Predictors of Survival in Favorable Risk Patients with Metastatic Renal Cell Carcinoma Treated with a Single-Agent First-Line Therapy

Introduction: The aim of this retrospective study was to elucidate predictors of survival in metastatic renal cell carcinoma (mRCC) patients in an International Metastatic Renal Cell Carcinoma Database Consortium favorable risk group treated with frontline therapy without immune checkpoint inhibitors. Methods: A total of 238 patients with mRCC were reviewed. Among them, 55 patients in favorable risk group treated with single-agent systemic therapy were retrospectively analyzed. 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 46.2 months after first-line treatment initiation, the median progression-free survival (PFS) was 29.3 months, and the median OS has not been reached. The estimated percentage of patients who were alive at 12 and 24 months were 96.1 and 94.1%, respectively. Multivariate analysis revealed that the long-term duration of first-line treatment (hazard ratio [HR]: 0.972, 95% confidence interval [CI]: 0.944-0.997, p = 0.0299) and the metastases limited to lung (HR: 3.852, 95% CI: 1.080-24.502, p = 0.0361) were independent predictors for longer OS in favorable risk mRCC patients. Conclusion: 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.