Update on the role of low-dose aspirin in colorectal cancer prevention

In 2022, the United States Preventive Services Task Force (USPSTF) released a recommendation statement on the use of daily, low-dose aspirin to prevent cardiovascular disease (CVD) and colorectal cancer (CRC).

The USPSTF recommended initiating low-dose aspirin use for the primary prevention of CVD and CRC in adults aged 50-59 who do not have an increased risk for bleeding, have a life expectancy of least 10 years, and are willing to take low-dose aspirin daily for at least 10 years. For adults aged 60 to 69 years, the choice to take daily low-dose aspirin should be an individual one. For adults younger than 50 or older than 70 years, the USPSTF concluded that the evidence was insufficient to assess the balance of benefits and harms of initiating aspirin use for the primary prevention of CRC.

In late 2021, based on new analyses of the evidence from primary CVD prevention populations, longer term follow-up data from the Women’s Health Study, and new trial evidence, the USPSTF concluded that the evidence is inadequate to support that low-dose aspirin use reduces CRC incidence or mortality.

It is important to note that the USPSTF is primarily challenged to provide broad, population-based recommendations. While there may be benefit to taking low-dose daily aspirin seen in narrowly defined populations that are treated in a specific way through clinical trials, it is difficult to take these findings and make them safely applicable to the population at large.

For example, A recent study pooled data from two large cohort studies following a total of 94,540 patients and data on their aspirin use over some 35 years found that those who used aspirin before age 70 and continued into their 70s or later had a reduced risk of CRC but initiating aspirin at an older age was not linked with a lower risk of developing CRC. Such findings apply to a very specific cohort of individuals and while the USPSTF does tailor its recommendations on such factors as age, these categories may not be specific enough to optimally predict who will benefit from a cancer prevention agent such as aspirin.

Conclusions

While the USPSTF is not able to make a broad, population-based recommendation on the use of aspirin for CRC prevention, researchers underline the fact that this should not nullify the potential of a promising agent like aspirin which has a very long-standing body of literature about its safety profile and benefits. Instead of completely disregarding its potential as a cancer preventive, it will be important to instead refocus research efforts towards making sure that aspirin remains an option for the right patients.

Take away message:

The United States Preventive Services Task Force (USPSTF) recently updated its 2016 recommendations on low-dose aspirin use for the prevention of colorectal cancer, stating that evidence is inadequate to support its use in the primary prevention of the disease. These findings, however, may not be a reflection of aspirin’s lack of benefit to individuals but rather the difficulty in transforming clinical trial data to a broad, population-based recommendation. Further research to refocus studies on aspirin and CRC to explore the benefit of aspirin in specific subsets of patients will be necessary.