Adenocarcinoma Versus Urothelial Carcinoma of the Urinary Bladder: Comparison Between Pathologic Stage at Radical Cystectomy and Cancer-specific Mortality

Abstract

To compare stage at radical cystectomy (RC) and cancer-specific mortality (CSM) after RC between non-urachal adenocarcinoma (ADK) and urothelial carcinoma (UC) of the urinary bladder. Within 17 Surveillance, Epidemiology and End Results registries, we identified ADK and UC patients who underwent a RC between 1988 and 2006. We examined differences in stage and grade at RC between ADK and UC patients. Kaplan-Meier plots depicted CSM after RC. Cox regression analyses examined CSM rates, adjusted for T and N stages, tumor grade, age, gender, race, and year of surgery. Thereafter, we relied on statistically significant variables from the multivariate Cox regression model to match ADK and UC patients. Finally, we plotted Kaplan-Meier survival curves of the matched ADK and UC patients. Of 306 ADK and 11 697 UC patients, 188 (61.4%) and 5538 (47.3%), respectively, showed extravesical disease (pT(3-4); P <.001) and 26.5% vs 21.7% had lymph node metastases at RC (P = .04), respectively. After adjustment for all covariates, including stage and grade, ADK was not associated with worse prognosis than UC (hazard ratio, 1.05; P = .6). Similarly, after matching, no difference in CSM was recorded between the 2 histologic subtypes (hazard ratio, 1.07; P = .5). ADK patients undergo RC at more advanced disease stages. However, stage- and grade-adjusted CSM is the same between ADK and UC patients. Efforts should be aimed at providing definitive treatment at earlier stages, especially in patients with ADK histologic subtype.