Hearing loss in acoustic neuromas following stereotactic radiotherapy

Background: Hearing preservation is a major concern in the management of acoustic neuroma (AN), whether treated by surgery or radiation or followed conservatively. Objective: To assess the change in hearing in patients who underwent radiotherapy for ANs and to compare it with data from conservatively managed patients. Design: Prospective case series. Setting: Neuro-otology, neurosurgery, and radiation oncology practices in tertiary care hospitals of the University Health Network, University of Toronto. Patients and Methods: Between 1991 and 1999, 32 patients who underwent radiotherapy were followed prospectively. Seventeen patients had pretreatment measurable hearing and a minimum 1-year follow-up. Twelve of these patients underwent Gamma Knife radiation and five had fractionated radiation therapy with a linear accelerator. Pre- and post-treatment hearing was classified according to the Gardner-Robertson (GR) classification and according to the 1995 guidelines of the American Academy of Otolaryngology-Head and Neck Surgery Committee on Hearing and Equilibrium (AAO-HNS CHE). Outcome Measure: Change in hearing post-treatment. Results: Mean follow-up was 48 months. Deterioration in the level of hearing was observed in 8 and 11 of the patients using the AAO-HNS CHE and the GR classifications, respectively. Forty-four to 70% of the patients had lost their pretreatment serviceable hearing, depending on the classification of hearing used and how serviceable hearing was defined. Compared with series of patients followed conservatively in our institution and in other studies, patients who receive stereotactic radiation appear to lose hearing at least at the same rate. Conclusion: Our data suggest that hearing loss continues to occur despite radiotherapy, and patients should be advised accordingly.