The Influence of Vestibular Schwannoma Tumor Volume and Growth on Hearing Loss

Objective: To ascertain the relationship among vestibular schwannoma (VS) tumor volume, growth, and hearing loss. Study Design: Retrospective cohort study. Setting: Single tertiary center. Subjects and Methods: Adults with observed VS and serviceable hearing at diagnosis were included. The primary outcome was the development of nonserviceable hearing as estimated using the Kaplan-Meier method. Associations of tumor volume with baseline hearing were assessed using Spearman rank correlation coefficients. Associations of volume and growth with the development of nonserviceable hearing over time were assessed using Cox proportional hazards models and summarized with hazard ratios (HRs). Results: Of 230 patients with VS and serviceable hearing at diagnosis, 213 had serial volumetric tumor data for analysis. Larger tumor volume at diagnosis was associated with increased pure-tone average (PTA) (P <.001) and decreased word recognition score (WRS) (P =.014). Estimated rates of maintaining serviceable hearing at 6 and 10 years following diagnosis were 67% and 49%, respectively. Larger initial tumor volume was associated with development of nonserviceable hearing in a univariable setting (HR for 1-cm³ increase: 1.36, P =.040) but not after adjusting for PTA and WRS. Tumor growth was not significantly associated with time to nonserviceable hearing (HR, 1.57; P =.14), although estimated rates of maintaining serviceable hearing during observation were poorer in the group that experienced growth. Conclusion: Larger initial VS tumor volume was associated with poorer hearing at baseline. Larger initial tumor volume was also associated with the development of nonserviceable hearing during observation in a univariable setting; however, this association was not statistically significant after adjusting for baseline hearing status.