title: Circulating tumor cells: a novel prognostic factor for newly diagnosed metastatic breast cancer.
abstract: OBJECTIVE
  Metastatic breast cancer (MBC) is incurable; its treatment is palliative. We investigated whether the presence of circulating tumor cells (CTCs) predicts treatment efficacy, progression-free survival (PFS), and overall survival (OS) in patients with newly diagnosed MBC who were about to start first-line therapy.
  
  
  METHODS
  One hundred seventy-seven patients with measurable MBC were enrolled onto a prospective study. Eighty-three of the 177 patients were entering first-line treatment, and these patients are the focus of this analysis. CTCs from 7.5 mL of whole blood drawn before treatment initiation (baseline) and monthly thereafter for up to 6 months were isolated and enumerated using immunomagnetics.
  
  
  RESULTS
  The mean (+/- standard deviation) follow-up time was 11.1 +/- 4.4 months (median, 12.2 months). Forty-three patients (52%) had > or = five CTCs at baseline. The median PFS was 7.2 months (95% CI, 4.9 to 9.4 months), and the median OS was more than 18 months. Patients with > or = five CTCs at baseline and at first follow-up (4 weeks) had a worse prognosis than patients with less than five CTCs (baseline: median PFS, 4.9 v 9.5 months, respectively; log-rank, P = .0014; median OS, 14.2 v > 18 months, respectively; log-rank, P = .0048; first follow-up: median PFS, 2.1 v 8.9 months, respectively; log-rank, P = .0070; median OS, 11.1 v > 18 months, respectively; log-rank, P = .0029). CTCs before and after the initiation of therapy were strong, independent prognostic factors.
  
  
  CONCLUSIONS
  Detection of CTCs before initiation of first-line therapy in patients with MBC is highly predictive of PFS and OS. This technology can aid in appropriate patient stratification and design of tailored treatments.
authors.affiliation: Department of Breast Medical Oncology, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Blvd, Box 424, Houston, TX 77030, USA. mcristof@mdanderson.org
authors.forename: Massimo
authors.initials: M
authors.lastname: Cristofanilli
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Hayes
authors.forename: G Thomas
authors.initials: GT
authors.lastname: Budd
authors.forename: Mathew J
authors.initials: MJ
authors.lastname: Ellis
authors.forename: Alison
authors.initials: A
authors.lastname: Stopeck
authors.forename: James M
authors.initials: JM
authors.lastname: Reuben
authors.forename: Gerald V
authors.initials: GV
authors.lastname: Doyle
authors.forename: Jeri
authors.initials: J
authors.lastname: Matera
authors.forename: W Jeffrey
authors.initials: WJ
authors.lastname: Allard
authors.forename: M Craig
authors.initials: MC
authors.lastname: Miller
authors.forename: Herbert A
authors.initials: HA
authors.lastname: Fritsche
authors.forename: Gabriel N
authors.initials: GN
authors.lastname: Hortobagyi
authors.forename: Leon W M M
authors.initials: LW
authors.lastname: Terstappen
mesh_terms: D001943:Breast Neoplasms / Q000401:mortality* / Q000473:pathology / Q000628:therapy; D005260:Female; D006801:Humans; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009360:Neoplastic Cells, Circulating / Q000473:pathology*; D011379:Prognosis; D011446:Prospective Studies; D015996:Survival Rate