title: Circulating tumor cells in metastatic breast cancer: from prognostic stratification to modification of the staging system?
abstract: BACKGROUND
  The aim of the current study was to assess the prognostic value of baseline circulating tumor cells (CTCs) in a large cohort of patients with newly diagnosed metastatic breast cancer (MBC).
  
  
  METHODS
  This retrospective study included 185 patients with newly diagnosed MBC evaluated between 2001 and 2007. CTCs were isolated and enumerated before patients started first-line treatment using the CellSearch system. Overall survival (OS) was calculated from the date of CTC measurement, estimated by the Kaplan-Meier product limit method, and compared between groups with the log-rank test. Cox proportional hazards models were fitted to determine the association between CTC levels and OS after controlling for other prognostic factors.
  
  
  RESULTS
  The median age of the patients at the time of MBC diagnosis was 49 years. Fifty-six (30.3%) patients presented with de novo metastatic disease, and 129 (69.7%) presented with newly recurrent breast cancer. A total of 114 patients (61.6%) had CTC<5, and 71 (38.4%) had CTC >or= 5. The median OS was 28.3 months and 15 months (P< .0001) for patients with CTC<5 and CTC >or= 5, respectively. Superior survival among patients with CTC<5 was observed regardless of hormone receptor and HER-2/neu status, site of first metastases, or whether the patient had recurrent or de novo metastatic disease. In the multivariate model, patients with CTC >or= 5 had a hazards ratio of death of 3.64 (95% confidence interval, 2.11-6.30) compared with patients with CTC <5.
  
  
  CONCLUSIONS
  The results of this large retrospective study confirms that CTCs are a strong independent predictor of survival among women with either de novo or newly recurrent MBC. CTCs should be considered as a new stratification method for women with newly diagnosed MBC.
authors.affiliation: Department of Breast Medical Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA. Shaheenah_d@yahoo.com
authors.forename: Shaheenah
authors.initials: S
authors.lastname: Dawood
authors.forename: Kristine
authors.initials: K
authors.lastname: Broglio
authors.forename: Vicente
authors.initials: V
authors.lastname: Valero
authors.forename: James
authors.initials: J
authors.lastname: Reuben
authors.forename: Beverly
authors.initials: B
authors.lastname: Handy
authors.forename: Rabiul
authors.initials: R
authors.lastname: Islam
authors.forename: Summer
authors.initials: S
authors.lastname: Jackson
authors.forename: Gabriel N
authors.initials: GN
authors.lastname: Hortobagyi
authors.forename: Herbert
authors.initials: H
authors.lastname: Fritsche
authors.forename: Massimo
authors.initials: M
authors.lastname: Cristofanilli
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis; D001943:Breast Neoplasms / Q000097:blood* / Q000473:pathology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D009367:Neoplasm Staging; D009360:Neoplastic Cells, Circulating / Q000473:pathology*; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate
chemical_list: D014408:Biomarkers, Tumor