title: Effect of raloxifene on mammographic density and breast magnetic resonance imaging in premenopausal women at increased risk for breast cancer.
abstract: BACKGROUND
  Mammographic density is a risk factor for breast cancer. Mammographic density and breast magnetic resonance imaging (MRI) volume (MRIV) assess the amount of fibroglandular tissue in the breast. Mammographic density and MRIV can be modulated with hormonal interventions, suggesting that these imaging modalities may be useful as surrogate endpoint biomarkers for breast cancer chemoprevention trials. We evaluated the effect of raloxifene on mammographic density and MRIV in premenopausal women at increased risk for breast cancer.
  
  
  METHODS
  Mammograms and MRI were obtained at baseline and after 1 and 2 years of 60 mg raloxifene by mouth daily for 27 premenopausal women. Mammographic percent dense area was calculated using a semiquantitative thresholding technique. T(1)-weighted spoiled gradient-echo MRI with fat suppression was used to determine breast MRIV using a semiautomatic method. Mean change in mammographic density and median change in MRIV were assessed by the Wilcoxon signed-rank test.
  
  
  RESULTS
  No significant change in mammographic density was seen after treatment with raloxifene. Mean change after 1 year was 1% [95% confidence interval (95% CI), -3 to +5] and after 2 years was 1% (95% CI, -2 to +5). MRIV decreased on raloxifene. Median relative change in MRIV after 1 year was -17% (95% CI, -28 to -9; P = 0.0017) and after 2 years was -16% (95% CI, -31 to -4; P = 0.0004).
  
  
  CONCLUSIONS
  In high-risk premenopausal women, mammographic density did not change on raloxifene, whereas MRIV significantly declined. Our findings suggest that MRIV is a promising surrogate biomarker in premenopausal women at increased risk for breast cancer and should be investigated further in breast cancer prevention trials.
authors.affiliation: Medical Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA. je95@georgetown.edu
authors.forename: Jennifer
authors.initials: J
authors.lastname: Eng-Wong
authors.forename: Jennifer
authors.initials: J
authors.lastname: Orzano-Birgani
authors.forename: Catherine K
authors.initials: CK
authors.lastname: Chow
authors.forename: David
authors.initials: D
authors.lastname: Venzon
authors.forename: Jianhua
authors.initials: J
authors.lastname: Yao
authors.forename: Claudia E
authors.initials: CE
authors.lastname: Galbo
authors.forename: Jo Anne
authors.initials: JA
authors.lastname: Zujewski
authors.forename: Sheila
authors.initials: S
authors.lastname: Prindiville
mesh_terms: D001943:Breast Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000517:prevention & control; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008327:Mammography / Q000379:methods*; D017697:Premenopause / Q000187:drug effects*; D011379:Prognosis; D020849:Raloxifene Hydrochloride / Q000008:administration & dosage*; D012307:Risk Factors; D020845:Selective Estrogen Receptor Modulators / Q000008:administration & dosage*; D013997:Time Factors
chemical_list: D020845:Selective Estrogen Receptor Modulators; D020849:Raloxifene Hydrochloride