15084 Background: Of patients who undergo R0 resection for GC with serosal invasion (T3–4), more than half recur mainly in the peritoneum, while TXL and S1 exhibited efficacy for diffuse type and peritoneal metastases in the phase II studies. Primary analysis of the sequential chemotherapy with TXL/S1 had shown its safety and tolerability, its survival benefit is being tested in a large phase III study (the SAMIT trial) with oral fluoropyrimidines as controls. The analysis for survival of this preceding phase II study is performed. Methods: Eligibility criteria included histologically proven GC; sT3–4; sN0–2; M0 (except peritoneal cytology: CY); post D2–3 gastrectomy and R0–1; ECOG PS 0–1; and 20–80 years old. On postoperative day 14 to 56, patients received 3 courses of weekly TXL (80mg/m2 on day 1, 8 for the 1st course and on day 1, 8, 15 for the 2nd and 3rd courses, repeated every 3 or 4 weeks) followed by 4 courses of S1 (80mg/m2 daily for 2 weeks, repeated every 3 weeks). The primary endpoints were % of patients who completed all 7 courses (compliance) to see whether the lower 95% confidence limit of compliance was greater than 69% and incidence of severe toxicities and the secondary endpoints were 3-year survival and toxicities. Results: 50 patients were accrued from May 2003 to March 2004. The median age was 63 (range 34–74); male/female: 34/16; pT2/T3/T4: 1/44/5; CY0/CY1: 4/46; f-stage2/3a/3b/4: 12/15/16/7. The overall compliance was 84%. Median follow up time was 1063 days for survivors (694–1332) and 1030 days for all. Three-year DFS were 64.6% for all, 66.1% for CY0 and 50.0% for CY1. Conclusions: Sequential TXL/S1 may serve as an active adjuvant for gastric cancer patients especially who are at high risk for peritoneal spread. No significant financial relationships to disclose.