Comparison of Stereotactic Radiosurgery (SRS) and Hypo-fractionated Radiosurgery (hSRS) for Vestibular Schwannomas: A Meta-Analysis of available literature

Introduction: Stereotactic Radiosurgery (SRS) and recently, hypo-fractionated Radiosurgery (hSRS) are increasingly utilized as treatment for Vestibular Schwannomas (VS). We performed a meta-analysis of literature comparing these modalities to compare the efficacy and safety of these practices.

Methods: The PubMed database of articles was searched for studies that compared SRS and hSRS in patients with VS. Variables analyzed include tumor control, hearing preservation, facial nerve preservation, trigeminal nerve preservation, and total complications. Heterogeneity across the studies was gauged using Higgins’s inconsistency index (I^2). Funnel plots and Egger’s regression intercept test were used to address the publication bias.

Results: Thirteen studies that satisfied the search criteria were selected for meta-analysis. The studies identified in our study included 353 SRS and 511 hSRS-treated patients. Analysis of heterogeneity showed that hSRS is employed for relatively larger tumor sizes in comparison to SRS. Pooled meta-analysis estimates showed no significant differences between SRS and hSRS in terms of tumor control (odds ratio [OR], 0.620; 95% CI, 0.21-1.86, P = 0.39), hearing preservation (OR, 1.07; 95% CI, 0.59-1.93, P = 0.83), facial nerve preservation (OR, 0.53; 5% CI, 0.23-1.21, P = 0.13), or trigeminal nerve preservation (OR, 0.67; 95% CI, 0.24-1.89, P = 0.49) at a mean follow-up of 39 months. Statistically significant heterogeneity was found across the studies only for tumor diameter (I^2 = 65.69%, P = 0.003) but not for other variables.

Conclusion : Meta-analysis of thirteen studies comparing SRS and hSRS as treatment for VS showed comparable tumor control, hearing preservation, facial nerve preservation, and trigeminal nerve preservation.