Add-Aspirin: A Trial Assessing the Effects of Aspirin on Disease Recurrence and Survival After Primary Therapy in Common Non Metastatic Solid Tumours

Add-Aspirin aims to assess whether regular aspirin use after standard curative therapy can prevent recurrence and improve survival in individuals with non-metastatic common tumours. The question will be assessed in four different tumour types (breast, colorectal, gastro-oesophageal and prostate) by means of parallel cohorts within an overarching trial protocol. Eligible participants will be randomly assigned (double-blind) to either aspirin 100mg, aspirin 300mg or a matched placebo, to be taken daily for at least 5 years. Disease recurrence and survival will be assessed, along with adherence, toxicity, and other potential effects of aspirin (eg. cardiovascular). There is a large body of evidence indicating that aspirin has anti-cancer effects. Meta-analyses of cardiovascular trials of aspirin have shown short-term effects on cancer mortality and a decrease in risk of metastases, suggesting a role for aspirin in the treatment as well as prevention of cancer. Additionally, large observational studies of individuals taking aspirin after cancer treatment have shown improved disease-specific and overall mortality for specific tumour types. In the treatment setting, the risks of side effects associated with aspirin are expected to be outweighed by potential benefits. However, this has not yet been assessed in a randomised trial. As a low cost, generic and widely available drug, which is generally safe, if aspirin is shown to be effective, it could have a huge impact on cancer outcomes globally.