title: Conservative management or gamma knife radiosurgery for vestibular schwannoma: tumor growth, symptoms, and quality of life.
abstract: BACKGROUND
  There are few reports about the course of vestibular schwannoma (VS) patients following gamma knife radiosurgery (GKRS) compared with the course following conservative management (CM). In this study, we present prospectively collected data of 237 patients with unilateral VS extending outside the internal acoustic canal who received either GKRS (113) or CM (124).
  
  
  OBJECTIVE
  The aim was to measure the effect of GKRS compared with the natural course on tumor growth rate and hearing loss. Secondary end points were postinclusion additional treatment, quality of life (QoL), and symptom development.
  
  
  METHODS
  The patients underwent magnetic resonance imaging scans, clinical examination, and QoL assessment by SF-36 questionnaire. Statistics were performed by using Spearman correlation coefficient, Kaplan-Meier plot, Poisson regression model, mixed linear regression models, and mixed logistic regression models.
  
  
  RESULTS
  Mean follow-up time was 55.0 months (26.1 standard deviation, range 10-132). Thirteen patients were lost to follow-up. Serviceable hearing was lost in 54 of 71 (76%) (CM) and 34 of 53 (64%) (GKRS) patients during the study period (not significant, log-rank test). There was a significant reduction in tumor volume over time in the GKRS group. The need for treatment following initial GKRS or CM differed at highly significant levels (log-rank test, P < .001). Symptom and QoL development did not differ significantly between the groups.
  
  
  CONCLUSIONS
  In VS patients, GKRS reduces the tumor growth rate and thereby the incidence rate of new treatment about tenfold. Hearing is lost at similar rates in both groups. Symptoms and QoL seem not to be significantly affected by GKRS.
authors.affiliation: Department of Neurosurgery, Haukeland University Hospital, Bergen, Norway. cathrine.nansdal.breivik@gmail.com
authors.forename: Cathrine Nansdal
authors.initials: CN
authors.lastname: Breivik
authors.forename: Roy Miodini
authors.initials: RM
authors.lastname: Nilsen
authors.forename: Erling
authors.initials: E
authors.lastname: Myrseth
authors.forename: Paal Henning
authors.initials: PH
authors.lastname: Pedersen
authors.forename: Jobin K
authors.initials: JK
authors.lastname: Varughese
authors.forename: Aqeel Asghar
authors.initials: AA
authors.lastname: Chaudhry
authors.forename: Morten
authors.initials: M
authors.lastname: Lund-Johansen
mesh_terms: D000970:Antineoplastic Agents / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology* / Q000517:prevention & control*; D009464:Neuroma, Acoustic / Q000453:epidemiology* / Q000628:therapy*; D009664:Norway / Q000453:epidemiology; D011788:Quality of Life; D016634:Radiosurgery / Q000706:statistics & numerical data*; D016896:Treatment Outcome; D047368:Tumor Burden
chemical_list: D000970:Antineoplastic Agents