Audiological Outcomes in Growing Vestibular Schwannomas Managed Either Conservatively, or With Stereotactic Radiosurgery

OBJECTIVE: Recent studies have suggested good hearing preservation following stereotactic radiosurgery (STRS) in patients with vestibular schwannomas (VS). This study aims to assess audiological outcomes in patients with growing VS treated either with STRS, or managed conservatively. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary referral center. PATIENTS: Out of 540 patients with VS, 69 patients with growing VS fulfilled the inclusion criteria; 24 treated conservatively and 45 with STRS. VS were considered growing if demonstrating more than 15% tumor volume increase during 1 year of watchful waiting. INTERVENTION: American Association of Otolaryngology-Head and Neck Surgery (AAOHNS) hearing threshold (dB averaged over 500-3000 Hz) deterioration and Gardner-Robertson class deterioration over time were used as the primary outcome measures. Rate of progression to loss of functional hearing (Gardner-Robertson class I-II) was also determined between cohorts. RESULTS: Mean follow-up was similar between treatment cohorts (STRS = 69.6 mo, conservative management = 71.7 mo). There was no significant difference in AAOHNS deterioration (t = 1.05, df = 53, p = 0.301) or Gardner-Robertson deterioration (χ = 0.47, df = 1, p = 0.492) between cohorts. Furthermore, rate of progression to loss of functional hearing was similar between cohorts (Hazard ratio = 0.704, 95% CI 0.287-1.728, p = 0.44). In STRS patients, AAOHNS deterioration was greater in those with lower AAOHNS thresholds at diagnosis (t = -2.683, df = 28, p = 0.0121). Similarly, Gardner-Robertson deterioration was significantly more likely in STRS patients with functional hearing (Gardner-Robertson class I-II) (Adjusted odds ratio = 32.14, 95% CI 3.15-328, p = 0.0034). CONCLUSIONS: STRS results in similar audiological outcomes compared with patients managed conservatively; Consequently, STRS given to patients with VS to preserve hearing is not justified. In contrast to recent studies, patients with preserved hearing at diagnosis have significantly greater audiological deterioration when undergoing STRS.