title: Effects of tibolone and continuous combined hormone therapy on mammographic breast density and breast histochemical markers in postmenopausal women.
abstract: OBJECTIVE
  To compare changes in mammographic density and the expression of markers of proliferation (Ki67) and apoptosis (Bcl-2) after 1 year of treatment with tibolone and continuous conjugated equine estrogens combined with medroxyprogesterone acetate (CEE-MPA).
  
  
  METHODS
  Comparative, randomized, evaluator-blinded study.
  
  
  METHODS
  City research hospital.
  
  
  METHODS
  Thirty-seven postmenopausal women.
  
  
  METHODS
  Tibolone (2.5 mg; n = 18) or continuous conjugated estrogens (0.625 mg) combined with medroxyprogesterone acetate (5 mg; n = 19) for 1 year.
  
  
  METHODS
  Mammographic density (BI-RADS density score), expression of immunohistochemical markers Ki67 and Bcl-2.
  
  
  RESULTS
  Mean breast density score decreased significantly from 2.22 to 1.67 in the tibolone group, compared with a significant increase in the CEE-MPA-treated group from 1.84 to 2.63. Ki67 expression decreased in 12 of 15, increased in 2 of 15, and remained unchanged in 1 of 15 subjects in the tibolone group, compared with 1 of 19, 15 of 19, and 3 of 19 subjects, respectively, in the CEE-MPA group. Bcl-2 expression decreased in 12 of 15, increased in 2 of 15, and remained unchanged in 1 of 15 subjects in the tibolone group, compared with 5 of 19, 9 of 19, and 5 of 19 subjects, respectively, in the CEE-MPA group.
  
  
  CONCLUSIONS
  One-year treatment with tibolone induced a decrease in breast density, with a reduction in proliferation and a stimulation of apoptosis, whereas 1-year treatment with CEE-MPA induced an increase in breast density, with stimulation of proliferation and inhibition of apoptosis, indicating that tibolone effects on the breast are different from those of CEE-MPA.
authors.affiliation: Department of Obstetrics and Gynecology, University of Chile, Santiago, Chile. imvaldivia@entelchile.net
authors.forename: Isabel
authors.initials: I
authors.lastname: Valdivia
authors.forename: Italo
authors.initials: I
authors.lastname: Campodónico
authors.forename: Augusto
authors.initials: A
authors.lastname: Tapia
authors.forename: María
authors.initials: M
authors.lastname: Capetillo
authors.forename: Arturo
authors.initials: A
authors.lastname: Espinoza
authors.forename: Pablo
authors.initials: P
authors.lastname: Lavín
mesh_terms: D015415:Biomarkers / Q000032:analysis; D001940:Breast / Q000187:drug effects / Q000378:metabolism*; D004359:Drug Therapy, Combination; D004966:Estrogens, Conjugated (USP) / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism*; D008327:Mammography; D017258:Medroxyprogesterone Acetate / Q000627:therapeutic use*; D008875:Middle Aged; D009652:Norpregnenes / Q000627:therapeutic use*; D017698:Postmenopause; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D016037:Single-Blind Method
chemical_list: D015415:Biomarkers; D004966:Estrogens, Conjugated (USP); D019394:Ki-67 Antigen; D009652:Norpregnenes; D019253:Proto-Oncogene Proteins c-bcl-2; D017258:Medroxyprogesterone Acetate; C027385:tibolone