Reproducibility and Accuracy of the PRIMARY Score on PSMA PET and of PI-RADS on Multiparametric MRI for Prostate Cancer Diagnosis Within a Real-World Database

• DOI: 10.2967/jnumed.123.266164
• Publication Date: 2023-11-30T17:45:17Z
• Authors: Louise Emmett; Nathan Papa; William Counter; Jeremie Calais; Francesco Barbato; Irene Burger; Matthias Eiber; Matthew J. Roberts; Shikha Agrawal; Anthony Franklin; Alan Xue; Krishan Rasiah; Nikeith John; Daniel Moon; Mark Frydenberg; John Yaxley; Phillip Stricker; Keith Wong; Geoff Coughlin; Troy Gianduzzo; Boon Kua; Bao Ho; Andrew Nguyen; Victor Liu; Jonathan Lee; Edward Hsiao; Tom Sutherland; Elisa Perry; Wolfgang P. Fendler; Thomas A. Hope
• Keywords: Multiparametric MRI; Prostate biopsy

The PRIMARY score is a 5-category scale developed to identify clinically significant intraprostate malignancy (csPCa) on ⁶⁸Ga-prostate-specific membrane antigen (PSMA)–11 PET/CT (⁶⁸Ga-PSMA PET) using combination of anatomic site, pattern, and intensity. Developed within the trial, requires evaluation in external datasets. This study aimed assess reproducibility diagnostic accuracy cohort patients who underwent multiparametric MRI (mpMRI) ⁶⁸Ga-PSMA PET before prostate biopsy for diagnosis cancer. <b>Methods:</b> In total, data from 242 men had undergone mpMRI transperineal were available this ethics-approved retrospective study. centrally collated cloud-based deidentified image database. Six experienced prostate-focused nuclear medicine specialists trained (1 h) applying with 30 sample images. radiologists read images as per Prostate Imaging–Reporting Data System (PI-RADS), version 2.1. All (with masking clinical information) at least twice, discordant findings sent masked third (or fourth) reader necessary. Cohen κ was determined both imaging scales 5 categories then collapsed binary (negative positive) (score 1 or 2 vs. 3, 4, 5). Diagnostic performance parameters calculated, an International Society Urological Pathology grade group defined gold standard. Combined-imaging–positive results any PI-RADS 4 1–3 3–5. <b>Results:</b> 227 histopathology, PET, included; 33% no csPCa, 67% csPCa. Overall interrater reliability higher (κ = 0.70) than 0.58) when assessed category (benign malignant). similar all 0.65 0.48). detect csPCa comparable between PSMA (sensitivity, 86% 89%; specificity, 76% 74%; positive predictive value, 88% 88%; negative 72% 76%). Using combined imaging, sensitivity 94%, specificity 68%, value 86%, 85%. <b>Conclusion:</b> applied by first-user showed substantial reproducibility, exceeding that mpMRI-experienced radiologists. modalities. should be considered interpreting intraprostatic