Utility of the prostate health index density for detecting clinically significant prostate cancer in patients with negative magnetic resonance imaging findings.

[BACKGROUND] Multiparametric magnetic resonance imaging (MRI) is widely used in prostate cancer diagnosis; however, a significant proportion of clinically important cancers can be missed in patients with negative MRI findings. Although attempts have been made to analyze prostate-specific antigen (PSA)-related parameters to improve the specificity of PSA testing, no evidence-based cutoff values have been established. This study aimed to evaluate the diagnostic performance of the prostate health index (PHI) and PHI density (PHID) in detecting clinically significant prostate cancer (csPCa) in the MRI-negative population.

[METHODS] A retrospective analysis was conducted on 339 MRI-negative patients with PSA levels of 3-15 ng/mL who underwent PHI testing and MRI between September 2022 and July 2024. MRI-negative patients were defined as those with Prostate Imaging Reporting and Data System (PI-RADS) category 1 or 2 lesions. Biopsies were performed in 181 patients. The diagnostic accuracies of PSA, % free PSA, PHI, PSA density, and PHID were assessed using the receiver operating characteristic curves.

[RESULTS] Among the 47 patients with PI-RADS 1 or 2 who underwent biopsy, 24 (51.1%) had prostate cancer, of whom 16 (66.7%) had csPCa. The PHID showed the highest diagnostic performance (area under the curve [AUC] = 0.8832 for any cancer; AUC = 0.7843 for csPCa). Two patients with a PHI <27.2 were diagnosed with low-risk cancer (Gleason 6).

[CONCLUSIONS] The PHI and PHID may serve as valuable adjuncts to MRI for the detection of csPCa and may help avoid unnecessary biopsies in patients with negative MRI findings.