Adenocarcinoma of the Bladder: Assessment of Survival Advantage Associated With Radical Cystectomy and Comparison With Urothelial Bladder Cancer.

PURPOSE:To evaluate the association between radical cystectomy (RC) and cancer-specific mortality (CSM) in patients diagnosed with adenocarcinoma of the bladder (ACB). Moreover, to directly compare the survival advantage of RC between ACB vs. urothelial bladder cancer (UBC). MATERIALS AND METHODS:Non-metastatic muscle-invasive ACB and UBC patients were identified within Surveillance, Epidemiology, and End Results database (SEER 2000-2018). All analyses were stratified between RC vs. no-RC, in either organ-confined (OC: T2N0M0) or non-organ-confined (NOC: T3-4N0M0 or TanyN1-3M0) stages. Propensity score matching (PSM), cumulative incidence plots, competing risks regression (CRR) analyses, and 3 months' landmark analyses were performed. RESULTS:Overall, 1,005 ACB and 47,741 UBC patients were identified, of whom 475 (47%) and 19,499 (41%) were treated with RC, respectively. After PSM, comparison between RC vs. no-RC applied to 127 vs. 127 OC-ACB, 7,611 vs. 7,611 OC-UBC, 143 vs. 143 NOC-ACB, and 4,664 vs. 4,664 NOC-UBC patients. 36-month CSM rates in RC vs. no-RC patients were 14 vs. 44% in OC-ACB, 18 vs. 39% in OC-UBC, 49 vs. 66% in NOC-ACB, and 44 vs. 56% in NOC-UBC patients. In CRR analyses, the effect of RC on CSM yielded a hazard ratio of 0.37 in OC-ACB, of 0.45 in OC-UBC, of 0.65 in NOC-ACB and of 0.68 in NOC-UBC patients (all P values<0.001). Landmark analyses virtually perfectly replicated the results. CONCLUSIONS:In ACB, regardless of stage, RC is associated with lower CSM. The magnitude of this survival advantage was greater in ACB than in UBC, even after control for immortal time bias.