Gemcitabine With Or Without Oxaliplatin in Treating Patients With Locally Advanced or Metastatic Bladder Cancer

DISEASE CHARACTERISTICS: * Histologically confirmed urothelial carcinoma, or transitional cell carcinoma of the bladder or upper urinary tract * Locally advanced disease (T4b) or metastatic disease (N2, N3, or M1) * Unable to receive cisplatin-based chemotherapy due to creatinine clearance 30-60 mL/min or performance status 2 * At least 1 unidimensionally measurable lesion according to RECIST criteria * No nonmeasurable lesions only, including any of the following: * Ascites * Pleural or pericardial effusion * Bone metastases * Lymphangitis * No symptomatic cerebral metastases unless they have been stabilized PATIENT CHARACTERISTICS: * See Disease Characteristics * Performance status 0-2 * ANC ≥ 1,500/mm³ * Platelet count ≥ 100,000/mm³ * Alkaline phosphatase ≤ 2 times normal (unless bone metastases are present) * Transaminases ≤ 2 times normal (5 times normal if hepatic metastases present) * Bilirubin ≤ 1.5 times normal * Not pregnant or nursing * Fertile patients must use effective contraception during and for at least 6 months after completion of treatment * No prior malignancy within the past 5 years except carcinoma in situ of the cervix or basal cell skin cancer * No peripheral neuropathy ≥ grade 2 * No uncontrolled infection * No other medical conditions that could interfere with evaluating tolerability, including any of the following: * Congestive heart failure * Angina pectoris that cannot be stabilized with medication * Myocardial infarction wit…