[Screening for prevention of colorectal carcinoma. Who, when, how?]

Long-term survival of patients with colon carcinoma is largely determined by the timing of the diagnosis. For the identification of early colorectal carcinoma, it is of particular importance to detect and remove local precursor lesions (polyps) by means of effective screening, before they undergo malignant degeneration. The gold standard for such screening continues to be colonoscopy, followed by sigmoidoscopy, which latter, however, leaves large segments of the proximal uninspected. Additional--though less sensitive and more complicated--current screening techniques are the test for occult blood in the stools and the barium Doppler contrast examination, and, possibly in the near future, virtual colonoscopy and genetic testing for tumor DNA in the stools. Detailed screening recommendations are to be found in the guidelines issued by the German Society for Digestive and Metabolic Diseases. A prerequisite for effective prevention of colorectal carcinoma is the provision of information to, and motivation of, both the population and the individual patient, to participate in screening measures.