title: Can patients at high risk for significant colorectal neoplasms and having normal quantitative faecal occult blood test postpone elective colonoscopy?
abstract: BACKGROUND
  Common reasons for elective screening and surveillance colonoscopy, at predetermined intervals, are family or personal history of colorectal cancer (CRC) or advanced adenoma (AAP). Quantified, human haemoglobin (Hb)-specific, immunochemical faecal occult blood tests (I-FOBT) detect bleeding.
  
  
  OBJECTIVE
  To determine I-FOBT sensitivity for CRC or AAP before elective colonoscopy in patients at high-risk of cancer or advanced adenoma.
  
  
  METHODS
  Prospective double-blind study of 1000 ambulatory asymptomatic high-risk patients (555 family history of CRC, 445 surveillance for past neoplasm), who prepared three I-FOBTs before elective colonoscopy. I-FOBTs quantified as ngHb/mL of buffer by OC-MICRO instrument and results >or=50 ngHb/mL considered positive.
  
  
  RESULTS
  At colonoscopy, eight patients had CRC, 64 others had AAP. Sensitivity for CRC and/or AAP was the highest, 65.3% (95% CI 54.3, 76.3), when any of the three I-FOBTs was >or=50 ngHb (15.4%), with specificity of 87.5% (95% CI 86.4, 90.5) identifying all CRCs and 62% of AAPs.
  
  
  CONCLUSIONS
  All cancers or an AAP were detected every third I-FOBT-positive colonoscopy (47/154), so colonoscopy was potentially not needed at this time in 84.6% (846 patients). I-FOBT screening might provide effective supervision of high-risk patients, delaying unnecessary elective colonoscopies. This favourable evaluation needs confirmation and cost-benefit study by risk-group.
authors.affiliation: Department of Gastroenterology, Rabin Medical Center, Beilinson Hospital, Petach Tikva, Israel.
authors.forename: R
authors.initials: R
authors.lastname: Hazazi
authors.forename: P
authors.initials: P
authors.lastname: Rozen
authors.forename: M
authors.initials: M
authors.lastname: Leshno
authors.forename: Z
authors.initials: Z
authors.lastname: Levi
authors.forename: Z
authors.initials: Z
authors.lastname: Samuel
authors.forename: A
authors.initials: A
authors.lastname: Waked
authors.forename: A
authors.initials: A
authors.lastname: Vilkin
authors.forename: E
authors.initials: E
authors.lastname: Maoz
authors.forename: S
authors.initials: S
authors.lastname: Birkenfeld
authors.forename: Y
authors.initials: Y
authors.lastname: Niv
mesh_terms: D000236:Adenoma / Q000175:diagnosis*; D003113:Colonoscopy / Q000706:statistics & numerical data*; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000235:genetics; D004198:Disease Susceptibility; D004812:Epidemiologic Methods; D005260:Female; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D009780:Occult Blood
chemical_list: D006454:Hemoglobins