Stage 1:First line therapy Sequential therapy of S1+Docetaxel followed by S1 is superior to concomitant S1+Docetaxel in the safety and clinical efficiency.

Stage 2:Second line therapy To explore the feasibility of single drug(S1) maintenance treatment for advanced gastric cancer.

Inclusion Criteria:

• Signed informed consent form
• Performance Status-Eastern Cooperative Oncology Group (ECOG) 0-1
• Histologically or cytologically confirmed gastric cancer
• Advanced or recurrent, metastatic disease
• At least have one measurable disease(according to RECIST, Response Evaluation Criteria in Solid Tumors )
• Life expectancy of at least 3 months
• Target target lesion has not received radiotherapy or non target lesion radiation at least 4 weeks
• Haematopoietic and Hepatic status:

Absolute neutrophil count >1.5x109/L,Platelet count > 100 x 109/L,Hemoglobin at least 9 g/dl,Bilirubin ≤ 1.5 x upper limit of normal (ULN),AST and ALT ≤ 2.5 times ULN(no liver metastasis), ≤5 times ULN(with liver metastasis)

• Cardiovascular: Baseline LVEF 50% measured by echocardiography

Exclusion Criteria:

• Symptomatic brain metastasis
• Active or uncontrolled infection
• Unresolved or unstable, serious toxicity from prior cancer treatment (any toxicities greater than grade 2; peripheral neuropathy of grade 2 or greater Symptomatic brain metastasis
• Known history of uncontrolled or symptomatic angina, clinically significant arrhythmias, congestive heart failure, uncontrolled hypertension (≥ 180/110), unstable diabetes mellitus, dyspnea at rest, or chronic therapy with oxygen
• History of other malignancy
• Pregnant or lactating women