大多数结肠癌可能来自原已存在的腺瘤(息肉-癌肿假说),而且从正常粘膜发展到腺瘤再到癌的演变时间需要7～12年。因此,如能检出息肉患者并去除息肉,可能是预防大多数结肠癌的一条途径。如果目前所用的大便隐血试验(FOBT)和乙状结肠镜普查只能检出50％的腺瘤患者,则将有很多患者被漏诊,而且其中有些病人可能发展为结肠癌。全结肠镜检是检出息肉最敏感 Most colon cancers may come from preexisting adenomas (polyposis-cancer hypothesis), and the evolution from normal mucosa to adenomas to cancer takes 7-12 years. Therefore, detecting polyps and removing polyps may be a way to prevent most colon cancers. If the currently used fecal occult blood test (FOBT) and sigmoidoscopy screening can only detect 50% of adenoma patients, many patients will be missed, and some of these patients may develop colon cancer. Colonoscopy is the most sensitive to the detection of polyps