The Association between Lymph Node Dissection and Survival in Lymph Node-Negative Upper Urinary Tract Urothelial Cancer

SIMPLE SUMMARY: The benefit of lymph node dissection (LND) for node-negative (N0) upper urinary tract urothelial cancer (UTUC) remains uncertain. We aimed to evaluate the association between the extent of LND during radical nephroureterectomy (RNU) and survival by analyzing real-world population-based data. The removal of at least four lymph nodes was associated with improved overall and cancer-specific survival compared to no or less extensive LND. Propensity score matching was performed to adjust for confounders. Further risk-stratified subgroup analysis confirmed the survival benefit of more extensive LND, especially for muscle-invasive UTUC. Our findings underscore the significance of performing an adequate LND during RNU for N0 UTUC. Further prospective studies are crucial to confirm our results. ABSTRACT: The benefit of lymph node dissection (LND) during radical nephroureterectomy (RNU) in lymph node (LN)-negative (cN0/pN0) UTUC remains controversial. We aimed to assess the association between LND and its extent and survival in LN-negative UTUC. The Surveillance, Epidemiology, and End Results database was searched to identify patients with non-metastatic chemotherapy-naïve cN0/pNx or pN0 UTUC who underwent RNU +/− LND between 2004 and 2019. Overall, 4649 patients with cN0/pNx or pN0 UTUC were analyzed, including 909 (19.55%) individuals who had LND. Among them, only in 368 patients (7.92%) was LND extended to at least four LNs, and the remaining 541 patients (11.64%) have had < four LNs removed. In the whole cohort, LND contributed to better cancer-specific survival (CSS) and overall survival (OS). Furthermore, a propensity score-matched analysis adjusted for confounders confirmed that improved CSS and OS was achieved only when ≥ four LNs had been removed, especially in muscle-invasive UTUC. A multivariable analysis further confirmed an association between the extent of LND and CSS. To conclude, adequate LND during RNU was associated with improved OS and CSS in LN-negative UTUC, particularly in muscle-invasive stage. This underscores that a sufficient LN yield is required to reveal a therapeutic benefit in patients undergoing RNU.