Colorectal carcinoma: is screening possible?

Colorectal cancer (CRC) is a major health problem in western countries. It is the most frequently diagnosed cancer in EU countries with about 220,000 new cases per year; the number of CRC deaths approaches 112,000. Most cancer arises from adenomatous polyps through the adenoma-carcinoma sequence; the natural history of the disease is long: the risk of invasive cancer in adenoma is about 2% per year. Given the natural history of CRC, early diagnosis represents the most appropriate tool to reduce the disease-related mortality. Several tests are available to screen healthy subjects at average risk for CRC: faecal occult blood tests, flexible sigmoidoscopy, combined faecal occult blood tests and flexible sigmoidoscopy, total colonoscopy and double contrast barium enema. Issues related to the introduction on a large scale of population-based screening programmes for CRC are discussed.