A California Cancer Registry Analysis of Urothelial and Non-Urothelial Bladder Cancer Subtypes: Epidemiology, Treatment, and Survival

ABSTRACT Introduction We evaluated epidemiological trends and survival for bladder cancer histological subtypes in California patients by comparing urothelial carcinoma of the bladder (UCB) and non-urothelial subtypes including squamous cell carcinoma (SCC), adenocarcinoma (ADC), and small cell carcinoma (SmCC). Materials and Methods The California Cancer Registry (CCR) was queried for incident bladder cancer cases from 1988–2012. Epidemiological trends based on tumor histology were described. The primary outcome was disease-specific survival (DSS). Kaplan-Meier and multivariable Cox regression survival analyses were performed. Results A total of 72,452 bladder cancer cases (66,260 UCB, 1,390 SCC, 587 ADC, 370 SmCC, 3,845 other) were included. Median age was 72 years (range: 18-109). ADC was more common in younger patients. Male: female ratios varied amongst cancer types (3.1 : 1 in UCB, 2.9 : 1 in SmCC, 1.6 : 1 in ADC, and 0.9 : 1 in SCC). Most non-urothelial cases (>60%) presented at advanced stages, whereas most UCB cases (80.6%) were localized. Kaplan-Meier analysis revealed the best 5-year DSS and overall survival (OS) in UCB, while the worst outcomes were seen with SCC and SmCC (p Conclusions Non-urothelial bladder cancers have worse oncological outcomes than UCB in California patients. SCC and SmCC are associated with the worst DSS based on univariable and multivariable analyses.