[Colorectal cancer: from diagnosis to screening].

Colorectal cancer fulfils the conditions required for mass screening. Data from controlled studies indicate that it is possible to reduce colorectal cancer mortality at a population level using faecal occult blood testing. Screenings rely on biennial testing in between 50 and 74average risk subjects. Compliance must be over 50%. Colorectal cancer mortality decrease in this case between 15 and 18% in the general population, 33 and 39% among participants to screening. The European Commission, on the basis of available data recommended to organise colorectal cancer screening in the European Union. Generalisation of screening has become a reality in France. Epidemiological studies allow us to define subjects at very high risk (genetic origin) and high risk for colorectal cancer. Colonoscopy screening is recommended in first degree relatives of patients with colorectal cancer or large adenoma diagnosed before 60years or with two affected first-degree relatives, in subjects with an extended inflammatory bowel disease, or with a personal history of large bowel cancer or large adenoma. Promising research strategies are arising: immunochemical tests in the short term, stool-based DNA tests in stools and proteome-based approach in the long term.