Low-dose aspirin is no longer the go-to preventive measure to ward off heart disease in healthy older adults. Now, a recent study shows that daily aspirin therapy may cause more harm than good for these individuals, especially when it comes to cancer.

Background: From 2010 through 2014, a clinical trial compared 100 mg of daily aspirin with a placebo pill in about 20,000 adults over age 65 who did not have cardiovascular disease, dementia or a physical disability when the study started. It was called the ASPREE (ASPrin in Reducing Events in the Elderly) trial. Previous trials in middle-aged adults had suggested that taking one low-dose aspirin each day could reduce heart disease risk and the risk for colorectal cancer.

This trial wanted to see if the same benefits were found in older adults. Three years into the trial, the researchers were surprised to find there was an increased risk of death from cancer in the aspirin group. Results of the ASPREE were reported in 2018.

Recent development: A new study from researchers at Massachusetts General Hospital, Berman Cancer Center in Minnesota and Monash University in Australia analyzed the data from ASPREE to learn more about older adults’ risk of taking daily aspirin. Their study was recently published in the Journal of the National Cancer Institute.

The new analysis found that in the ASPREE trial, 981 cancers occurred in the aspirin group compared with 952 cancers in the placebo group. The researchers did not find this to be statistically significant, and they concluded that aspirin does not increase the risk of cancer. However, in patients with cancer, the aspirin group was 19% to 22% more likely to have spreading or stage IV cancer, resulting in a higher risk of death.

Takeaway: The researchers conclude that older adults with cancer may be at higher risk for death from more advanced cancer if they’re taking daily low-dose aspirin—especially if they begin taking it later in life. Why this occurs is not known, but researchers suspect that aspirin may act differently on cancer cells in older people.

Important: The researchers do not advise people who are taking daily low-dose aspirin to stop this therapy without consulting their doctor, nor does the study suggest that low-dose aspirin recommendations should not include older adults, who generally get more benefits than risks from it if they have a history of heart attack, stroke or heart surgery. But the researchers do caution elderly individuals to proceed with caution and review aspirin intake carefully with their doctor, especially if they have cancer.  

Source: Study titled “Effect of Aspirin on Cancer Incidence and Mortality in Older Adults,” by researchers at National Cancer Institute, Bethesda, Maryland, published in Journal of the National Cancer Institute.