[Risk diseases for colorectal cancer].

Among the risk conditions with an increased prevalence or incidence of colorectal carcinomas hereditary and acquired disorders have to be differentiated. While in hereditary forms new in vitro tests may play a role in the identification of patients at risk we have to rely on screening and follow-up programmes in the other group of patients. The intervals of these surveillance programmes should be acceptable to the patient since many risk groups seem to be questionable on a cost-benefit evaluation.