PI-RADS Steering Committee: The PI-RADS Multiparametric MRI and MRI-directed Biopsy Pathway

Abstract

High-quality evidence shows that MRI in biopsy-naive men can reduce the number of men who need prostate biopsy and can reduce the number of diagnoses of clinically insignificant cancers that are unlikely to cause harm. In men with prior negative biopsy results who remain under persistent suspicion, MRI improves the detection and localization of life-threatening prostate cancer with greater clinical utility than the current standard of care, systematic transrectal US-guided biopsy. Systematic analyses show that MRI-directed biopsy increases the effectiveness of the prostate cancer diagnosis pathway. The incorporation of MRI-directed pathways into clinical care guidelines in prostate cancer detection has begun. The widespread adoption of the Prostate Imaging Reporting and Data System (PI-RADS) for multiparametric MRI data acquisition, interpretation, and reporting has promoted these changes in practice. The PI-RADS MRI-directed biopsy pathway enables the delivery of key diagnostic benefits to men suspected of having cancer based on clinical suspicion. Herein, the PI-RADS Steering Committee discusses how the MRI pathway should be incorporated into routine clinical practice and the challenges in delivering the positive health impacts needed by men suspected of having clinically significant prostate cancer.

Figure 1:

Infographic shows approximate diagnostic yields of systematic biopsy in biopsy-naive men on the MRI pathway. The MRI pathway consists of no biopsy in men with Prostate Imaging and Reporting Data System (PI-RADS) category 1 or 2 findings and MRI-targeted biopsy in men with PI-RADS category 3–5 findings, without additional clinical factor input. Data are for guidance only and are based on a combination of the MRI pathway and systematic biopsy as the reference standards. Data do not total 100% because of rounding and aggregation of different data sources reported by Drost et al (10). Data in parentheses are 95% confidence intervals for the mean values. ISUP = International Society of Urological Pathology. This graphic was prepared with data kindly provided by Ivo Schoots, MD, PhD (Erasmus University Medical Center, Rotterdam, the Netherlands).

Figure 2:

Images in a 75-year-old man with a serum prostate-specific antigen level of 14.6 ng/mL. A, T2-weighted MRI, B, apparent diffusion coefficient map, C, diffusion-weighted MRI (b value, 2000 sec/mm²), and, D, dynamic contrast-enhanced MRI show a lesion (arrows) classified as Prostate Imaging Reporting and Data System category 4 in A and C and as positive in D in the midline anterior apical transition zone. E, Targeted biopsy was performed with transrectal US/MRI and revealed Gleason grade 3+4 cancer in three of the four cores sampled from this lesion. F, Volume-rendered MRI shows mapping of the four targeted cores and systematic 12 cores. One of the 12 systematic biopsy cores revealed Gleason grade 3+3 prostate adenocarcinoma (5% core involvement), which made no difference for risk stratification in this patient.

Figure 3:

Diagram shows patient flow in the prostate cancer diagnostic pathway. Safety net monitoring consists of prostate-specific antigen monitoring and follow-up imaging as per local clinical practice and consistent with clinical goals for individual patients, with roles and responsibilities defined by multidisciplinary management teams (8,52). MDT = multidisciplinary team, mpMRI = PI-RADS-compliant multiparametric MRI, PI-RADS = Prostate Imaging Reporting and Data System, PSAD = prostate-specific antigen density.