Background The advent of targeted therapy has proved a milestone in the history of metastatic renal cell carcinoma treatment,and several guidelines now recommend sunitinib as first-or second-line treatment.But little is known about its efficacy in Asian patients.The aim of this article was to evaluate the efficacy of sunitinib monotherapy in patients with metastatic renal cell carcinoma treated at two Chinese centers.Methods One hundred and forty-one patients with metastatic renal cell carcinoma were included in the study.Of them,119 patients received single-agent sunitinib as first-line therapy and the remaining 22 patients received it as second-line therapy.One hundred and twenty patients received sunitinib in a dosage of 50 mg orally once daily on a 4-2 schedule (4 weeks on treatment,2 weeks off),while 21 patients received 37.5 mg/day continuously until either disease progression or unacceptable toxicity occurred.The overall response rate,survival outcomes,and safety were evaluated.Results Over a median follow-up time of 23 months (16 cycles; range 2-45 months),complete responses,partial responses,and stable disease lasting two cycles or longer were achieved in 2.8％,24.1％,and 60.3％ of patients respectively (objective response rate 26.9％; overall benefit 87.2％).The median progression-free survival was 14.2 months (range 3-39 months).During the study,53 patients died and the median survival time was 13.5 months (range 7-25 months).Dose modification or treatment interruption due to adverse events was required in 36.9％ of the patients.The most common adverse events were hand-foot syndrome (71.4％),thrombocytopenia (68.8％),hypertension (47.1％),and fatigue (46.3％).Conclusion Sunitinib had a favorable efficacy/tolerability profile in Chinese patients with metastatic renal cell carcinoma.