Abstract B95: Higher breast density is positively associated with larger tumor size and lymph node metastasis: A cross-sectional study of 910 Korean breast cancer patients
Authors: Lee Jong won , Cho Ja Young , Ahn Sei-hyun 
Published: January 2014

Although many western studies have demonstrated high breast density as a strong risk factor for breast cancer, it is poorly understood whether breast density differentially affects the diverse phenotypes of breast cancer. We examined the association between various tumor characteristics and mammographic breast density in women with breast cancer.

We conducted a cross-sectional analysis in 910 Korean women diagnosed with in situ or invasive breast cancer to evaluate the associations between breast density and tumor size, lymph node (LN) status, lymphatic or vascular invasion, histologic grade, estrogen receptor (ER), progesterone receptor (PR), HER2, p53, and CK5/6. Breast density was classified as fatty (percent density less than 50% by a computer-assisted thresholding program, named “Cumulus TM”; n = 470) or dense (percent density 50% or more; n = 440) for the cancer-free breast at the time of operation. A single pathologist measured all tumor markers. Blinded to the tumor markers' status, percent densities were also calculated by a single rater. Logistic regression was used to examine whether the relationships were modified by adjustment for body mass index, age at diagnosis, age at first birth, menopausal status, history of breast-feeding, and breast cancer staging.

The mean age was 48 (range 20-82) years old and mean percent density was 49.1% (SD = 15.2%: normally distributed, Kolmogorov-Smirnov test p=0.32). Women with a tumor size &gt;0.5cm were more likely to have dense breasts compared with women with a tumor size &lt;=0.5 cm (ORadj = 4.2, 95% CI = 1.6-11.2 for tumor sizes 0.6-1.0cm; ORadj = 3.4, 95% CI = 1.4-8.2 for tumor sizes 1.1-1.5cm; ORadj = 3.3, 95% CI = 1.4-7.9 for tumor sizes 1.6-2.0cm; and ORadj = 2.0, 95% CI = 0.7-5.5 for tumor sizes 2.1cm or more). An association between LN positivity and percent density had borderline significance (ORadj = 1.8, 95% CI = 0.997-3.215 for positive LN status). Percent density was not significantly associated with lymphatic or vascular invasion (p = 0.77), ER (p = 0.39), PR (p = 0.83), HER2 (p = 0.40), p53 (p=0.22), and CK5/6 (p = 0.62). An inverse association was suggested between tumor grade and percent density (OR = 0.56, 95% CI = 0.33-0.97), but insignificant after the adjustment (ORadj = 0.65, 95% CI = 0.31-1.37).

These results suggest that breast density is associated with tumor size and LN status. Additional studies are needed to address whether these associations are due to just density masking the detection of some tumors, biological causation, or both.

Citation Format: Jong won Lee, Ja Young Cho, Sei-hyun Ahn. Higher breast density is positively associated with larger tumor size and lymph node metastasis: A cross-sectional study of 910 Korean breast cancer patients. [abstract]. In: Proceedings of the Eleventh Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2012 Oct 16-19; Anaheim, CA. Philadelphia (PA): AACR; Cancer Prev Res 2012;5(11 Suppl):Abstract nr B95.