The Role of Salvage Stereotactic Radiosurgery in the Management of Progressed Vestibular Schwannomas Following Microsurgical Resection

Introduction: Stereotactic radiosurgery (SRS) is an established management strategy for vestibular schwannoma (VS). While the use of SRS as primary or adjuvant modality for VS has been extensively studied, data on its role as a salvage approach after VS progression/recurrence following surgical resection is largely lacking. The aim of this study is to determine the safety and efficacy of salvage SRS for tumor progression/recurrence following surgical resection of VS and to elucidate the factors influencing tumor control and freedom from additional treatment (FFAT).

Methods: Patients with VS who underwent microsurgical resection followed by salvage SRS for progressed or recurrent tumor were retrospectively reviewed. A total of 64 patients were identified and analyzed. The median patient age at time of SRS was 51.5 years and 30 (47.9%) were males. The median marginal dose was 12.5 at a median isodose of 50%. Hearing outcomes were measured using Gardner-Robinson scores.

Results: Among the 64 patients, the 10- and 15-year tumor control rates following salvage SRS were 90%, and 87.5%, respectively, while the 10- and 15-year FFAT rates were 92.5% and 90%, respectively. None of the studied factors were significantly associated with tumor control or FFAT in Cox or logistic models. The median time between microsurgical resection and salvage SRS was 38.8 months. Following SRS, the primary complication was worsening or new onset trigeminal neuropathy (n=10, 15.7%) while worsening hearing were reported in 9 cases (14%). Of the cohort, 32.8% experienced tumor regression, 51.5% had stable disease, and 15.7% showed tumor progression. Among the cases with progression after SRS, management strategies included repeat SRS for four patients, surgical resection for one patient, while others opted for monitoring or were lost to follow-up.

Conclusion : Salvage SRS is a safe and effective option for managing progressed or recurrent vestibular schwannomas following microsurgery Salvage SRS was associated with high tumor control and FFAT rates. Careful patient selection and continuous monitoring are essential. Further large-scale studies are needed to validate these findings and assess factors influencing outcomes and complications.