title: Stereotactic radiosurgery for acoustic neuromas: what happens long term?
abstract: OBJECTIVE
  To determine the clinical outcomes for acoustic neuroma treated with low-dose linear accelerator stereotactic radiosurgery (SRS) >10 years earlier at the Royal Adelaide Hospital using data collected prospectively at a dedicated SRS clinic.
  
  
  METHODS
  Between November 1993 and December 2000, 51 patients underwent SRS for acoustic neuroma. For the 44 patients with primary SRS for sporadic (unilateral) lesions, the median age was 63 years, the median of the maximal tumor diameter was 21 mm (range, 11-34), and the marginal dose was 14 Gy for the first 4 patients and 12 Gy for the other 40.
  
  
  RESULTS
  The crude tumor control rate was 97.7% (1 patient required salvage surgery for progression at 9.75 years). Only 8 (29%) of 28 patients ultimately retained useful hearing (interaural pure tone average ≤50 dB). Also, although the Kaplan-Meier estimated rate of hearing preservation at 5 years was 57% (95% confidence interval, 38-74%), this decreased to 24% (95% confidence interval, 11-44%) at 10 years. New or worsened V and VII cranial neuropathy occurred in 11% and 2% of patients, respectively; all cases were transient. No case of radiation oncogenesis developed.
  
  
  CONCLUSIONS
  The long-term follow-up data of low-dose (12-14 Gy) linear accelerator SRS for acoustic neuroma have confirmed excellent tumor control and acceptable cranial neuropathy rates but a continual decrease in hearing preservation out to ≥10 years.
authors.affiliation: Department of Radiation Oncology, Royal Adelaide Hospital, Adelaide, South Australia, Australia. daniel.roos@health.sa.gov.au
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Roos
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Potter
authors.forename: Brian P
authors.initials: BP
authors.lastname: Brophy
mesh_terms: D000328:Adult; D000368:Aged; D016001:Confidence Intervals; D005155:Facial Nerve Diseases / Q000209:etiology*; D005260:Female; D006309:Hearing / Q000502:physiology / Q000528:radiation effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016609:Neoplasms, Second Primary / Q000473:pathology; D009464:Neuroma, Acoustic / Q000473:pathology / Q000601:surgery*; D011446:Prospective Studies; D016634:Radiosurgery / Q000009:adverse effects; D011879:Radiotherapy Dosage; D016879:Salvage Therapy; D013997:Time Factors; D016896:Treatment Outcome; D020433:Trigeminal Nerve Diseases / Q000209:etiology*; D047368:Tumor Burden