title: Hematogenous tumor cell dissemination during colonoscopy for colorectal cancer.
abstract: BACKGROUND
  It has long been suspected that mechanical influences may enhance the release of viable colorectal cancer cells into the circulation. The objective of this study was to determine the extent of hematogenous tumor cell spread in colorectal cancer patients during colonoscopy.
  
  
  METHODS
  Peripheral venous blood samples were taken before and after colonoscopy from 44 patients with colorectal cancer. Blood samples were examined using a reverse-transcriptase polymerase chain reaction assay to amplify cytokeratin 20 transcripts.
  
  
  RESULTS
  Eleven patients with colorectal cancer displayed circulating tumor cells before and after colonoscopy (25%), whereas tumor cells were detected in six of 44 patients (14%) only after the procedure (p = 0.03, McNemar's test: tumor cell detection before after colonoscopy). All control samples consistently tested negative.
  
  
  CONCLUSIONS
  Mechanical forces may result in enhanced release of viable colorectal cancer cells into the circulation; however, the clinical significance of these results needs to be clarified.
authors.affiliation: Division for Molecular Diagnostics and Therapy, Department of Surgery, University of Heidelberg, INF 110, D-69120 Heidelberg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Koch
authors.forename: P
authors.initials: P
authors.lastname: Kienle
authors.forename: P
authors.initials: P
authors.lastname: Sauer
authors.forename: F
authors.initials: F
authors.lastname: Willeke
authors.forename: K
authors.initials: K
authors.lastname: Buhl
authors.forename: A
authors.initials: A
authors.lastname: Benner
authors.forename: T
authors.initials: T
authors.lastname: Lehnert
authors.forename: C
authors.initials: C
authors.lastname: Herfarth
authors.forename: M
authors.initials: M
authors.lastname: von Knebel Doeberitz
authors.forename: J
authors.initials: J
authors.lastname: Weitz
mesh_terms: D000230:Adenocarcinoma / Q000097:blood* / Q000175:diagnosis / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood; D003111:Colonic Polyps / Q000097:blood / Q000175:diagnosis / Q000601:surgery; D003113:Colonoscopy / Q000009:adverse effects*; D015179:Colorectal Neoplasms / Q000097:blood* / Q000175:diagnosis / Q000473:pathology; D005260:Female; D006801:Humans; D007327:Insufflation / Q000009:adverse effects; D007381:Intermediate Filament Proteins / Q000097:blood; D053554:Keratin-20; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009360:Neoplastic Cells, Circulating; D011446:Prospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012306:Risk; D013314:Stress, Mechanical
chemical_list: D014408:Biomarkers, Tumor; D007381:Intermediate Filament Proteins; C507499:KRT20 protein, human; D053554:Keratin-20