Low free and bioavailable testosterone levels may predict pathologically-proven high-risk prostate cancer: a prospective, clinical trial.
Level 3 - non-randomized controlled study
Prospective non-randomized cohort study evaluating biomarker levels across histological outcomes.
PubMed 28861300 · doi:10.5152/tud.2017.35467
What was done
A prospective study evaluated 405 men undergoing transrectal prostate biopsy for elevated PSA (>2.5 ng/mL) or abnormal digital rectal examination. Free and bioavailable testosterone levels were calculated using the ISSAM formula. Patients were classified as benign or stratified by D'Amico risk categories (low, intermediate, high-risk prostate cancer) and by the percentage of biopsy cores positive for cancer.
What was found
Prostate cancer was diagnosed in 160 of 405 men (39.5%). Total, free, and bioavailable testosterone did not differ between benign and malignant cases. Among cancer cases, mean free testosterone (5.2 vs. 6.2 ng/dL, p=0.02) and bioavailable testosterone (125 vs. 151 ng/dL, p=0.001) were significantly lower in high-risk versus low-to-intermediate risk disease. Free (p=0.002) and bioavailable testosterone (p=0.016) were also significantly correlated with the percentage of cancerous cores.
Why it matters
Calculated free and bioavailable testosterone levels may serve as adjunctive clinical markers to help identify men harboring more aggressive, high-risk prostate cancer prior to treatment selection.
Limits
Testosterone fractions were calculated rather than directly measured by mass spectrometry. The abstract does not report multivariable adjustment for confounding factors such as age or metabolic comorbidities, nor does it provide confidence intervals or clinical outcomes beyond biopsy.
Cited by
- supports Lower endogenous testosterone levels are associated with a higher risk of high-grade prostate cancer.