Prognostic significance of extent of venous tumor thrombus in patients with non-metastatic renal cell carcinoma: Results from a Canadian multi-institutional collaborative

•The prognostic significance of venous thrombus extent in RCC is controversial.•Most studies on this topic are limited by their inclusion of metastatic patients.•In this non-metastatic cohort, thrombus extent was not associated with RFS.•In this non-metastatic cohort, thrombus extent was not associated with CSS.•In this non-metastatic cohort, thrombus extent was not associated with OS. The prognostic significance of level of venous tumor thrombus (VTT) extension in patients with non-metastatic renal cell carcinoma (RCC) has been controversial. The aim of this study was to examine the prognostic significance of VTT extent in patients who underwent surgery for non-metastatic RCC. The Canadian Kidney Cancer information system database was used to identify patients who underwent surgery for non-metastatic RCC and VTT from January 2011 to December 2019. Association between VTT level and recurrence-free survival (RFS), cancer-specific survival (CSS) and overall survival (OS) was examined. Univariable and multivariable analyses were performed to estimate predictors of survival. Out of 6,340 patients during the study period, 228 patients (3.6%) had VTT. VTT was level 0 in 84 (37%), level I to II in 112 (49%), and level III to IV in 33 (14%) patients as per the Mayo Clinic classification. Median age was 65.4 years (interquartile range [IQR] 57.6–72.2) and 169 (74.1%) were male. After a median follow-up of 21.2 months, VTT level did not significantly impact the RFS, CSS, or OS. For VTT level 0, I to II, and III to IV, there was no significant difference in estimated 5-year RFS (31%, 23%, and 30.5%; P > 0.05), CSS (70%, 69%, and 55%; P > 0.05) and OS (64%, 66%, and 50%; P > 0.05). Adjusting for known prognostic factors, thrombus level was not associated with risk of recurrence or death. In a large, multi-institutional cohort of patients undergoing surgery for non-metastatic RCC with tumor thrombus, thrombus extent was not independently associated with recurrence or death.