And the best way to prevent cancer may be…

Aspirin’s heart benefits have been widely known for years. It’s become one of the top prescriptions for preventing heart attacks and other cardiac events. But some new data from a trio of articles published in the British journal Lancet shows even more potential benefits from this common, over-the-counter medication.

Researchers found that a low daily dose of aspirin (75-300mg) cut cancer risk by about 25 percent after only three years. It also reduced the risk of a cancer death by over 15 percent within five years. (This risk reduction took effect even sooner if the dose was higher than 300mg.) And if patients stayed on aspirin for longer, their cancer death risk went down by an impressive 37 percent.

Low-dose aspirin also appeared to significantly reduce the spread of cancers that did occur. By as much as half, in fact. (This effect was particularly strong in instances of bowel cancer.)

Of course, aspirin has faced its share of controversy over the years. In fact, many have observed that aspirin would probably never be approved by the FDA today as a drug. But being hundreds of years old, it was “grandfathered” into approval before the modern FDA approval process even took effect. 

Aspirin does have some well-known side effects. Things like as gastric bleeding, and thinning the blood (which probably contributes to its heart disease prevention). 

But despite these potential concerns about the safety of aspirin, it has a long history of use. In the 1960s and 70s, patients with severe arthritis were being prescribed up to one bottle of aspirin per day—and they survived.

In fact, aspirin is probably the most common prepared remedy ever used by men, women and children. After hundreds of years in use, you could say it has gone through the “mother” of all post-marketing surveillance. Which makes it a much better—and safer—bet than many of the newly approved drugs on the market today. And today, many brands of aspirin use enteric coatings that help prevent any gastric irritation.

What about the natural forms of aspirin you may have heard about? Indeed, Native Americans used the original, natural form of aspirin, white willow bark, for many healing purposes. But the reason aspirin has been synthesized for almost a century is because harvesting it from natural sources (like willow) is not always sustainable. So for practical purposes, you can stick with a synthetic aspirin.

“Short-term effects of daily aspirin on cancer incidence, mortality, and non-vascular death: analysis of the time course of risks and benefits in 51 randomised controlled trials,” Lancet 2012; 379(9,826): 1,602–1,612
“Effect of daily aspirin on risk of cancer metastasis: a study of incident cancers during randomised controlled trials,” Lancet 2012; 379(9,826): 1,591-1,601
“Effects of regular aspirin on long-term cancer incidence and metastasis: a systematic comparison of evidence from observational studies versus randomised trials,” Lancet Oncology 2012; 13(5): 518-527