The combination of Cisplatin and S-1 (CS) achieved a response rate of approximately 45% with the PFS being around 6 months and overall survival time being 13 months in Japanese and Chinese gastric patients. It remains unclear whether the addition of docetaxel to CS would further enhance the efficacy as it dose in DCF(docetaxel, cisplatin and 5-fluorouracil). This is a single center, phase II clinical trial to evaluate the efficacy of docetaxel, cisplatin and S-1 (DCS) as first line chemotherapy for patients with advanced gastric and gastroesophageal junction cancer.

This is a single arm trial. All Patients will receive up to 6 cycles of triple chemotherapy with docetaxel, cisplatin and S-1. Given the severe toxicity of DCF regimen, here the total dose of docetaxel and cisplatin is both reduced to 60mg/m2. For patients with CR/PR/SD disease after 6 cycles of chemotherapy, maintenance therapy with S-1 are recommended. Antitumor activity will be evaluated every two cycles according to RECIST1.1.

Inclusion Criteria:

• Histologically or cytologically confirmed unresectable advanced gastric or gastroesophageal junction cancer;
• No previous chemotherapy and radiation for advanced disease except palliative radiation for a local pain control;
• At least one evaluable lesion per RECIST (Response Evaluation Criteria in Solid Tumors) 1.1;
• ECOG (Eastern Cooperative Oncology Group) performance status 0-1;
• Recovery from the toxicities of previous therapy;
• Adequate bone marrow and organ function. Hb≥8 G/L; Absolute neutrophil ≥ 2.0 G/L; PLT ≥100 G/L ;ALT/AST ≤1.5 ULN or ≤5ULN with liver metastases; TBIL ≤1.5 ULN; Cr≤1.0 ULN;
• Life expectancy ≥3 months;
• For men and women of childbearing potential, agree on taking effective contraceptive method of birth control from the signed informed consent until 3 months after the last study drug administration;
• Signed informed consent.

Exclusion Criteria:

• Pathology type other than adenocarcinoma,such as squamous cell carcinoma;
• Previous treatment with taxanes, cisplatin or S-1;
• Relapse within 6 months after the end of adjuvant chemotherapy;
• Known brain metastases;
• Complete or incomplete intestinal obstruction or uncontrolled gastrointestinal bleeding;
• Known deficiency of DPD enzyme;
• Kown HIV infecton or drug addiction;
• Any acute or chronic medical or psychiatric condition that would make the patient inappropriate for entry into this trial in the judgement of investigators;
• Myocardial infarction within 6 months prior to the entry of this trial;
• Known history of allergic reaction to taxanes and platinum;
• Pregnant or breast feeding women.