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 neurofibromatosis Type 2 (NF2) patients .

METHODS: A series of 35 consecutive patients with 99 meningiomas in our department were retrospectively included from Jan 2000 to Dec 2015. Clinical records, MR image and follow-up data were reviewed.

RESULTS: A total of 35 patients(25 females and 10 males) with 99 NF2-associated meningiomas were identified. All patients were initially received GKRS. The patients' median age at the time of GKRS was 40 years, ranged from 16 to 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, ranged from 25 to 224 months.29patients received GKRS only once and 6 patients received multiple times. Six patients (17.1%) had radiation-related complications7.5±2.4 months after GKRS. Local control rates at 1,3 and 5 years was 100 %, 97.1 % and 90.6% respectively. Distant control rates at 1,3 and 5 years was 88.5 %,55.9 % and 45.5% respectively. Five patients died of concomitant neurological 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 high local control rate of NF2- associated meningiomas by GKRS, though, the distant control rate is low, especially in young patients. For these patients, retreatment with GKRS may still be the advisable method.