Aspirin Use in Older Adults May Alter Cancer Outcomes
Long-term follow-up from the ASPREE trial raises new questions about routine low-dose aspirin use and cancer mortality in seniors.
Extended follow-up of the ASPREE cohort suggests that starting low-dose aspirin in otherwise healthy older adults does not lower overall cancer risk and may be associated with a modest increase in cancer-related mortality, while effects vary by cancer type.
Study Details
Low-dose aspirin has long been studied for cancer prevention, particularly for colorectal cancer, with earlier benefits observed mainly in middle-aged populations after prolonged use. The ASPREE trial was designed to evaluate aspirin in a very different group: healthy adults aged 70 and older, or 65 and older for Black and Latino participants in the US, with no history of cardiovascular disease, dementia, or disability.
The original randomized ASPREE trial was followed by a multi-year extension, allowing investigators to examine cancer incidence and cancer mortality over nearly a decade. The latest analysis was published in JAMA Oncology.
Methodology
Researchers analyzed data from more than 19,000 older adults originally randomized to receive either low-dose aspirin at 100 mg daily or placebo. Participants were followed for a median of 8.6 years across the randomized phase and the ASPREE-XT extension.
Cancer outcomes were tracked using national cancer registries and adjudicated causes of death. Analyses compared cancer incidence, cancer-related mortality, and specific cancer subtypes between the aspirin and placebo groups.
Key Findings
Overall cancer incidence was nearly identical between aspirin and placebo groups over 10 years of follow-up.
Cancer-related mortality was about 15% higher among participants who took aspirin during the randomized phase.
Melanoma incidence was lower in the aspirin group, while brain cancer incidence was higher, though event numbers were small.
Colorectal cancer incidence and mortality showed no meaningful difference between groups.
During the extension phase alone, differences in cancer incidence and mortality were no longer statistically significant.
Implications for Practice
For older adults, these findings suggest that starting low-dose aspirin solely for cancer prevention may not provide benefit and could carry unanticipated risks. This contrasts with earlier prevention data in younger populations, reinforcing that age and biology may meaningfully alter aspirin’s effects.
For clinicians, the results support current caution against routine aspirin initiation in seniors without a clear cardiovascular indication. The study also highlights the importance of individualized decision-making, especially as future work explores whether genetic factors or specific cancer subtypes respond differently to aspirin exposure.
From a patient perspective, the message is not that aspirin is inherently harmful, but that its preventive role in later life appears more complex than once believed. Longer follow-up and mechanistic studies may still refine which subgroups, if any, could benefit.