Clinical Epidemiology of Nonurothelial Bladder Cancer: Analysis of The Netherlands Cancer Registry

Purpose: Nonurothelial malignancies represent a small fraction of bladder malignancies and are less extensively studied, resulting in sparse empirical data on these tumors. We sought insight into tumor characteristics and survival. Materials and Methods: Data were obtained from the nationwide Netherlands Cancer Registry on patient and tumor characteristics, and followup in all patients with primary invasive (T1 or greater) bladder tumors in The Netherlands between 1995 and 2006. Data were analyzed using frequency tables. Relative survival analysis was done. Results: We identified 28,807 patients with invasive bladder cancer, of whom 7.7% presented with nonurothelial carcinoma. Mean patient age range at diagnosis of adenocarcinoma and soft tissue tumors was 66.4 years, and 78.3 years at diagnosis of nonspecified tumors. Most histological subtypes were more common in males except squamous cell carcinoma and lymphoma. Muscle invasion was seen in 52.2% of urothelial carcinoma cases vs 87.5%, 71.9% and 89.0% of squamous cell carcinoma, adenocarcinoma and neuroendocrine tumor cases, respectively. For urothelial carcinoma, squamous cell carcinoma and adenocarcinoma women presented at more advanced stage. In the neuroendocrine group this stage difference was the opposite. Survival analysis showed a 5-year relative survival rate of 32.2%, 22.9%, 31.8% and 21.1% for T2 or greater urothelial carcinoma, squamous cell carcinoma, adenocarcinoma and neuroendocrine tumors, respectively. Conclusions: Patients with nonurothelial carcinoma present at more advanced stage and overall have worse survival. Relative survival of muscle invasive adenocarcinoma equals survival of muscle invasive urothelial carcinoma. For stage II and III disease these cases do even better. Muscle invasive squamous cell carcinoma and neuroendocrine tumors show worse survival regardless of stage.