Bone turnover markers in patients with prostate carcinoma: influence of sex steroids levels

There are limited data about bone turnover markers (BTM) in androgen deprivation therapy (ADT)-treated prostate cancer (PCa) patients, and the relationship between sex steroids, bone mass, and BTM has not been explored. Our objective was to analyze the influence of sex steroids levels on BTM in patients with PCa treated with or without ADT. We performed a cross-sectional study including 83 subjects with PCa (54% with ADT). BTM, bone mineral density (BMD), and sex steroids were determined. BTM were inversely related to serum level of estrogens. Tartrate-specific acid phosphatase (TRAP-5b) showed a negative correlation with free estradiol (Free E) (r = -0.274, p = 0.014) and Bio E (r = -0.256, p = 0.022) that remained after adjustment for age: Free E (β = -0.241, p = 0.03) and Bio E (β = -0.213, p = 0.063). Bone-specific alkaline phosphatase (BSAP) concentrations were inversely related to Free E (r = -0.281, p = 0.011, age-adjusted β = -0.256, p = 0.024). There was a negative correlation between osteocalcin (OC) levels and Free E (r = -0.195, p = 0.082; age-adjusted β = -0.203, p = 0.076) and Bio E (r = -0.215, p = 0.054; age-adjusted β = -0.240, p = 0.039). BTM and androgens were inversely related to TRAP-5b: total testosterone (total T) (r = -0.238, p = 0.033), Free T (r = -0.309, p = 0.05), and Bio T (r = -0.310, p = 0.05), but these correlations disappeared after age-adjustment. We did not find any relationship between BMD at different locations and sex steroids. In conclusion, in patients with PCa, estrogen levels influence bone resorption and bone formation whereas androgens may exert actions only in bone resorption. These results suggest that estradiol is the main sex steroid that regulates bone metabolism in males with prostate carcinoma.