Urinary Bladder Cancer in Bladder Exstrophy and Epispadias Complex: A Swedish Register Study and a Systematic Review of the Literature

Abstract

The congenital malformation bladder exstrophy and epispadias complex involves multiple organs and includes 3 subtypes: epispadias, classic bladder exstrophy, and cloacal exstrophy. The risk of urinary bladder cancer is known to be higher in individuals with classic bladder exstrophy and appears at a younger age compared with the general population. Purpose: The purpose of this study was to evaluate urinary bladder cancer in individuals with bladder exstrophy and epispadias complex. Materials and Methods: We performed 2 studies, a Swedish register-based case series reporting 12 novel cases and a systematic review summarizing published cases thus far. MEDLINE, EMBASE, Web of Science, and Google Scholar were searched in January 2022 following the Preferred Reporting Items for Systematic Review and Meta-Analysis statement. Publications reporting at least 1 case of bladder exstrophy and epispadias complex with urinary bladder cancer were eligible. Ninety-seven publications were included, reporting 165 cases. Results: The main result from the register study was the tumors being predominantly urothelial. Conversely, earlier published cases from the literature had a nonurothelial tumor type in 95%, whereof the majority were adenocarcinomas. Both substudies consistently indicate a young age at cancer diagnosis, with the majority being younger than 65 years. Conclusions: Urinary bladder cancer affects individuals with bladder exstrophy and epispadias complex at a young age. The most common tumor type in the register study is urothelial. The divergence between the 2 substudies in tumor types could reflect a slightly older age in our case series, likewise a possible publication bias.