The Relationship Between PSA and Total Testosterone Levels in Men With Prostate Cancer

Background: Prostate-specific antigen (PSA) secretion is a testosterone (T) dependent process. Published data suggest that a low T level is an independent predictor of higher-grade prostate cancer (PC). Aim: To evaluate the relationship between T and PSA in patients with PC. Methods: All men diagnosed with PC with a recorded pre-treatment total T level measurement were included in this analysis. We analyzed demographic, clinical, and pathological data. Patients were stratified according to pretreatment PSA levels: <2 ng/mL, 2-4 ng/mL, >4 ng/mL. Low T was defined as total T < 10.4 nmol/L (300 ng/dL), very low T < 6.9 nmol/L (200 ng/dL). Outcomes: T levels by PSA groups according to the PC pathology. Results: In this retrospective study, mean patient age was 61 years among 646 men. The distribution by PSA group was: 8% (<2), 17% (2-4), and 76% (>4). The mean T level across the entire cohort was 13 nmol/L (374 ng/dL). Overall, 30% had a T level < 10.4 nmol/L (300 ng/dL). The mean total T level by PSA group was: <2 ng/mL, 7 nmol/L (206 ng/dL); 2-4 ng/mL, 13 nmol/L (362 ng/dL); >4 ng/mL, 14 nmol/L (393 ng/dL), P <.001. PSA <4 ng/mL was a significant predictor of low T in men with PC GS >= 8. PSA <2 ng/mL was a significant predictor of very low T independent of the PC pathology. Clinical Implications: These findings suggest that clinicians should consider measuring T levels when a patient diagnosed with PC GS =8 and PSA level <4 ng/mL, and for each patient with PSA level <2 ng/mL independent of the PC pathology. Strengths & Limitations: Our study has several strengths including (i) inclusion of a large population of men, (ii) use of a database which is audited and reviewed for accuracy annually, and (iii) use of an accurate T assay (LCMS). Nonetheless, there are limitations: (i) the subjects of the study are from a single institution, and (ii) we did not measure free T levels. Conclusion: In men with PC with GS >= 8, PSA level <4 ng/mL predicts low T. PSA <2 ng/mL predicts very low T independent of the PC pathology. Copyright (C)22, International Society of Sexual Medicine. Published by Elsevier Inc. All rights reserved.

Automated summary

This study evaluates the relationship between testosterone (T) and prostate-specific antigen (PSA) in patients with prostate cancer (PC). The results suggest a significant association between low T levels and PSA levels below 4 ng/mL and 2 ng/mL, indicating the importance of measuring T levels in the diagnosis and treatment of PC.