title: Gamma knife surgery as monotherapy with clinically relevant doses prolongs survival in a human GBM xenograft model.
abstract: OBJECTIVE
  Gamma knife surgery (GKS) may be used for recurring glioblastomas (GBMs). However, patients have then usually undergone multimodal treatment, which makes it difficult to specifically validate GKS independent of established treatments. Thus, we developed an experimental brain tumor model to assess the efficacy and radiotoxicity associated with GKS.
  
  
  METHODS
  GBM xenografts were implanted intracerebrally in nude rats, and engraftment was confirmed with MRI. The rats were allocated to GKS, with margin doses of 12 Gy or 18 Gy, or to no treatment. Survival time was recorded, tumor sections were examined, and radiotoxicity was evaluated in a behavioral open field test.
  
  
  RESULTS
  In the first series, survival from the time of implantation was 96 days in treated rats and 72 days in controls (P < 0.001). In a second experiment, survival was 72 days in the treatment group versus 54 days in controls (P < 0.006). Polynuclear macrophages and fibrosis was seen in groups subjected to GKS. Untreated rats with GBM xenografts displayed less mobility than GKS-treated animals in the open field test 4 weeks after treatment (P = 0.04).
  
  
  CONCLUSIONS
  GKS administered with clinically relevant doses prolongs survival in rats harboring GBM xenografts, and the associated toxicity is mild.
authors: Department of Neurosurgery, Haukeland University Hospital, 5021 Bergen, Norway ; Institute of Surgical Sciences, Haukeland University Hospital, 5021 Bergen, Norway ; Oncomatrix Research Lab, Department of Biomedicine, University of Bergen, 5021 Bergen, Norway.
authors: Bente Sandvei
authors: BS
authors: Skeie
authors: Jian
authors: J
authors: Wang
authors: Ernest
authors: E
authors: Dodoo
authors: Jan Ingeman
authors: JI
authors: Heggdal
authors: Janne
authors: J
authors: Grønli
authors: Linda
authors: L
authors: Sleire
authors: Sidsel
authors: S
authors: Bragstad
authors: Jeremy C
authors: JC
authors: Ganz
authors: Martha
authors: M
authors: Chekenya
authors: Sverre
authors: S
authors: Mørk
authors: Paal-Henning
authors: PH
authors: Pedersen
authors: Per Øyvind
authors: PØ
authors: Enger
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D001932:Brain Neoplasms / Q000473:pathology / Q000601:surgery*; D004195:Disease Models, Animal; D004307:Dose-Response Relationship, Radiation; D005909:Glioblastoma / Q000473:pathology / Q000601:surgery*; D006801:Humans; D007150:Immunohistochemistry; D008279:Magnetic Resonance Imaging; D016634:Radiosurgery; D051381:Rats; D011923:Rats, Nude; D016019:Survival Analysis; D023041:Xenograft Model Antitumor Assays