title: Linear accelerator radiosurgery for vestibular schwannomas: Results of medium-term follow-up.
abstract: BACKGROUND
  To examine tumour control, via volume changes, and the complications of linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) treatment of vestibular schwannomas (VSs) on medium-term follow-up.
  
  
  METHODS
  Between September 2003 and November 2009 fifty consecutive patients with VSs treated with SRS using a marginal dose of 12.5 Gy utilizing a LINAC equipped with a micro-multileaf collimator were identified. Evaluation included serial magnetic resonance imaging (MRI), and neurological and hearing examinations.
  
  
  RESULTS
  The median tumour volume at treatment was 2.4 (range: 0.24-10.59) cm3. The intracranial diameter of the tumours ranged between 7.7 and 28.7 (median: 15.8) mm. Follow-up MRI was available for analysis on 49 patients. The median radiological follow-up period was 5.8 (range: 1.4-9.2) years. The median tumour volume at last follow-up was 1.1 (range: 0.03-5.3) cm3. VS decreased in size in 45 (90%) patients, with a median reduction in tumour volume of 1.46 (range: 0.06-9.29) cm3 or a median tumour size reduction of 59% of the baseline (range: 6-90%) in these patients. VS remained stable in 2 patients and increased in size in 2 patients. Only 1 patient (2%) required additional intervention (surgery). 15 patients had useful hearing pre-treatment; 10 post-treatment pure-tone audiograms of these patients were available. 5 (50%) patients still had useful hearing post treatment. Non-auditory adverse radiation effects included new (House-Brackmann grade II) or worsened facial nerve palsy (House-Brackmann grade II to grade V) in 2 (4%) patients and trigeminal sensory disturbance in 2 (4%) patients.
  
  
  CONCLUSIONS
  At medium term, the vast majority of VSs treated with LINAC-based SRS exhibit tumour shrinkage. The slightly higher rate of facial nerve palsy compared with Gamma Knife surgery (GKS) results may be related to the learning curve. Other complications were similar to reported GKS results for VSs of comparable sizes.
authors.affiliation: a Department of Neurosurgery , The Walton Centre for Neurology & Neurosurgery NHS Foundation Trust , Liverpool , UK.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Ellenbogen
authors.affiliation: b School of Medicine, University of Liverpool , Liverpool , UK.|c Institute of Ageing and Chronic disease, University of Liverpool , Liverpool , UK.
authors.forename: Mueez
authors.initials: M
authors.lastname: Waqar
authors.affiliation: d Department of Otolaryngology and Head & Neck Surgery , Aintree University Hospitals NHS Foundation Trust, Longmoor Lane , Liverpool , UK.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Kinshuck
authors.affiliation: a Department of Neurosurgery , The Walton Centre for Neurology & Neurosurgery NHS Foundation Trust , Liverpool , UK.|c Institute of Ageing and Chronic disease, University of Liverpool , Liverpool , UK.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Jenkinson
authors.affiliation: d Department of Otolaryngology and Head & Neck Surgery , Aintree University Hospitals NHS Foundation Trust, Longmoor Lane , Liverpool , UK.
authors.forename: Tristram H J
authors.initials: TH
authors.lastname: Lesser
authors.affiliation: e Clatterbridge Cancer Centre NHS Foundation Trust , Wirral , UK.
authors.forename: David
authors.initials: D
authors.lastname: Husband
authors.affiliation: f Department of Neurosurgery , Beaumont Hospital , Dublin 9 , Ireland.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Javadpour
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001301:Audiometry, Pure-Tone; D004428:Ear Neoplasms / Q000473:pathology / Q000601:surgery*; D020220:Facial Nerve Injuries / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009442:Neurilemmoma / Q000601:surgery*; D011183:Postoperative Complications / Q000453:epidemiology; D011829:Radiation Dosage; D016634:Radiosurgery / Q000379:methods*; D012086:Reoperation / Q000706:statistics & numerical data; D016896:Treatment Outcome; D014722:Vestibule, Labyrinth / Q000473:pathology / Q000601:surgery*; D055815:Young Adult
keywords: linear accelerator; stereotactic radiosurgery; vestibular schwannoma