Tumor localization by Prostate Imaging and Reporting and Data System (PI-RADS) version 2.1 predicts the prognosis of prostate cancer after radical prostatectomy

The Prostate Imaging and Reporting and Data System (PI-RADS) version 2.1 (v2.1) has been reported to have an improved reading agreement rate than the prior version. Our study assessed the PI-RADS v2.1 and tumor location in Japanese prostate cancer patients who underwent radical prostatectomy to determine the predictive efficacy of bi-parametric MRI (bp-MRI) for biochemical recurrence (BCR). Retrospective analysis was done on the clinical data from 299 patients who underwent radical prostatectomy at Chiba University Hospital between 2006 to 2018. The median prostate-specific antigen（PSA）before surgery was 7.6 ng/ml. Preoperative PI-RADS v2.1 categories were 1 - 2 /3 /4/ 5 for 35 /56 /138 /70, respectively. Tumor localization at the preoperative MRI was 107 in the transition zone (TZ) and 192 in the peripheral zone (PZ). The duration of BCR-free survival was significantly shortened in the PZ group (p = 0.01). Preoperative PI-RADS category 5, radiological tumor localization, pathological seminal vesicle invasion, and Grade group ≥ 3 of the total prostatectomy specimens were independent prognostic factors of BCR. The four risk factors have the potential to significantly stratify patients and predict prognoses. Radiological tumor localization and PI-RADSv2.1 category using bp-MRI may predict the BCR following radical prostatectomy.