title: Audiometric outcomes for acoustic neuroma patients after single versus multiple fraction stereotactic irradiation.
abstract: OBJECTIVE
  To compare tumor control and changes in audiometric parameters of acoustic neuroma patients treated with either linac-based stereotactic radiosurgery (SRS) or stereotactic radiotherapy (SRT) at Allegheny General Hospital.
  
  
  METHODS
  Twenty-three patients with acoustic neuroma were treated between February 2003 and April 2009 with either SRS (n = 13) or SRT (n = 10). The median age for all patients was 69 years and the median size of lesions was 1.2 cm (range 0.5-2.2 cm). The prescribed dose was a single dose of 1250 cGy for all SRS patients compared to 2500 cGy in 5 daily fractions for SRT patients. All patients had pre- and post-procedure audiometry including hearing acuity assessed using pure tone average (PTA), speech discrimination score (SDS), and speech reception threshold (SR). The results of treatment type and tumor variables resulting in hearing degradation were evaluated and compared.
  
  
  RESULTS
  At a median follow-up of 13 months (range 3-36 months), only 1 of 13 patients treated with SRS and 2 of 10 patients treated with SRT develped progression of disease. However; all patients developed deterioration in PTA, SDS, or SR on the treated side. There were no statistically significant audiometric differences between patients treated with SRT or SRS and tumor response was similar regardless of irradiation technique.
  
  
  CONCLUSIONS
  Both SRS and SRT provide excellent local control rates for the treatment of acoustic neuroma. While SRS demonstrated a trend toward worsening of SDS and the treatment of lesions >1.2 cm demonstrated a trend toward worsening of PTA, neither reached statistical significance. Our data suggest that single dose irradiation using the SRS technique should be considered primarily for patient convenience. All patients treated with radiotherapy for acoustic neuromas should undergo formal hearing testing before and after treatment.
authors.affiliation: Department of Radiation Oncology, Allegheny General Hospital, Pittsburgh, PA 15212, USA.
authors.forename: Woodrow
authors.initials: W
authors.lastname: McWilliams
authors.forename: Mark
authors.initials: M
authors.lastname: Trombetta
authors.forename: E Day
authors.initials: ED
authors.lastname: Werts
authors.forename: Russell
authors.initials: R
authors.lastname: Fuhrer
authors.forename: Todd
authors.initials: T
authors.lastname: Hillman
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001299:Audiometry; D001301:Audiometry, Pure-Tone; D003390:Cranial Nerve Neoplasms / Q000473:pathology / Q000601:surgery*; D018450:Disease Progression; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005500:Follow-Up Studies; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000473:pathology / Q000601:surgery*; D016634:Radiosurgery / Q000379:methods*; D013067:Speech Perception; D013069:Speech Reception Threshold Test; D016896:Treatment Outcome; D000160:Vestibulocochlear Nerve Diseases / Q000473:pathology / Q000601:surgery*