Do prostate-specific antigen parameters have a similar role in predicting prostate cancer regardless of serum testosterone levels in men with gray-zone prostate-specific antigen levels?

Background:To evaluate whether various prostate-specific antigen (PSA) parameters have a similar diagnostic value in predicting prostate cancer (PCa) in men with gray-zone PSA levels (4.0-10.0 ng/mL) depending on different serum testosterone levels. Methods:We retrospectively reviewed the data of 635 men with gray-zone PSA levels who underwent prostate biopsy between January 2015 and December 2019. The study cohort was divided into two groups according to serum testosterone levels: normal (≥300 ng/dL) and low (<300 ng/dL) testosterone. Using the area under the receiver-operating characteristic curve (AUC), we analyzed the diagnostic accuracy of PSA parameters (total PSA, free PSA, free-to-total PSA ratio, testosterone-to-PSA ratio, and PSA density) in predicting PCa and compared the results between the two groups. Results:The median age was 68 (range, 40-88) years, and 76.1% (483 of 635) of the men had low testosterone levels. The PCa incidence was higher in the low testosterone group than in the normal testosterone group (45.5% vs. 35.5%, P=0.030). The AUC of free-to-total PSA ratio for predicting PCa showed no difference between the normal and low testosterone groups (AUC 0.616 vs. 0.684, P=0.257). Moreover, total PSA, testosterone-to-PSA ratio, and PSA density showed similar performance in predicting PCa between the two groups. Conclusions:The analyzed PSA parameters showed a similar diagnostic value in predicting PCa regardless of testosterone levels in men with gray-zone PSA levels.