Efficacy and Safety of Gamma Knife Radiosurgery for Meningiomas in Patients with Neurofibromatosis Type 2: A Long-Term Follow-Up Single-Center Study

OBJECTIVE: To explore the efficacy and safety of Gamma Knife radiosurgery (GKRS) for meningiomas in patients with neurofibromatosis type 2 (NF2). METHODS: A series of 35 consecutive patients with 99 meningiomas in our department were retrospectively included from January 2000 to December 2015. Clinical records, magnetic resonance images, and follow-up data were reviewed. RESULTS: A total of 35 patients (25 women and 10 men) with 99 NF2-associated meningiomas were identified. All patients initially received GKRS. The patients' median age at the time of GKRS was 40 years (range, 16-61 years). The median prescription dose at the tumor margin was 13 Gy (range, 12-15 Gy). The median follow-up time was 96 months (range, 25-224 months). Twenty-nine patients received GKRS only once, and 6 patients received it multiple times. Six patients (17.1%) had radiation-related complications 7.5 +/- 2.4 months after GKRS. Local control rates at 1, 3, and 5 years were 100%, 97.1%, and 90.6%, respectively. Distant control rates at 1, 3, and 5 years were 88.5%, 55.9%, and 45.5%, respectively. Five patients died of concomitant neurologic symptoms. No malignant transformation was observed during the follow-up periods in all 35 patients. CONCLUSIONS: GKRS represents an effective and safe management strategy with minimal invasion for patients with NF2-associated meningiomas. Our data showed a high local control rate of NF2-associated meningiomas by GKRS; however, the distant control rate is low, especially in young patients. For these patients, retreatment with GKRS may still be the advisable method.