title: The development and validation of an endoscopic grading system for Barrett's esophagus: the Prague C & M criteria.
abstract: OBJECTIVE
  Barrett's esophagus (BE) is a premalignant condition for esophageal adenocarcinoma, its diagnosis relying initially on recognition of a columnar-lined distal esophagus. We aimed to develop and validate explicit, consensus-driven criteria for the endoscopic diagnosis and grading of BE.
  
  
  METHODS
  An international working group agreed on criteria and developed materials for their formal evaluation using video-endoscopic recordings gathered in a standardized manner in 29 patients. The criteria included assessment of the circumferential (C) and maximum (M) extent of the endoscopically visualized BE segment as well as endoscopic landmarks. The recordings were scored according to these criteria by a separate international panel of 29 endoscopists.
  
  
  RESULTS
  The Prague C & M Criteria give explicit guidance on the endoscopic recognition of BE and grading of its extent. The overall reliability coefficients (RC) for the assessment of the C & M extent of the endoscopic BE segment above the gastroesophageal junction were 0.95 and 0.94, respectively. The rates of exact agreement (for C & M values) for pairwise comparisons of individual patient values were 53% and 38%, respectively, whereas the values for agreement within a 2-cm interval were 97% and 95%, respectively. The overall RC for endoscopic recognition of BE >/=1 cm was 0.72, whereas for BE <1 cm, it was 0.22. The RCs for recognizing the location of the gastroesophageal junction and the diaphragmatic hiatus were 0.88 and 0.85, respectively.
  
  
  CONCLUSIONS
  The Prague C & M Criteria have high overall validity for the endoscopic assessment of visualized BE lengths.
authors.affiliation: Department of Veterans Affairs Medical Center, University of Kansas School of Medicine, Kansas City, Missouri, USA. psharma@kumc.edu
authors.forename: Prateek
authors.initials: P
authors.lastname: Sharma
authors.forename: John
authors.initials: J
authors.lastname: Dent
authors.forename: David
authors.initials: D
authors.lastname: Armstrong
authors.forename: Jacques J G H M
authors.initials: JJ
authors.lastname: Bergman
authors.forename: Liebwin
authors.initials: L
authors.lastname: Gossner
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Hoshihara
authors.forename: Janusz A
authors.initials: JA
authors.lastname: Jankowski
authors.forename: Ola
authors.initials: O
authors.lastname: Junghard
authors.forename: Lars
authors.initials: L
authors.lastname: Lundell
authors.forename: Guido N J
authors.initials: GN
authors.lastname: Tytgat
authors.forename: Michael
authors.initials: M
authors.lastname: Vieth
mesh_terms: D001471:Barrett Esophagus / Q000145:classification / Q000473:pathology*; D004724:Endoscopy; D006801:Humans