Phase II trial report of preoperative chemotherapy (CX) with S-1 plus cisplatin for stage IV gastric cancer (StIV GC).

107 Background: Prognosis of StIV GC is poor. S-1 plus cisplatin now becomes one of the Japanese standards for unresectable or recurrent GC. We conducted a multicenter phase II study of preoperative S-1 plus cisplatin for StIV GC (KYUH-UHA-GC03-01, NCT00088816). In ASCO 2010, we reported early outcomes, indicating that this regimen is feasible and safe. We will report here the results concerning prognosis and recurrence. Methods: Eligibility criteria included histologically proven StIV GC according to Japanese classification. Helical CT and staging laparoscopy were mandatory. Patients (pts) received oral S-1 (80-120 mg/body/day, day 1-21) and intravenous cisplatin (60 mg/m2 on day 8) every 5 weeks for 2 courses. After CX, operation was performed. S-1 (80-120 mg/body/day, day 1-14) was administered every 3 weeks for one year postoperatively. The primary endpoint was 2-year overall survival (OS), and the secondary endpoints were progression free survival (PFS), response, pathologic response, R0 resection, s...