Login to Access Video or Poster Abstract: MP16-05
Sources of Funding: None

Introduction

It remains the standard approach for assessing the prognosis of mRCC patients treated with molecular-targeted agents to use the MSKCC and IMDC risk classifications, while the significant prognostic impact of the objective tumor response to these novel agents in mRCC patients has recently been documented in various studies. We also reported that the overall survival (OS) in patients with mRCC was closely correlated with the degree of tumor shrinkage at 12 weeks after the introduction of first-line targeted agents (Target Oncol 2016; 11: 175-82). Of these, however, there was no study focusing on data from mRCC patients treated with second-line targeted agents outside clinical trials. The objective of this study was to evaluate the impact of early tumor shrinkage (ETS) induced by a second-line targeted agent on OS in mRCC patients.

Methods

This study retrospectively included 271 consecutive Japanese patients with mRCC who received second-line targeted therapy for at least 3 months. ETS was defined as the degree of tumor shrinkage at the first post-baseline radiological evaluation conducted 4 to 8 weeks after initiating second-line targeted therapy.

Results

Of the 271 patients, 26 had ETS from -100 to -50%, 70 from -49 to -25%, 84 from -24 to 0%, and the remaining 91 failed to achieve a reduction in the tumor size. The median OS following the initiation of second-line targeted therapy stratified according to ETS was 45.8, 30.9, 22.1 and 14.2 months, respectively. Univariate analysis identified prior nephrectomy, the MSKCC risk classification, C-reactive protein (CRP) level, number of metastatic organs, sarcomatoid feature, introduced second-line agent and ETS induced by a second-line agent as parameters significantly associated with OS, of which, only the MSKCC classification, CRP level and ETS appeared to have independent impacts on OS on multivariate analysis.

Conclusions

Collectively, these findings suggest that ETS at the first post-baseline assessment under treatment with a second-line targeted agent could serve as a useful parameter with an independent impact on OS in mRCC patients receiving second-line targeted therapy; therefore, it is highly recommended to select second-line targeted agents that make it possible to induce prompt tumor remission to further improve the prognosis of patients with mRCC following the failure of first-line targeted therapy.

Funding

None