A phase i study for adjuvant chemotherapy of gemcitabine plus S-1 in curatively resected patients with biliary tract cancer: Adjusting the dose of adjuvant chemotherapy according to the surgical procedures

Purpose We conducted a phase I study for adjuvant chemotherapy of gemcitabine (GEM) plus S-1 in order to determine the maximum tolerated dose and the recommended dose (RD) and to evaluate the efficacy and toxicity of the regimen in curatively resected patients with biliary cancer. Methods The study included 34 patients with adequate organ functions, Eastern Cooperative Oncology Group PS 0-1, under 80 years of age, who had curative resection after August, 2007. Patients received GEM on day 1 and day 15, and S-1 from day 1 to day 14. Dose-limiting toxicities were determined during first two treatment cycles. After determining RD, a feasibility study was continued in the following four treatment cycles. Results Hematological toxicity, particularly neutropenia and thrombocytopenia, was the most pronounced toxic effect of gemcitabine and S-1 adjuvant combination chemotherapy. The RD after pancreatoduodenectomy is GEM 1,000 mg/m ² + S-1 80 mg/m ², and RD after hemihepatectomy is GEM 800 mg/m ² + S-1 60 mg/m ². Conclusions The pharmacokinetics of GEM and S-1 indicate that changing the dose of adjuvant chemotherapy based on the operation method for biliary cancers is reasonable. We believe that this regimen will be established as an effective adjuvant chemotherapy for biliary cancer in the future.