Clinical Outcomes of Small Cell Carcinoma of the Bladder - Expert Commentary

Small cell carcinoma of the bladder (SCCB) is a rare, aggressive non-urothelial histologic variant of bladder cancer. Large-scale clinical data evaluating the various management approaches and outcomes are limited.


A recently published study by Chau et al. investigated treatment outcomes of SCCB patients. The authors collected clinical data from 409 patients with SCCB from 26 hospitals in the UK. The majority of patients were male (75%), with a median age at diagnosis of 71 years (range 35 – 96). A total of 189 (46%) patients had pure SSCB, and the rest had mixed histology. The median overall survival (OS) was 15.9 months for all the included patients. Meanwhile, patients with organ-confined disease, n=200 (49%), had significantly longer OS compared to those with N 1-3 or M1 disease (28.3 versus 12.7 months, p<0.001). Patients who received chemotherapy, n= 247 (61.5%), had significantly longer OS compared to those who did not (21.6 versus 9.1 months, p<0.001). Brain metastases were identified in only 6 of 409 patients (1.5%). Brain imaging as part of staging workup (10% of patients) and prophylactic cranial irradiation (n=2 patients) were uncommon.

Interestingly, the type of chemotherapeutic agents used did not significantly differ between cisplatin versus carboplatin backbone or the partner agent, i.e., etoposide versus gemcitabine. The most common definitive treatment modality for patients with the organ-confined disease was radiotherapy (52%) followed by radical cystectomy (31%). No significant difference in survival outcomes was found between the two modalities. The was no multivariate regression analysis to account for potential different clinical characteristics.   

This retrospective study confirmed the poor treatment outcomes of SCCB using the conventional management approaches. There is a lack of prospective clinical trials of SCCB that investigating novel treatment approaches. One prospective phase two trial used alternating doublet chemotherapy comprising ifosfamide plus doxorubicin (IA) and etoposide plus cisplatin in neoadjuvant treatment of 18 SCCB patients achieved median OS of 58 months with 5-year overall survival reaching 80%. More prospective trials are needed to improve the clinical outcome of this aggressive bladder cancer variant.  

Written by: Bishoy M. Faltas, MD, Director of Bladder Cancer Research, Englander Institute for Precision Medicine, Weill Cornell Medicine, New York City, New York

References:

  1. Chau C, Rimmer Y, Choudhury A, Leaning D, Law A, Enting D, et al. Treatment outcomes for small cell carcinoma of the bladder: results from a UK patient retrospective cohort study. Int J Radiat Oncol. 2021 Feb;doi: 10.1016/j.ijrobp.2021.02.003. PMID: 33561506
  2. Siefker-Radtke AO, Kamat AM, Grossman HB, Williams DL, Qiao W, Thall PF, et al. Phase II clinical trial of neoadjuvant alternating doublet chemotherapy with ifosfamide/doxorubicin and etoposide/cisplatin in small-cell urothelial cancer. J Clin Oncol. 2009 Jun 1;27(16):2592–7. PMID: 19414678

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