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Panel Adds Colon Cancer Protection to Benefits of Low-Dose Aspirin
By Candy Sagon, April 11, 2016 05:05 PM
Many Americans take a daily low-dose aspirin to protect against heart disease and stroke, but for the first time a federal advisory panel says taking it can also protect adults in their 50s and 60s against colon cancer.
The new recommendations from the U.S. Preventive Services Task Force — first proposed last September — find that the benefits of taking a low-dose aspirin (81 mg) to prevent a first heart attack are strongest for those ages 50 to 59 who are at increased risk for heart disease, but are not at risk for gastrointestinal bleeding from ulcers or other problems. The panel said adults in their 50s may also help prevent colon cancer by taking aspirin for at least 10 years.
Those who are 60 to 69 “can also benefit, but bleeding risk is higher in this group,” task force chair Kirsten Bibbins-Domingo, M.D., professor of medicine and biostatistics at the University of California, San Francisco, said in an email. While all patients should talk to their doctor to evaluate their risk factors for taking aspirin, “this is particularly important for people in their 60s,” she added.
The panel found insufficient evidence that aspirin helps those either under 50 or over 70. “Based on the current evidence, it is not clear whether starting aspirin in people who are 70 years and older is beneficial. More research is needed in this area,” Bibbins-Domingo said.
The new recommendations are an update — and a big change — from the panel's 2009 guidelines. “The biggest change is that the task force looked at the combined benefits and harms of taking low-dose aspirin to prevent both cardiovascular disease and colorectal cancer,” Bibbins-Domingo said. The recommendations also apply to a more narrow age range. Seven years ago, the panel recommended aspirin for those ages 45 to 79.
Some leading doctors, however, were skeptical of the panel’s recommendations.
Preventive cardiologist Mark Huffman, with Northwestern University Feinberg School of Medicine, pointed out in an email that the guidelines only look at aspirin by itself, “where we clinicians have multiple drugs for preventing cardiovascular disease, such as statins and blood pressure-lowering drugs, which are more effective and generally safer.”
For example, previous research has shown that aspirin lowers the risk of death by 6 percent, compared with 14 percent and 11 percent for statins and blood pressure drugs, respectively, he noted. “Aspirin reduces the risk of heart attack and stroke by 10 percent compared with 25 percent with statins.”
Huffman acknowledged that these drugs do not play a role in colon cancer prevention, “but the effects of aspirin on colorectal cancer are modest and not without risks, as the guideline states,” he said.
The biggest objection that Steven Nissen, M.D., chairman of the department of cardiovascular medicine at the Cleveland Clinic, has to the guidelines is that they recommend using low-dose aspirin as “primary prevention” — meaning to prevent a first heart attack or episode of heart disease — despite the increased risk of bleeding. “I do not agree [with the task force] and neither does the Food and Drug Administration [FDA],” Nissen said in an email.
Nissen served on an FDA advisory committee that in 2014 rejected Bayer’s application to label its low-dose aspirin as effective for primary prevention of heart disease, which the agency found was not supported by the available data. Instead, the evidence “supports the use of aspirin for preventing another heart attack or stroke” in patients who have already had one, or who have had other evidence of coronary artery disease, the FDA said. In those patients, “the known benefits of aspirin for secondary prevention outweigh the risk of bleeding.”
Nissen also questioned the panel’s age guidelines. “Does it make sense that a 49-year-old does not benefit, but a 51-year-old does? What exactly is it about being 50 to 70 that confers benefits to aspirin? This just isn’t a sensible recommendation.”
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