title: Diagnostic value of self-reported symptoms in Danish outpatients referred with symptoms consistent with colorectal cancer.
abstract: OBJECTIVE
  To assess the association between self-reported symptoms and a diagnosis of colorectal cancer (CRC) in symptomatic outpatients without CRC risk factors, defined by a Danish expert group.
  
  
  METHODS
  A cross-sectional study of patients aged 40 years and older referred by general practitioners to two Danish surgical outpatient clinics for symptoms consistent with CRC during a 16-month period. CRC was diagnosed at endoscopy and through follow up. Before their first appointment, participants completed a questionnaire about symptoms.
  
  
  RESULTS
  The study included 2172 patients. Of these, 122 were diagnosed with CRC (5.6%). Median age was 61 years (range: 40-97) and 44.0% were men. All symptoms had high (93.4-96.8%) negative predictive values for CRC. The highest positive predictive values (PPV) were found for dark rectal bleeding (PPV: 20.6%) and CRC was diagnosed in a first-degree relative over the age of 50 years (PPV: 11.2%). At multiple logistic regression analysis dark rectal blood was the most important predictor of CRC (OR: 7.4). Other predictors were age 60 years or older (OR: 3.0), change in frequency of bowel movements (OR: 2.5), CRC diagnosed in a first-degree relative over the age of 50 years (OR: 2.6), male gender (OR: 2.2) and mono-symptomatic fresh rectal blood (OR: 1.7).
  
  
  CONCLUSIONS
  No self-reported symptoms presented by outpatients without CRC risk factors can be used accurately to identify patients with CRC with certainty. For clinical purposes self-reported symptoms seems thus not to be a useful accurate tool to distinguish between symptomatic outpatients with and without CRC.
authors.affiliation: Department of Surgery P, Aarhus Hospital, Aarhus University Hospital, Aarhus, Denmark. ncb@dce.au.dk
authors.forename: N C
authors.initials: NC
authors.lastname: Bjerregaard
authors.forename: A
authors.initials: A
authors.lastname: Tøttrup
authors.forename: H T
authors.initials: HT
authors.lastname: Sørensen
authors.forename: S
authors.initials: S
authors.lastname: Laurberg
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000150:complications* / Q000175:diagnosis* / Q000235:genetics; D003430:Cross-Sectional Studies; D003672:Defecation; D003718:Denmark; D042241:Early Diagnosis; D005260:Female; D006471:Gastrointestinal Hemorrhage / Q000209:etiology; D006306:Health Surveys; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods; D008487:Medical History Taking; D008875:Middle Aged; D009780:Occult Blood; D016017:Odds Ratio; D010045:Outpatients; D010358:Patient Participation; D012306:Risk; D012737:Sex Factors