Inclusion Criteria

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