Background/Objectives: To evaluate the utility of the addition of C-reactive protein/albumin ratio (CAR) to the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC). Methods: A retrospective multicenter analysis was conducted. The main outcomes were overall survival (OS) and all-cause mortality (ACM). Receiver operating characteristic (ROC) analysis determined the optimal CAR cutoff. Cox multivariable analysis (MVA) identified independent predictors for ACM. Kaplan–Meier analysis (KMA) evaluated OS stratified by IMDC risk groups. C-index assessed predictive accuracy of the CAR-augmented model. Results: We analyzed 392 patients (80 favorable-IMDC, 298 intermediate-IMDC, and 14 poor-risk). ROC revealed an optimal elevated CAR as ≥2.53. High CAR (HCAR) was an independent predictor of ACM on MVA (HR = 1.84, p < 0.001). KMA comparing IMDC favorable/intermediate/poor-risk revealed 3-year OS of 86.8%/57.9%/50.0%, p = 0.001. Subdivision by CAR revealed alignment between favorable-HCAR with intermediate–normal-CAR (NCAR) and intermediate-HCAR with poor-risk. KMA with the addition of CAR to the IMDC, demonstrating 3-year OS 91.0%, 72.7%, and 48.4% across favorable, intermediate, and poor-risk, respectively. Based on the alignment of favorable-HCAR with intermediate-NCAR, and intermediate-HCAR with poor-risk, a CAR-augmented IMDC algorithm was developed in which favorable- and intermediate-risk patients with NCAR are considered suitable CN candidates, while intermediate-HCAR and poor-risk patients are unlikely to benefit from surgery. The CAR augmented model showed improved predictive capability compared to the IMDC with a C-index of 0.70 vs. 0.67. Conclusions: Integrating CAR into the IMDC model enhances prognostic precision for CN selection in mRCC. This approach identifies intermediate-NCAR as appropriate CN candidates based on favorable survival, while sparing intermediate-HCAR from surgery.
Ahdoot et al. (Wed,) studied this question.