title: Gamma Knife Radiosurgery in Recurrent Glioblastoma.
abstract: We evaluated Gamma Knife radiosurgery (GKRS) as a treatment option for patients with recurrent glioblastoma.
  
  
  
  42 patients with histopathologically diagnosed recurrent grade IV tumor were treated with GKRS. All patients had undergone standard multimodal first-line treatment. The average time from diagnosis to GKRS was 17.0 months. The median target volume was 5.1 cm3. The median margin dose was 10 Gy and the median central dose 20 Gy. In a subset of patients, O6-methylguanine methyltransferase (MGMT) promoter methylation analysis by pyrosequencing was performed.
  
  
  
  Most patients did not develop complications after GKRS. Time to radiological progression after initial GKRS was 4.4 months (95% CI: 3.1-5.7 months). Radiological progression mainly occurred beyond the GKRS-irradiated area. The median survival time after initial GKRS was 9.6 months (95% CI: 7.7-11.5 months). The median overall survival time from diagnosis was 25.6 months (95% CI: 21.8-29.3 months). Patients with MGMT promoter methylation survived significantly longer (33.4 months; 95% CI: 21.2-45.5 months) compared to patients without MGMT promoter methylation (16.0 months; 95% CI: 8.0-23.9 months).
  
  
  
  GKRS seems to be a relatively safe salvage treatment option for recurrent glioblastoma for highly selected patients but must be seen as part of a multimodal treatment algorithm.
authors.affiliation: Department of Neurosurgery, Medical University Vienna, Vienna, Austria.
authors.forename: Josa M
authors.initials: JM
authors.lastname: Frischer
authors.forename: Christine
authors.initials: C
authors.lastname: Marosi
authors.forename: Adelheid
authors.initials: A
authors.lastname: Woehrer
authors.forename: Johannes A
authors.initials: JA
authors.lastname: Hainfellner
authors.forename: Karin Ute
authors.initials: KU
authors.lastname: Dieckmann
authors.forename: Helmut
authors.initials: H
authors.lastname: Eiter
authors.forename: Wei-Te
authors.initials: WT
authors.lastname: Wang
authors.forename: Ammar
authors.initials: A
authors.lastname: Mallouhi
authors.forename: Adolf
authors.initials: A
authors.lastname: Ertl
authors.forename: Engelbert
authors.initials: E
authors.lastname: Knosp
authors.forename: Martin
authors.initials: M
authors.lastname: Filipits
authors.forename: Klaus
authors.initials: K
authors.lastname: Kitz
authors.forename: Brigitte
authors.initials: B
authors.lastname: Gatterbauer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000532:radiotherapy* / Q000601:surgery; D003131:Combined Modality Therapy; D005260:Female; D005909:Glioblastoma / Q000532:radiotherapy* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000532:radiotherapy* / Q000601:surgery; D016634:Radiosurgery; D012086:Reoperation; D016879:Salvage Therapy; D055815:Young Adult