Survival of contemporary patients with non-metastatic urachal vs. non-urachal adenocarcinoma of the urinary bladder

Purpose: To test the effect of tumor location (urachal vs. non-urachal) on cancer-specific mortality (CSM) in patients with adenocarcinoma of the urinary bladder (ADKUB). Materials and methods: Within the Surveillance, Epidemiology, and End Results registry (2004–2016), we identified patients with non-metastatic (≤ T4N0M0) ADKUB. Stratification was made according to tumor location: urachal vs. non-urachal ADKUB. Kaplan–Meier plots and multivariable Cox regression models were fitted before and after 1:3 propensity score (PS) matching and separate Cox regression models were refitted before and after inverse probability of treatment weighting (IPTW). Results: Of 1681 patients, 226 (13.5%) vs. 1455 (86.5%) harboured urachal vs. non-urachal ADKUB, respectively. Five-year cancer-specific survival (CSS) rates were, respectively, 75 vs. 67% for urachal vs. non-urachal ADKUB (p = 0.001). In subgroup analyses of ≤ T2N0M0 patients, 5-year CSS rates were, respectively, 84 vs. 73% for urachal vs. non-urachal ADKUB (p = 0.006). In subgroup analyses of T3-4N0M0 patients, 5-year CSS rates were, respectively, 68 vs. 49% for urachal vs. non-urachal ADKUB (p < 0.001). In multivariable Cox regression models, urachal ADKUB was associated with lower CSM rates (HR 0.6; p = 0.01). Virtually, the same findings were recorded after 1:3 PS matching (HR 0.6; p = 0.009) as well as when Cox regression models were refitted after IPTW (HR 0.7; p = 0.01). Conclusion: The distinction between urachal vs. non-urachal ADKUB indicates better prognosis when the origin of the tumor is urachal, regardless of methodological approach used for the comparison.