Effect of cimetidine on development of gastric cancer in rats after gastrojejunostomy

Objective: To find out if cimetidine has an immunomodulating effect on gast ric carcinogenesis in rats. Design: Experimental prospective study. Setting: Teaching hospital, Norway. Animals: 132 male PGV/Mol rats given gastrojejunostomies. Intervention: Half the rats were given cimetidine in their drinking water p ostoperatively for a minimum of 38 weeks. They were killed after 52 weeks' observation and the stomach was investigated macroscopically and microscopi cally. Main outcome measure: In the cimetidine fed group 19/48 animals developed c ancer (49%), versus 12/43 (28%) in the control group (p = 0.24). Conclusion: cimetidine had no immunomodulatory effect on the development of gastric cancer in rats.