A.C. Westphalen, C.E. McCulloch, Jordan M Anaokar 1, Sandeep Arora 1, Nimrod S Barashi 1, Jelle O Barentsz 1, Tharakeswara K Bathala 1, Leonardo K Bittencourt 1, Michael T Booker 1, Vaughn G Braxton 1, Peter R Carroll 1, David D Casalino 1, Silvia D Chang 1, Fergus V Coakley 1, Ravjot Dhatt 1, Steven C Eberhardt 1, Bryan R Foster 1, Adam T Froemming 1, Jurgen J Fütterer 1, Dhakshina M Ganeshan 1, Mark R Gertner 1, Lori Mankowski Gettle 1, Sangeet Ghai 1, Rajan T Gupta 1, Michael E Hahn 1, Roozbeh Houshyar 1, Candice Kim 1, Chan Kyo Kim 1, Chandana Lall 1, Daniel J A Margolis 1, Stephen E McRae 1, Aytekin Oto 1, Rosaleen B Parsons 1, Nayana U Patel 1, Peter A Pinto 1, Thomas J Polascik 1, Benjamin Spilseth 1, Juliana B Starcevich 1, Varaha S Tammisetti 1, Samir S Taneja 1, Baris Turkbey 1, Sadhna Verma 1, John F Ward 1, Christopher A Warlick 1, Andrew R Weinberger 1, Jinxing Yu 1, Ronald J Zagoria 1, Andrew B Rosenkrantz 1
BACKGROUND: Prostate MRI is used widely in clinical care for guiding tissue sampling, active surveillance, and staging. The Prostate Imaging Reporting and Data System (PI-RADS) helps provide a standardized probabilistic approach for identifying clinically significant prostate cancer. Despite widespread use, the variability in performance of prostate MRI across practices remains unknown.
PURPOSE: To estimate the positive predictive value (PPV) of PI-RADS for the detection of high-grade prostate cancer across imaging centers.
MATERIALS AND METHODS: This retrospective cross-sectional study was compliant with the HIPAA. Twenty-six centers with members in the Society of Abdominal Radiology Prostate Cancer Disease-focused Panel submitted data from men with suspected or biopsy-proven untreated prostate cancer. MRI scans were obtained between January 2015 and April 2018. This was followed with targeted biopsy. Only men with at least one MRI lesion assigned a PI-RADS score of 2-5 were included. Outcome was prostate cancer with Gleason score (GS) greater than or equal to 3+4 (International Society of Urological Pathology grade group ≥2). A mixed-model logistic regression with institution and individuals as random effects was used to estimate overall PPVs. The variability of observed PPV of PI-RADS across imaging centers was described by using the median and interquartile range.
RESULTS: The authors evaluated 3449 men (mean age, 65 years ± 8 [standard deviation]) with 5082 lesions. Biopsy results showed 1698 cancers with GS greater than or equal to 3+4 (International Society of Urological Pathology grade group ≥2) in 2082 men. Across all centers, the estimated PPV was 35% (95% confidence interval [CI]: 27%, 43%) for a PI-RADS score greater than or equal to 3 and 49% (95% CI: 40%, 58%) for a PI-RADS score greater than or equal to 4. The interquartile ranges of PPV at these same PI-RADS score thresholds were 27%-44% and 27%-48%, respectively.
CONCLUSION: The positive predictive value of the Prostate Imaging and Reporting Data System was low and varied widely across centers.