title: Clinical evaluation of CyberKnife in the treatment of vestibular schwannomas.
abstract: OBJECTIVE
  This study assessed the posttreatment tumor control and auditory function of vestibular schwannoma (VS) patients after CyberKnife (CK) and analyzed the possible prognostic factors of hearing loss.
  
  
  METHODS
  We retrospectively studied 117 VS patients, with Gardner-Robertson (GR) classification grades I to IV, who underwent CK between 2006 and 2012. Data including radiosurgery treatment parameters, pre- and postoperative tumor size, and auditory function were collected and examined.
  
  
  RESULTS
  With CK, 117 patients had excellent tumor control rates (99.1%), with a mean imaging followup of 61.1 months. Excluding 52 patients (GR III-IV pretreatment), 53 (81.5%) of the remaining 65 patients (initial GR I-II) maintained GR I or II hearing after CK, with a mean audiometric followup of 64.5 months. Twelve patients experienced hearing degradation (91.6% were GR II pretreatment); they appeared to have significantly larger tumor sizes, significantly smaller cochlear sizes, and higher prescribed cochlear doses, compared to the patients with preserved hearing.
  
  
  CONCLUSIONS
  Our data showed that CK treatment provided an excellent tumor control rate and a comparable hearing preservation rate in VS patients. Patients with pretreatment GR II hearing levels, larger tumor volumes, smaller cochlear sizes, and higher prescribed cochlear doses may have poor hearing prognoses.
authors: Department of Radiation-Oncology, Taipei Medical University Wan-Fang Hospital, Taipei 110, Taiwan ; Department of Radiation-Oncology, Taipei Medical University Shuang-Ho Hospital, New Taipei City 23561, Taiwan.
authors: Jo-Ting
authors: JT
authors: Tsai
authors: Jia-Wei
authors: JW
authors: Lin
authors: Chien-Min
authors: CM
authors: Lin
authors: Yuan-Hao
authors: YH
authors: Chen
authors: Hsin-I
authors: HI
authors: Ma
authors: Yee-Min
authors: YM
authors: Jen
authors: Yi-Hsun
authors: YH
authors: Chen
authors: Da-Tong
authors: DT
authors: Ju
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003051:Cochlea / Q000503:physiopathology; D003710:Demography; D005260:Female; D006309:Hearing; D006801:Humans; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000503:physiopathology / Q000517:prevention & control / Q000601:surgery*; D016634:Radiosurgery; D016896:Treatment Outcome; D055815:Young Adult