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Abstract
Worldwide, colorectal cancer ties with breast cancer as the third most frequent cancer, after gastric and lung cancers. In United States colorectal cancer is the fourth most frequently diagnosed cancer and has the second highest cancer related mortality rate after lung cancer. An important feature of colorectal cancer is the wide variation in incidence (as much as 30-fold) noted between population groups according to geographic region. These dif¬ferences do not appear to be solely the result of genetic factors because populations migrating from low to high incidence regions experience an increase in the rate of colorectal cancer. Such data provide indirect evidence that environmental factors are involved in the pathogenesis of this disease. The definite etiology of colorectal cancer is still obscure. However, many factors play a role in the development of such malignancy. Among possible predisposing factors; polyposis coli and chronic inflammatory bowel disease appear to be inconvertibly established.