A Trial of Induction Chemotherapy and Chemoradiotherapy With TS-1 and Cisplatin (SP) as First-line Treatment in Patients With High Risk Advanced Gastric Cancer

Inclusion Criteria:

* Histologically or cytologically documented gastric adenocarcinoma
* Patients must have unresectable disease or high-risk advanced tumor: borrmann type IV, large borrmann type III (\>8cm),locally extensive nodal disease (bulky N),locally advanced (T4) tumors,esophageal invasion
* Age: 20 to 75
* ECOG PS: 0 or 1
* Patients with adequate organ function : Absolute neutrophil count \> 1.5 x 109 / L, Platelet count \> 100 x 109 / L, Hemoglobin \> 9 g/dL (by transfusion permitted), Calculated creatinine clearance \> 60 ml/min, Serum total bilirubin \< 1.5 times upper normal limit (UNL), Serum alanine transaminase (ALT) \< 3 times UNL
* Signed informed consent
* Sexually active patients, in conjunction with their partner, must practice birth control during therapy. Female patients in child-bearing age must have negative pregnancy test.
* No other malignancies within the past 5 years except for curatively treated basal cell carcinoma of the skin and/or in situ carcinoma of the cervix
* No prior or concurrent significant medical conditions, including any of the following: Cerebrovascular disease within the past year/ Cardiovascular disease; myocardial infarction within the past year, uncontrolled hypertension while receiving chronic medication, unstable angina, New York Heart Association class II-IV congestive heart failure, serious cardiac arrhythmia requiring medication/ Major trauma, major surgery or open biopsy within the 28 days Serious nonhealing wound, ulcer, or bone fracture/ Evidence of bleeding diathesis or coagulopathy/ Recent history of any active gastrointestinal inflammatory condition
* No lack of physical integrity of the upper GI tract, malabsorption syndrome, or inability to take oral medication
* No bleeding from primary tumor or gastrointestinal stenosis
* sufficient oral intake
* No prior surgery for gastric cancer except for endoscopic membrane resection (EMR)
* No known peripheral neuropathy ≥ 1
* No prior chemotherapy
* No prior radiotherapy

Exclusion Criteria:

* Other tumor type than adenocarcinoma
* Metastasis to the sites out of abdomen (liver or other hematogenous metastasis)
* Patients with definite ascites in pre-operative abdomen CT
* documented inoperable peritoneal seeding disease determined by exploratory laparotomy
* Past or concurrent history of neoplasm other than gastric cancer, except for curatively treated non-melanoma skin cancer or in situ carcinoma of the cervix uteri
* Pregnant or lactating women, women of childbearing potential not employing adequate contraception
* Other serious illness or medical conditions: History of significant neurologic or psychiatric disorders including dementia or seizures/ Active uncontrolled infection/ Severe hypercalcemia of above 12 mg/dL uncontrolled with bisphosphonates/ Other serious underlying medical conditions which could impair the ability of the patient to participate in the study
* Concurrent treatment with corticosteroids (or equivalent) except as use for the prophylactic medication regimen, treatment of acute hypersensitivity reactions, or unless chronic treatment (initiated \> 6 months prior to study entry) at low dose (\<20 mg methyl prednisolone or equivalent)
* Concomitant or with a 4-week period administration of any other experimental drug under investigation
* Concomitant chemotherapy, hormonal therapy, or immunotherapy
* Prior palliative surgery (open and closure, passage operation)