Background: Primary adenocarcinomas of the bladder and urachus are rare malignancies, and knowledge of the patient demographics, pathologic characteristics, and survival associated with these tumors is poor. The current study compares disease-specific characteristics and survival associated with urachal and nonurachal primary bladder adenocarcinomas.
Methods: Incident cases of urachal and nonurachal primary adenocarcinomas of the bladder were identified from the Surveillance, Epidemiology, and End Results (SEER) Program. Demographic and pathologic characteristics at the time of diagnosis were compared. Risks of mortality among urachal and nonurachal primary adenocarcinomas of the bladder were compared using multivariate Cox regression.
Results: A total of 151 urachal and 1374 nonurachal adenocarcinomas of the bladder patients were identified. Compared to those with nonurachal tumors, patients with urachal adenocarcinoma were more likely to be younger (median age, 56 vs. 69 years, P <.0001) and female (45% vs. 36%, P = .02). Urachal lesions were less likely to be high grade (35% vs. 66%, P < .001), but more likely to involve distant metastases (30% vs. 15%, P < .001). Partial cystectomy was more common in urachal tumors (66% vs. 16%, P <.001). In multivariate analysis, subjects with urachal tumors had a lower risk of all cause (hazard ratio [HR] = 0.56, 95% confidence interval [CI]: 0.38-0.83) and disease-specific (HR = 0.59, 95% CI: 0.35-0.98) mortality compared with patients with nonurachal tumors. CONCLUSIONS. Urachal adenocarcinomas represent 10% of all primary adenocarcinomas of the bladder. Overall and disease-specific mortality risks are improved in patients with urachal lesions, even after controlling for numerous patient and tumor characteristics.