Depot leuprolide acetate versus danazol for treatment of pelvic endometriosis: changes in vertebral bone mass and serum estradiol and calcitonin.

Objective: To determine changes in trabecular vertebral bone mass, serum E2, and serum calcitonin during and after therapy of pelvic endometriosis with depot leuprolide acetate (LA) or danazol.
Design: Prospective, randomized, double-blind study.
Setting: Academic university hospital and department of obstetrics and gynecology.
Patients: Twelve women with symptomatic pelvic endometriosis diagnosed and staged by laparoscopy.
Interventions: All patients received blinded treatment with either 3.75 mg JM depot LA given every month and daily placebo tablets (n = 6) or 800 mg oral danazol daily with a monthly placebo injection (n = 6) for 24 weeks.
Main Outcome Measures: Quantitated computerized tomography of bone density of thoracic 12 to lumbar 4 vertebral bodies were determined before, at the end of 24 weeks of treatment, and 6 and 12 months after completing treatment. Gain or loss of bone mass was based against pretreatment levels. Serial serum levels of E2 and calcitonin before, throughout, and after therapy were compared with changes in bone mass.
Results: Bone loss with LA was 14.0% +/- 0.5% (mean +/- SEM), recovering to a deficit of 4.2% +/- 3.8% and 3.3%, 6 and 12 months after stopping therapy. Danazol increased bone by 5.4% +/- 2.2%, with a further gain to 8.2% +/- 3.5% and 7.5%, 6 and 12 months after stopping treatment. Serum E2 levels usually were < 25 pg/mL (conversion factor to SI unit, 3.671) with LA but > 47.3 pg/mL with danazol. Calcitonin levels did not change significantly with either treatment.
Conclusion: Depot LA produced marked sustained hypoestrogenemia and significant bone loss with incomplete recovery 1 year after stopping treatment. Danazol maintained normoestrogenemia and increased bone mass with the gain maintained even 1 year after stopping therapy.