PI-RADS v2 and Adverse Prostate Cancer Outcomes: A Cross-cohort Replication Study Across Three Centers

BACKGROUND AND OBJECTIVE: Magnetic resonance imaging (MRI) coupled with Prostate Imaging-Reporting and Data System (PI-RADS) provides standardization for assessing the clinical significance of prostate cancer (PCa). The association between PI-RADS and clinical endpoints has remained underexplored due to limited follow-up data. METHODS: Association of PI-RADS with prostate cancer-specific mortality (PCSM), overall survival (OS), metastasis-free survival (MFS), and biochemical recurrence (BCR) was investigated across three retrospective cohorts focusing on the PI-RADS v2 era. The Helsinki University Hospital included 4674 men with clinical suspicion of PCa (MRI during 2015-2019, median follow-up [mFU] 5.0 yr), Tampere University Hospital (N = 1159; 2016-2021, mFU 2.3 yr) with men diagnosed with PCa, and Lille University Hospital (N = 301; 2016-2024, mFU 6.2 yr) with radical prostatectomy-treated men with PCa. KEY FINDINGS AND LIMITATIONS: In Helsinki cohort, multivariable Cox regression found PI-RADS score 5 to be significantly associated with PCSM (hazard ratio 18.4, 95% confidence interval [6.62-51.1]), along with biopsy GG 5 (5.45 [1.82-16.3]), Charlson's Comorbidity Index (1.53 [1.42-1.7]), and prostate-specific antigen (1.28 [1.11-1.5]). PI-RADS score 5 associated with OS in the Helsinki and Tampere cohorts, and MFS and BCR in the Lille cohort. Main limitation of the work is that all data is retrospective. CONCLUSIONS AND CLINICAL IMPLICATIONS: PI-RADS score 5 is associated with elevated risk of adverse outcomes. The presented clinically strong endpoints have potential to affect decision-making in MRI-based PCa diagnosis and prognosis.