Hearing preservation and tumour control after radiosurgery for NF2-related vestibular schwannomas

Abstract

Objectives: We analyzed the effects of stereotactic radiosurgery on tumour control and cranial nerve function in patients with vestibular schwannomas (VS) secondary to neurofibromatosis type 2 (NF2). Irradiation was performed with a Gamma Knife, model C equipped with a high-precision, robotized positioning system (APS).

Methodology: This study included 18 patients with 25 VSs secondary to NF2 that were treated from 2001 to 2010 with radiosurgery at our Gamma Knife Center. The radiosurgical procedure included high-resolution conformational dose-planning with multiple, small-diameter isocenters, a single-fraction, low-dose irradiation prescription, and highly accurate gamma rays delivery to the target with the APS.

Results: The median follow-up time was 4.4 y. For 16 tumours in 12 patients with available follow-up data, we observed an actuarial tumour control of 87.5% at 2 y and 80.2% at 5 y, based on the Kaplan-Meier method. No patient developed facial weakness. Serviceable hearing was preserved in 78% of cases. Patients treated for bilateral and unilateral tumours had similar outcomes.

Conclusions: Radiosurgery could control tumour growth and preserve hearing function and facial weakness in patients with VS secondary to NF2. The enhanced techniques of radiosurgical irradiation provided with the Gamma Knife model C have improved the results of this treatment alternative to microsurgery.