Symptoms do not predict colorectal cancer in an FOB screened population.

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.