title: Breast density changes in a randomized controlled trial evaluating bazedoxifene/conjugated estrogens.
abstract: OBJECTIVE
  Breast density is associated with an increased risk of breast cancer. This study assessed changes in mammographic breast density after 24 months of treatment with bazedoxifene (BZA)/conjugated estrogens (CE) in postmenopausal women.
  
  
  METHODS
  This was an ancillary study in a subset of nonhysterectomized postmenopausal women enrolled in a randomized, double-blind, placebo-controlled, and active-controlled phase 3 study. Treatments evaluated were BZA 20 mg/CE 0.45 mg, BZA 20 mg/CE 0.625 mg, raloxifene 60 mg, and placebo. Women who were eligible for participation in the ancillary study must have completed 24 months of treatment and have mammograms at baseline and 24 months. The left craniocaudal views from each mammogram pair were digitized and analyzed by a radiologist who was blinded to treatment arm and mammogram date. The percent breast density was determined using validated software.
  
  
  RESULTS
  Mammogram pairs were obtained from 507 evaluable participants (mean age range, 55.2-56.3 y). The mean changes (95% CI) in mammographic breast density from baseline to 24 months were comparable among groups (-0.39% [-0.69 to -0.08], -0.05% [-0.38 to 0.27], -0.23% [-0.54 to 0.08], and -0.42% [-0.72 to -0.11] for BZA 20 mg/CE 0.45 mg, BZA 20 mg/CE 0.625 mg, raloxifene 60 mg, and placebo, respectively). These reductions from baseline were statistically significant for BZA 20 mg/CE 0.45 mg and placebo. The effect of both BZA/CE doses on breast density was generally consistent among subgroups based on age, body mass index, and years since menopause.
  
  
  CONCLUSIONS
  Treatment with BZA 20 mg/CE 0.45 mg or BZA 20 mg/CE 0.625 mg for 24 months did not affect mammographic breast density in this population of postmenopausal women.
authors.affiliation: Department of Radiology, University of Virginia Health System, Charlottesville, VA 22908, USA. JAH7W@virginia.edu
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Harvey
authors.forename: JoAnn V
authors.initials: JV
authors.lastname: Pinkerton
authors.forename: Edmund C
authors.initials: EC
authors.lastname: Baracat
authors.forename: Harry
authors.initials: H
authors.lastname: Shi
authors.forename: Arkadi A
authors.initials: AA
authors.lastname: Chines
authors.forename: Sebastian
authors.initials: S
authors.lastname: Mirkin
mesh_terms: D001940:Breast / Q000187:drug effects / Q000473:pathology*; D000071060:Breast Density; D001943:Breast Neoplasms / Q000139:chemically induced / Q000000981:diagnostic imaging* / Q000517:prevention & control; D004311:Double-Blind Method; D004966:Estrogens, Conjugated (USP) / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007211:Indoles / Q000008:administration & dosage* / Q000009:adverse effects; D042361:Mammary Glands, Human / Q000002:abnormalities; D008327:Mammography; D008875:Middle Aged; D010919:Placebos; D017698:Postmenopause; D020845:Selective Estrogen Receptor Modulators / Q000008:administration & dosage / Q000009:adverse effects
chemical_list: D004966:Estrogens, Conjugated (USP); D007211:Indoles; D010919:Placebos; D020845:Selective Estrogen Receptor Modulators; C447119:bazedoxifene