Daily use of aspirin may reduce the risk of colorectal adenomas, especially advanced lesions, according to the results of a study published in the Journal of the National Cancer Institute.
Colorectal cancer is a type of cancer that is highly preventable or curable in early stages through screening. In a majority of cases, colon cancer develops from small growths, or polyps, in the colon called adenomas. The larger the adenoma, the more likely it will eventually become cancerous.
Individuals who have adenomas are at an increased risk of developing future adenomas and also colon cancer. As a result these individuals are encouraged to undergo more stringent screening, such as colonoscopy, during which adenomas are removed to prevent the possibility that they may progress to cancer. In addition, researchers continue to evaluate the role of diet and other preventive factors that may help decrease the incidence of adenomas and colon cancer.
Researchers performed a meta-analysis on the data from all randomized, double-blind, placebo-controlled trials that have evaluated the use of aspirin for the prevention of colorectal adenomas. The data included four clinical trials with a total of 2,967 participants; these participants received 81-325 mg of aspirin per day. Among 2,698 participants who underwent colonoscopic follow-up after randomization, adenomas were found in 37% of those allocated to placebo and in 33% of those allocated to any dose of aspirin (advanced lesions were found in 12% and 9%, respectively).
The researchers concluded that “aspirin is effective for the prevention of colorectal adenomas in individuals with a history of these lesions.”
 Cole BF, Logan RF, Halabi S, et al. Aspirin for the chemoprevention of colorectal adenomas: Meta-analysis of the randomized trials. Journal of the National Cancer Institute. 2009; 101:256-266.