Composite Inflammatory Score for Predicting Progression-Free Survival in Metastatic Clear Cell Renal Cell Carcinoma Treated With First-Line Toripalimab Plus Axitinib

Routine inflammatory and nutritional markers may help stratify progression risk in metastatic clear cell renal cell carcinoma during immunotherapy-based treatment. This single-center retrospective study included 237 patients who received first-line toripalimab plus axitinib therapy. Ten indices were natural-log transformed and standardized, and domain-based selection yielded a compact composite inflammatory score (COMP-IS), which was internally validated using 1000 full-pipeline bootstrap resamples. The primary endpoint was progression-free survival (PFS). During a median follow-up of 19.84 months for PFS, 124 events occurred. COMP-IS comprised the neutrophil-to-lymphocyte ratio, C-reactive protein-to-albumin ratio (CAR), and prognostic nutritional index. After adjusting for the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) score, each standard deviation increase in COMP-IS was associated with shorter PFS (hazard ratio, 3.48; 95% confidence interval, 2.74-4.42). The apparent concordance index (C-index) for COMP-IS was 0.767, with a bootstrap-corrected C-index of 0.755, compared with corrected C-indices of 0.694 for CAR and 0.565 for the IMDC score. Adding IMDC to COMP-IS resulted in a corrected C-index of 0.756. In an exploratory post hoc comparison, the published Meet-URO risk groups had an apparent C-index of 0.593. COMP-IS demonstrated prognostic discrimination for PFS in this cohort; however, only internal validation was performed. Its clinical utility therefore remains uncertain, and independent external validation and prospective evaluation are needed before routine clinical use.