Inclusion Criteria:

1. Histologically or cytologically confirmed localized gastric adenocarcinoma as defined
by CT stage III and IV (M0) (but not N3, which is metastatic node in WHO TNM
classification), according to Japanese TNM classification system

2. No distant metastatic disease in laparoscopy

3. Age: 18-70 years

4. Eastern Cooperative Oncology Group (ECOG) performance status 0-1

5. Disease status must be that of measurable disease as defined by RECIST: Measurable
lesions: lesions that can be accurately measured in at least one dimension by
abdominal CT, if the longest diameter to be recorded is at least 10 mm with spiral CT

6. Adequate major organ function including the following: Hematopoietic function: WBC ³
4,000/mm3, ANC ³ 1,500/mm3, Platelet ³ 100,000/mm3Hepatic function: serum bilirubin £
1.5 mg/dl, AST/ALT levels £ 2.5 x UNLRenal function: serum creatinine £ 1.5 mg/dl

7. Patients should sign a written informed consent before study entry

Exclusion Criteria:

1. CT Stage I, II, M1 or N3, which is metastatic node in WHO TNM classification,
according to Japanese TNM classification system

2. Prior chemotherapy or radiotherapy

3. Inadequate cardiovascular function:New York Heart Association class III or IV heart
diseaseUnstable angina or myocardial infarction within the past 6 monthsHistory of
significant ventricular arrhythmia requiring medication with antiarrhythmics or
significant conduction system abnormality

4. Serious concurrent infection or nonmalignant illness that is uncontrolled or whose
control may be jeopardized by complications of study therapy

5. Other malignancy within the past 3 years except non-melanomatous skin cancer or
carcinoma in situ of the cervix

6. Psychiatric disorder that would preclude compliance

7. Pregnant, nursing women or patients with reproductive potential without contraception

8. Patients receiving a concomitant treatment with drugs interacting with S-1 such as
flucytosine, phenytoin, or warfarin et al.