Effect of tumor location on survival in urinary bladder adenocarcinoma: A population-based analysis

To investigate the prognostic significance of tumor location on survival outcomes in patients with urinary bladder adenocarcinoma (BAC).

We retrospectively analyzed cases of BAC with known tumor location from the Surveillance, Epidemiology, and End Results database from 1973 to 2012. Data regarding patient demographics, tumor characteristics, and oncological and survival outcomes were collected. Patients were subgrouped according to tumor location into urachal/dome (dome and urachus [UD]), lateral wall (anterior, posterior, and lateral bladder walls [LW]), and base (trigone, ureteral orifices, and bladder neck [BL]).

A total of 1,361 cases of BAC with known tumor location were identified. More UD tumors were low grade (grade I and II; 51%) than LW (33%) and BL (43%) tumors (P<0.0001). UD lesions were the most likely to have metastatic spread (23% vs. 17% for LW and 15% for BL) (P<0.0001). The 5-year overall survival (OS) and disease-specific survival (DSS) rates were 37.3% and 49.0%, respectively, for all BAC. Furthermore, the 5-year OS rates were 42.3%, 35.9%, and 28.4% for UD, LW, and BL lesions, respectively (P<0.0001), whereas the 5-year DSS rates were 50.2%, 51.7%, and 42.1% for UD, LW, and BL lesions, respectively (P = 0.0097). Multivariate Cox regression analysis controlling for tumor stage and grade demonstrated that both tumors of the LW (hazards ratio [HR] = 1.52 for OS and 1.30 for DSS) and BL (HR = 1.71 for OS and 1.57 for DSS) conferred a worse prognosis relative to those of the UD (P< 0.05).

Tumor location of BAC is an independent prognostic factor for disease outcome. Our results suggest that the urachal and dome locations are associated with relatively favorable survival and oncological outcomes, whereas basal location confers poorer outcomes.