title: Gamma knife surgery for brain metastases in patients harboring four or more lesions: survival and prognostic factors.
abstract: OBJECTIVE
  This study was performed to evaluate the role of gamma knife surgery (GKS) in patients with a large number (four or more) of metastatic brain lesions.
  
  
  METHODS
  The authors retrospectively reviewed the outcome in 130 patients who underwent GKS for metastatic lesions. Eighty-four patients presented with one to three lesions (Group A) and 46 presented with four or more lesions (Group B). The overall median survival time after GKS was 35 weeks. The median survival time in Group A (48 weeks) was significantly longer (p = 0.005) than the survival time in Group B (26 weeks). The recursive partitioning analysis (RPA) class was the only significant prognostic factor identified in multivariate analysis. The median survival for patients in RPA Classes I, II, and III was 72, 48, and 19 weeks, respectively, in Group A and 36 and 13 weeks for Classes II and III in Group B. The number of lesions, tumor volume, whole brain radiotherapy, primary tumor site, age, and sex did not affect survival significantly.
  
  
  CONCLUSIONS
  It is suggested that GKS provides an increase in survival time even in patients with a large number (four or more) of metastatic lesions. Concerning the selection of patients for GKS, RPA class should be considered as the most important factor and multiplicity of the lesions alone should not be a reason for withholding GKS.
authors.affiliation: Department of Neurosurgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Taek-Kyun
authors.initials: TK
authors.lastname: Nam
authors.forename: Jung-Il
authors.initials: JI
authors.lastname: Lee
authors.forename: Young-Jo
authors.initials: YJ
authors.lastname: Jung
authors.forename: Yong-Seok
authors.initials: YS
authors.lastname: Im
authors.forename: Hee-Ye
authors.initials: HY
authors.lastname: An
authors.forename: Do-Hyun
authors.initials: DH
authors.lastname: Nam
authors.forename: Kwan
authors.initials: K
authors.lastname: Park
authors.forename: Jong-Hyun
authors.initials: JH
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000401:mortality* / Q000556:secondary* / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016609:Neoplasms, Second Primary / Q000401:mortality / Q000601:surgery; D011379:Prognosis; D011829:Radiation Dosage; D016634:Radiosurgery / Q000295:instrumentation*; D015996:Survival Rate