Influence of aspirin on prevention of colorectal cancer: an updated systematic review and meta-analysis of randomized controlled trials.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 33682036 · doi:10.1007/s00384-021-03880-3
What was done
Authors searched Medline/PubMed, Ovid, Web of Science, and Cochrane Library for randomized controlled trials comparing daily aspirin to placebo in healthy individuals. The primary outcomes were the incidence of colorectal adenomas and advanced lesions (adenomas with villous component, diameter >=1 cm, high-grade dysplasia, or invasive cancer).
What was found
A total of 15 articles representing 11 RCTs were included. At 3 years, aspirin significantly reduced colorectal adenoma risk (RR = 0.84, P < 0.05) but not advanced lesions (RR = 0.82, P = 0.10). At 5 years, aspirin significantly reduced advanced lesions (RR = 0.68, P < 0.05) but not adenomas (RR = 0.87, P = 0.22). Beyond 5 years, aspirin showed no statistically significant effect on advanced lesions (HR = 0.82, P = 0.07) or adenomas (HR = 0.99, P = 0.82).
Why it matters
This review demonstrates that daily aspirin provides short-to-medium-term reduction in colorectal adenomas and advanced lesions, but pooled randomized evidence does not demonstrate protective efficacy beyond 5 years.
Limits
The abstract does not report participant counts, 95% confidence intervals, specific dosing regimens, or adverse outcomes such as gastrointestinal bleeding.
Cited by
- supports Aspirin is used as a repurposed drug to reduce the risk or progression of colon cancer.