S-1 and oxaliplatin versus tegafur-uracil and leucovorin as postoperative adjuvant chemotherapy in patients with high-risk stage III colon cancer (ACTS-CC 02): a randomized, open-label, multicenter, phase 3, superiority trial

Abstract Background The efficacy of S-1 plus oxaliplatin (SOX) as postoperative adjuvant chemotherapy for colon cancer has not been established. This randomized phase III study was designed to verify the superiority of SOX over tegafur-uracil and leucovorin (UFT/LV) in patients with high-risk stage III colon cancer (any T, N2, or positive nodes around the origin of the feeding arteries). Patients and methods Patients who underwent curative resection for pathologically confirmed high-risk stage III colon cancer were randomly assigned to receive either UFT/LV (300 mg/ m2 of UFT and 75 mg/day of LV on days 1-28, every 35 days, 5 cycles) or SOX (100 mg/m2 of oxaliplatin on day 1 and 80 mg/ m2 of S-1 on days 1-14, every 21 days, 8 cycles). The primary endpoint was disease-free survival (DFS). Results A total of 478 patients in the UFT/LV group and 477 patients in the SOX group were included in the primary analysis. The 3-year DFS was 60.6% (95% CI 56.0%–64.9%) in the UFT/LV group and 62.7% (95% CI 58.1%–66.9%) in the SOX group. The stratified HR for DFS was 0.90 (95% CI 0.74–1.09; stratified log-rank test, p=0.2780). In the N2b subgroup, the 3-year DFS was 46.0% (95% CI 37.5%–54.0%) in the UFT/LV group and 54.7% (95% CI 45.7%–62.7%) in the SOX group (HR: 0.76, 95% CI: 0.55-1.05). Conclusion As postoperative adjuvant chemotherapy, SOX was not superior to UFT/LV in terms of DFS in patients with high-risk stage III colon cancer.