Regular, low doses of aspirin for a minimum of 6 years correlated with a small, yet significant reduction in overall cancer risk, due primarily to reductions in risks for colorectal cancer and gastrointestinal cancer.1

The US Preventive Services Task Force recommends the regular use of aspirin among American adults to prevent colorectal cancer and cardiovascular disease. This study, published in JAMA Oncology, explored possible correlations of aspirin use across a range of doses and durations with the risk of other cancer subtypes.

Researchers led by Andrew Chan, MD, MPH, of the Massachusetts General Hospital, Boston, Massachusetts, examined data from 2 large, prospective cohort studies. The Nurses’ Health Study collected data on 88 084 women age 30 to 55 years at enrollment in 1976, with a final follow up in June 2012. The Health Professionals Follow-up Study collected data on 47 881 men age 40 to 75 years at enrollment in 1986, with a final follow-up in January 2010. Both cohorts reported on aspirin use biennially.

Regular aspirin use correlated with a lower risk for overall cancer (relative risk [RR], 0.97; 95% CI, 0.94-0.99), primarily due to a lower incidence of gastrointestinal cancers (RR, 0.85; 95% CI, 0.80-0.91), particularly colorectal cancer (RR, 0.81; 95% CI, 0.75-0.88).

In participants older than 50 years who had not undergone a lower endoscopy, regular aspirin use prevented 33 colorectal cancers per 100 000 person-years (population-attributable risk [PAR], 17.0%). In participants older than 50 years who had undergone a lower endoscopy, regular aspirin use prevented 18 colorectal cancers per 100 000 person-years (PAR, 8.5%).

Cancer risk reductions were evident with a range of 0.5 to 1.5 standard aspirin tablets per week. Regular aspirin use was not correlated with the risk for breast, advanced prostate, or lung cancers.

“Long-term aspirin use was associated with a modest but significantly reduced risk for overall cancer, especially gastrointestinal tract tumors. Regular aspirin use may prevent a substantial proportion of colorectal cancers and complement the benefits of screening,” wrote the researchers.

REFERENCE

1. Cao Y, Nishihara R, Wu K,  et al. Population-wide impact of long-term use of aspirin and the risk for cancer [published online ahead of print March 3, 2016]. JAMA Oncol. doi:10.1001/jamaoncol.2015.6396.