A large number of long-term studies have shown that the occurrence of cancer is reduced in the people who take aspirin. [References 1-7].

For example: in an overview of seven trials based on 23,535 people, aspirin taking for five years was associated with a reduction in new cancers of just over 30%.[ 4] Another pooled analysis of 34 trials showed that over a third fewer cancer deaths occurred after five years in the people who had taken daily aspirin.[5] Yet further confirmation of benefit has come from a very large study of women in the USA, in which bowel cancer was reduced by just over 20% in women who took aspirin.[8].

An especially valuable trial was conducted in patients with a genetic condition which carries a very high risk of bowel cancer. There were about half the number of cancers in patients who took aspirin for at least two years compared to patients who took no aspirin.[7].

In 2009 a wide ranging review of evidence from a variety of sources – botanical, animal, human and cellular – was reported. This showed a remarkable consistency in the relationship between aspirin and cancer.[9]

Doctors and health authorities evaluate drugs and other treatments by estimating the balance between the risks (bleeding) and the benefits (reductions in disease. Health authorities also have to take the cost of the treatment into account. A number of careful evaluations of aspirin, have shown its use in older people is highly favourable, with respect to both the risk-benefit balance, and the cost-effectiveness.[10-13]

Finally: a warning! If regular daily aspirin is taken, it should not be stopped suddenly. Suddenly stopping aspirin risks a rebound in vascular risk, and an increase in the risk of death (14). If it has to be stop the drug it should be withdrawn slowly.