Reclassifying renal cell carcinoma with pathologic lymph node metastasis: An approach to refining prognostic...

Lymph node metastasis is a well-established prognostic factor in renal cell carcinoma (RCC); however, the prognosis varies among patients with nodal metastases. Subclassification by T category may improve the prognostic stratification.

This study aimed to refine the prognostic stratification of advanced RCC by analyzing the overall survival and cancer-specific survival of patients classified as pT1-3N1M0. We retrospectively analyzed data from 364 patients with American Joint Committee on Cancer (AJCC) stage III and IV RCC who underwent nephrectomy with lymphadenectomy at multiple centers between 2010 and 2023. Five-year survival rates were estimated using Kaplan-Meier analysis, and the concordance index (C-index) was used to assess the stratification ability of the different staging systems. Multivariable analyses were conducted to adjust for potential confounders. Additionally, 194 and 1513 patients from The Cancer Genome Atlas and Surveillance, Epidemiology, and End Results databases were used to validate the prognostic values.

Patients with pT1-2N1M0 had significantly better 5-year survival rates than those with pT3N1M0 (overall survival: 62.4% vs. 31.5%, P = 0.003; cancer-specific survival: 62.4% vs. 38.5%, P = 0.008). Reclassifying pT3N1M0 from AJCC stage III to IV improved prognostic discrimination, as reflected by higher C-index values compared to the AJCC staging (8th edition) (ΔC-index: 0.03-0.10, all P values <0.05). The modified staging system demonstrated comparable performance to the previous system while avoiding the over-staging of patients with pT1-2N1M0 (ΔC-index: 0-0.04, most P values >0.05), as confirmed across local and external cohorts. These findings were supported by the Multivariable analyses.

Reclassifying pT3N1M0 as stage IV improves prognostic stratification in RCC.