Comparison of the diagnostic accuracy of clinically significant prostate cancer based on the PI-RADS: an interobserver study

Abstract

Objective To compare the diagnostic accuracy of clinically significant prostate cancer by general radiologist and uroradiology specialist based on the Prostate Imaging Reporting and Data System(PI-RADS). Methods A total of 45 men from Beijing United Family Hospital and Clinics undergoing prostate mpMRI examination and subsequent MRI-targeted biopsy were included in the study. The age of patients was (60.0±8.0) years, the median PSA level was 7.2 ng/ml (1.2-95.8 ng/ml) and the median prostate volume was 45.0 ml (18.3-127.0 ml). The general radiologists from Beijing United Family Hospital and Clinics made the diagnosis according to PI-RADS 2.0. One uroradiology specialist from Beijing Anzhen hospital reviewed all the mpMRIs retrospectively and marked new PI-RADS score based on PI-RADS 2.0. The PI-RADS≥3 lesion was recognized as suspicious of clinically significant prostate cancer. The distribution of PI-RADS score from different doctors and the diagnostic accuracy of clinically significant prostate cancer was compared. Results All the 45 patients underwent MRI-targeted cognitive biopsy and 14 cases of prostate cancer were detected, including 9 cases of clinically significant prostate cancer. There was no significant difference in the distribution of PI-RADS by general radiologist and uroradiology specialist(P=0.064). 82.8%(37/45) and 37.8%(17/45) patients were diagnosed with PI-RADS≥3 by general radiologist and uroradiology specialist respectively. The interobserver agreement was only 17.8%(8/45). The positive predictive value of PI-RADS≥3 was 35.1%(13/37) and 76.5%(13/17) for prostate cancer by general radiologist and uroradiology specialist respectively, and for clinically significant prostate cancer, the positive predictive value of PI-RADS≥3 was 21.6%(8/37) and 52.9%(9/17) respectively. Conclusions Uroradiology specialist achieved significantly superior in predictive value of PI-RADS for clinically significant prostate cancer compared with general radiologist. In the experienced centers, MRI-targeted biopsy could be performed only on high PI-RADS score lesions, thus to reduce unnecessary biopsies and to avoid over diagnosis and over treatment of prostate cancer. Key words: Prostatic neoplasms; Prostate imaging reporting and data system (PI-RADS); Magnetic resonance imaging; Targeted biopsy; Radiologist