Relationships between Circulating and Intraprostatic Sex Steroid Hormone Concentrations

Area of Science:

• Endocrinology
• Oncology
• Epidemiology

Background:

• Sex hormones are suspected to play a role in prostate cancer development.
• Previous epidemiological studies have yielded inconsistent results regarding sex hormones and prostate cancer risk.
• The relationship between circulating and intraprostatic sex hormone levels remains unclear.

Purpose of the Study:

• To investigate whether serum sex steroid hormone concentrations accurately reflect intraprostatic concentrations.
• To assess the utility of circulating hormones as surrogates for the intraprostatic hormonal environment in prostate cancer cases.

Main Methods:

• Analysis of serum and adjacent benign prostate tissue from prostate cancer surgery patients.
• Quantification of sex steroid hormones using radioimmunoassays after extraction and chromatographic separation.
• Linear regression models were employed to assess correlations and explain variance, controlling for covariates and potential effect modifiers (age, BMI, race, Gleason score).

Main Results:

• Circulating sex steroid hormones showed low-to-moderate correlations with intraprostatic concentrations, explaining only small proportions of variance.
• Androstane-3α,17β-diol glucuronide (3α-diol G) had the highest explained variance (r²=0.21), followed by testosterone/dihydrotestosterone (r²=0.10) and estrone (r²=0.09).
• No significant effect modification was observed for Gleason score, race, or age.

Conclusions:

• Serum sex steroid hormone concentrations are inadequate surrogates for the intraprostatic hormonal milieu.
• The discrepancy between circulating and tissue hormone levels may contribute to the lack of consistent associations between blood hormones and prostate cancer risk.