Clinical outcome of primary small cell carcinoma of the urinary bladder

PURPOSE: Primary small cell carcinoma of the urinary bladder is a rare malignant disease. It accounts for less than 1% of all urinary bladder carcinomas. The purpose of this study is to review the clinical features, the treatment modalities, and the overall survival of these patients. We also compare the clinical outcomes between patients of bladder small cell carcinoma (SCC) and bladder urothelial carcinoma (UC). MATERIALS AND METHODS: We reviewed the charts of patients with bladder tumors from January 1995 to December 2012 in the Chang Gung Memorial Hospital. A total of 2421 malignant bladder tumor patients were reviewed and there were 18 patients who were diagnosed with primary bladder SCC. The patients’ characteristics, including age, gender, smoking history, presented symptoms, tumor size, locations, clinical stages, treatment modalities, pathology appearance, recurrence conditions, and survival conditions were all recorded. We also compared the clinical outcomes and the overall survival rates between patients with bladder SCC and those with UC. RESULTS: Bladder SCC accounted for about 0.74% of all bladder malignancies in our institution. The mean age at diagnosis was 70.67 years, and the male-to-female ratio was 2.6:1. Thirteen patients had a history of cigarette smoking. All patients presented with symptoms of gross hematuria, and three of them had bladder tamponade requiring blood clot evacuation by cystoscopy. Only one patient had T1 disease, ten patients had stage III disease, and seven patients had lymph node or distant metastasis (stage IV disease). The mean tumor size was 4.29 cm in diameter. For the majority (61.11%) of patients, SCC coexisted with UC components. The average survival time was 10.92 months. Patients with bladder SCC had worse overall survival rates than those of stage III and stage IV bladder UC. Performing radical cystectomy does not significantly improve their overall survival rates. None of the clinicopathologic parameters, including the presence of coexisting nonsmall cell carcinoma component (P = 0.831), receiving radical cystectomy (P = 0.194), distant metastasis (P = 0.062), and gender (P = 0.564), were significantly associated with survival. CONCLUSION: SCC of the urinary bladder is a rare condition, and standard treatment outlines have not been well established. Most of the presented cases have a very poor prognosis. Prospective, multi-institutional, randomized studies are required to assess better treatment modalities. To the best of our knowledge, this is the largest reported case analysis of primary bladder SCC in a Taiwanese population.