Differences in Survival Among Patients With Sarcomatoid Carcinoma, Carcinosarcoma and Urothelial Carcinoma of the Bladder

Purpose: Sarcomatoid carcinoma and carcinosarcoma of the bladder are rare tumors that contain epithelial and mesenchymal elements, and may portend a worse prognosis than conventional urothelial carcinoma. We investigated the survival of patients with the 2 tumor subtypes compared to survival in those with urothelial carcinoma. Materials and Methods: Cases of sarcomatoid carcinoma, carcinosarcoma and high grade urothelial carcinoma of the bladder were identified from the Surveillance, Epidemiology and End Results Program. Demographic and pathological characteristics were compared. Differences in survival based on histological subtype were estimated using Kaplan-Meier analysis and multivariate Cox proportional hazards regression. Results: Overall unadjusted survival rates for 46,515 patients with urothelial carcinoma, 135 with sarcomatoid carcinoma and 166 with carcinosarcoma were 77%, 54% and 48% at 1 year, and 47%, 37% and 17% at 5 years, respectively. Sarcomatoid carcinoma and carcinosarcoma presented at a similar age but at a higher T stage and with more frequent regional and distant metastases compared to urothelial carcinoma. On multivariate analysis patients with sarcomatoid carcinoma (HR 1.18, 95% CI 0.91-1.52) and carcinosarcoma (HR 2.00, 95% CI 1.65-2.41) were at higher risk for death compared to those with urothelial carcinoma. Overall mortality was worse with carcinosarcoma than with sarcomatoid carcinoma (HR 1.70, 95% CI 1.23-2.34). Conclusions: Compared to patients with urothelial carcinoma those with sarcomatoid carcinoma and carcinosarcoma present at a more advanced stage and are at greater risk for death even after adjusting for stage at presentation. The survival rate of sarcomatoid carcinoma is better than that of carcinosarcoma, offering some justification for the continued differentiation of these tumor types for clinical prognostication.