KEY POINTS
- This retrospective multi-site single-institution study included 85 patients with vestibular schwannoma, with 36 treated using Gamma Knife radiosurgery and 49 using LINAC-based SRS between 2008 and 2017. Median follow-up was 27 months.
- All patients received single-fraction SRS. Gamma Knife treatment used 12.5 Gy prescribed to the 50% isodose line, while LINAC patients generally received 12 Gy; LINAC technique evolved during the study from frame-based treatment without margins to frameless VMAT-based radiosurgery.
- New vertigo developed in 1/28 Gamma Knife patients (3.6%) versus 2/31 LINAC patients (6.5%; p=0.785) among those without baseline vertigo. New gait disturbance occurred in 4/18 (22.3%) versus 4/26 (15.4%; p=1.000).
- New facial palsy occurred in 0/34 Gamma Knife patients versus 2/48 LINAC patients (4.2%; p=0.509). Both LINAC-associated facial palsies resolved by last follow-up.
- New tinnitus was uncommon, occurring in only 1 patient in each group: 7.7% of evaluable Gamma Knife versus 5.5% of LINAC patients without pretreatment tinnitus. A statistical difference emerged in multivariable modeling, but the authors considered the finding unlikely to be clinically meaningful given only two events.
- Tumor control was excellent: only 1/85 patients (1.2%) required further vestibular-schwannoma-directed intervention. No Gamma Knife patient required salvage treatment, while 1/49 LINAC patients (2.0%) underwent salvage surgery; overall freedom from additional intervention was 98.8%.
- Interpretation is limited by retrospective symptom assessment, only 85 patients, few toxicity events and changes in LINAC planning/immobilization over the study period. Hearing preservation and validated vestibular-schwannoma-specific quality-of-life instruments were also not consistently available.
CLINICAL TAKEAWAY
For appropriately selected vestibular schwannomas, these data support both Gamma Knife and modern LINAC SRS as reasonable options with excellent control and broadly comparable neurologic outcomes. The study supports platform flexibility rather than superiority of either technology.