Progression-free survival of first-line treatment with molecular-targeted therapy may be a meaningful intermediate endpoint for overall survival in patients with metastatic renal cell carcinoma.

The aim of the present study was to investigate the association between clinical parameters and the overall survival (OS) of Japanese patients with metastatic renal cell carcinoma (mRCC). The medical records of 59 consecutive mRCC patients receiving molecular-targeted therapy were retrospectively assessed. Kaplan-Meier and log-rank analyses were used to evaluate the progression-free survival (PFS) and OS, and a multivariate Cox proportional hazard model was used to analyze the clinical parameters for their prognostic relevance. The median OS for all patients was 23.7 months [95% confidence interval (CI): 17.9-30 months], and the median OS stratified by the Memorial Sloan Kettering Cancer Center risk classification was 28.5, 20.9 and 8.1 months for the favorable-, intermediate- and poor-risk groups, respectively (P=0.137; degree of freedom: 2). Univariate analyses identified prior nephrectomy, number of metastatic sites, anemia, best response to first-line treatment and PFS with first-line treatment as prognostic variables. Multivariate analyses identified number of metastatic sites [2: hazard ratio (HR)=3.351, 95% CI: 1.460-8.201, P=0.004; ≥3: HR=6.397, 95% CI: 1.939-20.209, P=0.003], time from diagnosis to therapy (≥1 year: HR=0.334, 95% CI: 0.137-0.755, P=0.008), PFS with first-line treatment (≥5.1 months: HR=0.353, 95% CI: 0.156-0.766, P=0.008) and number of lines of molecular-targeted agents (≥3: HR=0.248, 95% CI: 0.091-0.664, P=0.006) as independent prognostic factors. The results indicated that the PFS of first-line treatment may be a meaningful intermediate endpoint for OS in patients with mRCC who received treatment with molecular-targeted therapy.