Oxaliplatin and S-1 or Oxaliplatin and Capecitabine in Treating Patients With Recurrent, Metastatic, or Unresectable Gastric Cancer

DISEASE CHARACTERISTICS:

• Histologically confirmed adenocarcinoma of the stomach
• Unresectable advanced disease or recurrent disease after resection
• At least one radiographically documented (CT scan or MRI) measurable or evaluable lesion in a previously non-irradiated area according to RECIST
• No clinical evidence of brain metastases or history of other CNS disease unless adequately treated

PATIENT CHARACTERISTICS:

• ECOG performance status 0-2
• Estimated life expectancy > 3 months
• Hemoglobin ≥ 9 g/dL
• White blood cell ≥ 4,000/µL
• ANC ≥ 2,000/µL
• Platelets ≥ 100,000/µL
• Bilirubin ≤ 1.25 times upper limit of normal (ULN) (≤ 2.0 times ULN if hepatic metastasis present)
• Serum creatinine ≤ 1.5 times ULN
• Creatinine clearance ≥ 60 mL/min
• AST/ALT ≤ 3.0 times ULN (≤ 5.0 times ULN if hepatic metastasis present)
• Alkaline phosphatase ≤ 3.0 times ULN (≤ 5.0 times ULN if bone metastasis present)
• Must have an intact gastrointestinal tract
• Able to take oral medications
• No medically uncontrolled severe infections or complications
• No prior malignancy other than gastric cancer in the last 5 years except for basal cell cancer of the skin or preinvasive cancer of the cervix
• Not pregnant or nursing
• No neuropathy ≥ grade 2
• No clinically relevant heart disease
• No evidence of past medical history or psychosocial dysfunction that contraindicates the use of an investigational drug or puts the patient at risk
• No dementia, altered mental status, or any psychiatric condition that would prohibit the understanding or rendering of informed consent
• No uncontrolled hepatitis B or C, chronic liver disease, or diabetes mellitus
• No other evidence of inappropriate suspicious condition

PRIOR CONCURRENT THERAPY:

• No prior chemotherapy for advanced or recurrent disease
• Prior adjuvant chemotherapy allowed if finished > 6 months before start of study treatment
• No prior therapeutic radiotherapy
• Prior palliative radiotherapy allowed if it was not done for primary, evaluable, or intraabdominal lesions
• No prior capecitabine or oxaliplatin
• No other concurrent chemotherapy or radiotherapy (except localized radiotherapy for pain relief)
• No concurrent chemically related analogues, such as warfarin, phenytoin, or allopurinol
• No concurrent steroid therapy except as follows:
• Prophylactic use for hypersensitivity control or antiemetic purpose allowed
• Chronic low dose of steroid (less than methylprednisolone 20 mg or equivalent dose) allowed