Low-Dose Aspirin and the Prevention of Colorectal Cancer in Inflammatory Bowel Disease

Background: Patients with inflammatory bowel disease (IBD) are at increased risk of colorectal cancer (CRC). However, the chemopreventive role of aspirin remains uncertain due to conflicting findings in prior studies. Methods: The study sought to evaluate the association between long-term aspirin use and the risk of CRC and all-cause mortality in patients with IBD. We conducted a nationwide propensity score–matched cohort study using Taiwan’s National Health Insurance Research Database and Cancer Registry from 2008 to 2022. Time-dependent Cox models and Fine and Gray competing risk models were applied. Results: Among 2743 matched aspirin users and 2743 nonusers, aspirin use was associated with reduced CRC risk (adjusted hazard ratio, 0.42; 95% confidence interval, 0.31-0.57) and lower all-cause mortality (adjusted hazard ratio, 0.66; 95% confidence interval, 0.58-0.74). A dose-response relationship was found for cumulative exposure, while optimal daily intensity was near 80 mg/d. Conclusions: Long-term use of low-to-moderate-dose aspirin was associated with reduced risks of CRC and mortality in patients with IBD. These findings support aspirin’s potential as a chemopreventive agent and justify further randomized trials.