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Aspirin in the prevention of cancer
We write with regard to the Article by Peter Rothwell and colleagues,1 which indicates that low-dose aspirin might prevent cancer. Although we strongly endorse Rothwell and colleagues' publication, we urge caution.
If we presume that aspirin does have a chemoprotective role, it clearly does not work for everyone since at best 25% of people are estimated to get a cancer prevention benefit but this figure could be as low as 20%. This “aspirin resistance” in patients seems to be present widely in the population so we do not know who should respond.2 Genetic studies such as those undertaken by the Esophageal Adenocarcinoma Genetic Linkage (EAGLE) consortia are needed to assess which individuals will respond best to the chemopreventive effects of low-dose aspirin.
Additionally, meta-analysis of cardiac trials with reassessment of causes of cancer deaths might have inadvertently introduced bias. For example, the number of cases of gastrointestinal cancer death in Rothwell and colleagues' study was 182 out of almost 20 000 cases. In particular there were only 23 oesophageal cancers. Patients in these trials, especially those using aspirin, might have had complications that resulted in earlier presentation.
The AspECT chemoprevention trial3 was specifically designed to look at the effect of aspirin on oesophageal cancer development but will also give information on effects on colon cancer development as well as on cardiac deaths. To date, the data monitoring team and the trial steering team have not divulged any obvious trend between the four groups of this trial (low-dose proton-pump inhibitor [PPI], high-dose PPI, low-dose PPI with low-dose aspirin [300 mg], and high-dose PPI with low-dose aspirin). We need trials such as AspECT to report their preliminary findings of genetic stratification for response, as well as risk/benefit, dose, and length of therapy.
JJ has a consultancy to AstraZeneca Oncology, which makes esomeprazole—one of the agents in the AspECT trial. JJ has also received grants in aid from AstraZeneca previously. All authors are co-investigators in the AspECT trial.