title: Factors influencing reproducibility of tumour regression grading after high-dose chemoradiation of locally advanced rectal cancer.
abstract: OBJECTIVE
  High-dose chemoradiation is now considered the standard treatment of locally advanced rectal cancer. To provide feedback on the effect of this treatment, several regression grading systems have been proposed. For a grading system to be useful it has to be reproducible. The aim of this study was to test the reproducibility of a five-point grading system, proposed originally by Mandard, and to describe the sources of disagreement.
  
  
  RESULTS
  Tumour regression was assessed independently by two observers on 100 consecutive chemoradiated rectal cancer specimens. The grading system was extremely reproducible, with weighted and unweighted kappa values of 0.89 and 0.82, respectively. The most frequent source of disagreement was assessment of the relative amount of fibrosis. Displacement of epithelium was a minor source of disagreement.
  
  
  CONCLUSIONS
  The five-point grading system of Mandard is extremely reproducible.
authors.affiliation: Department of Clinical Pathology, Vejle Hospital, Kabbeltoft, 7100 Vejle, Denmark. jan.lindebjerg@slb.regionsyddanmark.dk
authors.forename: Jan
authors.initials: J
authors.lastname: Lindebjerg
authors.forename: Niels
authors.initials: N
authors.lastname: Hansborg
authors.forename: John
authors.initials: J
authors.lastname: Ploen
authors.forename: Soren
authors.initials: S
authors.lastname: Rafaelsen
authors.forename: Jens Christian Riis
authors.initials: JC
authors.lastname: Jorgensen
authors.forename: Anders
authors.initials: A
authors.lastname: Jakobsen
mesh_terms: D059248:Chemoradiotherapy; D005355:Fibrosis; D006801:Humans; D060787:Neoplasm Grading / Q000379:methods; D015588:Observer Variation; D012004:Rectal Neoplasms / Q000473:pathology* / Q000628:therapy*; D015203:Reproducibility of Results; D016896:Treatment Outcome