PATIENT CHARACTERISTICS: Age: Postmenopausal as defined below Sex: Female Menopausal status: Postmenopausal as defined by: 55 years of age and over, and amenorrhea for greater than 2 years OR Radiation menopause (at least 3 months previously) or surgical oophorectomy OR Natural amenorrhea for at least 1 year at breast cancer diagnosis Performance status: Not specified Life expectancy: Not specified Hematopoietic: WBC at least 4,000/mm3 Hemoglobin normal Hepatic: SGOT no greater than 2.5 times upper limit of normal (ULN) Renal: Creatinine no greater than 1.5 times ULN Cardiovascular: No significant cardiac disorder Other: No significant skeletal or endocrine disorders No clinical evidence of severe osteoporosis and/or history of osteoporotic fracture No other prior malignancy except basal cell skin cancer or carcinoma in situ of the cervix No psychiatric or addictive disorders