S0312, Gemcitabine and Capecitabine in Treating Patients With Advanced Renal Cell (Kidney) Cancer

DISEASE CHARACTERISTICS: Histologically or cytologically confirmed renal cell carcinoma Metastatic (M1) disease OR M0 provided the primary tumor is unresectable Measurable disease At least 1 unidimensionally measurable lesion Soft tissue disease that has been irradiated within the past 2 months is not considered measurable disease Soft tissue disease within a prior radiation field is measurable provided it has progressed since therapy and there is also measurable disease outside of the irradiated field No prior or concurrent brain metastases PATIENT CHARACTERISTICS: Age 18 and over Performance status Zubrod 0-2 Life expectancy Not specified Hematopoietic Absolute granulocyte count at least 1,500/mm^3 Platelet count at least 100,000/mm^3 Hepatic Bilirubin no greater than 1.5 times upper limit of normal (ULN) Aspartate aminotransferase (SGOT) no greater than 1.5 times ULN Renal Creatinine clearance at least 50 mL/min Cardiovascular No symptomatic congestive heart failure No unstable angina pectoris No cardiac arrhythmia Other Not pregnant or nursing Fertile patients must use effective contraception No other concurrent uncontrolled illness that would preclude study participation No psychiatric illness or social situation that would preclude study compliance No uncontrolled diabetes mellitus No ongoing or active infection No other malignancy within the past 5 years except adequately treated basal cell or squamous cell skin cancer, carcinoma in situ of the cervix, or stage I or II cancer currently in complete remission PRIOR CONCURRENT THERAPY: Biologic therapy No more than 2 prior immunotherapy regimens comprising interferon (IFN) and/or interleukin-2 (IL-2) At least 28 days since prior IFN or IL-2 and recovered Chemotherapy No prior chemotherapy for renal cell cancer Endocrine therapy Not specified Radiotherapy See Disease Characteristics No prior radiotherapy to 25% or more of the bone marrow At least 21 days since prior radiotherapy and recovered Surgery At least 28 days since prior surgery and recovered Prior resection of the primary tumor allowed (in patients with metastatic disease) Other At least 4 weeks since prior sorivudine or brivudine No concurrent sorivudine or chemically related analogues (e.g., brivudine)