CyberKnife radiosurgery for acoustic neuromas: Tumor control and clinical outcomes

J Clin Neurosci. 2019 May:63:72-76. doi: 10.1016/j.jocn.2019.01.046. Epub 2019 Feb 12.

Abstract

Fractionated CyberKnife radiosurgery (CKRS) treatment for acoustic neuromas may reduce the risk of long-term radiation toxicity to nearby critical structures compared to that of single-fraction radiosurgery. However, tumor control rates and clinical outcomes after CKRS for acoustic neuromas are not well described. We retrospectively reviewed all acoustic neuroma patients treated with CKRS (2004-2011) in a prospectively maintained clinical and radiographic database. Treatment failure, the need for additional surgical intervention, was evaluated using Kaplan-Meier analysis. For 119 treated patients, median values were 49 months (range, 6-133 months) of follow-up, 1.6 cm3 (range, 0.02-17 cm3) tumor volume, and 18 Gy (range, 13-25 Gy) prescribed dose delivered in 3 fractions (range, 1-5 fractions). Thirty-five of 59 patients (59%) with pre-radiosurgery serviceable hearing (American Academy of Otolaryngology-Head and Neck Surgery class A or B) maintained serviceable hearing at the last audio follow-up (median, 21 months). Two of 111 patients (2%) with facial nerve function House-Brackmann (HB) grade ≤3 progressed to HB grade >3 after radiosurgery. Koos grade IV was predictive of radiographic tumor growth after radiosurgery compared to grades I to III (p = 0.02). Treatment failure occurred in 9 of 119 patients (8%); median time to failure was 29 months (range, 4-70 months). The actuarial rates of tumor control at 1, 3, 5, and 7 years were 96%, 94%, 88%, and 88%, respectively. CKRS affords effective tumor control for acoustic neuromas with an acceptable rate of hearing preservation. Further studies are needed to compare CKRS to single-fraction radiosurgery for acoustic neuromas.

Keywords: Acoustic neuroma; CyberKnife; Progression-free survival; Radiosurgery; Tumor; Vestibular schwannoma.

MeSH terms

  • Child
  • Child, Preschool
  • Hearing
  • Humans
  • Infant
  • Neuroma, Acoustic / radiotherapy*
  • Neuroma, Acoustic / surgery
  • Postoperative Complications / epidemiology*
  • Radiosurgery / adverse effects*
  • Radiosurgery / methods
  • Survival Analysis