Background: Metastatic renal cell carcinoma (mRCC) treatment is partly informed by risk group. The two most commonly used prognostic models, the International Metastatic RCC Database Consortium (IMDC) and the Memorial Sloan-Kettering Cancer Center (MSKCC), stratify patients (pts) into favorable (0 risk factors [RFs]), intermediate (1–2 RFs) or high risk (≥3 RFs) groups. This study examined real-world outcomes according to IMDC and MSKCC RFs in sunitinib-treated pts with mRCC. Methods: Data were extracted on 19 June 2019 from a large, prospective German multicenter registry (STAR-TOR). Only pts with sufficient data for risk stratification by IMDC and MSKCC were included in this analysis. Progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method. The impact of RFs on survival was assessed using Cox’s regression analysis and the chi square test. Results: According to IMDC or MSKCC, 16.7% and 15.3%, 26.2% and 30.8%, 18.7% and 24.7%, and 38.5% and 29.2 of pts had 0, 1, 2 and ≥3 RFs, respectively. In IMDC intermediate pts, only < 1 year diagnosis to therapy (24.8%) was the most common RF; in MSKCC intermediate pts, < 1 year diagnosis to therapy with low hemoglobin (19.9%) were the most common. OS was not significantly different for pts with 0 vs 1 (p = 0.24), or 2 vs ≥3 (p = 0.16) IMDC RFs, but was significant according to MSKCC RFs (0 vs 1, p = 0.04; 2 vs ≥3, p < 0.01). OS was significantly longer for pts with 1 vs 2 RFs for IMDC (p = 0.03) and MSKCC (p = 0.04), but PFS was not (IMDC, p = 0.29; MSKCC, p = 0.12). OS was significantly longer for 0 vs 2, 0 vs ≥3, and 1 vs ≥3 RFs for IMDC and MSKCC RFs (all comparisons, p < 0.01). Similar results were observed for PFS with the exception of 0 vs 1 IMDC RF (p = 0.01). Conclusions: The intermediate risk group appears to be heterogeneous. OS for pts with 1 RF may align with the favorable risk group and pts with 2 RFs may align with the poor risk group.

mOS, median OS; mPFS, median PFS; ORR, objective response rate.