The Extent of Lymphadenectomy Seems to Be Associated with Better Survival in Patients with Nonmetastatic Upper-Tract Urothelial Carcinoma: How Many Lymph Nodes Should Be Removed?

Background: The role and extent of lymphadenectomy in patients with upper-tract urothelial carcinoma (UTUC) is debated. Objective: To establish whether the number of lymph nodes (LNs) removed might be associated with better cause-specific survival in patients with UTUC. Design, setting, and participants: The study included 552 consecutive patients who underwent radical nephroureterectomy (RNU) and lymphadenectomy between 1992 and 2006. Intervention: Patients were treated with RNU and lymphadenectomy. Measurements: Univariable and multivariable Cox proportional hazards regression models addressed the association between the number of LNs removed and cause-specific mortality (CSM). The number of LNs removed was coded as a cubic spline to allow for nonlinear effects. Finally, the most informative cut-off for the number of removed LNs was identified. Results and limitations: In the entire population, the number of LNs removed was not associated with CSM in univariable (hazard ratio [HR]: 0.99; p = 0.16) or in multivariable (HR: 0.97; p = 0.12) analyses. In contrast, in the subgroup of pN0 patients (n = 412), the number of LNs removed achieved the independent predictor status of CSM (HR: 0.93; p = 0.02). Eight LNs removed was the most informative cut-off in predicting CSM (HR: 0.42; p = 0.004). The inclusion of the variable defining dichotomously the number of removed LNs (