Single-dose aspirin does not increase sensitivity of fecal immunochemical testing

Reference

Brenner H, Calderazzo S, Seufferlein T, et al. Effect of a single aspirin dose prior to fecal immunochemical testing on test sensitivity for detecting advanced colorectal neoplasms. A randomized clinical trial. JAMA 2019;321(17):1686-1692.

Synopsis

Based on previous observational studies, aspirin may increase subclinical bleeding and increase the detection of advanced adenomas by FIT. These investigators identified 2134 adults, aged 40 to 80 years, who were scheduled for colonoscopy. The included patients had no recent use of aspirin or other antithrombotic medications. Prior to colonoscopy, the patients randomly received (concealed allocation assignment) a single 300-mg dose of aspirin or placebo. In addition, all participants received 4 stool collection kits for each of 2 fecal immunochemical tests, including both a quantitative test and a qualitative test. Stool samples were collected at baseline and 2 days, 3 days, and 4 days after trial medication intake. Colonoscopy was conducted within 3 months of recruitment. Individuals who assessed all outcomes remained masked to treatment group assignment. Valid samples were obtained from more than 90% of participants. Advanced neoplasms were identified in 10.5% of patients, including 0.4% with colorectal cancer. Using intention-to-treat analysis, no significant group difference occurred in the sensitivity of detecting advanced neoplasms (30.4% in the placebo group and 40.2% in the aspirin group; nonsignificant difference of 9.8%). Of more interest to clinicians, there were no significant group differences in both the positive and negative prediction rates. The study was 90% powered to detect a 24-percentage-point difference in sensitivity between the intervention and control groups, so it may have been underpowered to detect smaller but still clinically meaningful differences in sensitivity.