Efficacy and Safety of S-1 Plus Oxaliplatin in First-line Treatment of Ederly Patients With Advanced Gastric Cancer

Inclusion Criteria: * Histologically confirmed unresectable or recurrent gastric or gastroesophageal junction adenocarcinoma; * Aged≥60 * ability of oral administration; * CT or MRI can be used to assess measurable or non-measurable lesions according to the criteria of Response Evaluation Criteria In Solid Tumours (RECIST 1.1); * Untreated * more than 12 months after the last adjuvant/neoadjuvant chemotherapy; * ECOG=0-2; * Available organ function: ALT≤2.5xULN;AST≤2.5xULN;If patients have hepaticmetastasis,ALT≤2.5xULN,AST≤2.5xULN;ALP≤2xULN;TBIL≤1.0xULN;NEUT≥1.5×109/L;PLT≥100×109/L;Hb≥90g/L;Creatinine≤1.0xULN;Creatinine Clearance≥60ml/min * Informed consent; * Expected survival more than 3 months;More than 3 weeks after major surgery. Exclusion Criteria: * Neoadjuvant and/or adjuvant have been treated with more than two plans; * In the past two years, the total dose of oxaliplatin≥800mg/m2; * Other cancers in the past 5 years,except for cervical carcinoma in situ or non-melanoma skin cancer; * Symptomatic brain metastases or soft meningeal metastasis; * Myocardial infarction (in the last 6 months), severe instability angina, congestive heart failure; * Serious complications (including intestinal paralysis, gastrointestinal obstruction, interstitial pneumonia, pulmonary fibrosis, uncontrolled diabetes, renal insufficiency and cirrhosis); Chronic nausea, vomiting or diarrhea (more than 4 times per day, or watery);Gastrointestinal bleeding requires regular blood transfusion;HIV or AIDS; Mental illness; Neuropathy grade≥2;Infectious diseases or inflammation, temperature≥38℃; * Known allergy to drugs in the study; * Pregnant or lactating women; * Both male and female subjects of potential fertility have to agree effective birth control during the entire study; * Experimental drugs used no more than 4 weeks; * Other conditions the researchers considered ineligible for the study.