Overall mortality is reduced with long-term aspirin use, primarily due to decreased cancer-specific mortality, according to an observational study presented at the 2017 American Association for Cancer Research (AACR) Annual Meeting.1

“This was a very, very interesting study,” Manish Shah, MD, a gastrointestinal oncologist at Weill Cornell Medicine and New York-Presbyterian, New York, who was not affiliated with the study, told Cancer Therapy Advisor, “because it suggests for the first time that such an inexpensive drug can reduce not only the incidence of polyps and cancers, but it may also improve non-cancer survival.”

Follow-up data from cardiovascular disease trials suggest that long-term aspirin use may reduce the risk of cancer-specific mortality from colorectal, esophageal, lung, breast, and prostate cancers. The purpose of this study was to further examine this association.

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The observational study evaluated aspirin use and development of cancer among 86,206 women from the Nurses’ Health Study and 43,977 men from the Health Professionals Follow-up Study. Exclusion criteria included prior cancer, heart disease, or stroke. Use of aspirin was reported at baseline and every 2 years.

In the study, 22,094 women and 14,749 men died, of whom 8271 and 4591 died of cancer, respectively, during the 32 years of follow-up.

Regular aspirin use resulted in a decreased risk of overall mortality for women and men (risk ratio [RR], 0.93; 95% CI, 0.90-0.95 and 0.89; 95% CI, 0.86-0.93, respectively).

This was largely a result of a significant reduction in cancer-specific mortality with regular aspirin use among women (RR, 0.93; 95% CI, 0.89-0.97) and men (RR, 0.85; 95% CI, 0.80-0.90). This benefit was observed with 162 to 487.5 mg aspirin tablets per week taken for a minimum of 6 years. It is unclear whether a “baby” aspirin — 81 mg — provides the same benefit.

The risk reduction was particularly evident for colorectal (women: RR, 0.69; 95% CI, 0.59-0.81; men: RR, 0.70; 95% CI, 0.57-0.85), breast (RR, 0.89; 95% CI, 0.79-0.99), prostate (RR, 0.77; 95% CI, 0.65-0.90), and lung cancers (men only: RR, 0.86; 95% CI, 0.74-0.99).

According to Dr Shah, the reason for this benefit is “presumably by reducing inflammation although there are likely other mechanisms.”

Dr Shah also noted that “even though the investigators did a very good job controlling for everything they could, we should remember that this is not a randomized trial, so there may be inherent biases that we can’t control for.”

RELATED: Aspirin Use Does Not Reduce Risk of Colorectal Cancer Recurrence

The authors of the study cautioned in a press release that “we need to conduct additional work to balance these benefits against the harms of use, such as gastrointestinal tract bleeding and hemorrhagic stroke.”

A randomized trial for long-term aspirin use is unlikely to be conducted, Dr Shah said. Yet these data support the use of aspirin in high risk groups, including those with previous cancer or who are at high risk of developing cancer.


  1. Cao Y Stampfer M, Willett W, et al. Long-term aspirin use and total and cancer-specific mortality. Paper presented at: American Association for Cancer Research Annual Meeting 2017; April 1-5, 2017; Washington, D.C.
  2. Regular aspirin use is associated with lower cancer mortality [news release]. Washington, DC: American Association for Cancer Research; April 3, 2017. http://mb.cision.com/Public/3069 /2224884/92f4f1c28c85af40.pdf. Accessed April 4, 2017.