Prognostic Impact of Metastatic Pattern in Renal Cell Carcinoma: IMDC, IMDC-7, and Meet-URO Scores

The International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) score is widely used for prognostic stratification in metastatic renal cell carcinoma (mRCC); however, the value of extended models incorporating metastatic site information remains uncertain in patients treated with first-line tyrosine kinase inhibitor (TKI) monotherapy. We retrospectively analyzed 183 patients with mRCC who received first-line TKI therapy (sunitinib, pazopanib, or cabozantinib) between 2013 and 2023. The overall survival (OS) and progression-free survival (PFS) were assessed using Kaplan-Meier analysis and Cox regression models, and the prognostic performance of IMDC, IMDC-7, and Meet-URO scores was compared using Harrell's concordance index. At baseline, 47% of patients had metastases to high-risk sites (bone, liver, or brain), and 36% had three or more metastatic sites. In univariate analyses, bone, liver, and brain metastases as well as the presence of ≥3 metastatic sites were associated with significantly shorter OS and PFS. On multivariable analysis, anemia, poor performance status, absence of prior nephrectomy, and ≥3 metastatic sites independently predicted worse OS, while anemia, poor performance status, and bone metastasis remained independently associated with inferior PFS. All three prognostic models effectively stratified survival outcomes; however, IMDC-7 demonstrated the highest discriminatory ability for OS, followed by IMDC and Meet-URO. These findings highlight the strong prognostic impact of both metastatic burden and distribution in mRCC and support the incorporation of metastatic site assessment into routine risk stratification, particularly in settings where access to immune-based combination therapies remains limited.