For the first time, the official federal health panel has recommended aspirin to protect against colorectal cancer, as well as heart attack and stroke. But the guidance is far from clear-cut, with age restrictions and numerous caveats.
The U.S. Preventive Services Task Force issued draft recommendations this week on the use of low-dose (81 mgm) aspirin for primary prevention of cardiovascular disease (CVD) and colorectal cancer (CRC) among adults aged 50-69 with an elevated risk of (but no prior history of) CVD, and for that same age group for prevention of CRC. However, the panel pointed out that the possible benefit for lowering one's risk of CRC only kicks in after 10 years of regular use.
In 2009, this panel had similar recommendations on the use of aspirin to prevent heart attacks in older men and strokes in older women, but this is the first time the USPSTF has opined on the use of aspirin to prevent any cancer.
The USPSTF consists of a group of independent experts in prevention of disease. Its members, appointed by the Secretary of Health and Human Services, include both specialists and primary care physicians. Their mandate is to weigh evidence on a variety of medical issues, based on their confidence in the reliability of the evidence base and issue their recommendations after their own statistical evaluations. These recommendations carry great weight with clinicians and expert societies, and even the public, since they are perceived to be relatively insulated from external pressures from, e.g., the pharmaceutical and insurance industries.
CVD and cancer are the leading causes of death for American adults, with heart attacks and stroke causing 30 percent of deaths. CRC is the third most common cancer in the U.S., causing about 50,000 deaths last year. Currently, about 40 percent of Americans over age 50 take an aspirin at least several times a week to prevent CVD.
Many doctors have serious reservations about the current advisory. In May 2014, the Food and Drug Administration reviewed much of the same evidence and came up with quite a different conclusion: "The FDA has reviewed the available data and does not believe the evidence supports the general use of aspirin for primary prevention of a heart attack or stroke. In fact, there are serious risks associated with the use of aspirin, including increased risk of bleeding in the stomach and brain, in situations where the benefit of aspirin for primary prevention has not been established."
Dr. Steven Nissen, chief of cardiology at the Cleveland Clinic, who has served on various FDA panels including last year's panel on aspirin and heart disease, told Roni Caryn Rabin of the New York Times that "the task force 'has gotten it wrong, and we can t afford to get this wrong, because it affects tens of millions of Americans.'
The major concern regarding aspirin use is that it does increase the risk of stomach bleeding significantly, and increases the risk of devastating brain bleeds as well. But the latter are so rare as to not contribute substantially to the overall risk/benefit discussion.
Other experts were more supportive of the groundbreaking panel draft report. Dr. Allen Taylor, chief of cardiology at Georgetown University, told NBC News "they've tried to cut through a lot of the other recommendations that are out there using the most recent evidence, carefully evaluating it, and have come to what is about as clear as you can get it because there isn't a study for every possible scenario."
At the very least, Dr. Taylor said, it should get people talking.
"So there's really two sides. Get the right people on aspirin, and get the wrong people off aspirin," he said. "And so the more the public is aware of who can benefit from aspirin, the better off we are. It can trigger conversations with their doctors."
Another doctor expressed concern that people who hear of this report may decide, Well, I'm taking aspirin so I don't need to get my colonoscopy. That would be a bad decision, since colonoscopy remains the gold standard for prevention (and often, treatment) of CRC.
Clearly, the decision to take daily aspirin or not revolves around balancing potential risks and benefits. For those with a history of CVD, the balance weighs heavily towards taking aspirin. For primary prevention, the panel suggests the same approach but for those who have had bleeding in the past, that balance may well tip in the direction of avoiding aspirin. Generally, anyone in doubt should discuss this with their own doctor.
The draft proposal/recommendations will remain open for public comments until October 12.