Biparametric Prostate Imaging Reporting and Data System version2 and International Society of Urological Pathology Grade Predict Biochemical Recurrence after Radical Prostatectomy

Abstract

Background: We retrospectively assessed the clinical significance of the Prostate Imaging Reporting and Data System (PI-RADS), version 2, criteria based on biparametric magnetic resonance imaging (bp-MRI), together with the International Society of Urological Pathology (ISUP) grade, for predicting biochemical recurrence (BCR) after radical prostatectomy.

Materials and methods: The data from 126 patients who had undergone radical prostatectomy were retrospectively analyzed. The prognostic significance of the PI-RADS v2 score based on bp-MRI was assessed with other clinical factors, including the ISUP grade. We defined a positive PI-RADS and ISUP score as ≥ 4 and ≥ 3, respectively. Statistical analysis was performed using Cox proportional hazard models, logistic regression analysis, and the Kaplan-Meier method.

Results: The median age and median prostate-specific antigen level were 66 years and 7.96 ng/mL, respectively. The number of positive PI-RADS scores was 106 (84.1%) and the number of positive ISUP grade scores was 71 (56.3%). PI-RADS ≥ 4 (P = .0031) and ISUP ≥ 3 (P = .070) were the 2 independent prognostic factors predictive of BCR. A positive PI-RADS score was related to tumor volume (P = .014), and a positive ISUP score was related to prostate-specific antigen level (P = .043), extraprostatic extension (P = .029), and Gleason upgrading (P < .0001). After stratifying patients into risk groups according to PI-RADS and ISUP positivity, the poor-risk group (PI-RADS and ISUP grade positive) showed significantly worse BCR-free survival compared with that of the favorable- and intermediate-risk groups (P < .0001), with a median survival difference of 21 months.

Conclusion: Biparametric PI-RADS v2 and ISUP grade criteria predicted for BCR after radical prostatectomy. PI-RADS v2 combined with the ISUP grade might be helpful in choosing the treatment modality of patients with localized prostate cancer.

Keywords: Biparametric MRI; ISUP grade; PI-RADS; Prostate cancer; Tumor volume.