title: Volume reduction in meningiomas after gamma knife surgery.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the volume-reducing effects of gamma knife surgery (GKS) of meningiomas with and without previous surgical treatment.
  
  
  METHODS
  A group of 127 patients with a mean age of 57.1 years (range 9-81 years) with 142 meningiomas (128 World Health Organization Grade I and 14 Grade II) were included in this study. The management strategy reduces tumor volume with surgery when necessary (81 patients). Stereotactic GKS with a Gamma Knife model C was performed in all tumors of suitable size. Magnetic resonance imaging follow-up examinations with volumetric tumor analysis was performed 6 months after treatment and annually thereafter. The mean tumor volume was 5.9 cm3 (range < 5 to > 40 cm3). The mean follow-up time after GKS was 29.3 months (range 11-61 months). The mean prescription dose was 13.8 Gy (range 10-18 Gy). A reduction in volume occurred in 117 (82.4%) of all tumors, and in 20 tumors (14.1%) growth ceased. The overall tumor control rate of 96.4%. The mean volume reduction achieved with GKS was more than 46.1%. Only five tumors (3.5%) stowed a volume increase.
  
  
  CONCLUSIONS
  Gamma knife surgery was effective in reducing meningioma volume at short-term follow up. Further studies are needed to examine the development of these findings over a longer period.
authors.affiliation: International Neuroscience Institute, Hannover, Germany. feigl@ini-hannover.de
authors.forename: Guenther C
authors.initials: GC
authors.lastname: Feigl
authors.forename: Otto
authors.initials: O
authors.lastname: Bundschuh
authors.forename: Alireza
authors.initials: A
authors.lastname: Gharabaghi
authors.forename: Madjid
authors.initials: M
authors.lastname: Samii
authors.forename: Gerhard A
authors.initials: GA
authors.lastname: Horstmann
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008577:Meningeal Neoplasms / Q000473:pathology* / Q000601:surgery*; D008579:Meningioma / Q000473:pathology* / Q000601:surgery*; D008875:Middle Aged; D011446:Prospective Studies; D047368:Tumor Burden