Prognosis of scirrhous gastric cancer with minimal peritoneal metastasis was poor, and the role of resection has not been clarified yet. Analysis 1: Overall survival was examined in 79 patients who underwent R0/R1 resection during 1970-1995 at Kanagawa Cancer Center (Group A), and in 47 patients who underwent R0/R1 resection and received S1 chemotherapy at the 30 hospitals of Japan Clinical Oncology Group (Group B). Hazard ratio (HR) of group B to group A was examined. HR was 0.64 at 1 year, 0.76 at 2-year, and 0.92 at 3-year. Analysis 2: HR of S1 group in SPIRITS phase III trial to FU group in JCOG 9205 phase III trial was examined. HR was 0.64 at 1 year and 0.84 at 2-year. Analysis 3: HR was compared each other including HR of ACTS-GC phase III trial. HR was ACTS<analysis 1=analysis 2 at 1 year, and was ACTS<analysis 1<analysis 2 at 2-year. In conclusion, these results suggested that the significance of resection increased by post-operative S1 chemotherapy.