Prospective Assessment of Vesical Imaging Reporting and Data System (VI-RADS) and Its Clinical Impact on the Management of High-risk Non-muscle-invasive Bladder Cancer Patients Candidate for Repeated Transurethral Resection

Abstract

Background: Vesical Imaging Reporting and Data System (VI-RADS) score is adopted to provide preoperative bladder cancer (BCa) staging. Repeated transurethral resection of bladder tumor (Re-TURBT) is recommended in most of high-risk non-muscle-invasive bladder cancers (HR-NMIBCs) due to possibility of persistent/understaged disease after initial TURBT. No diagnostic tools able to improve patient's stratification for such recommendation exist.

Objective: To (1) prospectively validate VI-RADS for discriminating between NMIBC and muscle-invasive bladder cancer (MIBC) at TURBT, and (2) evaluate the accuracy of VI-RADS for identifying HR-NMIBC patients who could avoid Re-TURBT and detecting those at higher risk for understaging after TURBT.

Design, setting, and participants: Patients with BCa suspicion were offered multiparametric magnetic resonance imaging (mpMRI) before TURBT. According to VI-RADS, a cutoff of ≥3 to define MIBC was assumed. TURBT reports were compared with preoperative VI-RADS scores to assess accuracy of mpMRI for discriminating between NMIBC and MIBC. HR-NMIBC Re-TURBT reports were compared with preoperatively recorded VI-RADS scores to assess mpMRI accuracy in predicting Re-TURBT outcomes.

Intervention: Multiparametric MRI of the bladder before TURBT.

Outcome measurements and statistical analysis: Sensitivity, specificity, positive (PPV) and negative (NPV) predictive values were calculated for mpMRI performance in patients undergoing TURBT and for HR-NMIBC patients candidate for Re-TURBT. Performance of mpMRI was assessed by receiver operating characteristic curve analysis. Ƙ statistics was used to estimate inter- and intrareader variability.

Results and limitations: A total of 231 patients were enrolled. Multiparametric MRI showed sensitivity, specificity, PPV, and NPV for discriminating NMIBC from MIBC at initial TURBT of 91.9% (95% confidence interval [CI]: 82.2-97.3), 91.1% (95% CI: 85.8-94.9), 77.5% (95% CI: 65.8-86.7), and 97.1% (95% CI: 93.3-99.1), respectively. The area under the curve (AUC) was 0.94 (95% CI: 0.91-0.97). Among HR-NMIBC patients (n=114), mpMRI before TURBT showed sensitivity, specificity, PPV, and NPV of 85% (95% CI: 62.1-96.8), 93.6% (95% CI: 86.6-97.6), 74.5% (95% CI: 52.4-90.1), and 96.6% (95% CI: 90.5-99.3) respectively, to identify patients with MIBC at Re-TURBT. The AUC was 0.93 (95% CI: 0.87-0.97).

Conclusions: VI-RADS is accurate for discriminating between NMIBC and MIBC. Within HR-NMIBC cases, VI-RADS could, in future, improve the selection of patients who are candidate for Re-TURBT.

Patient summary: We investigated the accuracy of Vesical Imaging Reporting and Data System (VI-RADS) score to asses bladder cancer staging before transurethral resection of bladder tumors, and we explored the performance of VI-RADS score as a future preoperative predictive tool for the selection of high-risk non-muscle-invasive bladder cancer patients who are candidate for undergoing early repeated transurethral resection of the primary tumor site.

Keywords: Bladder cancer; High-risk non–muscle-invasive bladder cancer; Multiparametric magnetic resonance imaging; Muscle-invasive bladder cancer; Repeated transurethral resection of bladder tumor; Transurethral resection of bladder tumor.