title: Stereotactic radiosurgery for four or more intracranial metastases.
abstract: OBJECTIVE
  To evaluate the outcomes after a single stereotactic radiosurgery procedure for the care of patients with 4 or more intracranial metastases.
  
  
  METHODS
  Two hundred five patients with primary malignancies, including non-small-cell lung carcinoma (42%), breast carcinoma (23%), melanoma (17%), renal cell carcinoma (6%), colon cancer (3%), and others (10%) underwent gamma knife radiosurgery for 4 or more intracranial metastases at one time. The median number of brain metastases was 5 (range, 4-18) with a median total treatment volume of 6.8 cc (range, 0.6-51.0 cc). Radiosurgery was used as sole management (17% of patients), or in combination with whole brain radiotherapy (46%) or after failure of whole brain radiotherapy (38%). The median marginal radiosurgery dose was 16 Gy (range, 12-20 Gy). The mean follow-up was 8 months.
  
  
  RESULTS
  The median overall survival after radiosurgery for all patients was 8 months. The 1-year local control rate was 71%, and the median time to progressive/new brain metastases was 9 months. Using the Radiation Therapy Oncology Group recursive partitioning analysis (RPA) classification system, the median overall survivals for RPA classes I, II, and III were 18, 9, and 3 months, respectively (p < 0.00001). Multivariate analysis revealed total treatment volume, age, RPA classification, and marginal dose as significant prognostic factors. The number of metastases was not statistically significant (p = 0.333).
  
  
  CONCLUSIONS
  Radiosurgery seems to provide survival benefit for patients with 4 or more intracranial metastases. Because total treatment volume was the most significant predictor of survival, the total volume of brain metastases, rather than the number of metastases, should be considered in identifying appropriate radiosurgery candidates.
authors.affiliation: Department of Radiation Oncology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
authors.forename: Ajay K
authors.initials: AK
authors.lastname: Bhatnagar
authors.forename: John C
authors.initials: JC
authors.lastname: Flickinger
authors.forename: Douglas
authors.initials: D
authors.lastname: Kondziolka
authors.forename: L Dade
authors.initials: LD
authors.lastname: Lunsford
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000556:secondary* / Q000601:surgery*; D002648:Child; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016634:Radiosurgery; D011879:Radiotherapy Dosage; D012189:Retrospective Studies