title: Fecal occult blood and flexible sigmoidoscopy screening for colorectal cancer: modeling the impact on colonoscopy requirements and cancer detection rates.
abstract: OBJECTIVE
  The aim of this study was to estimate the colonoscopy requirements and the likely impact of fecal occult blood and flexible sigmoidoscopy screening on the detection of colorectal cancer by using previously published data.
  
  
  METHODS
  Fecal occult blood and flexible sigmoidoscopy screening programs were applied to the 2.04 million subjects aged 50-65 years, at a participation rate of 40%. The following strategies were evaluated: Fecal occult blood testing with colonoscopy follow up of all positive tests; flexible sigmoidoscopy with colonoscopy follow up of all adenomatous polyps; and flexible sigmoidoscopy with colonoscopy follow up of all adenomatous polyps > 10 mm in size.
  
  
  RESULTS
  The fecal occult blood program detected 5.6% of all colorectal cancer cases at a rate of 2,914 colonoscopies/percentage of detection of colorectal cancer. The flexible sigmoidoscopy program detected 14% of all colorectal cancer cases at a rate of 8,160 colonoscopies/percentage of detection of colorectal cancer. The flexible sigmoidoscopy program with follow up of adenomatous polyps > 10 mm in size detected 13% of all colorectal cancer cases at a rate of 1,230 colonoscopies/percentage of detection of colorectal cancer.
  
  
  CONCLUSIONS
  Flexible sigmoidoscopy screening followed by colonoscopic follow up of adenomatous polyps > 10 mm in size is the most efficient screening strategy in terms of colonoscopies generated and cases of colorectal cancer detected.
authors.affiliation: Departments of Medicine, University of Western Australia, Australia. jolynyk@cyllene.uwa.edu.au
authors.forename: J K
authors.initials: JK
authors.lastname: Olynyk
authors.forename: C F
authors.initials: CF
authors.lastname: Platell
authors.forename: J A
authors.initials: JA
authors.lastname: Collett
mesh_terms: D018256:Adenomatous Polyps / Q000175:diagnosis; D000368:Aged; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D005500:Follow-Up Studies; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D008962:Models, Theoretical; D009780:Occult Blood; D012812:Sigmoidoscopy