A randomized study of the effects of tibolone and transdermal estrogen replacement therapy in postmenopausal women with uterine myomas

Objective: To evaluate the effects of two types of hormone replacement therapy, an estrogen-progestin combination and tibolone, on uterine myomas in menopausal women. Study design: Thirty-eight menopausal women with one or more uterine myomas were randomized to treatment with a transdermal system continuously releasing estradiol 50 mu g/day combined with oral medroxyprogesterone acetate (MPA) 10 mg/day for 12 days/month or tibolone tablets 2.5 mg/day. The scheduled duration of both treatments was 12 months. Physical examination and abdominal/transvaginal ultrasonography were performed before entering the study and at 3, 6 and 12 months of treatment. At each ultrasonography the overall uterine volume was determined as well as the size of each myoma and the endometrial thickness and characteristics. Results: No statistically significant difference was detected between the two groups at any time during treatment. However, within-group analysis showed a significant increase of uterine volume and of myoma number and size in the estrogen-progestin group, whereas no such increase occurred in the patients treated with tibulone. Also, the mean endometrium width increased significantly from baseline to the end of treatment in the estrogen-progestin group, but not in the tibulone group. Conclusions: Tibolone seems a valid alternative in menopausal patients with uterine myomas as it provides adequate relief from menopausal symptoms and avoids volume increase of the uterus and myomas.