Variability of the Positive Predictive Value of PI-RADS for Prostate MRI across 26 Centers: What about the Negatives?

HomeRadiologyVol. 298, No. 1 PreviousNext CommunicationsFree AccessLetters to the EditorVariability of the Positive Predictive Value of PI-RADS for Prostate MRI across 26 Centers: What about the Negatives?Soroush Bazargani, Mark Bandyk, K. C. Balaji Soroush Bazargani, Mark Bandyk, K. C. Balaji Author AffiliationsDepartments of Urology and Radiology, University of Florida, Jacksonville College of Medicine, 653 W 8th St, LRC Bldg Fl 2, Jacksonville, FL 32209-6511e-mail: [email protected]Soroush BazarganiMark BandykK. C. Balaji Published Online:Nov 3 2020https://doi.org/10.1148/radiol.2020202870MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In Editor:The advances in prostate MRI and Prostate Imaging Reporting and Data System (PI-RADS) scoring have had a practice-changing impact on the detection of prostate cancer, especially clinically significant (CS) prostate cancer (PCa) (1). MRI demonstrates selective advantage in diagnosing men with CS PCa while avoiding the depiction of clinically insignificant prostate cancer. From a clinical standpoint, posttest probabilities (positive predictive value [PPV] and negative predictive value [NPV]) influence clinicians’ decisions and use of the tests. In this regard, the most useful performance characteristics of the PI-RADS scoring system in detecting CS PCa is the NPV. In other words, if NPV is shown to be very high (>90%) and MRI shows a lesion with PI-RADS score less than 4, urologists can confidently recommend against a prostate biopsy.However, posttest probabilities are influenced by the prevalence of the disease (direct relationship to PPV and inverse relationship to NPV). It would be interesting to analyze the data set for the difference in PPV between men who were biopsy naive and men with known prostate cancer. In their study published in the July 2020 issue of Radiology, Dr Westphalen and colleagues (2) demonstrated a large variance in PPV on analysis stratified by biopsy status (Table E4 in the online supplemental materials of their original study). We analyzed the proportion of lesion per patients and identified a significant increase in the incidence of lesions on MRI scans across the three groups that were studied (biopsy naive, or prior negative, or positive biopsy groups: 1.3, 1.4, and 1.5 lesions per patient, respectively). Whether the change in the prevalence of the incident lesions on MRI scans in each group contributed to the PPV variance and potential influence on NPV remains to be elucidated.The dilemma exists about how to evaluate patients with elevated prostate-specific antigen but MRI negative for lesions. From a clinical standpoint, it is important to be able to rely on a multiparametric MRI with negative results to avoid unnecessary biopsies during follow-up of either of the three groups of patients. Different studies investigated NPV and oncologic outcomes of a patient with negative results at multiparametric MRI (3–5). We think this large multicenter cohort would have provided an excellent opportunity to investigate the NPV and provide more robust evidence facilitating clinical decision making in an important subgroup of patients.Disclosures of Conflicts of Interest: S.B. disclosed no relevant relationships. M.B. disclosed no relevant relationships. K.C.B. disclosed no relevant relationships.References1. Stabile A, Giganti F, Emberton M, Moore CM. MRI in prostate cancer diagnosis: do we need to add standard sampling? A review of the last 5 years. Prostate Cancer Prostatic Dis 2018;21(4):473–487. Crossref, Medline, Google Scholar2. Westphalen AC, McCulloch CE, Anaokar JM, et al. Variability of the Positive Predictive Value of PI-RADS for Prostate MRI across 26 Centers: Experience of the Society of Abdominal Radiology Prostate Cancer Disease-focused Panel. Radiology 2020;296(1):76–84. Link, Google Scholar3. Panebianco V, Barchetti G, Simone G, et al. Negative Multiparametric Magnetic Resonance Imaging for Prostate Cancer: What’s Next? Eur Urol 2018;74(1):48–54. Crossref, Medline, Google Scholar4. Moldovan PC, Van den Broeck T, Sylvester R, et al. What Is the Negative Predictive Value of Multiparametric Magnetic Resonance Imaging in Excluding Prostate Cancer at Biopsy? A Systematic Review and Meta-analysis from the European Association of Urology Prostate Cancer Guidelines Panel. Eur Urol 2017;72(2):250–266. Crossref, Medline, Google Scholar5. Wang RS, Kim EH, Vetter JM, et al. Determination of the Role of Negative Magnetic Resonance Imaging of the Prostate in Clinical Practice: Is Biopsy Still Necessary? Urology 2017;102:190–197. Crossref, Medline, Google ScholarArticle HistoryPublished online: Nov 03 2020Published in print: Jan 2021 FiguresReferencesRelatedDetailsCited ByImplications and effects of COVID-19 on diagnosis and management of prostate cancerVinson Wai-ShunChan, AquaAsif, Jasmine Sze-ErnKoe, AlexanderNg, Chi FaiNg, Jeremy Yuen-ChunTeoh2022 | Current Opinion in Urology, Vol. 32, No. 3Recommended Articles Abbreviated Biparametric Prostate MR Imaging in Men with Elevated Prostate-specific AntigenRadiology2017Volume: 285Issue: 2pp. 493-505PI-RADS Steering Committee: The PI-RADS Multiparametric MRI and MRI-directed Biopsy PathwayRadiology2019Volume: 292Issue: 2pp. 464-474Biopsy in Prostate Cancer. 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