Sorafenib in Treating Patients With Metastatic or Unresectable Kidney Cancer

DISEASE CHARACTERISTICS: Inclusion Criteria: * Histologically or cytologically confirmed renal cell carcinoma (RCC) * Must have a component of conventional clear cell RCC * Predominant clear cell component ≥ 75% * Metastatic or unresectable disease (Measurable disease is defined as any lesion that can be accurately measured in at least one dimension (longest diameter to be recorded) as ≥ 20 mm by conventional techniques or ≥ 10 mm by spiral CT scan or MRI) * Measurable or nonmeasurable disease, includes any of the following: * Small lesions, longest diameter \< 20 mm by conventional techniques or \< 10 mm by spiral CT scan * Bone lesions * Leptomeningeal disease * Ascites * Pleural/pericardial effusion * Lymphangitis cutis/pulmonitis * Abdominal masses that are not confirmed and followed by imaging techniques * Cystic lesions * Irradiated lesions, unless progression is documented after radiotherapy * Paraffin RCC tissue blocks or unstained slides must be obtained for future chemistry staining of VEGF * Karnofsky performance status 70-100% * Fertile patients must use effective contraception (hormonal and/or barrier method) during and for 3 months after completion of study treatment * Granulocyte count ≥ 1,500/µL * Platelet count ≥ 100,000/µL * AST/ALT ≤ 2.5 times upper limit of normal (ULN) * Alkaline phosphatase ≤ 2.5 times ULN * Serum bilirubin ≤ 1.5 times ULN * Protein ≤ 1+ by urinalysis * Creatinine ≤ 1.5 times ULN * At least 4 weeks since prior major surgery and/or radiotherapy and recovered * Prior palliative radiotherapy for metastatic lesion(s) allowed provided there is at least one measurable and/or evaluable lesion(s) that has not been irradiated * More than 4 weeks since prior and no other concurrent anticancer therapy * Concurrent continuation of bisphosphonates allowed for bone metastases prophylaxis Exclusion Criteria: * Patients with true papillary, sarcomatoid features without any clear cell component, chromophobe, oncocytoma, collecting duct tumors, or transitional cell carcinoma are not eligible * No evidence of CNS metastases * No imaging (MRI or CT scan of the brain) abnormality indicative of CNS metastases within past 42 days * Not pregnant or nursing (negative pregnancy test) * No ongoing hemoptysis * No cerebrovascular accident within the past 12 months * No peripheral vascular disease with claudication while walking less than 1 block * No history of clinically significant bleeding * No deep venous thrombosis or pulmonary embolus within the past year * No significant cardiovascular disease, defined as NYHA class II-IV congestive heart failure, angina pectoris requiring nitrate therapy, or myocardial infarction within the past 6 months * No uncontrolled hypertension, defined as systolic BP \> 160 mm Hg and/or diastolic BP \> 90 mm Hg while on medication * No preexisting thyroid abnormality whose thyroid function cannot be maintained in the normal range by medication * No uncontrolled psychiatric disorder * No delayed healing of wounds, ulcers, and/or bone fractures * No currently active second malignancy except nonmelanoma skin cancer (patients are not considered to have a 'currently active' malignancy if they have completed anticancer therapy and are considered by their physician to be at less than 30% risk of relapse) * No more than one prior systemic therapy for RCC * No prior vascular endothelial growth factor receptor agents * No concurrent systemic corticosteroid therapy (except replacement therapy for adrenal insufficiency) o Topical and/or inhaled steroids allowed * No concurrent full-dose oral or parenteral anticoagulation o Low-dose warfarin (1 mg) for maintenance of catheter patency or daily prophylactic aspirin allowed * No concurrent Hypericum perforatum (St. John's wort) * No concurrent ketoconazole, itraconazole, ritonavir, rifampin, or products containing grapefruit juice * No concurrent hormonal therapy or chemotherapy o Concurrent hormones administered for non-disease related conditions (e.g., insulin for diabetes) allowed