A maximum of 8 cycles of chemotherapy will be administered. Depending on patients' tolerability, 8 cycles of chemotherapy will be given to the patients.

Single-center, open-label, prospective, single-arm, phase I-II study

About 37 patients (Phase I 18, Phase II 31 (including 12 patients from Phase I)

Inclusion Criteria:

1. Unresectable or metastatic advanced gastric adenocarcinoma confirmed by histology
2. Peritoneal seeding proven by histology or cytology
3. Completion of adjuvant chemotherapy 6 months before the study, or no previous chemotherapy (But, patients who received docetaxel or cisplatin as adjuvant chemotherapy should be excluded)
4. Age 18 to 70 years old
5. Eastern Cooperative Oncology Group performance status <_ 2
6. Estimated life expectancy of more than 3 months
7. Adequate bone marrow function (WBCs>3,000/µL and absolute neutrophil count (ANC) >1,500/µL and platelets>100,000/µL),
8. Adequate renal function: creatinine < 1 x upper normal limit (UNL) or creatinine clearance _> 60ml/min
9. Adequate hepatic function: bilirubin < 1.5 x UNL, AST/ALT levels < 2.5 x UNL, alkaline phosphatase < 5 x UNL (except in case of bone metastasis without any liver disease)
10. Written informed consent

Exclusion Criteria:

1. Contraindication to any drug contained in the chemotherapy regimen
2. Other tumor type than adenocarcinoma
3. Presence or history of CNS metastasis
4. Gastric outlet or bowel obstruction
5. Evidence of serious gastrointestinal bleeding
6. Peripheral neuropathy > grade 2
7. History of significant neurologic or psychiatric disorders
8. History of another malignancy within the last five years except cured basal cell carcinoma of skin and cured carcinoma in-situ of uterine cervix
9. Pregnant or lactating women, women of childbearing potential not employing adequate contraception
10. Other serious illness or medical conditions