[Mass screening of colorectal cancer: where are we up to?]

Considering the present state of knowledge on the question, only the strategy of screening for intestinal tumours at the asymptomatic stage would seem capable of reducing such a problem as colorectal cancer. Detection of occult blood in stool is currently being evaluated through a mass screening test. Methods used to obtain a high participation rate are now well-defined. In France, to achieve this goal, the test must be proposed by GPs and then mailed to those who do not consult GPs. Four case-control studies and one randomized study conducted among volunteers suggest the efficacy of screening with faecal occult blood testing to reduce mortality from colorectal cancer but they do not indicate effectiveness within a population. Four population-based studies have been set up in Europe (Denmark, England, Sweden and France). Results will be available within one to three years. They should lead to a national screening strategy.