In the study, almost 900 people with Lynch syndrome, which predisposes carriers to colorectal and other cancers, took an aspirin or placebo twice a day from 1999 to 2005.
By 2010, those taking aspirin twice a day were found to be 60% less likely to develop colorectal cancer.
However, the benefits of the aspirin took a few years to become apparent.
Cancer rates among those who had taken aspirin for only two years were roughly the same as those taking the placebo. However, the most recent results, published in the medical journal The Lancet, showed a decreased incidence of cancer in those who took aspirin for an average of four-and-a-half years over those taking the placebo.
They showed that by the end of the study, colorectal cancer had been diagnosed in only 4% of the aspirin takers, compared to 7% of those taking the placebo.
A regular aspirin has also been shown to help prevent heart disease, so this latest news seems to suggest that a daily aspirin could help many people.
But don't run to the drugstore for bottles of aspirin just yet. As reported by National Public Radio:
The U.S. Preventive Services Task Force, controversial as it can sometimes be, has a recommendation stretching back to 2007 that says the evidence doesn't support people at average risk [for] cancer taking aspirin to prevent colorectal cancer. The benefits don't outweigh the risks.
And taking aspirin regularly has a number of risks: Its side effects include gastrointestinal ulcers, stomach bleeding and hemorrhagic stroke, in which a brain blood vessel bursts. Even more, the subjects in this study were taking a much higher does of aspirin (600 mg) than those taking it to prevent heart disease (80 mg).
And, the side effects of aspirin get worse the more aspirin you take.
So, the researchers are focused on figuring out the proper dosage. They are now recruiting 3,000 people with Lynch syndrome for a trial aimed at doing just that.
Another caveat is that that Bayer was one of the study’s sponsors. As reported in Forbes, Bayer has been funding cancer research for years.
Still, this experiment is significant, because it was the first randomized study that tested aspirin's effectiveness in cancer prevention.