Endoscopic visualization of induced colonic tumors in rats

The visualization of induced colonic tumors in rats was investigated using either a rigid or flexible endoscope. There was 89% agreement between presence or absence of at least one tumor as visualized at endoscopy and necropsy. The agreement was 83% (p < 0.01) when the exact number of tumors was compared. Neither carcinogens (1,2-dimethylhydrazine or N-methylnitrosourea) nor dietary supplements affected the results.