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 (< 8 vs > or = 8) in the base model (age, Eastern Cooperative Oncology Group performance status, pathologic stage, grade, architecture, and lymphovascular invasion) significantly increased the accuracy in predicting CSM (+1.7%; p<0.001). CONCLUSIONS The extension of the lymphadenectomy in pN0 UTUC patients seems to be associated with CSM. Longer survival was observed in patients in whom at least eight LNs had been removed.