title: The anatomical distribution of colorectal polyps at colonoscopy.
abstract: BACKGROUND
  Colorectal carcinoma is one of the most common causes of cancer-related deaths in Australia. The distribution of polyps in the colon may effect the efficacy of a screening modality. The aim of this study was to determine the age-matched anatomic location and histologic type of colorectal polyps observed at colonoscopy over a 10-year period at our endoscopy unit.
  
  
  METHODS
  Endoscopy reports on 2,578 patients were reviewed; polyp/lesion histology and location (left, right, or both) were determined in 2,553.
  
  
  RESULTS
  Of all polyps observed, 1,310 (51%) cases were left-sided, 510 (20%) were right-sided, and 733 (29%) were synchronous. Adenomas were present in 1,659 cases (65%); of these, 734 (44%) were left-sided only and 405 (24.5%) were right-sided only. Carcinoma was observed in 189 (7%) cases, of which 71 (37.5%) were left-sided only. There was an increased right-sided prevalence of adenoma or carcinoma with age (p = 0.0029).
  
  
  CONCLUSIONS
  This was not a screening study, but it has shown that a significant number of adenomas and carcinomas lie proximal to the splenic flexure. Thus, in the absence of left-sided lesions, it is expected that examination of the colon limited to the splenic flexure would miss 23% of such lesions. The increasing right-sided prevalence of these lesions with age suggests that evaluation of the proximal bowel is particularly important in older people.
authors.affiliation: Perth Teaching Hospital, Endoscopy Group, Perth, Western Australia, Australia.
authors.forename: K
authors.initials: K
authors.lastname: Patel
authors.forename: N E
authors.initials: NE
authors.lastname: Hoffman
mesh_terms: D018256:Adenomatous Polyps / Q000175:diagnosis*; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002278:Carcinoma in Situ / Q000175:diagnosis; D003106:Colon / Q000473:pathology*; D003111:Colonic Polyps / Q000175:diagnosis*; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012004:Rectal Neoplasms / Q000175:diagnosis*; D012007:Rectum / Q000473:pathology; D012189:Retrospective Studies