title: Cytokeratin 20 positive circulating tumor cells are a marker for response after neoadjuvant chemoradiation but not for prognosis in patients with rectal cancer.
abstract: BACKGROUND
  Several studies have shown, that circulating tumor cells (CTC) have a negative prognostic value in colorectal cancer patients. Aim of this study was to evaluate the role of CTC in specifically rectal cancer patients regarding the influence on overall survival and to elucidate the impact of CTC in predicting response after chemoradiation (RCTX).
  
  
  METHODS
  In this prospective monocentric study 267 patients with rectal cancer were included. Patients with locally advanced tumors were treated with RCTX followed by surgery. The primary endpoints were: Evaluation of CTC at the time of surgery and correlation with main tumor characteristics, response to neoadjuvant RCTX and overall survival (OS). CTC were detected in the blood using CK20 RT-PCR.
  
  
  RESULTS
  Sixty-three patients were treated with neoadjuvant RCTX. In 46.8% of the patients receiving neoadjuvant RCTX CTC were detected, which was significantly higher than in the group without RCTX (p=0.002). Histopathologic regression after RCTX was evident in 27.8% of the patients. In the subgroup of responders after RCTX we found CTC at a significantly lower rate than in non-responders (p=0.03). No significant association was found between CTC detection and tumor characteristics and OS. The OS was significantly improved for responders compared to non-responders (p=0.007).
  
  
  CONCLUSIONS
  Responders after neoadjuvant RCTX had a lower incidence of CTC compared to non-responders, which might be a result of effective systemic and local treatment prior to surgery. Interestingly, detection of CTC did not correlate with tumor stage and OS, which is in contrast to previous reports of patients with colon cancer.
authors.affiliation: Department of General and Thoracic Surgery, University Hospital Schleswig-Holstein, Campus Kiel, Arnold-Heller Str. 7, 24105, Kiel, Germany. sebastian.hinz@uksh.de.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Hinz
authors.affiliation: Division Molecular Oncology, Institute for Experimental Cancer Research, Cancer Center North, University Hospital Schleswig-Holstein, Campus Kiel, Arnold-Heller Str. 7, 24105, Kiel, Germany. c.roeder@email.uni-kiel.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Röder
authors.affiliation: Clinic for General, Thoracic and Visceral Surgery, Klinikum Osnabrück, Am Finkenhügel 1, 49076, Osnabrück, Germany. juergen.tepel@klinikum-os.de.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Tepel
authors.affiliation: Department of General and Thoracic Surgery, University Hospital Schleswig-Holstein, Campus Kiel, Arnold-Heller Str. 7, 24105, Kiel, Germany. alexander.hendricks@uksh.de.
authors.forename: Alexander
authors.initials: A
authors.lastname: Hendricks
authors.affiliation: Department of General and Thoracic Surgery, University Hospital Schleswig-Holstein, Campus Kiel, Arnold-Heller Str. 7, 24105, Kiel, Germany. clemens.schafmayer@uksh.de.
authors.forename: Clemens
authors.initials: C
authors.lastname: Schafmayer
authors.affiliation: Department of General and Thoracic Surgery, University Hospital Schleswig-Holstein, Campus Kiel, Arnold-Heller Str. 7, 24105, Kiel, Germany. Thomas.becker@uksh.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Becker
authors.affiliation: Division Molecular Oncology, Institute for Experimental Cancer Research, Cancer Center North, University Hospital Schleswig-Holstein, Campus Kiel, Arnold-Heller Str. 7, 24105, Kiel, Germany. hkalthoff@email.uni-kiel.de.
authors.forename: Holger
authors.initials: H
authors.lastname: Kalthoff
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis / Q000097:blood*; D059248:Chemoradiotherapy; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D053554:Keratin-20 / Q000096:biosynthesis; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009360:Neoplastic Cells, Circulating / Q000473:pathology*; D016133:Polymerase Chain Reaction; D011379:Prognosis; D012004:Rectal Neoplasms / Q000097:blood* / Q000473:pathology* / Q000628:therapy; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; C507499:KRT20 protein, human; D053554:Keratin-20