Symptoms do not predict colorectal cancer in an FOB screened population

Scott Med J. 2013 May;58(2):95-8. doi: 10.1177/0036933013482638.


Background and aims: The Scottish Bowel Screening Programme aims to detect cancer in asymptomatic individuals. We aimed to measure the prevalence of lower gastrointestinal symptoms in faecal occult blood (FOB) screen-positive patients, to correlate the symptoms with neoplasia and to compare the predictive value of FOB screening with urgent symptomatic referrals in Ayrshire and Arran.

Methods: Data were collected prospectively on FOB screen-positive patients undergoing colonoscopy. Patients completed a symptom questionnaire. Positive predictive values (PPVs) for detecting neoplasia were calculated and a chi-square test was performed to determine any influence of symptoms in diagnosing neoplasia. Symptomatic patients undergoing colonoscopy via a general practice fast-track system were compared.

Results: A total of 378 FOB screen-positive patients were included. In all, 198 (52%) had colorectal symptoms. Overall, 32 were diagnosed with colorectal cancer and 93 had polyps . FOB positivity and symptoms gave a PPV of 34% for neoplasia. FOB positivity without symptoms gave a PPV of 32% for neoplasia. Urgent referral of symptomatic patients had a lower PPV of 21% for neoplasia (p < 0.001).

Conclusion: Half the FOB screen-positive patients had bowel symptoms. Symptoms in these patients had no correlation with an increased rate of neoplasia. The PPV for neoplasia is superior in symptomatic and asymptomatic screen-positive patients when compared to conventional urgent symptom-based referral.

Keywords: Bowel screening; colonoscopy; faecal occult blood; neoplasia.

MeSH terms

  • Colonoscopy*
  • Colorectal Neoplasms / complications
  • Colorectal Neoplasms / diagnosis*
  • Early Detection of Cancer
  • Female
  • Humans
  • Male
  • Occult Blood*
  • Prospective Studies
  • Symptom Assessment