Acetylsalicylic acid (ASA), also named aspirin, has antipyretic, analgesic and anti-inflammatory properties as well as anti-platelet properties. Low doses of ASA are being used for prevention of cardiovascular disease. Based on its pharmaceutical properties, it has been debated for several years whether ASA may have a role in cancer prevention.

The Directorate of Health asked us to examine the potential effect of ASA use on overall mortality, cancer mortality, cancer incidence and possible side effects, in patients without prior history, or increased risk, of cancer.

We included 12 systematic reviews. None of the included systematic reviews had examined the effect of ASA in the intended population. All identified studies were originally designed and performed to examine the role of ASA use in primary and secondary prevention of vascular events. The results:

• indicated a lower overall mortality associated with ASA use
• showed lower cancer mortality associated with ASA use
• showed lower cancer incidence associated with ASA use
• showed a clear increase in bleeding events associated with ASA use