Taking either high or low dose aspirin reduces the chances the people with colorectal polyps (adenomas) will get more.
A combined analysis of three randomized controlled trials that compared taking aspirin to a placebo after adenomas were removed found that people who took a daily low dose or baby aspirin had almost a 20 percent lower chance of another adenoma during their next colonoscopy. High-dose or regular adult strength aspirin reduced risk of polyp recurrence by about 15 percent.
Any aspirin reduced the risk of advanced adenomas by more than 35 percent.
Advanced adenomas include polyps over 10 millimeters or polyps that are especially risky for developing into cancer including those with significant villous features,high-grade dysplasia, or early invasive cancer.
In the three studies, over 2300 people with polyps on their initial colonoscopy were randomly assigned to aspirin or a placebo in the three studies, and 2,175 had a second colonoscopy to look for new polyps.
F. Gao and colleagues concluded,
This meta-analysis suggests that aspirin prevents recurrent colorectal adenomas among patients with a history of colorectal adenomas.
SOURCE: Gao et al., Colorectal Disease, Volume 11, Number 9, November, 2009.