ASCO GU 2018: Differences in survival among non-urothelial bladder cancers: Analyses of SEER 1988-2008

San Francisco, CA ( Urothelial carcinoma of the bladder represents the vast majority of bladder cancers diagnosed in the United States. Variant histologies of urothelial cancer as well as non-urothelial bladder cancer represent a unique subset of patients. Non-urothelial bladder cancers encompass only a very small proportion of all diagnosed bladder cancers, but are generally thought to be more aggressive than urothelial bladder cancer; management guidelines are limited due to the relative rarity of these conditions.

In this population-based analysis using the SEER dataset, the authors briefly assess survival outcome variations based on histology in non-urothelial bladder cancers. The histologies identified included: squamous cell carcinoma, adenocarcinoma, small cell carcinoma and sarcomas. The strength of such a study is its ability to capture a large number of patients with rare histologic conditions; the weakness is the lack of granularity regarding individual patient management.

They identified 235,537 bladder cancer cases diagnosed beween 1998 and 2008; of these, 3096 (1.3%) cases were squamous cell carcinoma, 1175 (0.5%) were neuroendocrine carcinoma (where small cell carcinomas made up the majority with 859 patients), 671 (0.28%) was comprised of adenocarcinomas, and sarcomas were 88 (0.03%) cases. Overall, non-urothelial bladder cancers represented approximately 2-3% of all bladder cancers diagnosed.

In terms of demographics, most patients were Non-hispanic White (90%). African-Americans were found to have a disproportionately higher presentation of adenocarcinoma (15%).

They provide a table highlighting the number of cases (stratified by stage of diagnosis – local, regional or distant disease) and associated 5-year disease specific survival. Median survival was greatest for adenocarcinoma at 179 months with a 5–year survival rate of 58%, followed by sarcomas with a median survival of 23 months, with a 5-year survival rate of 47%, followed by squamous cell carcinomas with a median survival time of 15 months and a 5-yr survival rate of 37% and the least favorable survival was for small cell carcinoma, 17 months median time, with a 5-yr survival rate of 31%.

Based on this, they conclude, as suspected, that non-urothelial cancers have uniformly worse disease specific survival compared to urothelial cancers. While this does highlight the need for improved therapeutic strategies in these cohorts of patients, they unfortunately don’t delve into the etiology of this worse survival – poor healthcare delivery, difficulty in diagnosis, lack of appropriate management, inefficient therapeutic options?

They have the potential, with the data they have, to provide much more information regarding areas of improvement. Unfortunately, they stop short with the abstract.

Presented by: Jeanny Aragon-Ching, MD, FACP Inova Schar Cancer Institute, Fairfax, VA; Uniformed Services University of the Health Sciences, Bethesda, MD

Co-Author: Donald Henson

Written by: Thenappan Chandrasekar, MD, Clinical Fellow, University of Toronto, Twitter: @tchandra_uromd at the 2018 American Society of Clinical Oncology Genitourinary (ASCO GU) Cancers Symposium, February 8-10, 2018 - San Francisco, CA  

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