In three Lancet articles (references below), Peter M. Rothwell et al of the University of Oxford in England concluded that “ long-term use of aspirin for cancer prevention in middle age in addition to appropriate dietary and lifestyle interventions" is beneficial. They drew their conclusions from their analysis of over 200 studies involving several million patients.
Eric Jacobs, PhD, a spokesperson for the American Cancer Society, referred to the studies as "important new evidence that long-term daily aspirin, even at low doses, may lower the risk of developing cancer." Even so, the decision to initiate regular aspirin use should be individualized after a discussion between patient and physician…..Because these results are new, it will take time for the broader scientific community to evaluate the data in the context of existing knowledge and to consider whether the clinical guidelines should be changed ... Clinical guidelines require a systematic analysis of for whom the benefits of aspirin use are likely to outweigh the risks."
Summary of the study findings related to regular aspirin use
Regular aspirin use leads to
o significant reductions in the risk of cancer, metastasis, and cancer mortality.”
o a reduced risk of vascular events in patients taking aspirin, but an increased risk of major bleeding.
o reduction in the risk of colorectal and other gastrointestinal cancers compared with nonusers.
o Cancer mortality was 15% lower among regular users of aspirin
o metastasis was 35% to 40% less common.
o Major extracranial bleeding did occurred less often in patients using low-dose aspirin (OR 0.32, P=0.009) compared with those who did not use aspirin.
Here are the references to the 3 studies if you would like more in depth statistics and analysis:
Rothwell PR, et al "Short-term effects of daily aspirin on cancer incidence, mortalilty, and nonvascular
death: Analysis of the time course of risks and benefits in 51 randomized controlled trials" Lancet 2012
Rothwell PM, et al "Effect of daily aspirin on risk of cancer metastasis: A study of incident cancers during
randomized controlled trials" Lancet 2012
Rothwell PM, et al "Effects of regular aspirin on long-term cancer incidence and metastasis: A systematic comparison of evidence from observational studies versus randomized trials" Lancet Oncol 2012;
comparison of evidence from observational studies versus randomized trials" Lancet Oncol 2012;