Expect Questions on Use of Low-Dose Aspirin to Help Prevent Colorectal Cancer

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Following a review of new data and additional analyses of previous data concerning colorectal cancer, the U.S. Preventive Services Task Force (USPSTF) “concluded the evidence is inadequate that low-dose aspirin use reduces colorectal cancer incidence or mortality.”1 Consequently, a draft recommendation statement updating the 2016 statement, Aspirin Use for the Prevention of Cardiovascular Disease and Colorectal Cancer, does not include colorectal cancer.

Andrew T. Chan, MD, MPH, expressed concern that the task force conclusion could “create some confusion and some doubt in people’s minds about the data related to cancer prevention.” That could lead, he said, to aspirin becoming “unnecessarily disregarded as a potential option for the right patient.” Dr. Chan is a gastroenterologist, Director of Epidemiology at Massachusetts General Cancer Center, and Professor of Medicine at Harvard Medical School.

Personalized Approach

In an article in The New York Times2 about the draft recommendations, Dr. Chan noted: “We need to think about personalizing who we give aspirin to and move away from the one-size-fits-all solutions.” Expanding on those more personalized risk factors in an interview with The ASCO Post, Dr. Chan said they include age, family history, and a history of polyps.

“Many of the patients I see as a gastroenterologist come from individuals with a history of polyps or families at high risk of colorectal cancer or are known, for example, to have a genetic predisposition in the form of Lynch syndrome,” Dr. Chan stated. “There was a very compelling clinical trial showing that aspirin reduced the risk of colorectal cancer in patients with Lynch syndrome.”3 That study, known as the CAPP2 study, “showed the effectiveness of aspirin and in many ways is practice changing,” Dr. Chan said. “We should be offering aspirin to these patients because we know that colonoscopy is not enough to reduce the risk.”

Complementary, Not Competing, Intervention

“Aspirin is one tool. It is not going to be enough for everybody. Just like screening is one tool, and it is not enough for everybody. We must think of these tools as complementary, not competing, interventions. We should do whatever we can to reduce the burden of cancer in our population,” Dr. Chan said. “The more options we have and the more options we offer our patients, the more impact we can have in terms of reducing the colorectal cancer rate.”

Dr. Chan continued: “As we have learned more about the risk profile of individuals who develop colorectal cancer, we understand more about the mechanisms by which specific cancers might develop. It is more than just genetics and more than just family history. There is definitely an opportunity going forward for understanding more about lifestyle and its potential relationship to the effectiveness of preventive agents like aspirin.”

Not for Lifelong Use

“There is also more of an understanding of the possibility that a drug like aspirin is not something that requires lifelong use. It may be that aspirin is a drug that is an important cancer preventive during an optimal window of time in which people are at risk for developing cancers yet at low risk of side effects of treatment. A drug like aspirin could be taken as a more short-term preventive agent and then discontinued,” Dr. Chan commented.

“There are a lot of opportunities and options for us to be thoughtful about how to tailor the short-term use of a drug like aspirin.”

The ultimate goal, Dr. Chan noted, is to tailor recommendations according to individual cancer risk. “Can we better personalize prevention based on cancer risk? And if we do that, does that create opportunities for us to really make a difference for the right group of patients?” 

DISCLOSURE: Dr. Chan has served as a consultant to Pfizer, Bayer AG, and Boehringer Ingelheim.


1. U.S. Preventive Services Task Force: Aspirin use to prevent cardiovascular disease: Preventive medication. Available at Accessed November 9, 2021.

2. Rabin RC: Aspirin use to prevent 1st heart attack or stroke should be curtailed, U.S. panel says. The New York Times, October 12, 2021. Available at Accessed November 9, 2021.

3. Burn J, Sheth H, Elliott F, et al: Cancer prevention with aspirin in hereditary colorectal cancer (Lynch syndrome), 10-year follow-up and registry-based 20-year data in the CAPP2 study: A double-blind, randomised, placebo-controlled trial. Lancet 395:1855-1863, 2020.

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