Treatment Patterns and Survival Outcomes for Patients with Small Cell Carcinoma of the Bladder

Background: Small cell carcinoma of the bladder (SCCaB) is a rare tumor without a standard treatment algorithm. Treatment patterns and survival outcomes from the National Cancer Database (NCDB) may provide insight into optimal treatment strategies.

Objective: To investigate the relationship between overall survival (OS) and treatment strategy.

Design, setting, and participants: This was an observational study of treatment-naïve patients who received treatment from 2004 to 2013. Patients with cT1-4aN0M0 SCCaB were identified from the NCDB, a hospital-based tumor registry that captures >70% of incident cancer cases in the USA.

Intervention: Treatment strategies included local therapy alone, chemotherapy (CT), radiation therapy (RT), chemoradiation therapy (CRT), radical cystectomy (RC), and RC plus chemotherapy (RC+C).

Outcome measurements and statistical analysis: OS was analyzed as a function of treatment modality adjusting for patient, demographic, and tumor-related factors. The Kaplan-Meier survival method, and the log-rank test and Cox regression were used for univariable and multivariable analyses.

Results and limitations: We identified 856 patients with median follow-up of 18.3 mo. The median OS for the entire cohort was 20.7 mo (95% confidence interval [CI] 18.3-23.2) and estimated 3-yr and 5-yr OS were 37.5% and 28.2%, respectively. The most common treatment modality was CT (225 patients; 26.3%) followed by CRT (203 patients; 23.7%) and RC+C (201 patients; 23.5%). The median OS was 18.4 mo (95% CI 15.2-21.5) for CT, 34.1 mo (95% CI 22.5-45.8) for CRT, and 32.4 mo (95% CI 20.8-44.1) for RC+C. OS did not significantly differ between CRT and RC+C (p=0.42). On multivariable analysis, the best OS was associated with CRT (hazard ratio [HR] 0.41, 95% CI 0.32-0.53; p<0.0001) and RC+C (HR 0.45, 95% CI 0.34-0.59; p<0.0001).

Conclusions: RC+C and CRT are associated with better OS compared to monotherapy among patients with SCCaB.

Patient summary: Small cell carcinoma of the bladder is a rare and highly aggressive cancer. According to National Cancer Database data, radical cystectomy plus chemotherapy and chemoradiation therapy are associated with better overall survival compared to monotherapy.