title: Linear accelerator-based stereotaxic radiosurgery for brain metastases:the influence of number of lesions on survival.
abstract: OBJECTIVE
  To evaluate the influence of the number of brain metastases on survival after stereotaxic radiosurgery and factors that affect the risk of delayed radiation necrosis after treatment.
  
  
  METHODS
  Between March 1989 and December 1993, 120 consecutive patients underwent linear accelerator-based stereotaxic radiosurgery for brain metastases identified by computed tomography (CT) or magnetic resonance imaging (MRI) scans. The influence of various clinical factors on outcome was assessed using Kaplan-Meier plots of survival from the date of radiosurgery, and univariate and multivariate analyses.
  
  
  RESULTS
  The median survival time was 32 weeks. Progressive brain metastases, both local and regional, caused 25 of 104 deaths. Patients with two metastases (n = 30) or a solitary metastasis (n = 70) had equivalent actuarial survival times (P = .07; median, 37 weeks; maximum, 211+ weeks). Patients treated to three or more metastases (n = 20) had significantly shorter survival times (P < .002; median, 14 weeks; maximum, 63 weeks). Prognostic factors associated with prolonged survival included a pretreatment Karnofsky performance status > or = 70% and fewer than three metastases. Delayed radiation necrosis at the treated site developed in 20 patients and correlated with prior or concurrent delivery of whole-brain irradiation and the logarithm of the tumor volume.
  
  
  CONCLUSIONS
  Survival duration is equivalent for patients with one or two brain metastases and is similar to that reported for patients with a solitary metastasis managed by surgical resection and whole-brain irradiation. Survival after radiosurgery for three or more metastases was similar to that reported for whole-brain irradiation.
authors.affiliation: Department of Radiation Oncology, Stanford University Medical Center, Stanford, CA, USA.
authors.forename: J
authors.initials: J
authors.lastname: Joseph
authors.forename: J R
authors.initials: JR
authors.lastname: Adler
authors.forename: R S
authors.initials: RS
authors.lastname: Cox
authors.forename: S L
authors.initials: SL
authors.lastname: Hancock
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000556:secondary* / Q000601:surgery*; D005260:Female; D006801:Humans; D015993:Life Tables; D008297:Male; D008875:Middle Aged; D010315:Particle Accelerators; D011237:Predictive Value of Tests; D016634:Radiosurgery / Q000009:adverse effects / Q000295:instrumentation; D012189:Retrospective Studies; D016019:Survival Analysis; D016896:Treatment Outcome