Long-Term Performance of Prognostic Models for Advanced Renal Cell Carcinoma in the Era of Improved Survival With Immune Checkpoint Inhibitors

PURPOSE In the era of prolonged survival for advanced renal cell carcinoma (aRCC) with standard-of-care first-line therapy now including immune checkpoint inhibitor, re-evaluation of the Memorial Sloan Kettering Cancer Center (MSKCC) and International Metastatic RCC Database Consortium (IMDC) prognostic models is overdue. METHODS Data from 1,052 patients with aRCC treated on the CheckMate-214 phase III randomized trial with first-line nivolumab + ipilimumab or sunitinib were analyzed after minimum 5 years of follow-up. The end point was overall survival (OS). To investigate long-term prognostication with each treatment approach, model performance based upon continuous risk score was assessed in a time-dependent manner of increasing 6-month intervals and globally over full follow-up, using discrimination concordance (c)-indices. RESULTS With time-dependent assessment, the IMDC and MSKCC models maintained their performance over approximately 2 years from sunitinib initiation (c ≥0.69 through 18-24 months); thereafter, the models' performances with long-term OS attenuated. Over full follow-up, the models' discrimination was c = 0.66 (95% CI, 0.658 to 0.664) and c = 0.64 (95% CI, 0.640 to 0.645), respectively, for the sunitinib group. After nivolumab + ipilimumab initiation, the IMDC and MSKCC models' global discrimination was c = 0.63 (95% CI, 0.628 to 0.634) and c = 0.61 (95% CI, 0.607 to 0.614), respectively. The models' performances were attenuated in the short term (c ranging 0.64-0.69 through 18-24 months) and the long term. CONCLUSION This retrospective analysis of the CheckMate-214 trial, in which nivolumab + ipilimumab improved survival versus sunitinib with 48% and 37% of patients, respectively, surviving beyond 5 years, confirmed the strength of the models' prognostication for the early years after first-line sunitinib initiation continuing to stratify three prognostic categories, but also diminished discrimination among long-term survivors and with initiation of nivolumab + ipilimumab. As novel treatments are developed and patients with aRCC live longer, new models to estimate long-term prognosis are needed.