Mammographic density and breast cancer risk in Chinese women.

Abstract Abstract #4081 Introduction: Mammographic density has been widely accepted as an important breast cancer risk factor. Women with high mammographic density are believed to have an elevated risk of breast cancer. However, no such association has been shown in native Chinese women so far. We carried out a matched case-control study to evaluate the relationship between mammographic density and the risk of breast cancer among Chinese women in a province of Northern China. Method: Cases included 220 women histologically confirmed with breast cancer at a cancer hospital in Northern China between 2005 and 2007. Each case was matched to a control subject with the similar age (within two years old) who attended the same hospital in the same year and diagnosed as benign breast disease or normal breast. Mammograms were the films used for diagnosis. Breast density was evaluated according to Wolf parenchyma patterns through digitalized normal Medio-Lateral Oblique (MLO) mammography view without knowledge of diagnosis. Risk factor information was obtained from archival database of patient-provided information. Results: Compared to women with low-risk (N1 and P1) mammographic parenchymal patterns, those with high-risk patterns (P2 and DY) had an increased risk of breast cancer (odds ratio = 1.9; 95% confidence interval: 1.1 - 3.2) after adjustment for body mass index, age at menarche, and number of full-term pregnancies. There was no statistically significant difference in this association between premenopausal and postmenopausal women. Conclusion: These results indicate that high mammographic density is associated with the risk of breast cancer in native Chinese women. A larger scale study with the validated computer-assisted mammographic density measurement method is being carried out to further confirm this association. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4081.