Active surveillance versus stereotactic radiosurgery for Koos grade I and II vestibular schwannoma in patients aged 60 years or older

OBJECTIVE: The aim of this study was to evaluate freedom from tumor progression and clinical outcomes in older adults with small- to medium-sized vestibular schwannoma (VS) managed by observation versus stereotactic radiosurgery (SRS) to better inform optimal management in this patient population. METHODS: In this international multicenter study, patients aged ≥ 60 years with Koos grade I or II VS managed by observation or SRS were retrospectively reviewed. Propensity score matching was conducted using patient characteristics, tumor size, and hearing assessments. Outcome measures of freedom from tumor progression, serviceable hearing preservation (SHP), and neurological function (tinnitus, vestibulopathy, House-Brackmann grade, and trigeminal nerve function) were assessed for both groups. RESULTS: The observation and SRS groups each comprised 51 matched patients (median age 68 years for both). Ipsilateral serviceable hearing was observed at presentation for 35 patients in each group. The median follow-up duration was 39 months in the observation group versus 27 months in the SRS group (p = 0.5). Tumor progression was significantly lower with SRS than with observation (2% vs 52.9%, p < 0.001). The rate of 5-year freedom from tumor progression was 100% in the SRS group versus 43% (95% CI 29%-64%) in the observation group. The rate of 10-year freedom from tumor progression was 90% (95% CI 73%-100%) in the SRS group versus 20% (95% CI 8.5%-49%) in the observation group. At the last follow-up, hearing loss occurred in 42.9% of the observation group and 51.4% of those who underwent SRS (p = 0.5). The 3-year SHP rate was 68% (95% CI 53%-88%) versus 65% (95% CI 49%-85%) (p = 0.8), and the 5-year SHP rate was 53% in both groups (95% CI 36%-78% in the observation group and 95% CI 35%-79% in the SRS group, p = 0.8). The composite endpoint of tumor progression and/or worsened neurological outcome, including hearing loss, tinnitus, vestibulopathy, facial nerve dysfunction (House-Brackmann grade), or trigeminal dysfunction, demonstrated a significantly lower rate in the SRS group (17.6%) compared with the observation group (66.7%) (p < 0.001). CONCLUSIONS: SRS in older patients for management of Koos grade I or II VS resulted in significantly superior rates of freedom from tumor progression, comparable hearing preservation rates, and significantly higher rates of favorable overall radiographic and neurological outcomes than observation alone. Compared with observation, SRS might be the preferred management option in this patient population.