The patient's study enrollment was too low.

After curative resection, patients with stage IIIB-IV (M0) gastric cancer were given chemotherapy as follows: S-1 orally at 80 mg/m2 divided in two daily doses for 14 days and oxaliplatin at 130 mg/m2 intravenously over 2 h every 21 days as one cycle. S1 was administered for 16 cycles (12 months) and oxaliplatin for 8 cycles (6 months).

Inclusion Criteria:

• Patients who voluntarily provide written informed consent prior to entering into this study
• Newly definitely diagnosed with primary gastric or gastroesophageal junction adenocarcinoma histologically
• Patients who underwent radical resection with wide lymph node dissection
• TNM stage (6th AJCC) of IIIB or IV on post-operative staging
• Patients who can be randomized within 6 weeks after surgery

Exclusion Criteria:

• Aged < 20 years or ≥ 76 years
• Eastern Cooperative Oncology Group (ECOG) performance status >2
• Patients who underwent surgery for neoplasm in stomach in the past
• History of malignant disease The following cases can be included in this study - adequately treated basal cell or squamous cell skin cancer, cervical carcinoma in situ
• Gastric or gastroesophageal junction adenocarcinoma with distant metastasis (M1) including distant lymph node (behind the pancreas, along the aorta, portal vein, behind the peritoneum, mesenteric lymph node)
• Residual cancer on post-operative staging (R1 and R2 resection)
• Patients who received adjuvant chemotherapy, or neoadjuvant chemotherapy and/or radiotherapy and/or immunotherapy in the past for treatment of gastric cancer
• Any of the following within 6 months prior to the study recruitment: Myocardial infarction, severe/unstable angina, coronary/peripheral artery bypass, NYHA class III or IV congestive heart failure, stroke or transient ischemic attack, serious cardiac arrhythmia requiring treatment
• Patients of childbearing potential who do not agree to use generally accepted effective method of birth control during the study treatment period and for at least 6 months after the end of study treatment
• Pregnant women, breastfeeding women, or women of childbearing potential whose pregnancy test result is positive•
• History of hypersensitivity to the investigational products (S1 and Oxaliplatin)