Metastatic small cell bladder cancer treated with sequential systemic therapy including pembrolizumab and amrubicin: A case report

Introduction

Small cell bladder cancer is a relatively rare tumor, representing <1% of all bladder tumors. Amrubicin monotherapy is used as second-line treatment for small cell lung cancer in Japan.

Case presentation

A 79-year-old woman presented with gross hematuria and was diagnosed with small cell bladder cancer (T2 or higher). Neoadjuvant chemotherapy with etoposide and cisplatin resulted in a partial response. Robot-assisted radical cystectomy was performed, and radical resection was achieved. As we identified metastasis in the pleura 1 year later, we administered carboplatin and etoposide, which resulted in a partial response. Although pembrolizumab was initiated as maintenance therapy, it was not effective. Amrubicin was given as third-line therapy, and stable disease was achieved without serious adverse effect for 6 months.

Conclusion

Although there is no established treatment for metastatic small cell bladder cancer, the current case report suggests the effectiveness of amrubicin in this setting.

Advanced small cell carcinoma of the bladder: clinical characteristics, treatment patterns and outcomes in 960 patients and comparison with urothelial carcinoma

To describe the clinical characteristics, treatment patterns and outcomes in advanced small cell bladder cancer (aSCBC) patients and compare to those with urothelial carcinoma (UC). Individuals in the National Cancer Data Base with a diagnosis of either nodal (TxN+M0) or distant metastatic (TxNxM1) disease were identified from 1998 to 2010. We assessed the relationships between stage, treatment modalities and survival in the aSCBC cohort and compared these to UC patients. In the 960 patient aSCBC cohort (62% M1), 50% received palliative therapy alone, 68% in M1 versus 21% in M0 groups (P < 0.0001). Single modality local therapy (15%) and surgical (21%) or radiation-based (14%) multimodal therapy (MMT) were used in the other 50%. Cystectomy-based MMT was utilized in 45% of N+M0 versus 6.4% of NxM1 patients (P < 0.0001). Median overall survival (OS) for aSCBC patients was 8.6 months; 13.0 months in N+M0 versus 5.3 months in NxM1 patients (P < 0.0001). Survival was similar between TxN1M0 and TxN2-3M0 patients (14.8 months vs. 12.1 months, P = 0.15). Urothelial carcinoma patients (n = 27,796, 45% M1) lived longer compared to aSCBC patients in the N+M0 group (17.3 months vs. 13.0 months, P = 0.0007). There were not clinically significant differences in OS between UC and aSCBC patients in the M1 group. Advanced SCBC is a rare disease with a poor survival and palliative therapy is common, especially in M1 patients. In comparison to UC, the outcomes for aSCBC patients are worse in those with lymph node only involvement but similar in those with distant disease.