Aspirin use decreases the risk of gastrointestinal cancers

Research by Cao et al published in JAMA Oncology suggests that regular aspirin use may be associated with lower risk of certain cancers.

The investigators looked at data on approximately 136,000 individuals who enrolled at two large US prospective cohort studies, the Nurses’ Health and Health Professionals studies. 

Among the 88 084 women and 47 881 men who underwent follow-up for as long as 32 years, 20 414 cancers were detected among women while 7571 cancers were found in men. Compared with nonregular use, regular aspirin use was associated with a lower risk for overall cancer, which was primarily due to a lower incidence of gastrointestinal tract cancers especially colorectal cancers. The benefit of aspirin on gastrointestinal tract cancers appeared evident with the use of at least 0.5 to 1.5 standard aspirin tablets per week; the minimum duration of regular use associated with a lower risk was 6 years. Among individuals older than 50 years, regular aspirin use could prevent 33 colorectal cancers per 100 000 person-years (PAR, 17.0%) among those who had not undergone a lower endoscopy and 18 colorectal cancers per 100 000 person-years (PAR, 8.5%) among those who had.

The researchers found that taking aspirin regularly—defined twice a week or more—for at least six years was associated with a 19% drop in risk for colon and rectum cancers, a 15% lower risk for gastrointestinal tract cancers and a 3% lower risk for cancers in general. The researchers did not find a link between regular aspirin use and risk reduction for some other cancers, including cancers of the breast, prostate and lung.

The benefits for GI cancers seemed to manifest even with a lower dose of aspirin, starting with half a standard aspirin tablet weekly. The authors found that taking aspirin regularly could prevent anywhere from 8-17% of colorectal cancers in people older than 50.

The authors concluded that long-term aspirin use was associated with a modest but significantly reduced risk for overall cancer, and may prevent a substantial proportion of colorectal cancers and thus complement the benefits of screening.