Bone mass in endometriosis patients treated with GnRH agonist implant or danazol

Before treatment, the trabecular bone mineral content of the lumbar spine and femoral neck was not significantly different between endometriosis patients and age-matched controls (N = 26). In 17 subjects treated with a monthly goserelin implant, serum estradiol (E2) levels were suppressed into the menopausal range. Mean decreases from pre-treatment values in the lumbar spine and femoral neck were -5.7 and -3.8% at 3 months and -8.2 and -7.7% at 6 months of treatment, respectively; lumbar spine values were significantly different (P less than .05) from those of the control group, whose values changed little during the same period. Significant increases over baseline values were also observed in urinary calcium-creatinine ratio and serum alkaline phosphatase. In nine danazol-treated subjects, serum E2 levels were generally within the early follicular-phase range. There were no significant changes in bone assessments. Normal menses returned within 2 months after cessation of either medication. Six months after goserelin treatment, the lumbar spine and femoral neck bone mineral content was still reduced but to values not significantly different from the pre-treatment and control values; urinary calcium-creatinine ratio was decreased, whereas serum alkaline phosphatase was still elevated. The rapid and deep suppression of ovarian steroidogenesis by a monthly goserelin implant induced significant bone loss compared with the control and danazol groups. This loss was not reversed completely 6 months after cessation of treatment, but bone densities at that time were not different from those of controls. Studies of larger numbers of patients followed for longer periods will be required to resolve the question of complete reversibility.