Randomized phase III study of adjuvant chemotherapy with S-1 versus capecitabine (cape) in patients with stage III colon cancer (CC): Results of Japan Clinical Oncology Group study (JCOG0910).

3512 Background: We previously reported the results of the JCOG0205 study, which indicated that D2/D3 lymph node dissection followed by adjuvant fluoropyrimidine (F) monotherapy resulted in better disease-free survival (DFS) and overall survival (OS) in Japan than in Western countries (EJC 2014). Cape is one of standard adjuvant chemotherapy for stage III CC (NEJM 2005). Recently, S-1 was demonstrated to be non-inferior to uracil and tegafur plus leucovorin in DFS (Ann Oncol 2014). This is the first report of JCOG0910, which compared S-1 with cape. Methods: Key eligibility criteria were: stage III, colorectal adenocarcinoma except for lower rectal cancer, R0 with D2/3 lymph node dissection, 20-80 years old. Patients were randomized to 8 courses of cape (2,500 mg/m2/day, days 1–14, q3w) or 4 courses of S-1 (80 mg/m2/day, days 1–28, q6w). Primary endpoint was DFS. Planned sample size was 1,550 to provide 80% power with a non-inferiority margin of hazard ratio (HR) of 1.24 and 1-sided α = 0.05; with interim ...