Aspirin Benefits May Now Include Cancer Prevention

Researchers at the University of Oxford (United Kingdom) studied individual patient data describing cancer-related outcomes of more than 200 randomized, cohort, and case control studies involving several million patients. Of these, 51 trials compared daily aspirin to no aspirin use in the prevention of vascular events, to examine the short-term effects of daily aspirin on cancer incidence, mortality, and nonvascular death. In trials of low-dose aspirin in primary prevention, the researchers also established the time course of effects on incident cancer, major vascular events, and major extracranial bleeding events, with stratification by age, sex, and smoking status.

The results showed that aspirin reduced cancer deaths, particularly from five years onwards, resulting in fewer nonvascular deaths overall. In trials in primary prevention, the reduction in nonvascular deaths accounted for 91% of 96 deaths prevented. In six trials of daily low-dose aspirin in primary prevention involving 35,535 participants, aspirin reduced cancer incidence from three years onwards in both women and men. While the reduced risk of major vascular events on aspirin was initially offset by an increased risk of major bleeding, effects on both outcomes diminished with increasing follow-up, leaving only the reduced risk of cancer from three years onwards. Case-fatality from major extracranial bleeds was also lower on aspirin than on control. The study was published early online on March 21, 2012, in the Lancet.

“In view of the very low rates of vascular events in recent and ongoing trials of aspirin in primary prevention, prevention of cancer could become the main justification for aspirin use in this setting, although more research is required to identify which individuals are likely to benefit most,” concluded lead author Peter Rothwell, MD, PhD, and colleagues of the Oxford Stroke Prevention Research Unit. “The findings add to the case for long-term use of aspirin for cancer prevention in middle age in addition to appropriate dietary and lifestyle interventions.”

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