Trends of Lymph Node Outcomes in Partial Cystectomy for Muscle-Invasive Urothelial Carcinoma of the Bladder

Introduction: Local tumor invasion depth has been associated with lymph node metastasis in urothelial carcinoma, and, for muscle-invasive bladder cancer (MIBC), pelvic lymph node dissection (PLND) is a critical step in curative surgery. Gold standard treatment includes radical cystectomy (RC), but partial cystectomy (PC) is an important bladder -preserving modality reserved for patients with certain favorable prognostic indicators. There is poor evidence concerning the utility of PLND in PC and we seek to further define its role by comparing survival outcomes when PLND was cursory or omitted. Methods: A retrospective analysis of 13,652 cT2N0M0 patients who underwent PC or RC between 2004 and 2016 was performed using the National Cancer Database. Patients undergoing PC were stratified by the presence of PLND as well as by node yield > 15. The primary outcome was overall survival, analyzed using the Kaplan-Meier Method and multivariable Cox-proportional hazards regression. Multivariable models were adjusted for confounding clinicopathologic variables. Results: From 2004 to 2016, PLND in PC increased from 44% to 57% with RC remaining over 90%. Compared to RC, PC was approximately twice as likely to be performed at community centers and approached laparoscopically/robotically ( P < .001). When stratifying PC PLND yield into 1 to 15 and > 15 compared to PC without PLND, the adjusted hazard ratios for overall mortality were 0.78 and 0.54, respectively ( P < .05). Conclusions: PC patients had a significantly lower rate of PLND compared to RC and improved survival when performed versus PC alone. Furthermore, increased node yield was associated with a larger reduction of adjusted mortality hazard. For MIBC patients that are appropriately selected for PC, high-yield PLND should be pr ior itized given the significantly improved survival outcomes.