Comparison of Tyrosine Kinase Inhibitor Versus Mammalian Target of Rapamycin Inhibitor as Second-line Molecular-targeted Therapy for Patients with Poor-risk Metastatic Renal Cell Carcinoma.

Abstract

The objective of this study was to compare the efficacies of tyrosine kinase inhibitor (TKI) and mammalian target of rapamycin inhibitor (mTORI) as second-line molecular-targeted therapy in patients with poor-risk metastatic renal cell carcinoma (mRCC). This study included 89 consecutive patients with mRCC who were classified into a poor-risk group after the failure of first-line molecular-targeted agent and subsequently received second-line targeted therapy. Of the 89 patients, 59 and 30 were treated with TKI and mTORI, respectively, as second-line targeted therapy, and no significant differences in the clinicopathological characteristics were noted between the TKI and mTORI groups. There was no significant difference in the response rate to the second-line agent between the TKI and mTORI groups; however, the proportion of patients with tumor shrinkage in the TKI group was significantly higher than that in the mTORI group. There was no significant difference in the progression-free survival between the TKI and mTORI groups, while the overall survival for the TKI group was significantly superior to that of the mTORI group (median of 15.0 vs. 7.6 months, respectively). Furthermore, the type of second-line agent (i.e. TKI vs. mTORI) was identified as an independent predictor of the OS, but not of PFS. Favorable disease control might be achieved by introducing TKI as second-line targeted therapy for patients with poor-risk mRCC.