To evaluate the efficacy of multiparametric magnetic resonance imaging (mp-MRI) using Prostate Imaging Reporting and Data System version 2.0 (PI-RADSv2) definitions in detecting organ-confined prostate cancer.

All patients who underwent radical prostatectomy between January 1, 2014 and December 30, 2014 were identified. All underwent mp-MRI within 180 days before surgery. Those with prior pelvic irradiation or androgen deprivation therapy were excluded. Fully embedded, whole-mount histopathology was centrally reviewed and correlated with imaging for tumour location, Gleason score (GS) and stage.

There were 39 patients included, of which 35 (90%) had mp-MRI done post-biopsy. A total of 93 cancer foci were identified on whole-mount pathology, of which mp-MRI detected 63 (68%). Of those detected by mp-MRI, 14 were PI-RADS 3 (n = 6 for GS 6, n = 8 for GS 7, no GS ≥ 8) and 49 were PI-RADS 4-5 (n = 7 for GS 6, n = 33 for GS 7, and n = 9 for GS ≥ 8). There were 30 (32%) cancer foci missed by mp-MRI (n = 15 for GS 6, n = 13 for GS 7 and n = 2 for GS ≥ 8). A lesion classified as PI-RADS 4-5 predicted a higher grade cancer on pathology as compared to PI-RADS 3 (for GS 7 lesions, odds ratio [OR] = 3.53, 95% CI: 0.93-13.45, p = 0.064). The mp-MRI size detection limit was 20 mm2 and 100 mm2 for 50% and 75% probability of cancer, respectively. In associating with radiological and pathologic stage, the weighted Kappa value was 0.69 (p < 0.0001). The sensitivity and positive predictive values for this study were 68% (95% CI: 57%-77%) and 78% (95% CI: 67%-86%), respectively.

In this predominantly post-biopsy cohort, mp-MRI using PI-RADSv2 reporting has a reasonably high diagnostic accuracy in detecting clinically significant prostate cancer.

Asian journal of urology. 2018 Jun 01 [Epub]

Edwin Jonathan Aslim, Yan Mee Law, Puay Hoon Tan, John Carson Allen, Lionel Tim-Ee Cheng, Viswanath Anand Chidambaram, Li Yan Khor, Benjamin Yongcheng Tan, Ernest Wencong Eu, Christopher Wai Sam Cheng, John Shyi Peng Yuen, Henry Sun Sien Ho, Lui Shiong Lee

Department of Urology, Singapore General Hospital, Singapore., Department of Diagnostic Radiology, Singapore General Hospital, Singapore., Division of Pathology, Singapore General Hospital, Singapore., Centre of Quantitative Medicine, DUKE-NUS Medical School, Singapore., Department of Anatomical Pathology, Singapore General Hospital, Singapore.