Comparative analysis of oncologic outcomes in surgically treated patients with renal cell carcinoma and renal vein thrombosis by pathologic subtypes.

This study compares recurrence-free survival (RFS) and overall survival (OS) in patients with non-clear cell (nccRCC) and clear cell renal cell carcinoma (ccRCC) undergoing surgical nephrectomy with thrombectomy (SNTx) for RCC with venous thrombus. Data from patients who underwent SNTx at two tertiary centers (June 1990-December 2022) were retrospectively reviewed. Patients were grouped as ccRCC or nccRCC and stratified by metastasis status at surgery. Primary endpoints were RFS and OS for metastasis-naive RCC and OS for the entire cohort, including both metastasis-naive and metastatic RCC. Kaplan-Meier analysis with log-rank tests and adjusted multivariable Cox proportional hazards models were performed, with TN adjustments for the metastasis-naive group and TNM adjustments for the entire population. Among 604 patients, 504 (83.5%) were ccRCC. In nccRCC, 44 (44.0%) were papillary, 17 (17.0%) were chromophobe, and 39 (39.0%) were rare subtypes, most commonly TFE3 rearranged RCC, followed by the RCC not otherwise specified subtype (according to the 2022 World Health Organization Classification of RCC). Median OS was 85.8 months for ccRCC, 37.7 for papillary, 90.2 for chromophobe, and 16.9 for rare subtypes. Rare RCC histology was significantly associated with worse RFS (HR 1.63, p = 0.038) and OS (HR 1.82, p = 0.039) in metastasis-naive RCC. For the entire cohort including metastatic diseases, rare subtypes had worse OS (HR 2.20, p < 0.001), while other nccRCC subtypes did not differ significantly from ccRCC in OS. In patients with RCC with venous thrombosis, rare nccRCC subtypes exhibited poorer survival outcomes, even after adjustment for TN(M) stage.