Daily low-dose aspirin linked to reduced cancer risk in older adults, study finds

Daily low-dose aspirin may reduce the risk of developing cancer by about 15% among older adults, a large Australian study suggests. Researchers tracked almost 10,000 adults for five years, with participants initially between 71 and 77 years old. Those who took a 100 mg tablet per day, compared with a placebo, showed a lower cancer incidence in the trial.

The analysis indicated the protective effect was more pronounced in the oldest subgroup, in nonsmokers, those with a lower body mass index, and individuals with a family history of cancer. A condition known as clonal hematopoiesis of indeterminate potential, or CHIP,—blood cell mutations that accumulate with age—was present in about 10% of participants and emerged as the strongest predictor of aspirin-related cancer risk reduction. The researchers noted that CHIP may influence how aspirin affects inflammatory pathways, potentially enhancing the drug's impact on cancer risk in this subset. The findings were published in JAMA Oncology.

Writing in the journal JAMA Oncology, the researchers cautioned that the findings are not conclusive proof that aspirin prevents cancer and that further research is vital. The study had limitations, including its focus on relatively healthy older white Australians and the possibility that initiation of aspirin at earlier ages could yield different long-term effects. The authors emphasized that conclusions about cancer prevention cannot yet be generalized to broader populations.

Long-term aspirin use is known to raise the risk of stomach ulcers and bleeding. If a low-dose daily aspirin is considered for cancer prevention, doctors must weigh the potential benefits against bleeding risk and other side effects, the authors noted. The study adds to a long-running discussion about aspirin's role beyond cardiovascular health, but it does not establish a new standard of care for cancer prevention.

Aspirin has long been hailed for its ability to lower the risk of heart attack and stroke. It is commonly prescribed for patients with coronary artery disease, the most commonly diagnosed type of heart disease. In the United Kingdom, coronary artery disease affects about 2.3 million people, underscoring the drug’s widespread use in cardiovascular care. While these cardiovascular benefits are well established, experts caution that any cancer-prevention claims require careful patient selection and monitoring.

Experts stressed that the current findings do not warrant broad recommendations to begin routine daily aspirin for cancer prevention. More research is needed to identify which populations could benefit, the ideal dosing strategies, and how factors such as CHIP status might guide decisions. In the meantime, individuals should discuss aspirin use with a clinician, particularly if they have a history of bleeding disorders, gastrointestinal ulcers, or are taking other medications that affect bleeding.