Vestibular Schwannoma Koos Grade II International Study of Active Surveillance Versus Stereotactic Radiosurgery: The VISAS-K2 Study

Abstract

BACKGROUND AND OBJECTIVES:This study assessed the efficacy and safety of stereotactic radiosurgery (SRS) in comparison with watchful waiting for managing Koos grade II vestibular schwannomas (VS).METHODS:A retrospective, multicentric analysis was conducted, focusing on patients with Koos grade II VS who either received SRS (SRS group) or were observed (observation group). To ensure comparability between groups, propensity score matching was used, including factors such as demographic characteristics, tumor dimensions, and hearing assessments. The primary end points examined were tumor control, maintenance of serviceable hearing, and neurological outcomes.RESULTS:A total of 92 patients were equally matched across both cohorts, with a median follow-up of 37 months for the SRS group and 27.5 months for those observed. The SRS cohort exhibited superior tumor control over observation across 3, 5, and 8 years, achieving a 100% control rate vs 47.9%, 40.1%, and 34.3% for the observation group at these time intervals, respectively (P