Researchers said that an aspirin a day could keep polyps which could lead to colorectal cancer at bay and act as prevention for high risk people.

The study was conducted by Bernard Cole a professor of statistics at the University of Vermont in Burlington, Vermont and colleagues. They used data from four studies involving a total of 2,698 people from the United States, Canada, Britain, Denmark and France to see the effect of a daily dose of aspirin on these polyps. All the people in the study had a history of adenomas, a type of precancerous polyp, or colorectal cancer and were followed for three years.

The researchers noted that people who took aspirin daily had a 28 % lower chance of developing advanced adenomas than those who took a placebo. These people were also found to have a 17 % lower risk of developing any type of adenoma at all.

"If we can find a way to prevent those precancerous lesions, then we have a really good chance of preventing colon cancer," said Cole. The study findings appear in the Journal of the National Cancer Institute.

According to the World Health Organization colorectal cancer is responsible for 639,000 deaths worldwide and the answer in disease control is to detect the polyps via screening tests and remove them before they can turn cancerous.

Cole said, “Probably all colon cancers start off as these lesions or adenomas, and if they are not resected they can develop into colon cancer.”

The study’s findings corroborate earlier studies which showed aspirin’s beneficial qualities in polyp prevention. The study authors said, the “substantial size” of the lowered risk of developing colon cancer “indicates the potentially important health benefits of aspirin use.”

How exactly aspirin works to prevent polyps is “not well understood,” though one theory is that the pathway to carcinogenesis is somehow interrupted by aspirin, Cole said.

However regular aspirin use for people who did not have polyps or a prior history of colorectal polyps was not recommended due to the increased risk of bleeding associated with the medicine, Cole said. "The take-home message here is that when you are getting a colonoscopy, if an adenoma is found, you might want to discuss with your doctor whether aspirin use is something that you might want to do in order to prevent future adenomas," Cole said.

The research was funded by German aspirin maker Bayer AG. (Harkiran contributed to this report)