ABSTRACT
Colorectal cancer is very common in Western countries. Worldwide, colorectal cancer constitutes 10% of the cancer incidence burden. The understanding of the pathogenesis of colorectal cancer at a molecular level has increased over the past 30 years. Normal mucosa first becomes dysplastic, then small benign adenomas develop. The most comprehensive data on sex differences in colorectal cancer incidence and mortality are available from the US. Japanese men in Hawaii, the descendants of migrants, are twice as likely to develop rectal or colon cancer as their cousins in Japan. High fibre intake appears to be generally protective, although cereal intake appears proportionately related to cancer risk in Italy and Japan. Animal protein consumption is generally associated with a risk of colorectal cancer, although fish and seafood consumption may be inversely related. Regular physical activity apparently protects against some cancers.
