title: Gamma knife for glioma: selection factors and survival.
abstract: OBJECTIVE
  To determine factors associated with survival differences in patients treated with radiosurgery for glioma.
  
  
  METHODS
  We analyzed 189 patients treated with Gamma Knife radiosurgery for primary or recurrent glioma World Health Organization (WHO) Grades 1-4.
  
  
  RESULTS
  
  
  
  CONCLUSIONS
  The median minimum tumor dose was 16 Gy (8-30 Gy) and the median tumor volume was 5.9 cc (1.3-52 cc). Brachytherapy selection criteria were satisfied in 65% of patients. Median follow-up of all surviving patients was 65 weeks after radiosurgery. For primary glioblastoma patients, median survival from the date of pathologic diagnosis was 86 weeks if brachytherapy criteria were satisfied and 40 weeks if they were not (p = 0.01), indicating that selection factors strongly influence survival. Multivariate analysis showed that increased survival was associated with five variables: lower pathologic grade, younger age, increased Karnofsky performance status (KPS), smaller tumor volume, and unifocal tumor. Survival was not found to be significantly related to radiosurgical technical parameters (dose, number of isocenters, prescription isodose percent, inhomogeneity) or extent of preradiosurgery surgery. We developed a hazard ratio model that is independent of the technical details of radiosurgery and applied it to reported radiosurgery and brachytherapy series, demonstrating a significant correlation between survival and hazard ratio.
  
  
  CONCLUSIONS
  Survival after radiosurgery for glioma is strongly related to five selection variables. Much of the variation in survival reported in previous series can be attributed to differences in distributions of these variables. These variables should be considered in selecting patients for radiosurgery and in the design of future studies.
authors.affiliation: Department of Radiation Oncology, University of California, San Francisco 94143, USA.
authors.forename: D A
authors.initials: DA
authors.lastname: Larson
authors.forename: P H
authors.initials: PH
authors.lastname: Gutin
authors.forename: M
authors.initials: M
authors.lastname: McDermott
authors.forename: K
authors.initials: K
authors.lastname: Lamborn
authors.forename: P K
authors.initials: PK
authors.lastname: Sneed
authors.forename: W M
authors.initials: WM
authors.lastname: Wara
authors.forename: J C
authors.initials: JC
authors.lastname: Flickinger
authors.forename: D
authors.initials: D
authors.lastname: Kondziolka
authors.forename: L D
authors.initials: LD
authors.lastname: Lunsford
authors.forename: W R
authors.initials: WR
authors.lastname: Hudgins
authors.forename: G M
authors.initials: GM
authors.lastname: Friehs
authors.forename: K
authors.initials: K
authors.lastname: Haselsberger
authors.forename: K
authors.initials: K
authors.lastname: Leber
authors.forename: G
authors.initials: G
authors.lastname: Pendl
authors.forename: S S
authors.initials: SS
authors.lastname: Chung
authors.forename: R J
authors.initials: RJ
authors.lastname: Coffey
authors.forename: R
authors.initials: R
authors.lastname: Dinapoli
authors.forename: E G
authors.initials: EG
authors.lastname: Shaw
authors.forename: S
authors.initials: S
authors.lastname: Vermeulen
authors.forename: R F
authors.initials: RF
authors.lastname: Young
authors.forename: M
authors.initials: M
authors.lastname: Hirato
authors.forename: H K
authors.initials: HK
authors.lastname: Inoue
authors.forename: C
authors.initials: C
authors.lastname: Ohye
authors.forename: T
authors.initials: T
authors.lastname: Shibazaki
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005260:Female; D005910:Glioma / Q000401:mortality / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D016634:Radiosurgery / Q000009:adverse effects; D015996:Survival Rate