Aspirin is a well known medicine that is easily available and inexpensive. In patients with cancer a small daily dose of aspirin has been shown to be associated with three beneficial effects:

• A reduction in the spread of cancer to other parts of the body
• A reduction in the risk of vascular complications of cancer
• It appears to prolong the survival of patients with cancer

During about the past 20 years many studies of patients with cancer have shown that the survival of patients taking a daily small dose of aspirin was increased. For example, in a recent research study, which included about 240,000 patients with a wide range of different cancers who were already taking aspirin for protection against a heart attack, aspirin taking was associated with an average survival about 20% longer than that of patients in the same study who were not taking aspirin.

As with all medicines, aspirin carries risks of undesirable side-effects, the most important being bleeding.  One or two patients in every thousand taking aspirin may experience a bleed, most often from the stomach or intestine. Such a bleed is a crisis! However, whether or not aspirin is being taken, similar bleeds can occur due to an ulcer or an infection in the stomach and these bleeds can be very severe and can lead to death. However, bleeds which are truly attributable to aspirin are much less serious and very rarely lead to death.

A very rare event with aspirin is a bleed causing a haemorrhagic stroke – perhaps one in ten thousand patients. A high blood pressure is the cause and appropriate management of blood pressure -if raised- removes this risk.  

Underlying all this are the ways that aspirin works – that is, the effects of aspirin upon cellular and other biological mechanisms of cancer within the body. Intensive research has led to an understanding of these mechanisms and of their importance to the clinical outcomes of cancer, and – as one researcher expressed it – the biological effect of aspirin give a reasonable basis for one to predict the observed the clinical benefits which have been repeatedly observed!

Patients with cancer should raise the topic of aspirin with their healthcare team and discuss whether or not the addition of a daily small dose of aspirin would be likely to be helpful for them.

The evidence presented in this website is drawn from studies of adult cancer patients.