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