PI-RADS Version 2.0 Versus Version 2.1: Comparison of Prostate Cancer Gleason Grade Upgrade and Downgrade Rates From MRI-Targeted Biopsy to Radical Prostatectomy.

Abstract

<b>BACKGROUND.</b> Precise risk stratification through MRI/ultrasound (US) fusion-guided targeted biopsy (TBx) can guide optimal prostate cancer (PCa) management. <b>OBJECTIVE.</b> The purpose of this study was to compare PI-RADS version 2.0 (v2.0) and PI-RADS version 2.1 (v2.1) in terms of the rates of International Society of Urological Pathology (ISUP) grade group (GG) upgrade and downgrade from TBx to radical prostatectomy (RP). <b>METHODS.</b> This study entailed a retrospective post hoc analysis of patients who underwent 3-T prostate MRI at a single institution from May 2015 to March 2023 as part of three prospective clinical trials. Trial participants who underwent MRI followed by MRI/US fusion-guided TBx and RP within a 1-year interval were identified. A single genitourinary radiologist performed clinical interpretations of the MRI examinations using PI-RADS v2.0 from May 2015 to March 2019 and PI-RADS v2.1 from April 2019 to March 2023. Upgrade and downgrade rates from TBx to RP were compared using chi-square tests. Clinically significant cancer was defined as ISUP GG2 or greater. <b>RESULTS.</b> The final analysis included 308 patients (median age, 65 years; median PSA density, 0.16 ng/mL²). The v2.0 group (<i>n</i> = 177) and v2.1 group (<i>n</i> = 131) showed no significant difference in terms of upgrade rate (29% vs 22%, respectively; <i>p</i> = .15), downgrade rate (19% vs 21%, <i>p</i> = .76), clinically significant upgrade rate (14% vs 10%, <i>p</i> = .27), or clinically significant downgrade rate (1% vs 1%, <i>p</i> > .99). The upgrade rate and downgrade rate were also not significantly different between the v2.0 and v2.1 groups when stratifying by index lesion PI-RADS category or index lesion zone, as well as when assessed only in patients without a prior PCa diagnosis (all <i>p</i> > .01). Among patients with GG2 or GG3 at RP (<i>n</i> = 121 for v2.0; <i>n</i> = 103 for v2.1), the concordance rate between TBx and RP was not significantly different between the v2.0 and v2.1 groups (53% vs 57%, <i>p</i> = .51). <b>CONCLUSION.</b> Upgrade and downgrade rates from TBx to RP were not significantly different between patients whose MRI examinations were clinically interpreted using v2.0 or v2.1. <b>CLINICAL IMPACT.</b> Implementation of the most recent PI-RADS update did not improve the incongruence in PCa grade assessment between TBx and surgery.