To compare the clinical validity and utility of Likert assessment and the Prostate Imaging Reporting and Data System (PI-RADS) v2 in the detection of clinically significant and insignificant prostate cancer.

489 pre-biopsy multiparametric MRI (mpMRI) scans in consecutive patients underwent prospective paired reporting using both Likert and PI-RADS v2 by expert uro-radiologists. Patients were offered biopsy for any Likert or PI-RADS score >/=4 or a score of 3 with PSA-density >/=0.12ng/ml/ml. Utility was evaluated in terms of proportion biopsied, and proportion of clinically significant and insignificant cancer detected (both overall and on a ‘per score’ basis). In those patients biopsied, overall accuracy of each system was assessed by calculating total and partial area under receiver operating characteristic curves (AUROC). The primary threshold of significance was Gleason >/=3+4; secondary thresholds of >/=Gleason 4+3, Ahmed/UCL1 (Gleason >/=4+3 or maximum cancer core length [CCL] >/=6 or total CCL >/=6) and Ahmed/UCL2 (Gleason >/=3+4 or maximum CCL >/=4 or total CCL >/=6) were also used.

Median age was 66 (IQR 60-72) years and PSA was 7 (IQR 5-10) ng/ml. A similar proportion of men met the biopsy threshold and underwent biopsy in both groups (83.8% [Likert] vs 84.8% [PI-RADS v2], p = 0.704). Likert predicted more clinically significant cancers than PI-RADS across all disease thresholds. Rates of insignificant cancers were comparable in each group. ROC analysis of biopsied patients showed that, although both scoring systems performed well as predictors of significant cancer, Likert was superior to PI-RADS v2, exhibiting higher total and partial AUROC.

Both scoring systems demonstrated good diagnostic performance with similar rates of decision to biopsy. Overall, Likert was superior by all definitions of clinically significant prostate cancer. It has the advantages of being flexible, intuitive and allows inclusion of clinical data. However, its use should only be considered once radiologists have developed sufficient experience in reporting prostate mpMRI.

BJU international. 2019 Oct 09 [Epub ahead of print]

Christopher C Khoo, David Eldred-Evans, Max Peters, Mariana Bertoncelli Tanaka, Mohamed Noureldin, Saiful Miah, Taimur Shah, Martin J Connor, Deepika Reddy, Martin Clark, Amish Lakhani, Andrea Rockall, Feargus Hosking-Jervis, Emma Cullen, Manit Arya, David Hrouda, Hasan Qazi, Mathias Winkler, Henry Tam, Hashim U Ahmed

Imperial Prostate, Division of Surgery, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, SW7 5NH., Department of Radiotherapy, University Medical Centre, Utrecht, 3584 CX, the Netherlands., Department of Radiology, Imperial College Healthcare NHS Trust, Charing Cross Hospital, London, W6 8RF., Imperial Urology, Imperial College Healthcare NHS Trust, Charing Cross Hospital, London, W6 8RF., Department of Urology, St. George’s Healthcare NHS Trust, St. George’s Hospital, London, SW17 0QT.