An Aspirin A Day Keeps Cancer At Bay, New Study Shows

Should you take an aspirin every day to prevent some types of cancer? The evidence is growing, and it all points to the same answer: yes.

In 2015, the US Preventive Services Task Force, a science-guided panel that reviews the evidence for a wide range of treatments, recommended regular low-dose aspirin use for people between the ages of 50 and 69 as a way to prevent heart attacks, strokes, and some types of cancer. For people younger than 50 or older than 69, the USPSTF said that the evidence was inconclusive.

The 2015 recommendations came with a caveat: long-term aspirin use carries a slightly increased risk of bleeding in the stomach and intestinal tract, and a small increase in the risk of a hemorrhagic stroke–although it reduces the risk of ischemic strokes. (Ischemic strokes are caused by blood clots in the brain, while hemorrhagic strokes are caused by bleeding. Aspirins reduces the blood's ability to clot, so this tradeoff makes sense physiologically.)

Then in 2016, a study by Yin Cao and colleagues at Harvard found that aspirin use reduced the risk of cancers, especially colon cancer. To be specific, they found a benefit from taking 0.5 to 1.5 aspirin tablets per week for at least 6 years (a standard tablet is 325 mg). For people who followed this regimen, the risk of colon cancer was about 19% lower.

Now, a new study also led by Yin Cao and others at Harvard, just reported in the annual meeting of the American Association for Cancer Research, shows even clearer benefit. They looked at long-term results in a group of 130,000 women (mostly nurses) and men (doctors and other health professionals) who have been followed since the 1980s. Overall, woman had a 7% reduction in the relative risk of dying from any cause and men had a 11% reduction.

Most of the reduction in mortality was due to the reduced risk in dying from colon cancer, breast cancer, and prostate cancer. Just as with the previous study, the benefit appeared in people who took 0.5 to 1.5 aspirin tablets per week for at least six years.

A decrease in the risk of dying by 7-11% seems like a mighty nice benefit from such a simple treatment. For those (like me) whose stomach is upset by aspirin, a low-dose aspirin tablet taken with food may be easier to tolerate. The low-dose pill contains 81mg, one-fourth of a standard tablet, so 2-6 of these per week is equivalent to the 0.5-1.5 tablets that provided a benefit in the latest study.