International collaboration for the prevention of colorectal cancer.

This brief paper describes the involvement of the World Health Organization in promoting international collaboration for the prevention of colorectal cancer, more than half a million cases of which are diagnosed every year. A WHO Collaborating Centre was designated in 1985 in the USA and the activities of this Centre have included the preparation of a series of six articles for publication in the Bulletin of the World Health Organization. These articles deal with primary prevention, risk and screening of average-risk individuals, as well as risk and surveillance of individuals with chronic ulcerative colitis, colorectal polyps, and heritable factors for colorectal cancer.