The impact of colonoscopy on colorectal carcinoma.

In an eight-year, ongoing study of 120 patients, 39 with carcinomas and 81 with adenomas, no patient has produced a new carcinoma despite a high incidence of metachronous adenomas. Colonoscopy can identify early carcinomas that can be resected for cure. In addition, colonoscopy can identify the adenomatous polyps and with polypectectomy prevent the progression to carcinoma. Colonoscopy is more accurate than air contrast barium enema, provides a tissue diagnosis, and allows polypectomy. When applied according to risk factors known to be cost effective, colonoscopy leads to earlier diagnosis and thus improved long-term survival.