Duke, Simon

Objective: To characterize patient outcomes after primary stereotactic radiosurgery (SRS) for the management of sporadic facial nerve schwannoma. Study design: Retrospective cohort study. Setting: Six tertiary referral centers across the United States and United Kingdom. Patients: Adults undergoing SRS from 2000 through 2023 for sporadic facial nerve schwannoma along any segment of the facial nerve were included. Patients with NF2-related schwannomatosis were excluded. Intervention: Stereotactic radiosurgery. Main outcome measure: Long-term tumor control. Results: Among 60 patients meeting inclusion, the median age at SRS was 52 years (IQR: 41 to 64) with a median tumor size of 19.5 mm (IQR: 14.7 to 22.8). Tumors commonly involved the internal auditory canal (73%), cisternal (49%), geniculate/labyrinthine (47%), and tympanic segments (22%). Two patients experienced SRS failure and underwent salvage treatment; salvage-free survival rates (95% CI; number still at risk) at 1, 3, 5, and 10 years after SRS were 100% (100 to 100; 55), 100% (100 to 100; 36), 100% (100 to 100; 18), and 87% (72 to 100; 9), respectively. Among 31 (52%) patients with House-Brackmann (HB) grade I facial function at presentation, only 6 demonstrated worse facial function at a median of 3.2 years (IQR: 1.7 to 6.6) after SRS. Of 18 patients with serviceable hearing (AAO-HNS class A/B) at SRS, 13 maintained serviceable hearing at a median of 1.0 years (IQR: 0.5 to 4.9) of post-SRS audiometric follow-up. Conclusions: Durable tumor control after primary SRS for sporadic facial nerve schwannoma is achieved in most patients. Among those with HB grade I facial function at presentation, treatment with SRS harbors limited additional risk of facial paresis beyond observation alone.

Importance In the literature, there is a lack of data reporting tumor control rates after radiotherapy in actively growing vestibular schwannomas (VS). Data for this rarely studied population are needed. Objective To estimate tumor control rates in radiologically growing VS treated with first-line radiotherapy. Design, Setting, and Participants This international, multicenter cohort study used prospectively collected data from patients with growing unilateral VS treated first-line with radiotherapy between January 2000 and December 2023 from 8 tertiary referral skull base units. The data were analyzed in June 2025. Exposures Radiotherapy as an initial treatment for VS. Main Outcomes and Measures The primary outcome was treatment failure, ie VS growth postradiotherapy, which was predefined as an increase in maximum intracranial tumor diameter (ICTD) of 3 mm or greater within the first 2 years after radiotherapy or 2 mm or greater thereafter. Secondary outcomes were treatment failure based on different definitions of VS growth: (1) an increase in ICTD of 2 mm or greater, (2) an increase in ICTD of 3 mm or greater, and (3) conversion to surgery. Results A total of 1883 patients (975 female individuals [51.8%]; median age at diagnosis, 63 years [IQR, 53-71 years]) were included in the study. Using the primary definition of treatment failure (an increase in ICTD of ≥3 mm within the first 2 years postradiotherapy or ≥2 mm thereafter), the Kaplan-Meier estimate yielded a 10-year tumor control rate of 76.1% (95% CI, 72.7%-79.2%). For secondary outcome definitions, 10-year tumor control rates were 60.1% (95% CI, 57.5%-64.3%) for an ICTD increase of 2 mm or greater, 78.3% (95% CI, 75.0%-81.2%) for an increase of 3 mm or greater, and 92.6% (95% CI, 90.4%-94.3%) for conversion to surgery. Neither pretreatment tumor size nor tumor location (intracanalicular vs extracanalicular) were significantly associated with treatment failure. Conclusions and Relevance The results of this cohort study provide tumor control outcomes for radiologically growing VS treated with radiotherapy using several clinically relevant definitions of growth. By focusing exclusively on this rarely isolated subgroup, the findings offer targeted data to potentially inform treatment expectations and future research.