Capecitabine and Oxaliplatin in Treating Patients With Locally Advanced, Unresectable, or Metastatic Stomach Cancer

DISEASE CHARACTERISTICS: Histologically or cytologically confirmed gastric cancer Locally advanced, unresectable, or metastatic disease Measurable disease, defined as at least 1 lesion that can be accurately measured in ≥ 1 dimension as ≥ 20 mm with conventional techniques or as ≥ 10 mm with spiral CT scan No known brain metastases PATIENT CHARACTERISTICS: ECOG performance status (PS) 0-2 or Karnofsky PS 60-100% WBC ≥ 3,000/mm³ Absolute neutrophil count ≥ 1,500/mm³ Platelet count ≥ 100,000/mm³ Bilirubin normal AST/ALT ≤ 2.5 times upper limit of normal Creatinine ≤ 1.5 mg/dL Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception during study and for 6 months after completion of study treatment Able to swallow No history of allergic reactions attributed to compounds of similar chemical or biologic composition to fluoropyrimidines or platinum chemotherapy agents No uncontrolled intercurrent illness including, but not limited to the following: Ongoing or active infection Symptomatic congestive heart failure Unstable angina pectoris Cardiac arrhythmia Psychiatric illness or social situations that would preclude study compliance PRIOR CONCURRENT THERAPY: More than 4 weeks since prior chemotherapy or radiotherapy (6 weeks for nitrosoureas or mitomycin C) and recovered At least 6 months since prior radiotherapy with capecitabine as a radioenhancer No concurrent combination antiretroviral therapy for HIV-positive patients No other concurrent chemotherapy No concurrent palliative radiotherapy No concurrent hormonal therapy except for the following: Steroids for adrenal failure Hormones for nondisease related conditions (e.g., insulin for diabetes) Intermittent use of dexamethasone as an antiemetic No other concurrent investigational agents No other concurrent anticancer agents or therapies