Possible bone-preserving capacity of high-dose intramuscular depot estrogen as compared to orchidectomy in the treatment of patients with prostatic carcinoma.

BACKGROUND

Treatment of prostatic disease with GnRH agonists or by orchidectomy affects bone mass negatively. Estrogen treatment has beneficial effects on bone mass in women and might hypothetically have a bone preserving capacity also in patients with prostatic cancer.

METHODS

We followed serum markers for bone and collagen metabolism and sex steroids for 18 months in patients with prostatic cancer treated by orchidectomy (N = 13) or by single-drug parenteral polyestradiol phosphate (240 mg intramuscularly every second week for the first two months, and then every fourth week; N = 17).

RESULTS

Total and free testosterone reached castration levels within 1.5 months of estrogen treatment. Four patients developing progressive disease and/or signs of metastasis were excluded from the analysis. In the remaining patients, serum osteocalcin, procollagen IIIP (PIIINP), procollagen (PICP), and the crosslinked carboxyterminal telopeptide of type I collagen (ICTP) increased significantly over time following orchidectomy (N = 11). Serum osteocalcin and PICP decreased significantly over time during estrogen treatment (N = 15). Treatment values of all four markers were significantly lower in estrogen-treated than in orchidectomized patients.

CONCLUSIONS

The changes in serum bone and collagen markers indicate an increased bone turnover in orchidectomized subjects. The opposite pattern was found in the estrogen-treated patients, indicating a reduced turnover. Estrogens may also have a bone mass-preserving capacity in elderly males with prostatic cancer.