Introduction:

In the United States, an estimated 80,980 new cases of kidney cancer with 14,510 associated deaths are projected in 2025. The majority are renal cell carcinomas (RCC), often with clear cell histology. A hallmark of RCC is venous invasion, with inferior vena cava (IVC) tumor thrombus present in 4–10% of cases. IVC involvement increases surgical complexity and worsens perioperative morbidity and survival. Radical nephrectomy with IVC thrombectomy is the standard treatment for non-metastatic disease. Preoperative renal artery embolization (PRAE) has been proposed to reduce blood loss and improve surgical dissection. Despite theoretical advantages, PRAE remains poorly utilized and controversial due to inconsistent evidence regarding its utility. Some data reports reduced blood loss and transfusion rates, while others show no difference in outcomes or survival This study sought out to evaluate the impact of PRAE in this setting.

Methods:

A retrospective analysis using data from the International Renal Cell Carcinoma – Venous Thrombus Consortium (IRCC-VTC) was conducted. RCC patients with Mayo-classified IVC thrombi (levels 0–IV) undergoing radical surgical excision were included. Extracted data included thrombus level, tumor size, Charlson Comorbidity Index (CCI), estimated blood loss (EBL), length of hospitalization (LOS), highest Clavien-Dindo complication grade, surgery date, and follow-up status. PRAE status was recorded. Patients were compared by PRAE status using standard parametric and categorical tests. A multivariable linear regression for EBL, operative time, transfusions, and LOS using PRAE, thrombus level, and CCI was performed. Grade 2 and 5 complications were modeled with logistic regression. Kaplan-Meier and Cox models assessed overall survival (OS) and cancer-specific survival (CSS), excluding levels 0–I. In the Cox model, thrombus level, tumor size, and CCI were controlled for. Sensitivity analyses assessed robustness across follow-up duration and center volume.

Results:

Among 489 patients, 98 underwent PRAE. PRAE was more common in patients with level IV thrombi (48% vs 22%). Those who underwent PRAE had smaller tumors (6.7 vs 9.9 cm), higher CCI (4.4 vs 3.5), shorter LOS (5.7 vs 15.2 days, p < 0.001), and lower EBL (1400 vs 1950 mL, p = 0.032). Multivariable models confirmed associations with 1190 mL lower EBL, 2.6 fewer transfused units (p = 0.006), and reduced LOS (p < 0.001). PRAE was associated with a 5-fold reduction in grade 2 complications. Grade 5 complications increased with thrombus level (HR 2.56). Kaplan-Meier analysis showed improved OS and CSS with PRAE (p < 0.001); median OS was 165 vs 36 months. On Cox modeling, PRAE (HR 0.127), serum creatinine (HR 1.63), CCI, thrombus level, and cytoreductive surgery were associated with survival. Survival advantages remained significant in sensitivity analyses across thrombus levels and high-volume centers.

Conclusion:

In this large, multi-institutional retrospective study, the impact of PRAE on perioperative and long-term outcomes in patients undergoing radical nephrectomy with IVC thrombectomy was evaluated. PRAE was associated with improved EBL, fewer transfusions, reduced LOS, and lower grade 2 complications, independent of thrombus level or comorbidity. While prior studies showed only modest benefits, these findings suggest more substantial improvements, possibly due to improved stratification by thrombus level. PRAE was also associated with improved OS and CSS, including a two-fold survival benefit. While the mechanism remains unclear, potential immunologic effects of embolization have been proposed. PRAE remains underutilized, performed in only 20% of patients, likely due to institutional variability and access to interventional radiology. Limitations include retrospective design, lack of embolization detail, and international variability. Nonetheless, consistent findings across centers support PRAE’s role. Prospective trials are warranted to confirm these benefits and guide best practices for patient selection and embolization strategy.

Funding: N/A