Accuracy of actual stage prediction using Vesical Imaging Reporting and Data System (VI-RADS) before radical cystectomy for urothelial carcinoma in SUPER-UC-Cx

BACKGROUND: Previous studies using the Vesical Imaging Reporting and Data System (VI-RADS) to predict muscle-invasive bladder cancer (MIBC) had some limitations. Most studies were performed with transurethral resection of bladder tumor (TUR-BT) specimens with few samples. This study was conducted to address these shortcomings and confirm the accuracy of VI-RADS for bladder cancer. METHODS: This study used data from the Seoul National University Prospectively Enrolled Registry for Urothelial Cancer-Radical Cystectomy (SUPER-UC-Cx). Patients who underwent multiparametric magnetic resonance imaging (mp-MRI) before radical cystectomy (RC) were included in this study between March 2020 and March 2022. All images were reported by radiologists and reviewed by two urologists. The patient characteristics and clinical information were blinded during the review. The performance of qualitative and quantitative variables in predicting muscle layer invasion or perivesical fat infiltration was verified by receiver operating characteristic (ROC) curve analysis. RESULTS: Of 208 patients, 182 (87.5%) underwent mp-MRI before RC. Twenty-three patients with non-urothelial carcinoma, inappropriate MRI scans, and bladder filling were excluded. Cut-off for muscle invasion, VI-RADS score of 4 had the highest area under the curve (AUC) (sensitivity 0.84; specificity 0.93; accuracy 0.90; positive predictive value (PPV) 0.84; negative predictive value (NPV) 0.93, and AUC 0.88). Cut-off for perivesical fat invasion and VI-RADS score of 5 had the highest AUC (sensitivity, 0.78; specificity, 0.99; accuracy, 0.95; PPV, 0.96; NPV, 0.95; and AUC, 0.89). CONCLUSIONS: VI-RADS is a good predictor of bladder cancer staging before RC and is especially helpful in predicting muscle invasion and perivesical fat infiltration.