Background Sunitinib has been proved an effective new option for treatment of metastatic renal cell carcinoma (mRCC).Analysis of clinical data of 22 patients,who were exposed to sunitinib for at least 1 year,was conducted to evaluate the long-term efficacy and safety of sunitinib for the treatment of mRCC.Methods A total of 54 patients with mRCC were treated with sunitinib malate,50 mg/d orally,on a 4-weeks-on and 2-weeks-off dosing schedule in Peking University First Hospital.Treatment continued until disease progression,unacceptable adverse events (AEs),or death.Among them,22 patients continued treatment for at least 1 year.The clinical data of these 22 patients were prospectively collected for analysis.AEs were assessed according to the National Cancer Institute Common Terminology Criteria for Adverse Events,Version 3.0.Tumor response was evaluated in accordance with the Response Evaluation Criteria in Solid Tumors.Results Median progression-free survival was 19.5 months until last follow-up.The best efficacy results achieved were complete response,partial response,and stable disease for 2,9,and 11 patients,respectively.Objective response rate was 50％.The most common AEs were hand-foot syndrome (95％) and hypertension (91％).Other common AEs were thyroid-stimulating hormone elevation (82％),platelet decrease (77％),and loss of appetite (77％).Only one patient withdrew from treatment for cardiac infarction.Another nine patients experienced dose modifications or short-term suspensions.Conclusion Long-term exposure to sunitinib malate showed encouraging efficacy in the treatment of mRCC.At the same time,the tolerability was good.