Prognostic significance of non-urothelial carcinoma of bladder: analysis of nationwide hospital-based cancer registry data in Japan

To identify the prognosis of pure non-urothelial carcinoma (non-UC) of bladder and to compare them with those of pure urothelial carcinoma (UC). We used Japan's nationwide hospital-based cancer registry data to extract histologically confirmed pure non-UC and UC cases of bladder diagnosed in 2008-2009. We estimated the 5-year overall survival (OS) by a Kaplan-Meier analysis. A total of 8094 patients with confirmed histological subtypes of bladder cancer were identified. The most common pure non-UC was squamous cell carcinoma (SQ, n = 192, 2.4%) followed by adenocarcinoma (AC, n = 138, 1.7%) and small cell neuroendocrine carcinoma (SmC, n = 54, 0.7%). The proportion of female patients (48%) was significantly higher in the SQ group compared with the pure UC group (P