Table 5_Prognostic performance of baseline serum immunoglobulin G in patients with metastatic renal cell carcinoma receiving first-line ICI–TKI therapy.xlsx

Elevated baseline IgG was associated with higher IMDC risk (P = 0.022). Kaplan–Meier analysis showed significantly worse overall survival (OS; P < 0.001) and progression-free survival (PFS; P = 0.049) in patients with elevated IgG. In multivariable analysis, elevated IgG was not associated with PFS but remained an independent predictor of inferior OS (HR = 2.55; 95% CI, 1.30–5.00; P = 0.006).

Incorporating IgG into the IMDC model improved the C-index from 0.645 to 0.689, with the greatest incremental benefit observed for 3-year OS prediction. The exploratory nomogram demonstrated acceptable calibration, particularly for 3-year OS prediction.</p>Conclusions<p>Baseline serum IgG is an independent prognostic biomarker for OS in mRCC patients treated with first-line ICI–TKI therapy. Its integration into the IMDC model improves survival prediction and provides additional prognostic information in the immunotherapy era.</p>