Prevention of colon polyposis and carcinomas by right hemicolectomy and indomethacin in animal model.

Rats were given intrarectal instillations of N-methylnitrosourea. The experimental groups with right hemicolectomy and oral indomethacin had a significantly reduced rate of large bowel tumors. The inhibition rate of tumor development was 88% in incidence and 94% in number. This inhibition was associated with a decrease of fecal bile acid level and a shortened intestinal transit time. It was hypothesized that the change of fecal bile acid composition after surgery and the prostaglandin synthesis inhibition by indomethacin affected the promotion phase of large bowel carcinogenesis.