Prognostic stratification of the IMDC intermediate risk group after treatment with first-line molecular-targeted therapy for metastatic renal cell carcinoma

Background/Aim: The therapeutic outcomes of patients with metastatic renal cell carcinoma (mRCC) have dramatically improved with the introduction of moleculartargeted agents. The observational multicenter study was conducted to develop a novel stratification system for the intermediate risk group of the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) model. Patients and Methods: The present study included 252 Japanese patients with mRCC who received first-line molecular-targeted therapy at four institutions. Results: The 252 patients were classified into the favorable, intermediate, and poor risk groups by the IMDC model. For the intermediate risk group, multivariate analysis of the six factors included in the IMDC model revealed that a low performance status, anemia, and a high platelet count were independent predictors of poor overall survival (OS). The intermediate risk group was subsequently divided into the following two groups (int-group 1 and 2) by the three independent OS predictors. Significant differences in the OS were noted among the IMDC favorable risk group, intgroup 1, int-group 2, and poor risk group. Conclusion: The novel stratification presented in this study could be a useful tool for further prognostication of patients with mRCC classified into the intermediate risk group according to the IMDC model after first-line molecular-targeted therapy.