Abstract
Background: The Meet-URO score combines the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) criteria with neutrophil-to-lymphocyte ratio (NLR) and bone metastasis status. Although developed in immune checkpoint inhibitor (ICI) cohorts, its performance among patients receiving first-line tyrosine kinase inhibitor (TKI) monotherapy is uncertain. Methods: We performed a multicenter, retrospective cohort study of 301 adults with histologically confirmed metastatic renal cell carcinoma (mRCC) treated with first-line TKI monotherapy (sunitinib, pazopanib, or cabozantinib) between 2008 and 2025 across five tertiary centers in Turkey. The primary endpoint was overall survival (OS). Meet-URO was calculated at treatment start and analyzed as prespecified risk strata (0-4, 5-8, 9). Kaplan-Meier estimates, Cox models, and Harrell's C-index assessed discrimination, with bootstrapped 95% CIs. Results: Median follow-up was 40 months; median OS (mOS) was 25 months (95% CI, 21-29) and median progression-free survival was 10 months (95% CI, 8-12). Meet-URO stratified OS: 41 months for scores 0-4, 21 months for 5-8, and 7 months for 9 (log-rank p < 0.001). In multivariable analysis, Meet-URO remained independently prognostic (HR 1.73 for 5-8 vs. 0-4; HR 3.57 for 9 vs. 0-4; both p < 0.001). Discrimination was modest (C-index 0.722) and slightly lower than IMDC (C-index 0.745). NLR ≥ 3.2 was associated with inferior OS (19 vs. 37 months; p < 0.001). Bone metastasis was not significantly associated with OS (p = 0.27). Conclusions: Meet-URO is a valid prognostic tool for mRCC patients treated with first-line TKIs and identifies an ultra-high-risk subgroup (score = 9) with poor survival. While not superior to IMDC, Meet-URO may offer complementary risk information to support clinical monitoring and trial referral, particularly in settings where ICI combinations are restricted.