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

Purpose: 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.

Materials and methods: 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.

Results: 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.

Conclusion: 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.