title: Breast density changes associated with postmenopausal hormone therapy: post hoc radiologist- and computer-based analyses.
abstract: OBJECTIVE
  The aim of this study was to assess the impact of oral hormone therapy (HT) on breast density in postmenopausal women and to compare the use of computer-based automated approaches for the assessment of breast density with reference to traditional methods.
  
  
  METHODS
  Low-dose oral estrogen (1 mg) continuously combined with drospirenone (2 mg) was administered to postmenopausal women for up to 2 years (26 treatment cycles, 28 d/cycle) in a randomized, placebo-controlled trial. This post hoc analysis assessed the changes in breast density measured from digitized images by two radiologist-based approaches (Breast Imaging Reporting and Data System score and interactive threshold) and one computer-based technique (heterogeneity examination of radiographs). Correlations of temporal changes in breast density with changes in serum estradiol levels, biochemical markers of bone metabolism, and bone mineral density at the spine and femur were also assessed.
  
  
  RESULTS
  Breast density assessed by the radiologist-based approaches increased significantly from baseline in the HT group (P < 0.01), with significant divergence from placebo at 2 years (P < 0.01). Heterogeneity examination of radiograph score by computer-based technique was unchanged in the HT group and decreased significantly with placebo (P < 0.001) to produce a significant group divergence (P < 0.05). Changes in mammographic markers by radiologist- and computer-based approaches correlated with each other in the HT group (P < 0.01) but not in the placebo group.
  
  
  CONCLUSIONS
  HT for 2 years in postmenopausal women significantly increased radiologist-assessed breast density compared with placebo, in addition to significant changes in estrogen levels, markers of bone metabolism, and bone mineral density. Computer-automated techniques may be comparable with and offer advantages over traditional methods.
authors.affiliation: Department of Computer Sciences, University of Copenhagen, Copenhagen, Denmark. madsn@nordicbioscience.com
authors.forename: Mads
authors.initials: M
authors.lastname: Nielsen
authors.forename: Paola C
authors.initials: PC
authors.lastname: Pettersen
authors.forename: Peter
authors.initials: P
authors.lastname: Alexandersen
authors.forename: Gopal
authors.initials: G
authors.lastname: Karemore
authors.forename: Jakob
authors.initials: J
authors.lastname: Raundahl
authors.forename: Marco
authors.initials: M
authors.lastname: Loog
authors.forename: Claus
authors.initials: C
authors.lastname: Christiansen
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D000736:Androstenes / Q000008:administration & dosage; D015519:Bone Density; D024042:Collagen Type I; D004958:Estradiol / Q000097:blood; D015914:Estrogen Replacement Therapy; D004967:Estrogens / Q000008:administration & dosage; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D008327:Mammography; D008875:Middle Aged; D000451:Mineralocorticoid Receptor Antagonists / Q000008:administration & dosage; D015675:Osteocalcin / Q000097:blood; D010446:Peptide Fragments / Q000097:blood; D010455:Peptides; D017698:Postmenopause; D011347:Procollagen / Q000097:blood; D011857:Radiographic Image Interpretation, Computer-Assisted
chemical_list: D000736:Androstenes; D024042:Collagen Type I; D004967:Estrogens; D000451:Mineralocorticoid Receptor Antagonists; D010446:Peptide Fragments; D010455:Peptides; D011347:Procollagen; C052929:collagen type I trimeric cross-linked peptide; D015675:Osteocalcin; D004958:Estradiol; C035144:drospirenone