The effect of combined androgen blockade on bone turnover and bone mineral density in men with prostate cancer

Summary Our study and previous reports suggest that castration results in increased bone turnover and lowered BMD and that these changes might be attenuated by anti-androgens, such as BL and EMP. Introduction Recent studies have shown that castration for PC decreases bone mineral density (BMD), while estrogen therapy or bicalutamide (BL) monotherapy maintains BMD. However, the effect of combined androgen blockade (CAB) on bone turnover is not well studied. Methods A total of 204 men were evaluated in the study (control group: n = 56, castration group: n = 102, ‘CAB with BL’ group: n = 22, ‘CAB with estramustine phosphate (EMP)’ group: n = 24). We measured steroid hormone levels, BMD (measured at one-third distal radius), bone turnover markers (levels of urinary N-telopeptide cross links of type 1 collagen (u-NTx) and deoxypyridinoline (u-DPD), serum concentrations of osteocalcin (OC)) in order to assess differences between groups. Results The BMD % Z score of the castration group was significantly lower than that of the control group or the ‘CAB with EMP’ group (90.6% vs. 95.5%, 98.6%; p < 0.042, p < 0.044, respectively). Levels of u-NTx, u-DPD, OC of the castration group were the highest followed by the control group, then the ‘CAB with BL’ group and the ‘CAB with EMP’ group. Conclusions Our study and previous reports suggests that castration results in increased bone turnover and lowered BMD and that these changes might be attenuated by anti-androgens, such as BL and EMP.