Beyond PI-RADS: Combining MRI PI-RADS and PSMA-PET/CT PRIMARY Score in a Composite (P) Score for More Accurate Diagnosis of Clinically Significant Prostate Cancer.

The PI-RADS score is standard of care for clinically significant prostate cancer (csPCa) diagnosis. The PRIMARY-score (PSMA-PET/CT) also has high diagnostic accuracy for csPCa. This study aimed to develop an easily calculated combined (P) score for csPCa detection (ISUP ≥ 2) incorporating separately read PI-RADS and PRIMARY scores, with external validation.

Two datasets of men with suspected PCa, no prior biopsy, recent MRI and 68Ga-PSMA-11-PET/CT, and subsequent trans-perineal biopsy were evaluated. The development sample (n = 291, 56% csPCa) a prospective trial and the validation sample (n = 227, 67% csPCa) a multi-centre retrospective database. Primary outcome was detection of csPCa (ISUP ≥ 2), with ISUP ≥ 3 cancer detection a secondary outcome. Score performance was evaluated by AUC, sensitivity, specificity, and decision curve analysis.

The 5-point combined (P) score was developed in a prospective dataset. In the validation dataset, csPCa was identified in 0%, 20%, 52%, 96% and 100% for P score 1 to 5. The AUC was 0.93 (95%CI: 0.90-0.96), higher than PI-RADS 0.89 (95%CI: 0.85-0.93, P = .039) and PRIMARY score alone 0.84 (95%CI: 0.79-0.89, P < .001). Splitting scores at 1/2 (negative) vs 3/4/5 (positive), P score sensitivity was 94% (95%CI: 89-97) compared to PI-RADS 89% (95%CI: 83-93) and PRIMARY score 86% (95%CI: 79-91). For ISUP ≥ 3, P score sensitivity was 99% (95%CI: 95-100) vs 94% (95%CI: 88-98) and 92% (95%CI: 85-97) for PI-RADS and PRIMARY scores respectively. An SUVmax > 12 (P score 5) was ISUP ≥ 2 in all cases with 93% ISUP ≥ 3.

The P-score is easily calculated and improves accuracy for csPCa over both PI-RADS and PRIMARY scores. It should be considered when PSMA-PET is undertaken for diagnosis.

The Journal of urology. 2024 May 17 [Epub ahead of print]

Louise Emmett, Nathan Papa, Thomas A Hope, Wolfgang Fendler, Jeremie Calais, Irene Burger, Matthias Eiber, Francesco Barbato, Daniel Moon, William Counter, Nikeith John, Alan Xue, Anthony Franklin, James Thompson, Kris Rasiah, Mark Frydenberg, John Yaxley, James Buteau, Shikha Agrawal, Bao Ho, Andrew Nguyen, Victor Liu, Jonathan Lee, Henry Woo, Edward Hsiao, Thomas Sutherland, Elyse Perry, Phillip Stricker, Michael S Hofman, Veeru Kasivisvanathan, Matthew Roberts, Declan Murphy

Theranostics and Nuclear medicine, St Vincent's Hospital, Sydney, Australia., Garvan Institute of Medical Research, Sydney, Australia., Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California., Department of Nuclear Medicine, University of Duisburg-Essen and German Cancer Consortium (DKTK)- University Hospital Essen, Essen, Germany., Ahmanson Translational Theranostics, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, California., Department of Nuclear Medicine, Kantonsspital Baden, Baden, Switzerland., Department of Nuclear Medicine, School of Medicine, Technical University Munich, Munich, Germany., Division of Cancer Surgery, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia., Department of Surgery, Faculty of Medicine, Monash University., Department of Urology, Royal Brisbane and Women's Hospital, Brisbane, Australia., Royal North Shore Hospital, Sydney, Australia., The Wesley Hospital, Brisbane, Australia., Prostate Cancer Theranostics and Imaging Centre of Excellence (ProsTIC), Department of Molecular Imaging and Therapeutic Nuclear Medicine, Cancer Imaging, Peter MacCallum Cancer, Melbourne, Australia., Department of Uro-Oncology, Chris O'Brien Lifehouse, Sydney, Australia., Department of Radiology St Vincent's Hospital, Melbourne, Australia., Department of Urology, StVincent's Hospital Sydney., Division of Surgery and Interventional Science, University College London, United Kingdom.