title: Flat colorectal neoplasms and the impact of the revised Vienna Classification on their reporting: a case-control study in UK and Japanese patients.
abstract: OBJECTIVE
  The prevalence and interpretation of flat colorectal neoplasms in the East or West remain highly variable. Several factors may contribute to this variability including differences in reporting techniques between Japanese and Western histopathologists when lesions are classified. The aims of this study were (i) to determine the frequency and characteristics of flat colorectal neoplasms in British and Japanese patients, (ii) to examine whether histopathological discrepancies exist between Western and Japanese-trained pathologists applying conventional classification methods and (iii) to determine the impact of the revised Vienna Classification on any differences observed.
  
  
  METHODS
  One hundred and forty-four patients in the United Kingdom with neoplastic lesions prospectively identified by a colonoscopist, fully-trained in Japan, were age and gender-matched with 144 Japanese patients with neoplastic lesions detected by the same colonoscopist. Two British and two Japanese pathologists were independently asked to assess all neoplasms using both conventional and revised Vienna Classification methods.
  
  
  RESULTS
  No significant difference in the frequency of flat neoplasms was found between British and Japanese patients; however, flat neoplasia from Japanese patients tended to contain more advanced pathologies. Discrepancies in histological diagnoses were observed between pathologists but which were reduced with the revised Vienna Classification. Japanese pathologists tended to diagnose higher grades of dysplasia for the same lesion compared to their British counterparts.
  
  
  CONCLUSIONS
  The frequency of flat neoplasms in British and Japanese patients is similar. However, Japanese lesions, especially flat (IIb) and slightly depressed (IIc) neoplasms tend to be more biologically aggressive. The revised Vienna Classification achieves greater consensus.
authors.affiliation: Wolfson Unit for Endoscopy, St Mark's Hospital, Watford Road, Harrow, Middlesex HA1 3UJ, UK. n.suzuki@imperial.ac.uk
authors.forename: Noriko
authors.initials: N
authors.lastname: Suzuki
authors.forename: Ashley B
authors.initials: AB
authors.lastname: Price
authors.forename: Ian C
authors.initials: IC
authors.lastname: Talbot
authors.forename: Kouichi
authors.initials: K
authors.lastname: Wakasa
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Arakawa
authors.forename: Shingo
authors.initials: S
authors.lastname: Ishiguro
authors.forename: Chris
authors.initials: C
authors.lastname: Fraser
authors.forename: Brian P
authors.initials: BP
authors.lastname: Saunders
mesh_terms: D044466:Asian People; D015179:Colorectal Neoplasms / Q000145:classification* / Q000175:diagnosis / Q000453:epidemiology / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D006113:United Kingdom; D044465:White People