CyberKnife Stereotactic Radiosurgery for Growing Vestibular Schwannoma: Longitudinal Tumor Control, Hearing Outcomes, and Predicting Post-Treatment Hearing Status

Laryngoscope. 2024 Jan:134 Suppl 1:S1-S12. doi: 10.1002/lary.30731. Epub 2023 May 13.

Abstract

Objectives: (1) To determine tumor control rates for treating growing vestibular schwannoma (VS) with CyberKnife stereotactic radiosurgery (CK SRS); (2) to determine hearing outcomes after CK SRS; (3) to propose a set of variables that could be used to predict hearing outcomes for patients receiving CK SRS for VS.

Study design: Retrospective case series review.

Methods: 127 patients who received CK SRS for radiographically documented growing VS were reviewed. Tumors were monitored for post-procedure growth radiographically with linear measurements and three-dimensional segmental volumetric analysis (3D-SVA). Hearing outcomes were reviewed for 109 patients. Cox proportional hazard modeling was used to identify variables correlated with hearing outcomes.

Results: Tumor control rate was 94.5% for treating VS with CK SRS. Hearing outcomes were categorized using the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) classification system. As of their last available audiogram, 33.3% of patients with pre-treatment class A and 26.9% of patients with class B retained their hearing in that class. 15.3% of patients starting with class A or B with extended follow-up (>60 months), maintained hearing within this same grouping. Our final model proposed to predict hearing outcomes included age, fundal cap distance (FCD), tumor volume, and maximum radiation dose to the cochlea; however, FCD was the only statistically significant variable.

Conclusion: CK SRS is an effective treatment for control of VS. Hearing preservation by class was achieved in a third of patients. Finally, FCD was found to be protective against hearing loss.

Level of evidence: 4 Laryngoscope, 134:S1-S12, 2024.

Keywords: hearing; hearing preservation; prediction; radiosurgery; stereotactic; treatment outcomes; vestibular schwannoma.

MeSH terms

  • Follow-Up Studies
  • Hearing
  • Hearing Loss* / etiology
  • Hearing Loss* / prevention & control
  • Hearing Loss* / surgery
  • Humans
  • Neuroma, Acoustic* / radiotherapy
  • Neuroma, Acoustic* / surgery
  • Radiosurgery* / adverse effects
  • Radiosurgery* / methods
  • Retrospective Studies
  • Treatment Outcome