By Dennis Thompson
Taking aspirin three or more times a week is associated with a lower risk of cancer death as well as death for any reason, a new study reports.
Low-dose aspirin reduced overall cancer death risk by 15% and all-cause death by 19% among more than 146,000 people who participated in a cancer screening trial conducted between 1993 and 2008, the study authors said.
"Our primary focus was really on colorectal cancer deaths, since there's a lot of evidence to suggest that aspirin use may lower risk of gastrointestinal deaths," said lead researcher Holli Loomans-Kropp, a cancer prevention fellow with the U.S. National Cancer Institute.
The study results support the standing recommendation of the U.S. Preventive Services Task Force (USPSTF), which says people 50 to 59 should take low-dose aspirin to prevent colon cancer if they're not at increased risk for bleeding.
Daily aspirin use as a preventive health measure has become controversial over the past few years, however.
In March, the American College of Cardiology and the American Heart Association changed their guidelines to restrict low-dose aspirin use to people at high risk for heart disease or stroke. The two groups argued that the bleeding risk from aspirin outweighed the heart benefits for healthy people.
The USPSTF continues to recommend low-dose aspirin for middle-aged people for heart health, if they have a 10% or greater chance of developing heart disease within the next decade.
The new study involved a re-analysis of data gathered during the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial, which was sponsored by the National Cancer Institute.
No one knows why aspirin might have this protective effect, but Loomans-Kropp said evidence points toward its anti-inflammatory action.
"Gastrointestinal cancers are highly inflammation-associated cancers, and where the strongest effect has been is with the gastrointestinal cancers," Loomans-Kropp said.
It's also possible that aspirin's blood-thinning effect might play a role, said Eric Jacobs, senior scientific director of epidemiology research at the American Cancer Society.
"Aspirin may help prevent cancer the same way that it helps prevent heart attacks, which is by blocking the activation of blood platelet cells," Jacobs said. "We know that activated platelets can release factors that help tumors grow, and activated platelets may also help cancers spread throughout the body."
People worried about colon cancer should talk with their doctor about getting screened for the disease, since a colonoscopy can remove polyps before they can develop into cancer, Jacobs said.
"Aspirin use is not the only way or the best way to lower risk of colorectal cancer," Jacobs said, adding that maintaining a healthy weight, being physically active, quitting smoking and eating less red meat also can help reduce your risk.
Anyone thinking about taking daily aspirin should discuss it with their doctor first, said Dr. Merry Jennifer Markham, a spokesperson for the American Society of Clinical Oncology and a cancer doctor with the University of Florida.
"It's important to have a discussion with the physician about whether the benefits of regular aspirin use outweigh the harms," Markham said. "I don't believe this is a one-size-fits-all approach, and must be individualized based on the individual person's other health issues and bleeding risks."
The new study was published online Dec. 4 in JAMA Network Open.