Efficacy and safety of single-fraction radiosurgery in vestibular schwannoma: a 10-year experience

PURPOSE: This study aimed to evaluate long-term tumor control, safety, and prognostic factors following single-fraction stereotactic radiosurgery (SRS) for vestibular schwannoma (VS). MATERIALS AND METHODS: In this retrospective single-institution study, 68 patients with VS were treated with photon-based single-fraction SRS (mean dose, 13.1 Gy; range, 12 to 15 Gy). Treatment planning was based on computed tomography-magnetic resonance imaging (MRI) fusion with organ-at-risk sparing and a planning target volume margin of 0-2 mm. The primary endpoint was local control (LC). Secondary endpoints included toxicity and predictors of treatment failure. RESULTS: After a median follow-up of 68 months, LC was maintained in 95.6% of patients. Actuarial LC rates at 5 and 10 years were both 98.5%. MRI showed tumor shrinkage in 41.2% and stability in 57.4% of cases. Treatment was well tolerated. Acute adverse events were infrequent and mild. Localized alopecia occurred acutely in one patient (1.5%) and did not persist into late follow-up. Vertigo and tinnitus were analyzed as disease-related symptoms rather than treatment-related toxicities. Severe toxicity (grade ≥ 3) was rare (<3%). Cox regression revealed no statistically significant predictors of local failure, though trends suggested higher risk after prior surgery and with doses ≥14 Gy. CONCLUSION: Single-fraction SRS provides durable long-term LC of VS with a favorable toxicity profile, supporting its role as a primary treatment modality. Optimal outcomes appear to be associated with lower prescription doses (<14 Gy) and treatment of de novo tumors.