The Complementary Roles of the Prostate Health Index and Multiparametric Magnetic Resonance Imaging in Optimizing the Detection of Clinically Significant Prostate Cancer in Patients With Prostate-Specific Antigen Levels Below 10 Ng/mL.

OBJECTIVE: To evaluate complementary roles of Prostate Health Index (phi) and multiparametric magnetic resonance imaging (mpMRI) in detection of any prostate cancer (PC) and clinically significant PC (csPC) and to investigate likelihood of risk stratification for recommending prostate biopsy in men with prostate-specific antigen (PSA) ≤ 10 ng/mL. METHODS: This exploratory post hoc analysis of the prospective multicenter PROPHET cohort included 108 Japanese men who underwent prebiopsy mpMRI. All MRI findings were retrospectively reviewed by one specialized radiologist and scored using Prostate Imaging Reporting and Data System (PI-RADS) v2.1. csPC was defined as ISUP grade group (GG) of 2-5. Then, the likelihood of risk stratification for detecting any PC and csPC based on PI-RADS categories and a significant [-2]proPSA-related index assessed by receiver operating characteristic (ROC) analyses was retrospectively investigated. RESULTS: PC was detected in 51 of 108 men (47.2%). The ROC analyses revealed the superiority of phi in detecting PC and csPC. Among men with phi ≤ 36.0 and PI-RADS 1-3, csPC was detected in 2 of 36 men (5.6%), but no GG 3-5 cancers were observed. In contrast, in men with phi > 36.0, the risk of detecting PC/csPC was 42.9% (9/21)/23.8% (5/21), 42.9% (3/7)/42.9% (3/7), and 89.3% (25/28)/71.4% (20/28) in PI-RADS 1-2, 3, and 4-5, respectively. CONCLUSIONS: phi and mpMRI have complementary roles for biopsy decision-making in men with PSA ≤ 10 ng/mL. Men with phi ≤ 36.0 and PI-RADS 1-3 may be candidates for biopsy avoidance, whereas phi > 36.0 may be a high-risk group recommending prostate biopsy regardless of mpMRI findings. REGISTRY AND REGISTRATION NO. OF THE STUDY/TRIAL: This study was registered with the UMIN Clinical Trials Registry (UMIN-CTR), registration number UMIN000047187.