reduced in 47.3% of the patients and was stationary in 49.4% on the last follow-up images. Symptomatic adverse radiation effects (AREs) developed in 7.3% and permanent AREs were observed in 2.2%. In subgroup analysis, studies having mean marginal dose of ≤13 Gy showed statistically significantly lower development of symptomatic AREs than those having mean marginal dose of >13Gy (2.0% vs. 10.8%; P = 0.008). Conclusions: SRS using a relatively low marginal dose can be a safe and effective treatment for BSCM. Further prospective studies are necessary to confirm the optimal radiation dose and efficacy of SRS for BSCMs.