Sorafenib and sunitinib are inhibitors of receptor protein tyrosine kinases 
(TKIs) and are approved for the treatment of metastatic renal cell carcinoma 
(mRCC). Although the mTOR inhibitor everolimus is effective for the treatment of 
patients who have failed TKI therapy, it is important to consider all available 
treatment options before switching therapy mode of action. Herein, we report 
outcomes in patients with mRCC switched to sorafenib following disease 
progression on sunitinib treatment. The medical records of 35 patients treated 
between November 2006 and November 2009 at two large referral centers in Greece 
were retrospectively analyzed for time-to-progression (TTP), overall survival 
(OS), and tolerability of sorafenib after sunitinib. Median TTP and OS on 
sorafenib were 4.9 and 11.5 months, respectively. Among 33 patients evaluable 
for tumor response, three had a partial response and 17 achieved disease 
stabilization (objective response rate 8.5%; total clinical benefit rate 57%). 
Sorafenib was well tolerated, with mostly grade 1/2 adverse events and no 
treatment-related deaths. Sorafenib was effective and well tolerated in this 
group of patients. The TTP with sorafenib following sunitinib was comparable to 
outcomes reported previously, providing further support that TKIs should be used 
in sequence before switching to an mTOR inhibitor.