The Clinical Features of Incidentally Diagnosed Urothelial Bladder Cancer: A Retrospective Data Analysis

Abstract

Introduction: The aim of this study was to evaluate the prevalence and clinical features of incidental bladder cancer (BC) diagnosis, with special emphasis on possible associations between incidental diagnosis and primary disease stage or grade. Methods: We retrospectively included 501 consecutive patients who underwent transurethral resection of bladder tumor and were diagnosed with primary urothelial carcinoma of the bladder between January 2013 and February 2021 in a university hospital. The type of diagnosis (incidental or nonincidental), patient baseline characteristics and primary stage and grade were studied for interdependencies. Results: 28.5% of all patients and 19.8% of high grade (HG) BC patients had been diagnosed incidentally, most commonly with ultrasound. Incidental diagnosis was associated with lower primary stage and grade of the disease. Most importantly, on multivariable analysis, which included baseline patient characteristics and type of diagnosis, in the subgroup of HG BC patients, muscle-invasive BC (MIBC) or metastatic disease was three times less likely to be diagnosed incidentally than non-MIBC (odds ratio: 0.31, 95% confidence interval: 0.14–0.71, p = 0.006). Conclusions: The study is first to demonstrate that incidental diagnosis of HG BC may be surprisingly prevalent and associated with lower rates of muscle invasion or metastatic disease.