Diagnostic Accuracy of VI-RADS for Determining Muscle Invasion - Expert Commentary

Treatment selection in bladder cancer (BC) depends on the accurate determination of muscle invasion in transurethral resection of bladder tumor (TURBT). However, there are various limitations to TURBT as a diagnostic tool, including cost, risk of complications, and inaccurate staging. To improve accuracy in identifying muscle-invasive bladder cancer (MIBC) versus nonmuscle-invasive bladder cancer (NMIBC), the Vesical Imaging Reporting and Data System (VI-RADS) was developed to standardize multiparameter MRI imaging assessments before TURBT.

A recent study evaluated the diagnostic and predictive accuracy of VI-RADS. The retrospective study cohort included 283 patients with suspected primary BC who underwent multiparametric MRI (mpMRI) before TURBT. The VI-RADS algorithm categorizes patients according to a computed score reflecting the probability of muscle invasiveness (≤2: low probability, 3: questionable, ≥4: high probability). The sensitivity and specificity rates of VI-RADS in distinguishing NMIBC from MIBC among patients with a score of at least 3 were 95.7% and 92.5%, respectively. The positive predictive value (PPV) was 86.6%, while the negative predictive value (NPV) was 97.7%. In patients with a VI-RADS score of 4 or more, sensitivity was 77.8%, specificity was 99.4%, PPV was 98.6%, and NPV was 89.9%.

The investigators subsequently tested whether VI-RADS evaluation could have prevented high-risk NMIBC patients from undergoing repeated TURBT (Re-TURBT). This analysis revealed that 41% of high-risk NMIBC patients with a VI-RADS score of ≤2 would not have received Re-TURBT. In patients with a VI-RADS score of 3, 66.7% would not have undergone Re-TURBT. In patients with a VI-RADS score of ≥4, 8% would not have undergone Re-TURBT.

The VI-RADS-based approach exhibits high accuracy as a promising alternative to unnecessary TURBT procedures. However, this technique is associated with some technical limitations. Importantly, while VI-RADS may accurately reflect invasiveness, it does not enable tumor resection as TURBT does. Future research is needed to refine VI-RADS-based protocols and to define optimal patients for less invasive imaging-guided treatment pathways.

Written by: Bishoy M. Faltas, MD, Director of Bladder Cancer Research, Englander Institute for Precision Medicine, Weill Cornell Medicine

References:

  1. Şam Özdemir M, Keskin ET, Savun M, Yüzkan S, Kaya N, Özdemir H. VI-RADS-based Algorithm for Bladder Cancer Management Randomized Retrospective Study. Urology. Published online October 18, 2024. doi:10.1016/j.urology.2024.10.002
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