Abstract
PURPOSE: Studies evaluating inter-institutional discrepancies in muscle-invasive bladder cancer diagnosis, particularly when radical cystectomy is recommended, are scarce. In this study, we aimed to examine the inter-institutional concordance rate of pathological stages in patients diagnosed with muscle-invasive bladder cancer. METHODS: We reviewed tissue samples from patients pathologically diagnosed with muscle-invasive bladder cancer at other hospitals who subsequently sought a second opinion at our hospital between January 1, 2013 and December 31, 2023. Data were acquired retrospectively by retrieving clinical data from medical records. We investigated the inter-institutional concordance rate of pathological stages assigned to each patient and examined the tumor characteristics and prognoses of patients with pathological stage discrepancies. RESULTS: Of the 170 patients evaluated, 22 (12.9%) were downstaged upon pathological examination at our hospital. The tumor characteristics of stage discrepancy cases were small tumor size, solitary lesions, and vesical imaging reporting data system score < 3. Eleven patients were treated for non-muscle-invasive bladder cancer based on the re-evaluation findings. Eight patients had no evidence of disease, two patients had Ta bladder recurrence, and one patient had lung metastasis despite no bladder recurrence. CONCLUSION: This study highlights the importance of pathological re-evaluation of patients diagnosed with muscle-invasive bladder cancer. The significant discrepancy rate and its impact on the treatment decisions are noteworthy. Standardization of diagnostic practices is essential to mitigate variability among pathologists and facilities and to ensure optimal care for patients with muscle-invasive bladder cancer.