URUrology Research3083-49102981-8230Bio-Byword Scientific Publishing Pty. Ltd.10.26689/UR.v4i3.15711ArticleCombined Use of PI-RADS, PSA Density, and the Free-to-Total PSA Ratio for Prostate Cancer Diagnosis in the PSA Gray Zone: A Narrative Reviewhttps://artdesignp.com/journal/UR/4/3/10.26689/UR.v4i3.15711LiuTao2026432026-10-20When total prostate-specific antigen (tPSA) is between 4 and 10 ng/mL, the result alone often cannot distinguish prostate cancer from benign prostatic disease. The combination of the Prostate Imaging Reporting and Data System (PI-RADS) score and PSA density (PSAD) provide additional information for biopsy decisions in this population. The free-to-total PSA ratio (f/tPSA) is another commonly used adjunct, although some evidence supporting its diagnostic value predates the widespread use of magnetic resonance imaging (MRI). This narrative review examines studies of these three measures, with particular attention to age, model composition, and biopsy outcomes. Available evidence supports combining PI-RADS with PSAD to improve risk stratification. The f/tPSA ratio has also shown diagnostic value in certain age groups and MRI-defined populations. However, good performance of a multivariable model does not establish that every included predictor provides additional information. In men aged ≥ 60 years with tPSA levels of 4–10 ng/mL, direct comparisons of models with and without f/tPSA are needed. Reporting both the number of biopsies avoided and the number of clinically significant cancers missed would help clarify the clinical value of the three-variable approach.Prostate cancer, PSA gray zone, PI-RADS, PSA density, Free-to-total PSA ratio, Combined diagnostic assessment

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