[Aspirin and colorectal cancer]

Colorectal cancer is a worldwide public health problem. Aspirin has been identified as a protective factor against the apparition of colorectal cancer. There are several mechanisms about the actions by aspirin on colorectal tumorogenesis. These are not perfectly known nowadays. On one hand, there are direct mechanisms on colorectal mucosa, on the other hand there are indirect mechanisms through platelet functions. Aspirin also plays a role by its anti-inflammatory action and the stimulation of antitumor immunity. Several studies show that long-term treatment with low-doses of aspirin decreases the incidence of adenomas and colorectal cancers. In the United States, aspirin is currently recommended for primary prevention of the risk of colorectal cancer in all patients aged 50 to 59, with a 10-year risk of cardiovascular event greater than 10 %. However, primary prevention with aspirin should not be a substitute for screening in colorectal cancer. Furthermore, aspirin seems to be beneficial when used in post-diagnosis of colorectal cancer. It could actually decrease the risk of metastasis in case of a localized colorectal cancer, and increase the survival in particular, concerning PIK3CA mutated tumors. The association of aspirin with neoadjuvant treatment of colorectal cancer by radiochimiotherapy seems to have beneficial effects. French prospective randomized study is currently being conducted to investigate postoperative aspirin in colorectal cancers with a PIK3CA mutation.