The role of lymph node dissection in non-metastatic renal cell carcinoma with tumor thrombosis: a retrospective analysis

Background To assess therapeutic value of lymph node dissection (LND) in non-metastatic renal cell carcinoma (RCC) with tumor thrombosis (TT) and identify the prognostic factor in these population. Methods We retrospectively reviewed 128 patients with RCC and TT in our institution from February 2015 to January 2019. The baseline characteristics of LND and no LND group were compared. Kaplan–Meier analysis, univariable and multivariable Cox regression models were used to analyze these population. Results Of 128 patients, 58(45%) underwent LND and 70(55%) without LND. Patients who received LND had significantly higher cN1 rate (64% vs 37%; P = 0.004), longer operation time (357 min vs 307 min; p = 0.002) and longer hospital stay (12.6d vs 9.5d; p = 0.094) than that in no LND group. There were 102 patients (79.7%) received followed up with the median 12 months (IQR:8 ~ 19). Estimated three-year overall survival was worse in LND group (75% vs 90%; p = 0.048) but were not significantly different in subgroup of cN0 and cN1. The overall survival were not significantly different between two groups after adjustment for age, tumor size, surgical approach, tumor thrombosis level and histologic type. Non-CCRCC (HR:4.97; 95%CL:1.56 ~ 15.78; P = 0.006) and occurrence of major complication (HR:3.33; 95%CL:1.05 ~ 10.58; P = 0.041) were the predictors of worse OS while positive lymph node is the only independent predictor of worse OS (HR:5.26; 95%CL:1.28 ~ 21.66; P = 0.021) in these populations after receiving LND. Conclusion In this study, we confirm that LND in non-metastatic RCC with TT was not associated with a survival benefit, even we adjusted for clinic node status. Category like age, tumor size, surgical approach, tumor thrombosis level and histologic type were not a indication for LND. Lymph node positive was identified as an independent poor prognostic factor. Therefore, LND in RCC with TT should be considered as a staging procedure rather than therapeutic one.