Prognostic significance of pT3a staging subclassifications in renal cell carcinoma: Not all pT3a are equal.

ABSTRACT

OBJECTIVE: To examine the prognostic significance of perinephric fat, renal sinus fat, and renal vein invasion in patients with pT3a renal cell carcinoma (RCC) by histologic type. METHODS: A population-based retrospective cohort study of patients with pT3aN0M0 RCC was performed using Surveillance, Epidemiology, and End Results (SEER) data for the years 2010 through 2019. Cox proportional hazards models were used to examine the relationship between pT3a subclassification groups and cancer-specific survival (CSS) by histological subtype (clear cell, papillary, chromophobe, and other). RESULTS: The cohort consisted of 10,170 patients with pT3a RCC, including 8,446 (83.0%) with clear cell RCC and 1,724 (17.0%) with nonclear cell RCC (nccRCC). Median follow up was 36 months. Differences in CSS by pT3a subclassification groups were observed in all histological subtypes but were most pronounced in nccRCC, specifically papillary RCC. Compared to perinephric fat (PF) invasion only, renal vein (RV) invasion (HR = 4.9, 95%CI 2.5-9.3, P < 0.01), renal sinus fat invasion (HR = 3.0, 95%CI 1.4-6.2), RV and PF invasion (HR = 7.5, 95%CI 3.5-16.0), and combination of all three characteristics (HR = 4.4, 95%CI 1.2-15.5) were associated with worse CSS in patients with papillary RCC. CONCLUSION: We examined the prognostic role of pT3a staging subclassifications in RCC by histologic subtype and observed survival differences, particularly in papillary RCC. Our findings highlight the need to refine pT3a staging criteria to help guide individualized, multimodal treatment strategies for locally advanced RCC.