Aspirin reduces cancer risk, study says

If all you had to do to prevent cancer was take an aspirin every day, that would be amazing.

Of course, it's not quite that simple. But new research supports the idea that an aspirin does more than relieve pain and prevent cardiovascular events in some people: It also may guard against certain kinds of cancers.

A study in the Lancet looking at data from more than 25,000 patients, following up on previous trials. Researchers found that a daily aspirin reduced cancer risk by at least 20 percent during the 20-year period. Most study participants were from the United Kingdom.

When looking at specific cancers, aspirin appeared to lower esophageal cancer death risk by 60 percent, bowel cancer death risk by 40 percent, lung cancer death risk by 30 percent, and prostate cancer death risk by 10 percent. Other cancers had a smaller number of deaths associated with them in the sample of participants, so it was hard to define a risk reduction for them.

In a previous study, researchers showed that low-dose aspirin taken over a five-year period appears to lower the risk of colorectal cancer.

For a person who's healthy, middle aged, and has more than a 10 percent chance of a vascular event, heart attack or stroke, taking a daily aspirin is already recommended, said Dr. Peter Rothwell of the University of Oxford in England.

"If you accept that the current balance favors treatments in a lot of people anyway, these fairly large benefits from a cancer point of view, I think, just tip the balance further," he said at a news conference Monday.

Aspirin appears to affect the early development of cancer cells, Rothwell told the BBC. Aspirin may reduce the rate of growth of cancer cells, and even prompt the mutated cells to self-destruct.

Another potential explanation is that aspirin reduces inflammation, including chronic inflammation, which can lead to cancer, said Dr. Ed Kim, lung cancer expert at the University of Texas M.D. Anderson Cancer Center, who was not involved with the study.

Because the risk of cancer goes up with age, the benefit from aspirin also goes up with age, and it also appears to increase the longer you take aspirin, Rothwell said.

It would be sensible to begin taking the daily aspirin before your cancer risk goes up - perhaps around age 45, Rothwell said. He suggests continuing the regimen for 25 or 30 years and then stopping, because the risk of bleeding from aspirin goes up dramatically at age 75.

Aspirin can impair platelets, the part of the blood that helps clotting occur, Kim said. As a result, bleeding may not stop immediately if an older person taking aspirin has a bruise or cut. Bleeding in the stomach and intestine due to irritation may also occur, which can be dangerous.

The U.S. Preventive Services Task Force, the same group that some 40-something women are still angry at because of last year's mammogram guidelines, recommends against taking aspirin to prevent colorectal cancer in people with average risk for that disease.

Dr. Igor Astsaturov of the Fox Chase Cancer Center in Philadelphia, Pennsylvania, said that if he were a primary care physician, he would recommend aspirin to patients based on the benefits for cancer and cardiovascular risk. He noted that the most pronounced effects for cancer prevention were seen around age 65 in this study, but that the long-term users are the ones who got the most benefit.

Kim said he will personally "strongly consider" taking the daily aspirin as a result of this study, but would not automatically start any patient on it without discussing all risks and benefits. This research does not definitively prove that aspirin protects against cancer, he said, and it has its own limitations.

Bottom line: The results are not entirely conclusive, but if you are interested, ask your doctor if aspirin is right for you.