Five-year outcomes of a phase II study of adjuvant chemotherapy with S-1 plus docetaxel for stage III gastric cancer after curative D2 gastrectomy (OGSG1002).

ABSTRACT

BACKGROUND: Adjuvant S-1 monotherapy is standard of care for stage II and III gastric cancer (GC), but there is still a need to improve the efficacy of treatment for stage III disease. We conducted phase II study of eight cycles of S-1 plus docetaxel (DS) followed by S-1 monotherapy for up to 1 year after D2 gastrectomy for stage III GC. PATIENTS AND METHODS: Sixty-two patients with stage III GC were enrolled. They received oral S-1 (80 mg/m2/day) for 2 consecutive weeks and intravenous docetaxel (40 mg/m2) on day 1, repeated every 3 weeks for 8 cycles, followed by S-1 until 1 year postgastrectomy. Treatment safety, tolerability, and survival were evaluated. RESULTS: The completion rate for eight cycles of DS therapy was 77.4% [95% confidence interval (CI) 65.0-87.1%]. Subsequent S-1 monotherapy for 1 year was feasible in 71.0% (95% CI 58.1-81.8%) of patients. The incidence of neutropenia, leukopenia, anorexia, and fatigue of grade 3 or higher was 10% or higher. There were no treatment-related deaths. The 5-year overall survival (OS) and disease-free survival (DFS) rates were 72.4% (95% CI 62.1-84.5%) and 60.0% (95% CI 48.8-73.9%), respectively. Subgroup analyses by disease stage showed 5-year OS and DFS rates of 74.5% (95% CI 60.7-91.5%) and 59.3% (95% CI 43.8-80.2%) for stage IIIA and 70.0% (95% CI 55.4-88.5%) and 60.0% (95% CI 44.8-80.4%) for stage IIIB, respectively. CONCLUSIONS: Adjuvant eight cycles of DS therapy might be safe and manageable and has promising OS and DFS for stage III GC.