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

BACKGROUND: We have previously reported the superior feasibility and safety of adjuvant S-1 plus docetaxel in patients with stage III gastric cancer during a prospective phase II study. We report 3-year follow-up data on patients enrolled in this study. PATIENTS AND METHODS: Fifty-three patients with histologically confirmed stage III gastric cancer who underwent gastrectomy with D2 lymphadenectomy were enrolled into this study. They received oral S-1 (80 mg/m(2)/day) for 2 consecutive weeks and intravenous docetaxel (40 mg/m(2)) on day 1, repeated every 3 weeks (one cycle). Treatment was initiated within 45 days after surgery and repeated for four cycles, followed by S-1 monotherapy (4 weeks on, 2 weeks off) until 1 year after surgery. Three-year overall survival (OS) and disease-free survival (DFS) were evaluated. RESULTS: The OS rate at 3 years was 78.4 % [95 % confidence interval (CI), 67.9-90.6 %] and the DFS rate at 3 years was 66.2 % (95 % CI, 54.4-80.7 %). Subgroup analyses according to disease stage showed a 3-year OS and DFS rate of 85.7 % (95 % CI, 74.9-98.1 %) and 70.8 % (95 % CI, 57.1-87.8 %) for stage IIIA, and 62.5 % (95 % CI, 42.8-91.4 %) and 56.2 % (95 % CI, 36.5-86.7 %) for stage IIIB, respectively. CONCLUSIONS: On the basis of 3-year follow-up data, postoperative adjuvant therapy with S-1 plus docetaxel yielded promising OS and DFS in stage IIIA gastric cancer patients who had undergone D2 gastrectomy. We believe that this regimen is a candidate for future phase III trials studying the optimal adjuvant chemotherapy regimen for stage III gastric cancer.