[Groups at risk and early detection of cancer of the colon and rectum].

Early detection of cancer of the colon and rectum is fundamental because survival is linked to the pathologic stage. The population groups at high risk are reviewed, as well as the different screening techniques: search for occult blood in stool (Hemoccult), rectal palpation, rigid rectosigmoidoscopy, flexible fiberoptic sigmoidoscopy, radiology and determination of carcinoembryonic antigen. It is concluded that the Hemoccult test is the most useful technique for early diagnosis and it should be performed in individuals over 40 years and in the high risk population. The other diagnostic tests should be carried out if this test is positive.