The US Preventive Services Task Force (USPSTF) has released new research and guidelines on the use of daily aspirin to reduce the risk of colorectal cancer (CRC) and cardiovascular disease (CVD).1,2
The new guidelines say there is insufficient evidence to support using aspirin to reduce CRC incidence or mortality.1 Therefore, CRC has been eliminated from the USPSTF recommendations related to aspirin and CVD.
This is a change from the 2016 USPSTF guidelines, which recommended low-dose aspirin for the primary prevention of CVD and CRC in adults aged 50 to 59 years who have a 10% or greater 10-year risk of CVD, are not at increased risk for bleeding, have a life expectancy of at least 10 years, and are willing to take low-dose aspirin daily for at least 10 years.3
In addition to eliminating the recommendation for CRC, the new guidelines recommend that clinicians decide on a case-by-case basis when it is appropriate to start low-dose aspirin for the primary prevention of CVD in adults aged 40 to 59 years who have a 10% or greater 10-year CVD risk.1 The guidelines also recommend against low-dose aspirin for the primary prevention of CVD in adults age 60 or older.
As noted in a related editorial, the new guidelines do not recommend routine preventive aspirin for anyone.4
Evidence to Support Guidelines
To inform the guidelines, researchers conducted a systematic review on the effectiveness of aspirin to reduce the risk of CVD events and mortality, CRC incidence and mortality, all-cause mortality, major bleeding, and hemorrhagic stroke.2
The review included 134,470 patients from 11 low-dose primary prevention randomized controlled trials (RCTs) and 1 pilot RCT with 400 patients. The data suggested that aspirin is associated with a significant decrease in major CVD events but not CVD-related mortality or all-cause mortality.
Pooled data from 4 RCTs showed no association between aspirin use and CRC incidence at 5 to 10 years of follow-up. However, in 1 RCT (the Women’s Health Study), patients randomly assigned to aspirin had a significantly lower incidence of CRC at 20 years.
Pooled data from 2 RCTs suggested that 5 to 10 years of aspirin use might be associated with an increased risk of CRC mortality, but the result was not statistically significant. One of the trials (ASPREE) showed a significant increase in CRC mortality at 5 years, and the other (Women’s Health Study) showed no significant association at 10 years.
“There was limited trial evidence on benefits for colorectal cancer, with the findings highly variable by length of follow-up and statistically significant only when considering long-term observational follow-up beyond randomized trial periods,” the researchers wrote.
“A large low-dose aspirin trial examining CRC effects at 20 years after randomization would be ideal to examine the marginal effects of aspirin use in the context of contemporary CRC screening practices,” they added. “Future trials should also account for baseline CRC screening as well as CRC risk factors, potential confounders not addressed in most of the CVD prevention trials included in this review.”
Implications for Practice
The 2016 USPSTF guidelines were the first to mention the prevention of CRC as a potential benefit of daily aspirin use, wrote Allan S. Brett, MD, of the University of Colorado School of Medicine in Aurora, in an editorial.4
With the new guidelines, “the pendulum has swung further away from aspirin prophylaxis for primary prevention,” Dr Brett wrote.
“For patients 60 years or older, clinicians should not initiate aspirin for primary prevention; clinician-initiated discussions about aspirin prophylaxis are unnecessary, except for inquiring whether patients are already taking aspirin based on their own decisions,” Dr Brett wrote.
For patients aged 40 to 59 years, clinicians should decide for themselves whether and when to start discussions about aspirin prophylaxis for CVD, but such discussions are unnecessary in the context of CRC.
Dr Brett noted that the new guidelines focus on the initiation of aspirin, so it is unclear how clinicians should manage patients who are already taking aspirin for primary prevention of CVD and CRC.
“This omission is unfortunate, given that an estimated 28% of adults 40 years or older (and 46% of those 70 years or older) were using aspirin for primary prevention as recently as 2019, according to a nationally representative survey,” Dr Brett wrote.
The USPSTF authors did note that “it may be reasonable to consider stopping aspirin use around age 75 years,” but there is no specific recommendation.1
Disclosures: The research was supported by USPSTF. All authors reported having no conflicts of interest.
- US Preventive Services Task Force. Aspirin use to prevent cardiovascular disease: US Preventive Services Task Force Recommendation Statement. JAMA. Published online April 26, 2022. doi:10.1001/jama.2022.4983
- Guirguis-Blake JM, Evans CV, Perdue LA, Bean SI, Senger CA. Aspirin use to prevent cardiovascular disease and colorectal cancer: Updated evidence report and systematic review for the US Preventive Services Task Force. JAMA. Published online April 26, 2022. doi:10.1001/jama.2022.3337
- US Preventive Services Task Force. Aspirin use for the primary prevention of cardiovascular disease and colorectal cancer: US Preventive Services Task Force recommendation statement. Ann Intern Med. 2016;164(12):836-845. doi:10.7326/M16-0577
- Brett AS. Should patients take aspirin for primary cardiovascular prevention? Updated recommendations from the US Preventive Services Task Force. JAMA. Published online April 26, 2022.