Published in:
Open Access 01-10-2007 | Original Article
Effect of gastrectomy on the pharmacokinetics of S-1, an oral fluoropyrimidine, in resectable gastric cancer patients
Published in: Cancer Chemotherapy and Pharmacology | Issue 5/2007
Login to get accessAbstract
Purpose
The effect of gastrectomy on pharmacokinetics after S-1 administration was investigated.
Patients and methods
A dose of 40 mg/m2 of S-1 was administered orally twice daily for 7 days (80 mg/m2/day) preoperatively in ten patients with resectable gastric cancer, and the same dose of S-1 was administered for 28 consecutive days after gastrectomy. Plasma concentrations of tegafur, gimeracil, and oteracil potassium, all the components of S-1, and 5-FU were measured on pre- and postoperative days. Concentrations of 5-FU in tumor and normal tissues were also determined.
Results
At day 4 from the initial preoperative administration of S-1, the AUC of 5-FU was 1,055 ± 304 ng h/ml. At day 18, day 28, and day 42 after gastrectomy, it was 1,012 ± 331, 1,070 ± 403, and 946 ± 226 ng h/ml, respectively. No significant differences for plasma 5-FU were observed between pre- and postoperative days. In the resected tumor tissues, concentrations of 5-FU were 242 ± 83 ng/g around 4.5 h and 91.7 ± 37.0 ng/g around 20 h after the final administration, respectively.
Conclusion
Gastrectomy does not affect on pharmacokinetics of 5-FU derived from S-1 regardless of partial or total gastrectomy, indicating that S-1 can be a useful drug in postoperative adjuvant chemotherapy for gastric cancer.