Improving PI-RADS 4 Lesion Biopsy Accuracy with Ultrasound and Multidisciplinary Protocols

PI-RADS 4 lesions are classified as having a high likelihood of clinically significant prostate cancer (csPCa), yet targeted biopsies often reveal a range of histological outcomes. To address this discordance, a multidisciplinary Quality Improvement (QI) protocol was implemented at Duke Health to enhance diagnostic accuracy and inform clinical management. This retrospective study analyzed 248 patients with 286 PI-RADS 4 lesions undergoing fusion-targeted biopsy from 2017 to 2021. The QI protocol included re-evaluation of multiparametric MRI (mpMRI) and a reverse fusion technique to assess biopsy accuracy. The study also explored potential heterogeneity within the PI-RADS 4 category by subcategorizing lesions based on Apparent Diffusion Coefficient (ADC) values into higher suspicion (PI-RADS 4+) and lower suspicion (PI-RADS 4-). Initial Positive Predictive Values (PPVs) for detecting >GG1 and >GG2 lesions were 55% and 34%, respectively, but increased to 67% and 43% after radiologic reconciliation. Subcategorization further revealed notable differences: PI-RADS 4+ lesions had cancer detection rates (CDR) of 75% and 61% for >GG1 and >GG2, with 52% containing csPCa. Conversely, PI-RADS 4- lesions demonstrated a much lower PPV, comparable to PI-RADS 3 lesions, with only 12% showing csPCa. These findings underscore the heterogeneity within PI-RADS 4 lesions and highlight the value of structured protocols and lesion subcategorization in improving biopsy accuracy and patient management. The integration of ultrasound and multidisciplinary collaboration within this protocol demonstrates significant potential for advancing the precision of prostate cancer diagnostics.