Capecitabine and Gemcitabine in Treating Patients With Metastatic Kidney Cancer

DISEASE CHARACTERISTICS: Histologically confirmed renal cell carcinoma Clinically confirmed metastatic disease (histologic documentation of metastatic disease not required) Sarcomatoid renal cell carcinomas allowed No pure sarcomas No collecting duct (duct of Bellini) tumors, oncocytomas, or transitional cell tumors Measurable disease At least 20 mm by conventional techniques OR At least 10 mm by spiral CT scan Nonmeasurable lesions include the following: Bone lesions Leptomeningeal disease Ascites Pleural/pericardial effusion Lymphangitis cutis/pulmonis Abdominal masses that are not confirmed and followed by imaging techniques Cystic lesions Patients with known brain metastases are eligible if they have undergone prior surgical resection and/or cranial irradiation, they currently do not require steroids or anticonvulsants, and there is no progressive disease on CT scan or MRI at least 4 weeks after completion of radiotherapy PATIENT CHARACTERISTICS: Age 18 and over Performance status ECOG 0-2 Life expectancy Not specified Hematopoietic 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 Renal Creatinine clearance at least 30 mL/min Cardiac No clinically significant cardiac disease No congestive heart failure No symptomatic coronary artery disease No cardiac arrhythmias not well controlled with medication No myocardial infarction within the past 12 months Other Not pregnant or nursing Negative pregnancy test Fertile patients must use effective barrier contraception during and for 3 months after study No prior severe reaction to fluoropyrimidine therapy or known sensitivity to fluorouracil No malabsorption syndrome or lack of physical integrity of the upper gastrointestinal tract that would preclude absorption of capecitabine PRIOR CONCURRENT THERAPY: Biologic therapy Not specified Chemotherapy At least 4 weeks since prior chemotherapy and recovered No prior gemcitabine No prior fluoropyrimidines (e.g., fluorouracil, floxuridine, capecitabine, or fluorouracil-uracil) No other concurrent chemotherapy Endocrine therapy See Disease Characteristics At least 4 weeks since prior megestrol No concurrent hormones (e.g., megestrol) except steroids for adrenal failure, hormones for nondisease-related conditions (e.g., insulin for diabetes), or intermittent dexamethasone as an antiemetic Radiotherapy See Disease Characteristics At least 4 weeks since prior radiotherapy and recovered Prior radiotherapy to any lesion that may produce disability (e.g., unstable femur) allowed No concurrent palliative radiotherapy Surgery See Disease Characteristics At least 4 weeks since prior major surgery and recovered Other Any number of prior regimens allowed