One main concern for long-term aspirin use is the potential for gastrointestinal bleeding. Participants in more than one of the CVD prevention trials had a significant increase in gastrointestinal bleeding.1,2 While gastrointestinal bleeding falls within our wheelhouse, we are not always privy to a patient’s risk factors for bleeding. For example, patients may receive multiple courses of steroids for arthritis or chronic pulmonary disorders and not take concomitant acid suppression. These risks are dynamic and require continual reassessment as individuals age, new diagnoses are made, and new medications are started or stopped by providers other than their gastroenterologist. If a patient is taking aspirin, regardless of the reason, we need to make sure it is correctly recorded in their medication list, especially if they are obtaining it over the counter. This is one area where we should definitely play a role.
There is a population in which I do recommend aspirin for reduction of CRC chemoprevention – individuals with Lynch syndrome. I believe the data for the protective effects of aspirin on CRC incidence are much stronger for individuals with Lynch syndrome than the average-risk population. The CAPP2 trial was a randomized trial with a two-by-two factorial design where individuals with Lynch syndrome were randomly assigned to aspirin 600 mg/day or aspirin placebo or resistant starch or starch placebo for up to 4 years. The primary endpoint of this trial was development of CRC (unlike the CVD trials referred to earlier in this article). Long-term follow-up of the CAPP2 trial participants found a significantly decreased risk of CRC after 2 years of aspirin use (hazard ratio, 0.56, 95% confidence interval, 0.34-0.91).4 The current CAPP3 trial will answer questions about the effectiveness of lower doses of aspirin (100 mg and 300 mg).
The recommendation for aspirin use for CRC chemoprevention in average-risk individuals depends on multiple factors (life expectancy, determination of CVD risk, and dynamic assessment of gastrointestinal bleeding risk) that are outside the purview of a gastroenterologist who sees the patient only at a screening or surveillance colonoscopy. This is not in our lane. What is in our lane, however, is the recommendation for aspirin use for CRC chemoprevention in select high-risk populations such as individuals with Lynch syndrome.
Dr. Weiss is associate professor in the division of gastroenterology and hepatology and director of the University of Wisconsin Gastroenterology Genetics Clinic at University of Wisconsin School of Medicine and Public Health. She reports receiving research support from Exact Sciences as a site-PI of a multisite trial.
References
1. Liang PS et al. Clin Gastroenterol Hepatol. 2021 Jul;19(7):1327-36. doi: 10.1016/j.cgh.2021.02.014
2. Katona BW and Weiss JM. Gastroenterology. 2020 Jan;158(2):368-88. doi: 10.1053/j.gastro.2019.06.047
3. United States Preventive Services Task Force. “Aspirin Use to Prevent Cardiovascular Disease: Preventive Medication.” Accessed April 5, 2022.
4. Burn J et al. Lancet. 2020 Jun13;395(10240):1855-63. doi: 10.1016/s0140-6736(20)30366-4
