The Impact of Histological Variants on Oncological Outcomes After Surgical Resection of a Nonmetastatic Renal Cell Carcinoma with Tumor Thrombus: A Multi-institutional Study.

ABSTRACT

Background: There is no definitive evidence of the prognosis impact of histological variants (HVs) in patients who undergo surgical resection of a nonmetastatic renal cell carcinoma (nm-RCC) with venous tumor thrombus (TT). Objective: To investigate the impact of HVs on the prognosis of patients with nm-RCC with TT after radical surgery. Design setting and participants: Patients who underwent radical nephrectomy with the removal of the venous TT for an nm-RCC were included in a retrospective study. Outcome measurements and statistical analysis: Three groups were identified clear cell (ccRCC), papillary (pRCC), and chromophobe (chRCC) RCC. The primary outcome measures (disease-free and overall survival [OS]) were assessed using the Kaplan-Meier method and compared using the log-rank test. Univariate and multivariate Cox proportional hazard models were used to study the impact of HVs on survival. Results and limitations: A total of 873 patients were included. The histological subtypes were distributed as follows ccRCC in 780 cases, pRCC in 58 cases, and chRCC in 35 cases. At the time of data analysis, 612 patients were recurrence free and 228 had died. A survival analysis revealed significant differences in both OS and recurrence-free survival across histological subtypes, with the poorest outcomes observed in pRCC patients (p < 0.05). In a multivariable analysis, pRCC was independently associated with worse disease-free survival and OS (hazard ratio [HR] 1.71; p = 0.01 and HR 1.24; p = 0.04), while chRCC was associated with more favorable outcomes than ccRCC (HR 0.05; p < 0.001 and HR 0.02; p < 0.001). A limitation of the study is its retrospective nature. Conclusions: In this multicentric series, HVs appeared to impact the medium-term oncological prognosis of kidney cancer with TT. Patient summary: This study investigated the differences in oncological outcomes among histological variants (clear cell, papillary, and chromophobe) in a cohort of nonmetastatic renal cell carcinoma patients with venous tumor thrombus extension. We observed that these histological variants within this specific subgroup exhibit distinct outcomes, with papillary renal cell carcinoma being associated with the worst prognosis.