Effect of raloxifene on mammographic density and breast magnetic resonance imaging in premenopausal women at increased risk for breast cancer.
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.
Eng-Wong
Jennifer
J
Medical Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA. je95@georgetown.edu
Orzano-Birgani
Jennifer
J
Chow
Catherine K
CK
Venzon
David
D
Yao
Jianhua
J
Galbo
Claudia E
CE
Zujewski
Jo Anne
JA
Prindiville
Sheila
S
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
D020845:Selective Estrogen Receptor Modulators; D020849:Raloxifene Hydrochloride