title: Prognostic factors for stereotactic radiosurgery-treated patients with cerebral metastasis: implications on randomised control trial design and inter-institutional collaboration.
abstract: BACKGROUND
  Defining key prognostic factors for patients with cerebral metastases who underwent stereotactic radiosurgery (SRS) treatment will greatly facilitate future clinical trial designs.
  
  
  METHODS
  We adopted a two-phase study design where results from one cohort were validated in a second independent cohort. The exploratory analysis reviewed the survival outcomes of 1017 consecutive patients (with 3610 metastases) who underwent Gamma radiosurgery at the University of California, San Diego (UCSD)/San Diego Gamma Knife Center (SDGKC). Multivariate analysis was performed to identify prognostic factors. Results were validated using data derived from 2519 consecutive patients (with 17,498 metastases) treated with SRS at the Katsuta Hospital.
  
  
  RESULTS
  For the SDGKC cohort, the median overall survival of patients following SRS was 7 months. Two year follow-up data were available for 85% of the patients. Multivariate analysis found that patient age, Karnofsky Performance Status, systemic cancer status, tumour histology, number of metastasis and cumulative tumour volume independently associated with overall survival (p<0.001). All statistical associations were validated by multivariate analysis of data derived from the Katsuta Hospital cohort.
  
  
  CONCLUSIONS
  This is the first integrated study that defined prognostic factors for SRS-treated patients with cerebral metastases using an inter-institutional validation study design. The work establishes a model for collaborative interactions between large volume centers and provides prognostic variables that should be incorporated into future clinical trial design.
authors: Center for Translational and Applied Neuro-Oncology, Division of Neurosurgery, University of California, San Diego, USA.
authors: D D
authors: DD
authors: Gonda
authors: Center for Translational and Applied Neuro-Oncology, Division of Neurosurgery, University of California, San Diego, USA.
authors: T E
authors: TE
authors: Kim
authors: San Diego Gamma Knife Center, San Diego, USA.
authors: S J
authors: SJ
authors: Goetsch
authors: Katsuta Hospital Mito GammaHouse, 5125-2 Nakane, Hitachi-naka 312-0011, Japan; Department of Neurosurgery, Kyoto Prefectural University of Medicine Graduate School of Medical Sciences, 465 Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566, Japan.
authors: T
authors: T
authors: Kawabe
authors: Katsuta Hospital Mito GammaHouse, 5125-2 Nakane, Hitachi-naka 312-0011, Japan; Department of Neurosurgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8575, Japan.
authors: S
authors: S
authors: Watanabe
authors: Center for Translational and Applied Neuro-Oncology, Division of Neurosurgery, University of California, San Diego, USA.
authors: J F
authors: JF
authors: Alksne
authors: Department of Neurosurgery, Tokyo Women's Medical University Medical Center East, 8-1-10 Nishiogu, Arakawa-ku, Tokyo 116-8567, Japan.
authors: J A
authors: JA
authors: Hattangadi
authors: Department of Radiation Oncology, University of California, San Diego, USA.
authors: M
authors: M
authors: Nitta
authors: San Diego Gamma Knife Center, San Diego, USA.
authors: K
authors: K
authors: Ott
authors: San Diego Gamma Knife Center, San Diego, USA.
authors: D W
authors: DW
authors: Hodgens
authors: Center for Translational and Applied Neuro-Oncology, Division of Neurosurgery, University of California, San Diego, USA.
authors: B S
authors: BS
authors: Carter
authors: San Diego Gamma Knife Center, San Diego, USA; Department of Neurosurgery, Tokyo Women's Medical University Medical Center East, 8-1-10 Nishiogu, Arakawa-ku, Tokyo 116-8567, Japan.
authors: M
authors: M
authors: Yamamoto
authors: Center for Translational and Applied Neuro-Oncology, Division of Neurosurgery, University of California, San Diego, USA. Electronic address: clarkchen@ucsd.edu.
authors: Clark C
authors: CC
authors: Chen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000556:secondary* / Q000601:surgery*; D015331:Cohort Studies; D003299:Cooperative Behavior; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D017567:Karnofsky Performance Status; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D017063:Outcome Assessment, Health Care / Q000379:methods*; D010348:Patient Care Team; D011379:Prognosis; D016634:Radiosurgery / Q000379:methods*; D016032:Randomized Controlled Trials as Topic / Q000379:methods; D047368:Tumor Burden; D055815:Young Adult
keywords: Brain metastases; Cumulative tumour volume; Prognostic factors; Randomised clinical trial design; Stereotactic radiosurgery