Estrogen exposure fails to link breast, bone density to breast cancer
4 March 2005
Estrogen exposure may not be the mechanism connecting breast density to risk of breast cancer, research published in the Journal of the National Cancer Institute suggests.
"Mammographic breast density and bone mineral density (BMD) are markers of cumulative exposure to estrogen," Karla Kerlikowske (University of California, San Francisco) and fellow investigators say.
Following research indicating that women with high mammographic breast density or high BMD are at increased risk of breast cancer, the team conducted a cross-sectional study with 15,254 women aged 28 years or older who had undergone screening mammography and hip or spine BMD measurement in the previous 2 years.
A nested case-control study was also performed with 208 women with breast cancer and 436 healthy individuals.
In total, 3105 women were given an American College of Radiology Breast Imaging Reporting and Data System (BI-RADS) category result, while 644 women had a mammographic density reading.
Analysis revealed that neither BI-RADS breast density, nor percentage breast density significantly correlated with hip or spine BMD. Moreover, no relationship was detected between risk of breast cancer and hip or spine BMD in the patients.
In contrast, women with breast density in the highest sextile (66.8% or higher) were 2.7 times more likely to develop breast cancer than those in the lowest sextile (less than 23.9%) for density, the authors report. Taking into consideration hip or spine BMD did not alter this correlation, they add.
"Breast density is strongly associated with increased risk of breast cancer, even after taking into account reproductive and hormonal risk factors, whereas BMD, although a possible marker of lifetime exposure to estrogen, is not," Kerlikowske et al therefore conclude.
"Thus, a component of breast density that is independent of estrogen-mediated effects may contribute to breast cancer risk."
J Natl Cancer Inst 2005; 97: 368-374
http://jncicancerspectrum.oupjournals.org/cgi/content/abstract/jnci;97/5/368
© 2008 CMG
"Mammographic breast density and bone mineral density (BMD) are markers of cumulative exposure to estrogen," Karla Kerlikowske (University of California, San Francisco) and fellow investigators say.
Following research indicating that women with high mammographic breast density or high BMD are at increased risk of breast cancer, the team conducted a cross-sectional study with 15,254 women aged 28 years or older who had undergone screening mammography and hip or spine BMD measurement in the previous 2 years.
A nested case-control study was also performed with 208 women with breast cancer and 436 healthy individuals.
In total, 3105 women were given an American College of Radiology Breast Imaging Reporting and Data System (BI-RADS) category result, while 644 women had a mammographic density reading.
Analysis revealed that neither BI-RADS breast density, nor percentage breast density significantly correlated with hip or spine BMD. Moreover, no relationship was detected between risk of breast cancer and hip or spine BMD in the patients.
In contrast, women with breast density in the highest sextile (66.8% or higher) were 2.7 times more likely to develop breast cancer than those in the lowest sextile (less than 23.9%) for density, the authors report. Taking into consideration hip or spine BMD did not alter this correlation, they add.
"Breast density is strongly associated with increased risk of breast cancer, even after taking into account reproductive and hormonal risk factors, whereas BMD, although a possible marker of lifetime exposure to estrogen, is not," Kerlikowske et al therefore conclude.
"Thus, a component of breast density that is independent of estrogen-mediated effects may contribute to breast cancer risk."
J Natl Cancer Inst 2005; 97: 368-374
http://jncicancerspectrum.oupjournals.org/cgi/content/abstract/jnci;97/5/368
© 2008 CMG
