在经济发达国家 ,大肠癌在恶性肿瘤发病率中居第二位 ;在世界范围内 ,则居第三位。在男性肿瘤中 ,仅次于肺癌、胃癌 ;女性肿瘤中 ,仅次于乳腺癌和宫颈癌。在大肠癌病因中饮食因素较遗传因素更重要。因此 ,在其预防策略中 ,初级预防以饮食预防为主 ;二级预防是早期发现并消除癌 In economically developed countries, colorectal cancer ranks second in the incidence of malignant tumors; in the world, it ranks third. Among male tumors, it is second only to lung cancer and gastric cancer, and second only to breast cancer and cervical cancer in female tumors. In the etiology of colorectal cancer, dietary factors are more important than genetic factors. Therefore, in its prevention strategy, primary prevention is based on diet prevention; secondary prevention is early detection and elimination of cancer