Survival analysis of adjuvant chemotherapy with S-1 plus cisplatin for stage III gastric cancer.
107 Background: The efficacy of S-1 for stage II-III gastric cancer has been shown. However, the survival of stage III remains unsatisfactory (the 3-year recurrence free survival rates in stage IIIA and IIIB receiving S-1 were 68.0% and 49.8%, respectively). We already reported the feasibility of S-1 plus cisplatin as adjuvant chemotherapy for Stage III gastric cancer after curative resection (ASCO-GI 2009, Cancer Chemother Pharmacol 2011). Here we evaluate the recurrence and survival as secondary endpoints. Methods: Japanese patients with stage III gastric cancer who underwent D2 gastrectomy were enrolled. Treatment consisted of 3 cycles of S-1 (40 mg/m2 po) twice daily on days 1-21 and CDDP (60 mg/m2 iv) on day 8 and S-1 monotherapy was given on days 1-28 every 6 weeks until 1 year post surgery. Results: From August 2007 to September 2009, 63 patients were accrued. 35 patients were stage IIIA, the rest 28 patients were IIIB. After a median follow-up 2.9 years, 15 patients experienced recurrence, and 12 patients died. The 3-year recurrence free survival rate was 76.4% (95%CI:63.0-85.4%, IIIA 88.8%, IIIB 60.1%). The 3-year overall survival rate was 78.5% (95%CI:63.4-87.9%, IIIA 85.0%, IIIB 71.9%). The site of recurrence was mainly peritoneum (n=10), liver (n=3), and lymph node (n=3). Conclusions: Our results indicated that adjuvant therapy with S-1 plus 3 cycles of cisplatin may reduce recurrence and improve survival of stage III gastric cancer. This treatment should be considered as an experimental arm comparing with S-1 monotherapy for the next postoperative adjuvant phase III trial.