[Effect of intraperitoneal chemotherapy on experimental peritoneal dissemination of gastric cancer].

In vitro chemosensitivity test using a collagen-gel method was done on 165 primary gastric cancers. All of 5-FU, CBDCA, CDDP and docetaxel showed a high sensitivity. The effects of per oral (po) administration of TS-1, a combination of po TS-1 and intraperitoneal (ip) administration of CDDP, ip 5-FU and ip docetaxel, were evaluated in athymic mice bearing peritoneal dissemination of a gastric cancer cell line (MKN-45-P that shows a high rate of metastasis to the peritoneal cavity of nude mice). Nude mice were inoculated by ip with 10(7) MKN-45-P cells. No survival benefit was obtained after po administration of TS-1 (12 mg/kg) alone or ip CDDP alone. However, a combination of po TS-1 (8 mg/kg x 10 days, from day 3) and ip CDDP (3.5 mg/kg, day 6 and 13) showed a significant survival improvement than that of po TS-1 or ip CDDP treatment alone. ip administration of 30 mg/kg (3 times/week x 3 weeks) or 15 mg/kg (6 times/week x 3 weeks) of 5-FU significantly improved the survival of mice bearing MKN-45-P. 5-FU concentration of ascites after ip administration of 30 mg/kg of 5-FU was 600-fold higher than po administration of 12 mg/kg of TS-1 at peak level. ip injections of docetaxel of 8 mg/kg, and 2 mg/kg improved the survival of 4 and 1 mice, respectively, and they were tumor-free on day 90. Survival of mice treated with ip injection of CBDCA (100 mg/kg, on day 3, or 50 mg/ kg on day 3 and 10) was significantly better than the control group. These results suggest the potential of po TS-1 + ip CDDP, ip 5-FU, ip docetaxel and ip CBDCA administration for the treatment of peritoneal dissemination of gastric cancer.

Effect of intraperitoneal administration of docetaxel on peritoneal dissemination of gastric cancer.

The effect of intraperitoneal (i.p.) administration of docetaxel was evaluated for preclinical evidence of anticancer activity in athymic mice bearing a gastric cancer cell line, MKN-45-P that shows a high rate of metastasis to the peritoneal cavity of nude mice. Nude mice were inoculated i.p. with 10(7) MKN-45-P cells. On days 2, 5, 9, 12, 16 and 19 after tumor inoculation, mice were treated with i.p. injection of docetaxel. Treatment doses of docetaxel were 8 mg/kg (N = 7) 2 mg/kg (N = 7) and 0.5 mg/kg (N = 7). Intraperitoneal carcinoembryonic antigen (CEA) levels, animal body weight, mortality and survival were determined. All control mice developed ascites and died within 19-40 days. The median survival time in the control group was 32 days, while those of mice treated with 8, 2 and 0.5 mg/kg were 90, 63 and 49.5 days, respectively. One of seven mice treated with 8 mg/kg of docetaxel died of toxicity on day 12. Four mice were tumor-free on day 90, but two had tumors in the abdomen when autopsied on day 90. One mouse treated with 2 mg/kg was ascertained to be tumor-free on day 90. All seven mice treated with 0.5 mg/kg of docetaxel died of peritoneal dissemination within 71 days. The results suggest the potential of intraperitoneal docetaxel administration for the treatment of peritoneal dissemination of gastric cancer.