title: The prevalence of small, flat colorectal cancers in a western population.
abstract: OBJECTIVE
  Small, flat colorectal cancers have been widely reported in the Japanese literature but are thought to occur rarely outside Japan. The aim of this retrospective cohort study was to clarify the prevalence of flat colorectal cancer in a Western population.
  
  
  METHODS
  One thousand and twenty-six consecutive colonoscopies performed by a single experienced endoscopist were retrospectively analysed over a two-year period. The morphology, site and histological appearance of all documented colorectal cancers (CRC) were recorded.
  
  
  RESULTS
  Forty-seven cases of CRC were detected, five of which (10%) demonstrated flat configuration. Flat cancers varied between 8 and 15 mm in diameter (mean 11 mm). Histologically, all flat lesions were moderately differentiated Dukes A adenocarcinomas. Two of these cancers contained no adenomatous component.
  
  
  CONCLUSIONS
  This study confirms that small, flat colorectal cancers are not an uncommon finding at colonoscopy in Western patients. Compared to polypoid neoplastic lesions, flat cancers appear to undergo malignant change at a smaller size.
authors.affiliation: Wolfson Unit for Endoscopy Academic Department of Histopathology, St Mark's Hospital, Harrow, UK.
authors.forename: N
authors.initials: N
authors.lastname: Suzuki
authors.forename: I C
authors.initials: IC
authors.lastname: Talbot
authors.forename: B P
authors.initials: BP
authors.lastname: Saunders
mesh_terms: D000230:Adenocarcinoma / Q000453:epidemiology* / Q000473:pathology / Q000601:surgery; D000368:Aged; D000369:Aged, 80 and over; D003082:Colectomy / Q000379:methods; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012189:Retrospective Studies; D006113:United Kingdom / Q000453:epidemiology