The control of large bowel cancers. Present status and it challenges.

The incidence of carcinoma of the large bowel in the United States is higher than for any other site. In Japan it is about one quarter as frequent, and the cause of this discrepancy appears to be more environmental than genetic on the basis of migrant studies. The incidence of carcinoma in familial polyposis approaches 100% and in villous adenoma the incidence of carcinoma is 40-50%. The relation of adenomatous polyps to carcinoma is not so strong, yet there is a notable association between the occurrence of polyps and carcinoma in the same bowel. With modern surgical techniques, the risk of removing polypoid lesions of the colon transabdominally appears much lower than the average risk of leaving such lesions alone unless and until they give signs and symptoms of carcinoma. The greater use of the colonoscope should, however, greatly reduce the need for laparotomy.