Diagnostic value of self-reported symptoms in Danish outpatients referred with symptoms consistent with colorectal cancer

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. Method 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). Conclusion 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.