Stereotactic Radiosurgery and Radiotherapy for Vestibular Schwannoma in NF2‐Related Schwannomatosis.

Objectives: To determine the long‐term control rates and hearing outcomes for growing vestibular schwannoma in NF2‐related schwannomatosis (NF2) treated with stereotactic radiosurgery (SRS) and fractionated radiotherapy (FRT). Methods: Retrospective review of all patients treated with SRS/FRT between 1986 and2021 from a tertiary NF2 unit. Overall tumor control was defined as: (1) growth control (growth failure was defined as growth in any dimension of 3 millimetres or more from baseline post‐SRS/FRT), and (2) treatment control (no need for further intervention). Loss of serviceable hearing was defined as a drop in speech discrimination score below 50% after SRS/FRT. Results: There were 81 cases, with a mean duration of follow‐up of 125 months. Overall control rate was 72% (58/81), with 80% (65/81) growth control and 74% (60/81) treatment control. There was a 5‐year actuarial survival of 77% and 10‐year survival of 71%. Forty‐three percent (30/69) of cases did not have serviceable hearing at baseline. Of those remaining, 49% (19/39) preserved serviceable hearing during follow‐up at a mean of 106 months. Actuarial survival for preservation of serviceable hearing at 5 and 10 years was 69% and 53%. There were poorer outcomes with increasing genetic severity, and with baseline tumor size >3 cm. No cases of SRS/FRT‐related malignancy were identified at a mean follow‐up of 10 years. Conclusion: Stereotactic radiosurgery/fractionated radiotherapy are an effective option to treat growing vestibular schwannoma in patients with NF2 with the potential for hearing preservation in a proportion of patients. Level of Evidence: 4—Case Series Laryngoscope, 134:2364–2371, 2024 [ABSTRACT FROM AUTHOR]