title: Predictive value of common symptom combinations in diagnosing colorectal cancer.
abstract: BACKGROUND
  This study compared the diagnostic values of age and single symptoms of colorectal cancer with those of age and symptom combinations.
  
  
  METHODS
  Consecutive patients with lower gastrointestinal symptoms referred to a surgical clinic over a 12-year period were studied prospectively. The diagnostic value of age and common symptoms of bowel cancer, individually and in combination, was determined by measuring positive predictive value, sensitivity and specificity.
  
  
  RESULTS
  In total, 467 (5.5 per cent) of 8529 patients had colorectal cancer. Symptom combination analyses showed that patients presenting with rectal bleeding and change in bowel habit without anal symptoms had the highest risk of cancer. Those with rectal bleeding and perianal symptoms without change in bowel habit were at the lowest risk of having cancer. Symptom subgroups defined by age had positive predictive values for cancer that varied from less than 1 to 35 per cent.
  
  
  CONCLUSIONS
  Symptom combinations defined by age have greater diagnostic value than single symptoms alone.
authors: Department of Surgery, Queen Alexandra Hospital, Portsmouth, UK.
authors: M R
authors: MR
authors: Thompson
authors: R
authors: R
authors: Perera
authors: A
authors: A
authors: Senapati
authors: S
authors: S
authors: Dodds
mesh_terms: D015746:Abdominal Pain / Q000209:etiology; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D003951:Diagnostic Errors; D006471:Gastrointestinal Hemorrhage / Q000209:etiology; D006801:Humans; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies