A new study suggests that taking aspirin regularly over several years may help prevent gastrointestinal cancers. The results of the study were presented recently at an American Association for Cancer Research meeting in Philadelphia.

Although results of the study showed a 20% lower risk of cancers of the gastrointestinal tract, especially in the colon and rectum, among people taking aspirin, the lead researcher, Yin Cao, a postdoctoral research fellow at the Harvard School of Public Health in Boston, doesn’t think people should start taking aspirin to prevent cancer until more research is done. In addition, patients and their doctors need to consider the potential risks of taking aspirin, including stomach bleeding. Still, the researcher indicated that the data suggest that along with the benefits of aspirin in the prevention of heart attacks and strokes, long-term regular aspirin use may have even more significant health benefits than known before.

The benefit of aspirin in reducing overall cancer risk appeared to depend on how much one took. The more aspirin taken, the more the risk was reduced. Amounts ranged from less than one aspirin a week to 15 or more, the researchers said. Getting the biggest benefit from aspirin required taking it for at least 16 years. The benefit was no longer seen within four years of stopping it, the researchers found. According to the study authors, the association of aspirin with reduced cancer risk was the same for women and men regardless of race, history of diabetes, family history of cancer, weight, smoking, regular use of other painkillers, or taking multivitamins.

Although aspirin is recommended for most people who have had a heart attack and has some benefits for cancer risk as well, at this point the American Cancer Society does not recommend that people use aspirin specifically to prevent cancer because it is not clear that the benefits with respect to cancer outweigh the risks. While not common, aspirin can cause serious, even occasionally fatal, stomach bleeding, even at low doses.