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

<b><i>Introduction:</i></b> 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. <b><i>Methods:</i></b> 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. <b><i>Results:</i></b> 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, <i>p</i> = 0.006). <b><i>Conclusions:</i></b> 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.

<b><i>引言：</i></b> 本研究旨在评估偶发性膀胱癌（bladder cancer, BC）的诊断患病率及临床特征，重点探讨偶发性诊断与原发性疾病分期、分级之间的潜在关联。<b><i>方法：</i></b> 本研究回顾性纳入2013年1月至2021年2月间，某大学医院中接受经尿道膀胱肿瘤切除术且被确诊为原发性膀胱尿路上皮癌的501例连续性患者。针对诊断类型（偶发性或非偶发性）、患者基线特征、原发性疾病分期与分级的相互关联展开分析。<b><i>结果：</i></b> 全体患者中28.5%、高级别（high grade, HG）膀胱癌患者中19.8%为偶发性诊断，其中最常见的诊断方式为超声检查。偶发性诊断与较低的原发性疾病分期和分级显著相关。尤为关键的是，在纳入患者基线特征与诊断类型的多变量分析中，高级别膀胱癌亚组患者内，肌层浸润性膀胱癌（muscle-invasive bladder cancer, MIBC）或转移性疾病的偶发性诊断概率仅为非肌层浸润性膀胱癌的1/3（优势比（odds ratio）：0.31，95%置信区间（confidence interval）：0.14~0.71，<i>p</i>=0.006）。<b><i>结论：</i></b> 本研究首次证实，高级别膀胱癌的偶发性诊断患病率高得出人意料，且与更低的肌层浸润或转移性疾病发生率相关。