Hearing outcomes between multi-session and single-session radiosurgery for vestibular schwannoma: a single center study

Abstract

Background: Hearing preservation rate after Gamma Knife radiosurgery (GKRS) for vestibular schwannoma (VS) remains low. The aim of this study was to study hearing outcomes between multisession and single session GKRS in patients with VS and determine prognostic factors associated with hearing preservation. Methods: A retrospective analysis of 561 consecutive patients with VS subjected to multisession (74 patients) or single session (487 patients) GKRS (from June 2011 to April 2015) was performed. Propensity score matching (PSM) based on patient age, gender, tumor volume and pre-GKRS hearing was used to compare the two groups. The tumor control rate and complications were evaluated, especially hearing preservation and its prognostic factors. Results: According to PSM, 29 patients from each group with similar characteristics were selected for the study. Patients’ age, tumor volume, pre-GKRS pure tone average (PTA) and radiographic follow-up period were not significantly different between the two groups (P>0.05). The tumor control rate was 75.9% for the multisession group compared with 62.1% for the single session group (P=0.1142); 20 patients had a less than 20 dB change in PTA in multisession group, with the hearing preservation rate of 69.0% (20/29) compared with 65.5% (19/29) in single session group (P=0.08). Multivariate analysis revealed that linear internal auditory canal (IAC) length was the only significant predictor of hearing loss in the multisession group. At last follow-up, one patient complaining of sudden hearing loss was diagnosed with tumor bleeding 12 months after multisession GKRS. One patient from multisession group and two patients from single session group suffered from temporal facial numbness. Facial spasm developed in one patient after multisession GKRS. Conclusions: Our results supported that multisession GKRS could be an effective and safe treatment option for VS compared to single session GKRS. The hearing preservation rate after multisession GKRS was not superior to single session radiosurgery in our short-term follow-up study. However, patients with longer IAC length may benefit from multisession strategy in terms of hearing preservation.