Predictive factors of recurrence after surgery in patients with non-metastatic renal cell carcinoma with venous tumor thrombus (UroCCR-56 Study).

PURPOSE: To assess the oncological outcomes of renal cell carcinoma (RCC) associated with tumor thrombus and identify predictive factors of recurrence. METHODS: Multi-institutional study that included patients with cT3-4N0-1M0 RCC with tumoral thrombus identified in the prospective UroCCR database (CNIL DR 2013-206; NCT03293563). pT3a without involvement of the renal vein were excluded. All patients underwent radical nephrectomy and a thrombectomy of the renal vein ± inferior vena cava ± right atrium. The primary endpoint was recurrence-free survival (RFS). Thirty-two patients who had adjuvant therapies (tyrosine kinase inhibitors or mTOR inhibitor) were compared to control group (surveillance) in a propensity score-matched 1:1 sub-analysis RESULTS: A total of 432 patients were included: 70.4% pT3a, 20.1% pT3b, 4.2% pT3c and 5.3% pT4. Tumor characteristics were: 90.7% clear cell RCC, 13.9% pN1, and 87.1% high Fuhrman grade. 173 patients (40%) had disease recurrence, and median RFS was 37.3 months (95% CI, 26.4-46.7). In a multivariate analysis (Cox model), predictive factors of recurrence were: pT4 (HR 2.66; 95% CI, 1.42-4.99; p = 0.002), pN1 (HR 2.53; 95% CI, 1.46-4.39; p < 0.001), tumor necrosis (HR 2.92; 95% CI, 1.85-4.62; p < 0.001), tumor size > 10 cm (HR 1.56; 95% CI, 1.08-2.24; p = 0.018). Adjuvant therapy was a protective factor of cancer recurrence (HR 0.33; 95% CI, 0.17-0.66; p = 0.002). Propensity score-matched sub-analysis of adjuvant vs control (surveillance) confirmed adjuvant treatment as a protective factor of cancer recurrence (Log rank p = 0.015). CONCLUSIONS: In this contemporary multi-institutional cohort of RCC + tumor thrombus, we reported higher recurrence rate shortly after surgical excision and demonstrated an oncological benefit of adjuvant treatment.