Colorectal cancer. Epidemiology, etiology, pathogenesis and prevention.

Colorectal cancer (CRC) is a neoplasm with a steadily growing incidence in Western countries. Moreover the age of 50 and over is a critical risk factor. The relationship between dietary, environmental factors and CRC has been evaluated. At present, a number of genetic risk factors such as the genetic susceptibility, tumor suppressor genes and oncogenes are thought to play a major role. The correlation of CRC with adenomatous polyps and chronic inflammatory disease, ulcerative colitis in particular, has been evaluated. Prevention of CRC is mainly based on a rational diet and in the adoption of mass screening programmes.