Abstract / Summary
Background: Inflammation-based biomarkers may refine prognostic stratification in patients with metastatic renal cell carcinoma (mRCC). This study evaluated the prognostic value of the pretreatment C-reactive protein-to-albumin ratio (CAR) and systemic immune-inflammation index (SII) in patients with mRCC receiving first-line systemic therapy.
Methods: We retrospectively analyzed 117 patients who received first-line systemic therapy between January 2001 and April 2022. Pretreatment CAR and SII were evaluated as readily available blood-based inflammatory biomarkers. Overall survival (OS) was defined as the primary outcome, and progression-free survival (PFS) was defined as the secondary outcome. Exploratory cutoffs were CAR 0.0731 and SII 533.81.
Results: High CAR and high SII were independently associated with shorter OS after adjustment for IMDC risk classification and nephrectomy status. The adjusted HRs were 2.36 for high CAR (95% CI, 1.30-4.27; p = 0.005) and 2.58 for high SII (95% CI, 1.42-4.69; p = 0.002). Patients with concurrent elevation of both CAR and SII had the shortest OS compared with those with neither marker elevated (HR, 6.39; 95% CI, 2.76-14.77; p < 0.001). Adding CAR and SII to International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) improved the optimism-corrected C-index for OS from 0.641 to 0.733.
Conclusions: Pretreatment CAR and SII were associated with OS in patients with mRCC receiving first-line systemic therapy. These readily available biomarkers may help refine OS risk assessment when used alongside established clinical factors, but external validation is required before clinical implementation.