title: Long-term hearing outcomes following stereotactic radiosurgery for vestibular schwannoma: patterns of hearing loss and variables influencing audiometric decline.
abstract: OBJECTIVE
  The goals of this retrospective cohort study were as follows: 1) to describe the long-term prevalence and timing of hearing deterioration following low-dose (12- to 13-Gy marginal dose) stereotactic radiosurgery (SRS) for vestibular schwannoma (VS); and 2) to identify clinical variables associated with long-term preservation of useful hearing following treatment.
  
  
  METHODS
  Patients with serviceable hearing who underwent SRS for VS between 1997 and 2002 were studied. Data including radiosurgery treatment plans, tumor characteristics, pre- and posttreatment pure tone average, speech discrimination scores, and American Academy of Otolaryngology-Head and Neck Surgery hearing class were collected. Time to nonserviceable hearing was estimated using the Kaplan-Meier method. Univariate and multivariate associations with time to nonserviceable hearing were evaluated using Cox proportional hazards regression models.
  
  
  RESULTS
  Forty-four patients met the study criteria and were included. The median duration of audiometric follow-up was 9.3 years. Thirty-six patients developed nonserviceable hearing at a mean of 4.2 years following SRS. The Kaplan-Meier estimated rates of serviceable hearing at 1, 3, 5, 7, and 10 years following SRS were 80%, 55%, 48%, 38%, and 23%, respectively. Multivariate analysis revealed that pretreatment ipsilateral pure tone average (p < 0.001) and tumor size (p = 0.009) were statistically significantly associated with time to nonserviceable hearing.
  
  
  CONCLUSIONS
  Durable hearing preservation a decade after low-dose SRS for VS occurs in less than one-fourth of patients. Variables including preoperative hearing capacity and tumor size may be used to predict hearing outcomes following treatment. These findings may assist in pretreatment risk disclosure. Furthermore, these data demonstrate the importance of long-term follow-up when reporting audiometric outcomes following SRS for VS.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic School of Medicine, Rochester, Minnesota 55905, USA.
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Carlson
authors.forename: Jeffrey T
authors.initials: JT
authors.lastname: Jacob
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Pollock
authors.forename: Brian A
authors.initials: BA
authors.lastname: Neff
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Tombers
authors.forename: Colin L W
authors.initials: CL
authors.lastname: Driscoll
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Link
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001299:Audiometry; D003051:Cochlea / Q000528:radiation effects; D018450:Disease Progression; D005260:Female; D006309:Hearing / Q000528:radiation effects*; D034381:Hearing Loss / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D006320:Hearing Tests; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000601:surgery*; D011379:Prognosis; D016016:Proportional Hazards Models; D016634:Radiosurgery / Q000009:adverse effects* / Q000379:methods; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome