Targeted Multiparametric Magnetic Resonance Imaging/Ultrasound Fusion Biopsy for Quantitative Gleason 4 Grading Prediction in Radical Prostatectomy Specimens: Implications for Active Surveillance Candidate Selection

Background: Quantitative Gleason grading appears to be a reliable prognostic parameter and provides broader risk stratification then the traditional Gleason grading in patients with prostate cancer (PCa) treated with radical prostatectomy (RP).Objective: To determine if quantification of Gleason pattern (GP) 4 for targeted and sys-tematic biopsy (TBx + SBx) cores together with further clinical variables can identify the lowest quantitative GP 4 fraction on RP.Design, setting, and participants: A total of 548 patients underwent TBx + SBx of the pros-tate and then RP, with pathology revealing Gleason score 3 + 4, 4 + 3, or 4 + 4 disease.Intervention: TBx + SBx of the prostate followed by RP.Outcome measurements and statistical analysis: GP 4 fraction thresholds of <5%, <10%, <15%, <20%, and <25% were compared between the TBx + SBx and RP specimens. The sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and accuracy for predicting the GP 4 fraction in the RP specimen were determined. Logistic regression models were used to establish a probabilistic relationship between various combinations of clinical and biopsy variables and the GP 4 fraction in the RP specimen. Results and limitations: GP 4 fractions of <5%, <10%, <15%, <20%, and <25% was observed in 33%, 49%, 58%, 65%, and 70% of patients on TBx, and 18%, 41%, 53%, 63%, and 70% of patients on RP, respectively. The sensitivity, specificity, NPV, PPV, and accu-racy were 75%, 67%, 91%, 39%, and 74% for a TBx GP 4 fraction of <5%, and 65%, 85%, 65%, 85%, and 79% for a TBx GP 4 fraction of <25%, respectively. A model combining quanti-fied TBx + SBx GP 4 with clinical parameters demonstrated the highest diagnostic accu-racy. Limitations include the retrospective study design.Conclusions: Our results demonstrate that the combination of MRI-TBx + SBx and GP 4 quantification allowed precise detection of a low fraction of GP 4 when using RP speci-mens as the reference standard. Moreover, we found that clinical variables including Prostate Imaging-Reporting and Data System score without biopsy are limited in detec-tion of low GP 4 fractions.Patient summary: Combination of targeted biopsy alone as well as combined with sys-tematic biopsy and quantitative Gleason grading of biopsy specimen showed high agree-ment with pathology findings after surgical removal of the prostate. This could help in identifying patients who are suitable for active surveillance.(c) 2022 European Association of Urology. Published by Elsevier B.V. All rights reserved.