Evaluation of endoscopic examination of colon tumors in rats.

This study is an evaluation of the use of endoscopic examination to detect MNNG-induced large-bowel tumors in rats. The smallest human fiberbronchoscope was used as a colonoscope for the rats and the full length of the distal large bowel was visualized. The correct diagnosis rate in all rats with and without large-bowel tumors was 94%. Of rats with colon tumors, 85% were correctly diagnosed endoscopically. Even tumors 1 or 2 mm in diameter were detected. The examination was easy and reliable. This procedure may be an adjunct in experimental work with this and other animal models of colon cancer.