Contemporary rates of pathological features and mortality for adenocarcinoma of the urinary bladder in the USA

OBJECTIVES: To examine contemporary rates of pathological features and mortality for adenocarcinoma of the urinary bladder in the USA using population-based data analysis.

METHODS: We relied on 10 024 patients with non-metastatic bladder cancer diagnosed between 2004 and 2013 within the Surveillance, Epidemiology and End Results registries. Logistic regression analyses focused on grade and stage. Kaplan-Meier analyses assessed cancer-specific mortality rates in adenocarcinoma and urothelial carcinoma of the bladder. Cox regression analyses assessed the impact of histological subtype on cancer-specific mortality.

RESULTS: Overall, 215 (2.1%) adenocarcinoma and 9809 (97.9%) urothelial carcinoma patients were identified. The rate of non-organ-confined disease was higher in adenocarcinoma (64.7% vs 50.8%, P < 0.001). In multivariable logistic regression analyses, adenocarcinoma patients had a 2.2-fold higher risk of harboring non-organ-confined disease (95% confidence interval 1.7-3.0; P < 0.001) than urothelial carcinoma patients. Cancer-specific mortality-free survival rates were lower in adenocarcinoma (P < 0.01). This disadvantage only applied to non-organ-confined disease (P = 0.044), and not to organ-confined disease (P = 0.9). In multivariable Cox regression analyses, adenocarcinoma conferred a 1.3-fold higher rate of cancer-specific mortality (hazard ratio 1.30, 95% confidence interval 1.05-1.60; P = 0.01). Among adenocarcinoma patients, 30.7% harbored signet-ring cell adenocarcinoma and portended particularly poor cancer-specific mortality rates.

CONCLUSIONS: In bladder cancer, adenocarcinoma presents at higher stages than urothelial carcinoma. However, cancer-specific mortality rates do not differ. A more unfavorable stage at diagnosis and higher cancer-specific mortality apply to the signet-ring cell variant.