title: Does the presence of circulating tumor cells in the venous drainage of curative colorectal cancer resections determine prognosis? A meta-analysis.
abstract: BACKGROUND
  Hepatic metastasis can occur following curative colorectal cancer surgery despite favorable prognostic indicators, raising the question of whether detecting circulating tumor cells in the venous drainage of colorectal cancers at resection using reverse-transcriptase polymerase chain reaction would help determine prognosis. This study compares lymph node positivity, hepatic metastasis rates, and disease-free survival in circulating tumor positive versus negative patients.
  
  
  METHODS
  A Medline, Embase, Ovid, and Cochrane database search was conducted on all studies between 1999 and 2006 reporting the outcomes of interest. Meta-analysis was performed in line with recommendations from the Cochrane Collaboration and the Quality of Reporting of Meta-Analyses guidelines.
  
  
  RESULTS
  Nine studies reporting on 646 subjects published between 1998 and 2006 matched the selection criteria and were suitable for inclusion in this meta-analysis. There was a significantly higher incidence of circulating tumor cells (50%) in lymph node positive compared with negative groups (21%) [odds ratio (OR) = 3.83, confidence interval (CI) = 2.46-5.94], and a significantly increased hepatic metastases rate (21%) in circulating tumor cells positive compared with in negative patients (8%, OR = 6.38; CI = 2.67-15.25. Disease-free survival was significantly higher in the circulating tumor cell negative versus positive groups at 1 year [hazard ratio (HR) = 0.04, CI = 0-0.46], 2 years (HR = 0.05, CI = 0.01-0.31), and 3 years (HR = 0.08, CI = 0.02-0.34) post resection.
  
  
  CONCLUSIONS
  This study highlights the potential importance of free cancer cell detection in the venous drainage of colorectal cancers as a prognostic indicator and a mode of staging colorectal cancers.
authors.affiliation: Department of Biosurgery and Surgical Technology, Imperial College London, St Mary's Hospital, 10th Floor, QEQM Wing, St Mary's Campus, Praed Street, London W2 1NY, UK.
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Katsuno
authors.forename: Emmanouil
authors.initials: E
authors.lastname: Zacharakis
authors.forename: Omer
authors.initials: O
authors.lastname: Aziz
authors.forename: Christopher
authors.initials: C
authors.lastname: Rao
authors.forename: Samer
authors.initials: S
authors.lastname: Deeba
authors.forename: Paraskeva
authors.initials: P
authors.lastname: Paraskeva
authors.forename: Paul
authors.initials: P
authors.lastname: Ziprin
authors.forename: Thanos
authors.initials: T
authors.lastname: Athanasiou
authors.forename: Ara
authors.initials: A
authors.lastname: Darzi
mesh_terms: D014408:Biomarkers, Tumor / Q000097:blood*; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000097:blood* / Q000473:pathology; D018572:Disease-Free Survival; D006801:Humans; D008113:Liver Neoplasms / Q000097:blood* / Q000556:secondary; D008207:Lymphatic Metastasis; D009364:Neoplasm Recurrence, Local / Q000097:blood* / Q000235:genetics; D009367:Neoplasm Staging; D009360:Neoplastic Cells, Circulating / Q000473:pathology*; D011379:Prognosis; D012333:RNA, Messenger / Q000097:blood / Q000235:genetics; D012334:RNA, Neoplasm / Q000097:blood / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012307:Risk Factors; D015996:Survival Rate; D014680:Veins
chemical_list: D014408:Biomarkers, Tumor; D012333:RNA, Messenger; D012334:RNA, Neoplasm