Adjuvant Chemotherapy With S-1 Plus Oxaliplatin Versus S-1 Alone in Locally Advanced Gastric Cancer

Inclusion Criteria: * sign written informed consent form * age ≥ 18 years, ≤69 years * ECOG status: 0\~2 * pathologically confirmed gastric cancer at stage II or IIIA (AJCC 7th version) * negative peritoneal cytology * underwent curative distal gastrectomy with D2 lymph node dissection * no prior antitumor treatment is allowed, including chemotherapy, radiotherapy, immune therapy or target therapy * adequate organ function as defined below: Hematologic ANC ≥ 2\*109/L, Platelets ≥ 100\*109/L, AST and ALT ≤ 2.5×ULN, TBIL ≤ 1.5×ULN. Exclusion Criteria: * be enrolled in other clinical trials * underwent prior antitumor treatment * allergic reaction to S-1 or oxaliplatin * abnormal GI tract function * female in pregnancy or lactation, or refuse to receive Contraception measures during chemotherapy * other situation to be judged not adaptive to the study by investigators