Predictors for metastatic renal cell carcinoma in IMDC favorable risk group treated with a single agent first line systemic therapy.

e16518 Background: With the induction of molecular targeted agents, which interfere with proteins that play critical roles in tumor growth and progression, and immune checkpoint inhibitors, the scenario of systemic treatment of metastatic renal cell carcinoma (mRCC) have dramatically been changed with improved survival. Prognostic risk assessment is essential for choosing the most appropriate first line treatment option, with selection based on International Metastatic RCC Database Consortium (IMDC) Risk Category. This study was designed to evaluate the actual efficacy of a single agent systemic therapy in the IMDC favorable risk group patients with mRCC. Methods: A total of 240 patients with mRCC who received systemic therapy were retrospectively reviewed (Institutional review board approval No 2013-0425). Among them, 55 patients were classified as favorable risk group based on the IMDC Risk Category and received a single agent systemic therapy. Clinical and pathological data were retrieved and analyzed retrospectively. The prognostic effect of each marker on overall survival (OS) was investigated with univariate and multivariate Cox’s proportional hazards regression models. Results: After a median follow-up of 46 months after first-line treatment initiation, the median progression free survival (PFS) for first line treatment and OS of patients in favorable risk group were 29 months (95% CI 21–34)) and not reached, respectively. The estimated percentage of patients who were alive at 12 and 24 months were 96 and 94%, respectively. Multivariate analysis revealed that the long-term duration of first-line treatment (hazard ratio [HR]: 0.97, 95% confidence interval [CI]: 0.94–0.99, p = 0.0299) and the metastases limited to lung (HR: 3.85, 95% CI: 1.08–24.50, p = 0.0361) were independent predictors for longer OS in favorable risk mRCC patients. Conclusions: First-line systemic therapy for favorable risk mRCC patients with a single agent resulted in relatively longer PFS and OS. A longer duration of first-line treatment and lung only metastases are correlated with longer OS.