▸ Aromatase inhibitors. “Bone loss is clearly associated with breast cancer therapies,” said Dr. LeBoff. Aromatase inhibitors can lead to bone loss of about 2.6% per year, though long-term data are not yet available. Gonadotropin-releasing hormones can lead to bone loss of 4%–6% per year. Ovarian failure can lead to bone loss of about 8% per year. Oophorectomy is associated with bone loss of 11% per year.