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 III Superiority Trial.

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/m of UFT and 75 mg/day of LV on days 1-28, every 35 days, 5 cycles) or SOX (100 mg/m of oxaliplatin on day 1 and 80 mg/m 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% confidence interval [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 hazard ratio for DFS was 0.90 (95% CI, 0.74-1.09; stratified log-rank test, P = .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 (hazard ratio, 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.