title: Circulating tumour cells in peripheral blood: potential impact on breast cancer outcome.
abstract: BACKGROUND
  In breast cancer, the metastatic process may involve the dissemination of circulating tumour cells (CTCs) through the blood and lymphatic system prior to the colonisation of distant organs. Here we demonstrate the predictive capacity of CTCs for detecting risk of death in breast cancer patients during established time intervals.
  
  
  METHODS
  CTCs were identified by immunocytochemical methods following isolation by selective immunomagnetic cell separation of cytokeratin-positive cells. Serial blood samples from 65 patients were collected at roughly monthly intervals for up to 50 months. Follow-up was conducted at different intervals: 1-5, >5-12, >12-24 and >24-50 months.
  
  
  RESULTS
  Both presence and number of CTCs were correlated to risk of death: patients with CTCs at any time during follow-up had a higher risk of death (p=0.035) than patients without CTCs. Furthermore, during the first 5 months of therapy, patients with >5 CTCs had a higher risk of death than patients with <5 CTCs (p=0.002).
  
  
  CONCLUSIONS
  Our results show that the persistence of CTCs after chemotherapy, particularly during the first 5 months, could define a group of patients with a high risk of relapse.
authors.affiliation: Pfizer - Universidad de Granada - Junta de Andalucía, Centre for Genomics and Oncological Research (GENYO), Health Sciences Technologic Park, Granada, Spain. mjose.serrano@genyo.es
authors.forename: María José
authors.initials: MJ
authors.lastname: Serrano
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Lorente
authors.forename: Miguel
authors.initials: M
authors.lastname: Delgado Rodríguez
authors.forename: Ana
authors.initials: A
authors.lastname: Fernández
authors.forename: Mónica
authors.initials: M
authors.lastname: Fernández
authors.forename: Capilla
authors.initials: C
authors.lastname: de la Torre
authors.forename: Jaime
authors.initials: J
authors.lastname: Fernández Izquierdo
authors.forename: Pedro
authors.initials: P
authors.lastname: Sánchez Rovira
mesh_terms: D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000097:blood; D001943:Breast Neoplasms / Q000097:blood* / Q000188:drug therapy / Q000473:pathology*; D002469:Cell Separation; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D009360:Neoplastic Cells, Circulating / Q000473:pathology*; D011379:Prognosis
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor