Tumor Growth and Hearing Changes in the Natural Progress of Vestibular Schwannoma

Background and Objectives Vestibular schwannoma is a benign neoplasm originating from the vestibular nerve, and the most common symptom caused by the tumor is unilateral hearing loss. This study is aimed to review the clinical outcomes of tumor growth and hearing changes in the natural progress of vestibular schwannoma. Subjects and Method We retrospectively reviewed 28 patients who were diagnosed with vestibular schwannoma and treated with the ‘wait and scan’ modality for more than a year. We analyzed the patients’ audiological changes and tumor growth by reviewing the temporal bone MR images. Patients were classified into an intrameatal group and extrameatal group according to the involvement of the cerebropontine angle. Results The overall mean follow-up was 45.6±25.8 months. Among the 28 patients, 6 (21.4%) showed tumor growth after ‘wait and scan.’ Hearing thresholds and speech discrimination scores showed deterioration after ‘wait and scan’ in both groups. Among the 12 patients with serviceable hearing at initial diagnosis, 9 (75.0%) preserved serviceable hearing after ‘wait and scan.’ When the pure tone average and speech discrimination scores were applied to the scattergram, most values were positioned near the center of the scattergram, which implied slight changes after ‘wait and scan.’ Conclusion The percentage of patients showing tumor growth after the ‘wait and scan’ policy was low. Patients with serviceable hearing at diagnosis would most likely preserve their hearing after ‘wait and scan.’ Considering the limited tumor growth and minimal hearing changes, rather than microsurgery or radiation surgery, the conservative ‘wait and scan’ policy can be an alternative treatment modality in patients with small-sized, non-growing vestibular schwannomas. Key words: Growth ㆍ Hearing ㆍ Observation ㆍ Vestibular schwannoma