The role of low-dose aspirin in the prevention of colorectal cancer.

INTRODUCTION: Colorectal cancer (CRC) is a prevalent disease that is associated with considerable morbidity and mortality. The progression of normal mucosa through adenomatous polyps to overt cancer can span for 10 - 15 years, making early detection, as well as the use of chemopreventive agents such as aspirin, an attractive option. The effects of aspirin in reducing CRC incidence and mortality have consistently been demonstrated in a number of studies. However, a greater understanding of how aspirin exerts its anti-cancer effects is warranted. AREAS COVERED: The aim of this non-systematic review, which was developed using published randomized and epidemiological studies, as well as key references known to the authors, was to consider the role of aspirin in CRC prevention. Areas covered include the effects of aspirin on cardiovascular disease, CRC and colorectal adenoma (CRA) prevention, mode of action of aspirin and the benefit-to-risk of aspirin in disease prevention. EXPERT OPINION: Incorporating CRC and CRA benefits into coronary heart disease (CHD) risk scores would be particularly useful for determining the benefit-to-risk ratio for aspirin use in borderline cases. For instance, patients with an annual CHD risk around 0.7 - 1.4%, but with a high risk of colorectal neoplasm may benefit from aspirin. The strong association between CRC and age may also be useful for re-examining the benefit-to-risk ratio for aspirin use in older patients. However, it has to be noted that a cancer prevention indication for aspirin is not approved regulatory-wise anywhere.