title: Prospective determination of distal colon findings in average-risk patients with proximal colon cancer.
abstract: BACKGROUND
  Recent guidelines indicate that colonoscopy and sigmoidoscopy are both acceptable options for screening average-risk patients for colorectal cancer. Retrospective studies have found that a majority of patients with cancer proximal to the splenic flexure have a normal screening flexible sigmoidoscopy.
  
  
  METHODS
  This was a multicenter, prospective description of colonoscopic findings and family history in consecutive patients with proximal colon cancer.
  
  
  RESULTS
  Among 116 prospectively identified average-risk patients with cancer proximal to the splenic flexure, 40 (34.5%) had neoplasia distal to the splenic flexure. The prevalence of patients with adenomas greater than or equal to 1 cm, with only one tubular adenoma less than 1 cm, and with only hyperplastic polyps were 16.4%, 8.6%, and 6.9%, respectively.
  
  
  CONCLUSIONS
  Most average-risk patients with cancer proximal to the splenic flexure will have a normal screening flexible sigmoidoscopy. These patients have an unexpectedly high prevalence of large distal adenomas, but the prevalence of both single small tubular adenomas and hyperplastic polyps alone is similar to that expected during screening of the general population. Clinicians and payers should continue to seek methods to improve the cost-effectiveness and availability of screening colonoscopy in average-risk persons.
authors.affiliation: Department of Medicine, Division of Gastroenterology/Hepatology, Indiana University School of Medicine, Indianapolis, USA.
authors.forename: D K
authors.initials: DK
authors.lastname: Rex
authors.forename: A
authors.initials: A
authors.lastname: Chak
authors.forename: R
authors.initials: R
authors.lastname: Vasudeva
authors.forename: T
authors.initials: T
authors.lastname: Gross
authors.forename: D
authors.initials: D
authors.lastname: Lieberman
authors.forename: I
authors.initials: I
authors.lastname: Bhattacharya
authors.forename: E
authors.initials: E
authors.lastname: Sack
authors.forename: M
authors.initials: M
authors.lastname: Wiersema
authors.forename: F
authors.initials: F
authors.lastname: Farraye
authors.forename: M
authors.initials: M
authors.lastname: Wallace
authors.forename: D
authors.initials: D
authors.lastname: Barrido
authors.forename: E
authors.initials: E
authors.lastname: Cravens
authors.forename: L
authors.initials: L
authors.lastname: Zeabart
authors.forename: D
authors.initials: D
authors.lastname: Bjorkman
authors.forename: T
authors.initials: T
authors.lastname: Lemmel
authors.forename: S
authors.initials: S
authors.lastname: Buckley
mesh_terms: D000230:Adenocarcinoma / Q000453:epidemiology / Q000235:genetics / Q000473:pathology*; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D003110:Colonic Neoplasms / Q000453:epidemiology / Q000235:genetics / Q000473:pathology*; D003111:Colonic Polyps / Q000453:epidemiology / Q000235:genetics / Q000473:pathology*; D003113:Colonoscopy / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D017678:Sex Distribution; D012811:Sigmoid Neoplasms / Q000453:epidemiology / Q000235:genetics / Q000473:pathology*; D012812:Sigmoidoscopy / Q000379:methods