Early results with hypofractionated gamma knife radiotherapy for treatment of vestibular schwannoma

Objective

Vestibular schwannoma (VS) management with stereotactic radiation previously only included stereotactic radiosurgery with Gamma Knife (GKRS) or LINAC-based radiotherapy (LBR). Hypofractionated Gamma Knife radiotherapy (hfGKRS) is a novel protocol potentially producing less toxicity than the alternatives. This study examines early results in tumor control, complications and hearing preservation outcomes in a consecutive series of VS patients treated with hfGKRS.

Study design

A retrospective review was conducted for all patients with unilateral VS treated with primary hfGKRS at an academic center between 2017 and 2023.

Setting

Tertiary referral center.

Interventions

Therapeutic.

Main outcome measures

Pre- and post-treatment imaging, notes and audiograms were analyzed. Tumor volumes were tabulated. Audiometric data recorded were pure-tone average (PTA), word recognition score (WRS), and speech reception threshold (SRT). Collected data included tinnitus, imbalance, House-Brackmann score, and facial spasms. Outcomes obtained were compared to literature controls of GKRS and LBR.

Results

Twenty-five hfGKRS cases were identified. Mean tumor volume was 1.79 cm³ (range 0.14–9.29cm³). Mean patient follow-up was 28 months (range 6–86 months). Pre-treatment versus post-treatment hearing results were: PTA 62.9 dB versus 68.6 dB, WRS 40 % versus 30.8 % and SRT 33.1 dB versus 34.1 dB. The tumor control was 96 % and hearing was preserved in 80 % of patients with pre-treatment serviceable hearing. hfGKRS complications included tinnitus (12.5 %), dizziness (12.5 %), facial pain (8 %), and facial spasms (4 %).

Conclusion

Short term results for VS treated with hfGKRS had high rates of tumor control, favorable hearing results and comparable complication rates to literature reports for GKRS and LBR. Further follow-up is needed to adequately evaluate long-term outcomes of hfGKRS in tumor control, toxicity and hearing results in order to compare this technique with GKRS and LBR. However, these results support further evaluation of hfGKRS as a potential technique to improve outcomes in stereotactic radiation treatment of VS.