Colonoscopy is the method of choice for not only detecting adenomas or carcinomas, but also combining diagnosis with biopsy and therapeutic removal of polyps. It is the most accurate diagnostic tool for colon cancer, detecting 95% of polyps. But it does have a higher complication rate than the double contrast barium enema viz. 0.1-0.3% perforation and 1% hemorrhage rate (10:250).18. Weilin, S.; Weilin, G. The double contrast examination of the colon. Experiences with the Welin modification. Stuttgart: Georg Thieme. endoscopy. Third edition. Boston: Blackwell Scientific Publications; 1990. Small polyps (2-5 mm) may be just as difficult to snare and retrieve. They should not be ignored (assuming they are hyperplastic), since 70% of small polyps in the colon are adenomatous and might acquire neoplasia. They are best coagulated by the "hot biopsy" method, where insulated biopsy forceps are used to grasp the small polyp which is coagulated until it is white half way down, and then pulled out. Larger polyps cannot be treated this way because of local heating effects which cause tissue damage leading to ulcers and bleeding (15:87). One has to be especially careful in the thinner walled right colon. If blanching is not immediate, the procedure should be stopped and snaring resorted to. Dietary fiber is another factor, in this case protecting against colon carcinogenesis. Again there are epidemiological and animal studies to support its role in preventing colon cancer (19:325). It is even effective in nullifying the effect of high fat intake. A dramatic example is in rural Finland where the high intake of saturated fats due to a diet high in dairy products, would seem to have predicted a high incidence of distal colon cancer. The surprisingly low incidence is apparently due to the concurrent ingestion of high bran cereals. In fact the level of bile acids was 4 mg/g stool, the same as for people on low-fat diets. The fact that they also have i |
