[Controversies in early detection of colorectal cancer]

In recent years, a great advance has been brought in an early detection of colorectal cancer, especially early colorectal cancer. But some controversies are present as follows: 1. Mass screening for colorectal cancer. Immunologic tests for fecal occult blood increased the sensitivity and specificity for detecting colorectal neoplasia without a question. However, this screening method has not proven to get the effectiveness in decreasing mortality of colorectal cancer, although a case control study is under way in our department. 2. Adenoma-carcinoma sequence or de nov carcinoma. These two theories on histogenesis of colorectal cancer are on "hot" discussion to be better understood. 3. Strip biopsy for colorectal lesions. This method is now begun to be introduced to apply for small type-II lesions of colon. 4. Others (barium enema or endoscopy, a new method of colonic preparation which replaces Brown's method, tumor marker in colorectal cancer etc.). Today's status and future prospects were made on these matters.