Usefulness of free PSA ratio to enhance detection of clinically significant prostate cancer in patients with PI-RADS<3 and PSA≤10

Abstract

Background: The necessity of prostate biopsy in patients with a Prostate Imaging-Reporting and Data System (PI-RADS) score below 3 and prostate-specific antigen (PSA) levels of 4-10 ng/ml remains controversial. We tested the diagnostic performance of the free PSA ratio (%fPSA) in detecting clinically significant cancer (CSC) in patients with PI-RADS <3 and PSA <= 10 ng/ml. Methods: We analyzed 1435 prostate biopsies performed by a single operator between April 2018 and January 2023 at a single institution. PSA and free PSA results on the day of biopsy or within 1 month were used, and all biopsies were performed after prostate magnetic resonance imaging (MRI). CSC was defined as Gleason grade group >= 2. Results: Among 208 men with PI-RADS <3 and PSA <= 10 ng/ml, CSC was detected in 37 (17.8%) patients. The median age was 65 years (interquartile range [IQR] 61-71), with a median PSA level of 5.06 ng/ml (IQR 3.98-7.08) and a median %fPSA of 18.2% (IQR 13.7-22.0). The area under the curve was 0.757 (95% confidence interval, 0.674-0.841), with a %fPSA cutoff of 17.6%, sensitivity of 86.5%, specificity of 63.7%, positive likelihood ratio (LR) of 2.38, and negative LR of 0.21. CSC was diagnosed in 5 out of 114 patients (4%) with %fPSA >17.6%, compared to 32 out of 94 patients (34%) with %fPSA <17.6%. Conclusions: In patients with PI-RADS <3 and PSA <= 10 ng/ml, %fPSA values < 17.6% may facilitate early prostate cancer diagnosis in those who might not undergo biopsy based on MRI results alone. Additionally, unnecessary biopsies could be avoided in patients with elevated PSA levels when %fPSA exceeds 17.6%. (c) 2025 The Asian Pacific Prostate Society. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).