Objective: Quantitative information on adverse reactions associated with colorectal cancer (CRC) screening tests is useful to estimate the balance between benefit and risk in different strategies.
Setting: Six Italian screening centres.
Methods: Thirty-day active follow-up (interview about side-effects and acceptability of the screening procedure and review of hospital admissions) among average-risk people undergoing flexible sigmoidoscopy (FS), total colonoscopy (TC), fecal immunochemical test (FIT) in a multicentre randomized trial of CRC screening. Multivariable logistic models were used to assess determinants of completion rate and self-reported pain.
Results: The attendance rate following the first invitation and mail reminder was 28.2% (1696/6018) in the FS and 23.0% (1382/6021) in the TC arm. Response rate to the 30-day follow-up questionnaire was 88.6% (1502/1696) among people undergoing FS, and 86.7% (1198/1382) among those undergoing TC. The proportion of people complaining of serious reactions following bowel preparation (odds ratio [OR], 5.17; 95% confidence interval [CI] 3.70-7.24) or reporting severe pain immediately after the exam (OR, 1.86; 95% CI 1.47-2.34) was higher for TC than for FS. The most common post-procedural complaints were abdominal distension and pain. People mentioning pain or bowel distension following preparation were more likely to report severe pain both after FS (OR, 2.13; 95% CI 1.52-2.97) and TC (OR: 2.03; 95% CI 1.41-2.90). The 30-day hospitalization rate was similar after FS, TC and FIT.
Conclusions: Screenees reported higher pain levels after TC than FS. The proportion of people complaining of severe side effects after discharge was similar. Bowel preparation was poorly tolerated by people undergoing TC. Subjects' reactions to the bowel preparation was predictive of post-procedural discomfort. A commitment of at least 48 hours was required of people undergoing TC, compared with 3-4 for FS.