Effects of TS-1 on peritoneal dissemination of gastric cancer in nude mice.

Background/aims: We investigated the effects of TS-1 on the survival of nude mice developing peritoneal dissemination of gastric cancer.

Methodology: MKN-45 cells were injected into the peritoneal cavity of nude mice and a model of peritoneal dissemination was developed. TS-1 was administered orally every day from day 1 to day 10 or day 10 to day 19.

Results: Survival time of these treatment groups was significantly longer than untreated controls. In a pharmacokinetic study, TS-1 was administered on day 10 and the 5-fluorouracil levels were retained and maintained for a longer time, in the ascites and tumor than in plasma. The area under the concentration curve for 5-FU in the tumor was higher, than in plasma or ascites.

Conclusions: TS-1 could be effective in treating peritoneal dissemination of gastric cancer, due to the supply of 5-fluorouracil in the tumor by systemic and intraperitoneal circulation.