Contemporary Trends and Efficacy of Pelvic Lymph Node Dissection at Radical Cystectomy for Urothelial and Variant Histology Carcinoma of the Urinary Bladder

To test 1) contemporary pelvic lymph node dissection (PLND) trends at radical cystectomy (RC) in variant histology bladder cancer (VHBC) patients and urothelial carcinoma of the urinary bladder (UCUB), as well as 2) to test the effect of PLND extent on cancer specific mortality (CSM) after RC.Within the Surveillance, Epidemiology and End Results Registry (SEER, 2004-2016), we identified non-metastatic stage T1-2 or T3-4 VHBC and UCUB patients, who underwent RC. CSM and lymph node invasion (LNI) rates were stratified according to PLND extent, as well as coded continuously in multivariate Cox and logistic regression models.Of 19,020 patients, 1736 (9.1%) were coded as having VHBC (46.9% squamous cell carcinoma, 22.5% adenocarcinoma, 18.9% neuroendocrine carcinoma, 11.7% not otherwise specified) vs 17,284 (90.9%) UCUB. PLND was performed in 80.1 of VHBC vs. 83.5% UCUB patients. In both histological groups, PLND rates increased over time (70.9-89.6% and 76.2%-90.1%, both P < .01). PLND extent did not significantly affect CSM in stage T1-2 or T3-4 VHBC patients. Conversely, PLND extent was associated with lower CSM in T1-2, as well as in T3-4 UCUB patients, which was confirmed in multivariate Cox analyses (Hazard ratio [HR] 0.99, P < .001). Rates of LNI increased with extent of PLND in logistic regression analyses in stage T3-4 VHBC (Odds ratio [OR] 1.01, P = .001), stage T1-2 UCUB (OR 1.01, P < .001) and T3-4 UCUB (OR 1.01, P < .001), but not in stage T1-2 VHBC (OR 1.01, P = .3).PLND rates do not differ between VHBC and UCUB patients. A potential survival benefit related to more extensive PLND is operational in UCUB patients, but not in VHBC patients.