title: Mammographic breast density during hormone replacement therapy: differences according to treatment.
abstract: OBJECTIVE
  Our purpose was to investigate the effects of various hormone replacement regimens on mammographic breast density.
  
  
  METHODS
  Mammographic density was recorded in women participating in a population-based screening program. All women were nonusers of hormone replacement therapy at first mammogram and thereafter reported continuous use of the same treatment: estrogen alone (n = 50) or estrogen in cyclic (n = 75) or continuous (n = 50) combination with progestogen. Mammographic density was quantified according to the Wolfe classification.
  
  
  RESULTS
  An increase in mammographic density was much more common among women receiving continuous combination hormone replacement therapy (52%) than among those receiving cyclic (13%) and estrogen-only (18%) treatment. The increase in density was apparent already at first visit after the start of hormone replacement therapy. There was little change in mammographic status during long-term follow-up.
  
  
  CONCLUSIONS
  Regimens of hormone replacement therapy were shown to have different effects on the normal breast. There is an urgent need to clarify the biologic nature and significance of a change in mammographic density during treatment and, in particular, its relation to symptoms and breast cancer risk.
authors.affiliation: Department of Obstetrics and Gynecology, Karolinska Hospital, Stockholm, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Lundström
authors.forename: B
authors.initials: B
authors.lastname: Wilczek
authors.forename: Z
authors.initials: Z
authors.lastname: von Palffy
authors.forename: G
authors.initials: G
authors.lastname: Söderqvist
authors.forename: B
authors.initials: B
authors.lastname: von Schoultz
mesh_terms: D000328:Adult; D000368:Aged; D001940:Breast / Q000033:anatomy & histology*; D015914:Estrogen Replacement Therapy / Q000009:adverse effects*; D004967:Estrogens / Q000008:administration & dosage; D005260:Female; D006801:Humans; D008327:Mammography; D008875:Middle Aged; D011372:Progestins / Q000008:administration & dosage
chemical_list: D004967:Estrogens; D011372:Progestins