Prospective Evaluation of PI-RADS Version 2.1 for Prostate Cancer Detection

Abstract

OBJECTIVE. The purpose of this study was to prospectively evaluate Prostate Imaging Reporting and Data and System version 2.1 (PI-RADSv2.1), which was released in March 2019 to update version 2.0, for prostate cancer detection with transrectal ultrasound-MRI fusion biopsy and 12-core systematic biopsy. SUBJECTS AND METHODS. This prospective study included 110 consecutively registered patients who underwent multiparametric MRI evaluated with PI-RADSv2.1 criteria followed by fusion biopsy and systematic biopsy between April and September 2019. Lesion-based cancer detection rates (CDRs) were calculated for prostate cancer (Gleason grade group, > 0) and clinically significant prostate cancer (Gleason grade group, > 1). RESULTS. A total of 171 lesions (median size, 1.1 cm) in 110 patients were detected and evaluated with PI-RADSv2.1. In 16 patients no lesion was detected, and only systematic biopsy was performed. Lesions were categorized as follows: PI-RADS category 1, 1 lesion; PI-RADS category 2, 34 lesions; PI-RADS category 3, 54 lesions; PI-RADS category 4, 52 lesions; and PI-RADS category 5, 30 lesions. Histopathologic analysis revealed prostate cancer in 74 of 171 (43.3%) lesions and clinically significant prostate cancer in 57 of 171 (33.3%) lesions. The CDRs of prostate cancer for PI-RADS 2, 3, 4, and 5 lesions were 20.0%, 24.1%, 51.9%, and 90.0%. The CDRs of clinically significant prostate cancer for PI-RADS 1, 2, 3, 4, and 5 lesions were 0%, 5.7%, 14.8%, 44.2%, and 80.0%. In 16 patients with normal multiparametric MRI findings (PI-RADS 1), the CDRs were 50.0% for PCa and 18.8% for clinically significant prostate cancer. CONCLUSION. This investigation yielded CDRs assessed with prospectively assigned PI-RADSv2.1 scores. CDRs increased with higher PI-RADSv2.1 scores. These results can be compared with previously published outcomes derived with PI-RADS version 2.0.

Keywords: PI-RADS; early detection; multiparametric MRI; prostate biopsy; prostate cancer.

Fig. 1—

Chart shows that 59 of 110 patients included in study had cancer detected at biopsy, eight of whom had negative multiparametric MRI results. Distribution of highest International Society of Urological Pathology (ISUP) score for each patient who had cancer at biopsy shows that total of 43 patients had clinically significant prostate cancer (ISUP > 1, red). PI-RADSv2.1 = Prostate Imaging Reporting and Data and System version 2.1.

Fig. 2—

Chart shows that 171 lesions were detected in 110 patients. Fusion biopsy revealed that 97 lesions were benign and 74 were cancer. Distribution of International Society of Urological Pathology (ISUP) scores for cancerous lesions shows that total of 57 lesions were clinically significant prostate cancer (ISUP > 1, red). PI-RADSv2.1 = Prostate Imaging Reporting and Data and System version 2.1.

Fig. 3—

Chart shows lesion-based cancer detection rate (CDR) for all prostate cancers (PCa) and clinically significant PCa (csPCa) for each Prostate Imaging Reporting and Data and System version 2.1 (PI-RADSv2.1) category as validated by fusion biopsy. Differences in CDR were statistically significant for all PCa and csPCa between PI-RADS categories 3 and 4 and PI-RADS categories 4 and 5.

Fig. 4—

73-year-old man with prostate-specific antigen level of 6.67 ng/mL. Dashed arrows indicate two additional Prostate Imaging Reporting and Data and System (PI-RADS) category 4 lesions visible in peripheral zone. A, Axial T2-weighted MR image shows mostly encapsulated nodule (solid arrow) in right mid transition zone. Greatest dimension is 1.2 cm, consistent with PI-RADS score of 2 on T2-weighted image. B and C, Apparent diffusion coefficient map (B) shows lesion (solid arrow) in same location as lesion in A is hypointense, and DW image (b = 2000 s/mm²) (C) shows it is hyperintense, making it PI-RADS assessment category 4. D, Dynamic contrast-enhanced MR image shows hypervascularity (solid arrow) within same location as lesion in A–C with early enhancement for overall PI-RADS version 2.1 score of 3, prompting biopsy. MRI–transrectal ultrasound fusion biopsy revealed Gleason 3 + 4 prostate cancer in lesion.