Effects of Tibilone on Bone Density, Menopause Symptoms and Breast Density in Women After Prophylactic Oophorectomy

Inclusion Criteria:

* Good overall health
* Premenopausal at the time of enrollment if before their oophorectomy
* Will undergo or have undergone an oophorectomy
* Negative breast examination and negative breast imaging studies

Exclusion Criteria:

* History of breast cancer, ductal carcinoma in situ (DCIS) or other cancer except for carcinoma in situ of the cervix or basal cell carcinoma of the skin
* History of ovarian cancer, breast cancer (or DCIS) or other malignancy
* Low bone mass compared with age-adjusted controls
* Current or recent exposure (within 3 months) to medications that alter bone metabolism
* Estrogens, progesterones, androgens, tamoxifen or raloxifene within 3 months of randomization
* History of significant medical problems potentially related to estrogens
* History of Paget's disease of bone, ankylosing spondylitis, rheumatoid arthritis or other metabolic bone disease, vitamin D deficiency, hyperparathyroidism, or newly diagnosed hyperthyroidism
* Body mass index (BMI) \> 32
* High-density lipoprotein (HDL) cholesterol \< 40 mg/dl
* Women whose uterus was retained and who have a history of uterine abnormalities