title: Conservative management of 386 cases of unilateral vestibular schwannoma: tumor growth and consequences for treatment.
abstract: OBJECTIVE
  The object of this study was to evaluate the natural history, pattern, and occurrence of tumor growth and its consequences for treatment of small-sized vestibular schwannomas (VSs).
  
  
  METHODS
  From 1990 to 2005, 386 patients underwent conservative management for VS because of the following: age > 60 years, poor health/medical risks, risk of deterioration of good hearing, small tumor size, minimal or no incapacitating symptoms, and/or patient preference. Tumor size was measured by MR imaging according to the guidelines of the Committee on Hearing and Equilibrium. The first MR imaging study was performed 1 year after diagnosis, and subsequent imaging was performed yearly or every 2 years depending on the appearance of new symptoms, tumor growth, or both.
  
  
  RESULTS
  Sixty-one patients were lost to follow-up the first year after presentation. Of the 325 patients for whom 1-year follow-up data were available, 39 showed tumor growth > or = 3 mm. Conservative management was discontinued for these 39 patients. The patients who returned for follow-up were evaluated at 1- or 2-year intervals depending on tumor growth. The authors extrapolated to obtain data for 2-year intervals, yielding data for 160, 56, 21, and 8 patients at 3, 5, 7, and 9 years after initial presentation, respectively. The overall mean tumor growth rate (+/-standard deviation) was 1.15 +/- 2.4 mm/year. This rate was estimated by pooling all values of tumor growth that had been determined for all patients and dividing by the total number of "events," with each assessment constituting an event. In 58.6% of patients, the annual tumor growth rate was < 1 mm/year; in 29.2%, 1-3 mm/year; and in 12.2%, > or = 3 mm/ year. The growth rates of intrameatal (1.02 +/- 1.8 mm/year) and extrameatal (1.40 +/- 3.1 mm/year) tumors did not differ significantly. No significant association was found between tumor growth rate and sex, age, initial hearing status, or initial tumor grade. Delay in diagnosis was the only significant factor associated with tumor growth rate. During follow-up, conservative management was discontinued for 77 (23.7%) of the 325 patients for whom at least 12-month follow-up data were available; surgery was performed in 60 (77.9%) and radiation therapy in 17 (22.1%).
  
  
  CONCLUSIONS
  The results of this study support the role of a conservative "wait-and-scan" policy of management for small-sized VSs because most have a slow growth rate. Long-term neuroimaging follow-up is needed even with non-growing tumors.
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Laboratoire de Neurobiologie et des Réseaux Sensorimoteurs, LNRS CNRS 7060, France.
authors.forename: Wissame El
authors.initials: WE
authors.lastname: Bakkouri
authors.forename: Romain E
authors.initials: RE
authors.lastname: Kania
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Guichard
authors.forename: Guillaume
authors.initials: G
authors.lastname: Lot
authors.forename: Philippe
authors.initials: P
authors.lastname: Herman
authors.forename: Patrice Tran Ba
authors.initials: PT
authors.lastname: Huy
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000473:pathology / Q000628:therapy*; D012189:Retrospective Studies; D016896:Treatment Outcome