Daily aspirin does not lower cancer risk in older adults

For decades, low-dose aspirin has been considered by some as a potential shield against cancer. However, mounting evidence, particularly from the ongoing ASPREE study, is challenging that long-held belief, especially for older adults. The latest data suggests that initiating daily aspirin for cancer prevention may offer little to no benefit in this population.

Aspirin and Cancer: The Evolving Evidence

Initial findings from the Aspirin in Reducing Events in the Elderly (ASPREE) trial, with a follow-up period of 4.7 years, showed no discernible difference in cancer incidence between those taking daily low-dose aspirin and those receiving a placebo. Now, an extended observational phase of the study, known as ASPREE-XT, has prolonged that scrutiny to a median of 8.6 years, and the results remain consistent: no association between aspirin and overall cancer incidence.

Did You Know? The ASPREE-XT study followed over 14,000 individuals who were cancer-free at the conclusion of the original ASPREE trial.

“Given the longer follow-up, we thought that would be a long enough timeframe to see if anything had changed,” explained Associate Professor Suzanne Orchard, director of the ASPREE-XT study. “But we didn’t see any change in cancer incidence rates over the long-term.” The research, published in JAMA Oncology, analysed data from 3448 incident cancers and 1173 cancer deaths.

Nuances in the Findings

While an overall association between aspirin and cancer incidence wasn’t found (hazard ratio 0.98), a potentially protective effect was observed regarding melanoma incidence (HR 0.77). However, individuals in the aspirin group were 15% more likely to die following a cancer diagnosis compared to those in the placebo group, although this risk appeared to diminish over time as participants stopped taking the study medication.

Expert Insight: The findings suggest that the potential cancer-related mortality risk observed during the clinical trial phase may be a temporary effect, slowly dissipating once aspirin use is discontinued.

Over the past decade, the ASPREE research, including ASPREE-XT, has revealed no link between daily low-dose aspirin and a range of health outcomes, including promoting a healthy lifespan, reducing all-cause mortality (though it increased it by 14%), preventing stroke (but increasing the risk of intracranial bleeding), preventing fractures (but increasing the risk of serious falls), and avoiding major gastrointestinal bleeds. It also showed no benefit in major adverse cardiovascular events, slowing cognitive decline associated with sleep apnea, slowing declines in kidney function or hearing loss, or reversing frailty.

Interestingly, daily low-dose aspirin was found to reduce the incidence of type 2 diabetes.

What Does This Mean for the Future?

Professor Orchard stated unequivocally that older adults should refrain from starting daily aspirin solely for cancer prevention. She emphasized that much of the existing research on aspirin’s effects comes from studies involving middle-aged individuals, and that the drug may not function the same way in older bodies due to age-related changes. Researchers believe that age-related declines in immune function and chronic inflammation may lessen any potential anti-tumor effects of aspirin.

Guidelines are already shifting in response to this evolving understanding. The Australian Cancer Council now restricts its low-dose aspirin recommendation to those aged 60-69, advising those over 70 to discuss the risks and benefits with their doctor. The United States Preventive Services Task Force withdrew its 2016 recommendation for low-dose aspirin for colorectal cancer prevention in individuals over 70.

Further research is planned. The ASPREE study will continue with a third phase, ASPREE-LT, following participants for another five years to gather even more long-term data.

Professor Orchard cautioned that individuals already prescribed aspirin for other medical reasons, such as cardiovascular disease prevention, should not stop taking it without consulting their healthcare provider. This study specifically addresses the use of aspirin as a primary cancer prevention strategy.

Frequently Asked Questions

What did the ASPREE-XT study find regarding cancer incidence?

The ASPREE-XT study found no association between low-dose aspirin and overall cancer incidence after a median follow-up of 8.6 years.

Was there any potential benefit observed with aspirin use?

A potentially protective association was observed between aspirin and melanoma incidence.

Should people currently taking aspirin stop taking it based on these findings?

No. Individuals prescribed aspirin by their healthcare provider for other medical conditions should continue taking it as directed and consult their doctor if they have concerns.

As research continues to refine our understanding of aspirin’s complex effects, how might these findings influence your conversations with your healthcare provider about preventative medications?