Effect of long-term hormone replacement therapy on the bone in ovariectomized women with cancer

Objective: To evaluate longitudinally the effectiveness of long-term hormone replacement therapy (HRT) in preserving the bone mineral density (BMD) over a 5-year period in ovariectomized patients treated for gynecologic malignancies. Methods: A total of 70 pre-menopausal women ovariectomized for gynecologic malignancies at our hospital were divided non-randomly into two groups: HRT (+) group (n=59) and HRT (−) group (n=11). HRT was administered in a sequential regimen of 0.625–1.25 mg conjugated estrogen for 24 days and 5–10 mg medroxyprogesterone acetate for 10 days. Results: The BMD of the lumbar vertebrae decreased significantly in the HRT (−) group (pre-operative BMD was 91.8%, 91.0% and 91.3% at 1, 2 and 3 years post-ovariectomy), but no decrease in the BMD was observed in the HRT (+) group (pre-operative BMD was 98.4%, 99.0%, 99.4%, 98.8% and 98.7% at 1, 2, 3, 4 and 5 years post-ovariectomy); the difference in BMD between the two groups was statistically significant (P<0.01). Serum alkaline phosphatase levels were significantly lower in the HRT (+) group than in the HRT (−) group (P<0.01). There were four recurrences of cancer in the HRT (+) group. Conclusion: HRT appeared to have beneficial effects on bone metabolism by maintaining BMD for 5 years in ovariectomized patients for gynecologic malignancies.