title: Volumetric response to radiosurgery for brain metastasis varies by cell of origin.
abstract: OBJECTIVE
  The aim of this study was to evaluate the imaging response of brain metastases after radiosurgery and to correlate the response with tumor type and patient survival.
  
  
  METHODS
  The authors conducted a retrospective review of patients who had undergone Gamma Knife radiosurgery for brain metastases from non-small cell lung cancer (NSCLC), breast cancer, or melanoma. The imaging volumetric response by tumor type was plotted at 3-month intervals and classified as a sustained decrease in tumor volume (Type A), a transient decrease followed by a delayed increase in tumor volume (Type B), or a sustained increase in tumor volume (Type C). These imaging responses were then compared with patient survival and tumor type.
  
  
  RESULTS
  Two hundred thirty-three patients with metastases from NSCLC (96 patients), breast cancer (98 patients), and melanoma (39 patients) were eligible for inclusion in this study. The patients with NSCLC were most likely to exhibit a Type A response; those with breast cancer, a Type B response; and those with melanoma, a Type C response. Among patients with NSCLC, the median overall survival was 11.2 months for those with a Type A response (76 patients), 8.6 months for those with a Type B response (6 patients), and 10.5 months for those with a Type C response (14 patients). Among patients with breast cancer, the median overall survival was 16.6 months in those with a Type A response (65 patients), 18.1 months in those with a Type B response (20 patients), and 7.5 months in those with a Type C response (13 patients). For patients with melanoma, the median overall survival was 5.2 months in those with a Type A response (26 patients) and 6.7 months in those with a Type C response (13 patients). None of the patients with melanoma had a Type B response. The imaging response was significantly associated with survival only in patients with breast cancer.
  
  
  CONCLUSIONS
  The various types of imaging responses of metastatic brain tumors after stereotactic radiosurgery depend in part on tumor type. However, the type of response only correlates with survival in patients with breast cancer.
authors.affiliation: Departments of Neurological Surgery and.
authors.forename: Aditya
authors.initials: A
authors.lastname: Iyer
authors.forename: Gillian
authors.initials: G
authors.lastname: Harrison
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Kano
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Weiner
authors.forename: Neal
authors.initials: N
authors.lastname: Luther
authors.forename: Ajay
authors.initials: A
authors.lastname: Niranjan
authors.forename: John C
authors.initials: JC
authors.lastname: Flickinger
authors.forename: L Dade
authors.initials: LD
authors.lastname: Lunsford
authors.forename: Douglas
authors.initials: D
authors.lastname: Kondziolka
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000401:mortality / Q000556:secondary* / Q000601:surgery*; D001943:Breast Neoplasms / Q000473:pathology*; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008545:Melanoma / Q000473:pathology; D008875:Middle Aged; D016634:Radiosurgery; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000473:pathology*; D015996:Survival Rate; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D047368:Tumor Burden
keywords: GKRS = Gamma Knife radiosurgery; Gamma Knife; NSCLC = non–small cell lung cancer; WBRT = whole-brain radiation therapy; brain metastasis; breast cancer; melanoma; non–small cell lung cancer; oncology; stereotactic radiosurgery