[Pharmacokinetic study of S-1 for the treatment of peritoneal metastasis from colon cancer--using a mouse peritoneal metastasis model].

OBJECTIVE: To investigate the usefulness of S-1 for the treatment of peritoneal metastasis from colon cancer using a colon cancer peritoneal metastasis model. METHODS: Colon 26 PMF-15 cells were transplanted intraperitoneally into mice. The concentrations of 5-fluorouracil (5-FU) and gimeracil (CDHP) in the plasma and peritoneal tissue of the mice were determined at 6 sampling time points, i. e., pre-dosing and at 30min, 1, 2, 4 and 8 hrs after oral administration of S-1 (10mg/kg equivalent of FT) on day 20 post-transplantation. RESULTS: The AUC0-8h values of both 5-FU and CDHP were greater in the peritoneal tumor tissue than in the normal peritoneal tissue. The AUC of 5-FU in the peritoneal tumor tissue was 2. 90 times higher than that in plasma. CONCLUSION: The results suggest that S-1 may exert an antitumor effect on peritoneal metastasis arising from colon cancer and be potentially useful as a therapeutic agent in cases of colon cancer with peritoneal metastasis, which is generally recognized as carrying an unfavorable prognosis.