Long-Term Follow-up of Prospective U.S. Cohorts Shows Reduced Risk of GI Tract Cancers With Regular Aspirin Use

Key Points

  • Regular aspirin use was associated with a reduced risk for GI tract cancers among both men and women.
  • No significant effect was observed for risk of breast cancer or prostate cancer.

In a long-term follow up of two large U.S. prospective cohorts reported in JAMA Oncology, Cao et al found that regular use of aspirin was associated with a reduced risk of gastrointestinal (GI) tract cancers. In 2015, the U.S. Preventive Services Task Force recommended the use of aspirin in individuals with specific cardiovascular risk profiles for prevention of cardiovascular disease and colorectal cancer.

Study Details

The study included 135,965 health-care professionals (88,084 women and 47,881 men) in the Nurses’ Health Study cohort and the Health Professionals Follow-up Study cohort. Participants provided information on aspirin use for any reason every 2 years. During follow-up of up to 32 years, 20,414 cancers were identified in women and 7,571 were found in men.

Reduced Risk

Compared with nonregular use, regular use of aspirin, defined as use of standard or low-dose aspirin at least two times per week, was associated with a lower overall risk for cancer on multivariate analysis (relative risk [RR] = 0.97, 95% confidence interval [CI] = 0.94–0.99); relative risks were 0.98 (95% CI = 0.95–1.01) among women and 0.93 (95% CI = 0.89–0.97) among men. The reduced risk primarily reflected a reduced risk of GI cancers, with relative risks of 0.85 (95% CI = 0.80–0.91) overall, 0.87 (95% CI = 0.80–0.95) among women, and 0.82 (95% CI = 0.75–0.90) among men; relative risks for colorectal cancer were 0.81 (95% CI = 0.75–0.88) overall, 0.84 (95% CI = 0.76–0.93) among women, and 0.77 (95% CI = 0.68–0.87) among men.

No significant effect was observed for breast cancer in women (RR = 0.98, 95% CI = 0.93–1.02), advanced prostate cancer (RR = 0.97, 95% CI = 0.85–1.10), or for lung cancer overall (RR = 1.05, 95% CI = 0.97–1.14; relative risk = 1.11, 95% CI = 1.00–1.23, among women and 0.96, 95% CI = 0.84–1.11, among men.

Population Benefit

The benefit of aspirin for reducing the risk of GI tract cancers appeared to be evident with use of at least 0.5 to 1.5 standard aspirin tablets per week, and the minimum duration of regular use associated with preventive benefit was 6 years. It was estimated that among individuals aged > 50 years, regular aspirin use could prevent 33 colorectal cancers per 100,000 person-years in those who had not undergone lower endoscopy and 18 per 100,000 person-years in those who had undergone lower endoscopy.

The investigators concluded: “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.”

The study was supported by the National Institutes of Health.

Andrew T. Chan, MD, MPH, of Massachusetts General Hospital, is the corresponding author of the JAMA Oncology article.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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