Higher sex hormone-binding globulin and lower bioavailable testosterone are related to prostate cancer detection on prostate biopsy

Abstract

Objective. Recent studies show an inverse relationship between testosterone levels and prostate cancer (PCa). The usefulness of hormonal patterns in PCa diagnosis is controversial. This study aimed to determine the relationship between hormonal patterns and PCa, and to find a cut-off point of hormone levels to assess PCa risk. Material and methods. A prospective analysis was undertaken of 279 patients referred for first or second prostate biopsy in the Hospital Clínic Barcelona from November 2006 to May 2009. The indication for prostate biopsy was suspicion of PCa based on the results of digital rectal examination (DRE) and/or elevation of serum prostate-specific antigen (PSA). Screening was carried out with a 5+5-core transrectal ultrasound-guided prostate biopsy. Age, prostate volume, DRE (normal or abnormal), biopsy findings (normal or report of PCa), PSA, free-to-total PSA, PSA density, testosterone and sex hormone-binding globulin (SHBG) were also prospectively recorded. Free and bioavailable testosterone were calculated using Vermeulen's formula. Results. In the multivariate analysis, abnormal DRE [odds ratio (OR = 5.46, p < 0.001], SHBG levels ≥ 66.25 nmol/l [OR = 3.27; 95% confidence interval (CI) 1.52 to 7.04, p < 0.002] and bioavailable testosterone levels ≤ 104 ng/dl (OR = 4.92, 95% CI 1.78 to 13.59, p = 0.002) were related to the diagnosis of prostate adenocarcinoma. Age, free testosterone, PSA, testosterone, PSA/testosterone, PSA/free testosterone and PSA/bioavailable testosterone were not related to PCa diagnosis. Conclusions. Low bioavailable testosterone levels and high SHBG levels were related to a 4.9- and 3.2-fold risk of detection of PCa on prostate biopsy owing to PSA elevation or abnormal DRE. This fact may be useful in the clinical scenario in counselling patients at risk for PCa.

Key Words::

• bioavailable testosterone
• hormonal pattern
• prostate biopsy
• prostate cancer
• SHBG

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.