Cancer-specific Mortality After Radical Nephrectomy and Thrombectomy for Renal Cell Carcinoma with Tumor Thrombus According to Histological Subtypes.

Abstract

Background and objective: We tested the effect of histological subtypes on cancer-specific mortality (CSM) after radical nephrectomy (RN) with thrombectomy for nonmetastatic renal cell carcinoma with tumor thrombus (RCC-TT) within the Surveillance, Epidemiology and End Results database (2010-2021).

Methods: We used propensity score matching (PSM), multivariable competing-risk regression (CRR) analyses, and cumulative incidence functions to test differences in CSM between papillary RCC (pRCC) and clear-cell RCC (ccRCC), and between chromophobe RCC (chRCC) and ccRCC.

Key findings and limitations: Of 5516 patients with nonmetastatic RCC-TT, 180 (3.3%), 186 (3.4%), and 5150 (93%) harbored pRCC, chRCC, and ccRCC, respectively. TT was limited to the renal vein in 135 (75%), 168 (91%), and 4457 (87%) patients with pRCC, chRCC, and ccRCC, respectively. After 1:3 PSM, 180 (100%) pRCC cases were compared with 540 (11%) ccRCC cases. The 5-yr CSM rate was 43% in pRCC versus 26% in ccRCC. Multivariable CRR revealed that pRCC independently predicted higher CSM relative to ccRCC (hazard ratio [HR] 1.81, 95% confidence interval [CI] 1.31-2.50; p < 0.001). After 1:3 PSM, 186 (100%) chRCC cases were compared with 558 (11%) ccRCC cases. The 5-yr CSM rate was 14% in chRCC versus 19% in ccRCC. Multivariable CRR revealed no significant difference in CSM between chRCC and ccRCC (HR 0.62, 95% CI 0.37-1.03; p = 0.07). Limitations include the retrospective nature of the study and a lack of data on disease progression and subsequent treatment.

Conclusions and clinical implications: For patients with RCC-TT treated with RN with thrombectomy, pRCC independently predicted a 1.8-fold higher CSM rate in comparison to ccRCC, with no significant difference in CSM rates between chRCC and ccRCC. Adjuvant therapy should be considered for patients with pRCC or chRCC in the TT setting.