Maida J. Sewitch, PhD, Assistant Professor, Department of Medicine, McGill University, and the Divisions of Gastroenterology and Clinical Epidemiology, The Research Institute of the McGill University Health Centre, Montreal, QC.
Caroline Fournier MSc, Research Associate, Division of Clinical Epidemiology, The Research Institute of the McGill University Health Centre, Montreal, QC.

Colorectal cancer (CRC) is a commonly diagnosed cancer and a leading cause of cancer deaths in Canada and the industrialized world. According to cancer registries, incidence varies by age, geographical location, site, and time. CRC screening reduces both CRC incidence through removal of premalignant polyps and CRC deaths through early detection and treatment. Health Canada considers CRC an ideal target for mass screening of individuals 50 years of age and older. This article reviews the epidemiology of CRC and the reasoning behind the development of screening guidelines for persons 50 years of age and older. Various Canadian and U.S. guidelines are detailed. Routine screening of average-risk individuals is advocated. Finally, the review highlights trends in patient utilization of CRC screening as well as the role of screening in an aging population.
Keywords: aging, colorectal cancer, epidemiology, screening, adenomatous polyps.