Prior studies, largely among middle-aged adults, have reported that taking aspirin reduces the risk of cancer after 10 years, particularly for colorectal cancer. However, new Monash University research has found that for healthy older adults who took a low-dose of aspirin daily, there was no effect on overall cancer incidence but increased risk of cancer-related mortality.
The study published in JAMA Oncology involved 19,114 Australian and American adults predominantly aged 70 years or over, who previously entered the ASPREE clinical trial (conducted from 2010 to 2017) and had no prior history of cardiovascular disease events, dementia, or independence-limiting physical disability at enrolment, and who were then followed in the post-trial ASPREE-eXTension (ASPREE-XT) study from 2018 to 2024.
The long-term results consist of the original ASPREE clinical trial (the intervention phase), where participants were randomly allocated to receive either 100mg of aspirin daily or a matched placebo, combined with the following ASPREE-eXTension study (observational phase) where participants stopped taking the study medication (either the aspirin or placebo), to measure the association between aspirin and cancer.
First author Associate Professor Suzanne Orchard, from the School of Public Health and Preventive Medicine said that during the combined follow-up period of 8.6 years (median follow-up time), there was no difference in cancer incidence among older adults who were originally assigned to the low-dose aspirin group compared to the placebo group, including when exploring this by cancer stage (stages 1 to 4) and extent of disease (non-metastatic / metastatic).
"Whilst we found overall no change in cancer incidence risk with aspirin when initiated in older age, we found cancer mortality remained significantly elevated by 15 per cent. However, the elevated cancer mortality risk seen with aspirin for participants in the original ASPREE trial period did not persist into the post-trial ASPREE-eXTension study, suggesting no lasting aspirin effect, although longer follow up of the cohort is warranted," Associate Professor Orchard said.
"From these findings, commencing a program of low-dose aspirin for a number of years for the prevention of cancer is not recommended in older adults. Individuals who are concerned about their cancer risk should speak to their doctors about the right strategy for their individual health care."
*About ASPREE
ASPREE (ASPirin in Reducing Events in the Elderly) was a large primary prevention aspirin trial in more than 19,000 participants in Australia and the US, mostly aged 70 years and older, and continues today as a longitudinal study. The ASPREE project is funded by the National Institutes of Health (USA) and the NHMRC (Australia) and is led by Monash University in Australia and the Berman Center for Outcomes & Clinical Research in the US. Visit: https://aspree.org/aus/
DOI: https://doi.org/10.1001/jamaoncol.2025.6196
