SY11-6 - Adjuvant S-1 Therapy for Patients with Resected Biliary Tract Cancer

Abstract

Background: The survival benefit of adjuvant chemotherapy has not been clarified for patients with resected biliary tract cancer (BTC). This study aimed to assess the feasibility and efficacy of S-1 after surgery for BTC.Methods: A multicenter phase II feasibility study of adjuvant S-1 therapy was initially designed. The primary endpoint was treatment compliance. Treatment was considered feasible at a completion rate (actual S-1 dose / intended S-1 dose >75%) of >50%. S-1 treatment began within 10 weeks after surgery and comprised 4-week S-1 chemotherapy cycles (oral dose of 40 mg/m2, twice daily) followed by a 2-week break. The main eligibility criteria were curatively resected carcinoma of the extrahepatic bile duct (EHBD), gallbladder (GB), ampulla of Vater (AV), or intrahepatic bile duct (IHBD); T2-4N0M0 or T1-4N1M0 carcinoma of the EHBD, GB, or AV or T1-4N0-1M0 carcinoma of the IHBD according to the UICC classification; R0 or R1 resection; and age 20-80 years. The estimated enrollment was 30 patients.Results: The feasibility study enrolled 33 patients. The primary tumor sites were the EHBD (n = 16), GB (n = 5), AV (n = 8), and IHBD (n = 4). The operative procedures were pancreatoduodenectomy (n = 20), major hepatectomy (n = 8), and minor hepatectomy (n = 5). The treatment completion rate was 82%. The most common grade 3 toxicity was neutropenia (18%); the incidence rates of other grade 3 toxicities were <5%.Conclusions: The high completion rate and mild toxicity indicated that S-1 chemotherapy was feasible for resected BTC. On the basis of the results of this feasibility study, a phase III study of adjuvant S-1 therapy versus observation alone for resected BTC was designed. The primary endpoint is overall survival. The main eligibility criteria and adjuvant S-1 therapy regimen are the same as those in the feasibility study. The calculated sample size is 350 patients. This phase III trial was registered as UMIN 000011688 and was activated in September 2013.