Abstract P5-02-01: The relationship of breast density in mammography and magnetic resonance imaging (MRI) in women with triple negative breast cancer (TNBC)
Authors: Chun J , Schnabel F , Gooch J , Lee J , Jubas T , Goodgal J , Guth A , Moy L 
Published: May 2019

Abstract
Introduction:
TNBC represent 10%–20% of invasive breast cancers. Previous studies showed that TNBC usually present with benign features on mammography, ultrasound and MRI. However, there is a dearth of information on the relationship of mammographic breast density (MBD), background parenchymal enhancement (BPE) and fibroglandular tissue (FGT) on MRI with TNBC. The purpose of this study was to evaluate the relationship between BD, BPE, and FGT in women with TNBC compared to non-TNBC in a contemporary cohort of women with breast cancer.
Methods:
The Institutional Breast Cancer Database was queried for women who had invasive breast cancer and underwent mammography and MRI between (2010-2017). Variables of interest included clinical, pathologic, and imaging characteristics. Statistical analyses included Pearson's Chi Square and logistic regression.
Results:
Of 2224 women, 210 (9%) had TNBC. The median age was 59 years (22-95) and median follow up was 4 years. When we looked at the clinical characteristics of women with TNBC compared to non-TNBC, race, BRCA1,2 status, method of presentation, palpability, histology, grade, and Ki67 were statistically different (Table 1). When we looked at the correlation of MBD, FGT, and BPE for women with TNBC, MBD was correlated with FGT (r=0.64) but weakly correlated with BPE (r=0.22). We found a significant association of low BPE and TNBC compared to the non-TNBCs (p=0.021) (Table 1). In a short period of time, only 8 women with TNBC had a recurrence with no significant association with MBD, BPE, or FGT (Table 1).
Table 1.Imaging Characteristics among TNBC compared to non-TNBCVariableTNBC (N=210)%Non-TNBC (N=2014)%P-valueRace 0.001White13665153376 Black35171749 Hispanic1261156 Asian23111739 Other42191 BRCA1/2 &lt;0.001Positive3025425 Negative897579195 Method of Presentation &lt;0.001Breast exam1125475738 Mammography7737105753 Ultrasound731106 MRI126553 Palpable &lt;0.001Yes1185783342 No9144115258 Histology &lt;0.001DCIS with Microinvasion21382 IDC19693159079 ILC5226913 Invasive Other731176 Invasive Grade &lt;0.001Grade 11131016 Grade 22714111858 Grade 31688650126 ER &lt;0.001Positive00189194 Negative2101001226 PR &lt;0.001Positive00160080 Negative21010041221 Ki67 &lt;0.001Median (range)60 (0-99) 10 (0-99) Mammographic Density 0.165Less dense82417846 More dense11959103454 MRI BPE 0.021Low BPE707655564 High BPE222431236 MRI FGT 0.370Less dense475440449 More dense404642151
Conclusions:
In our study population, MBD and FGT did not differ between patients with TNBC compared to non-TNBC. Interestingly, we found a higher proportion of women with lower BPE in the TNBC compared to the non-TNBC group. BPE refers to the amount of enhancing fibroglandular tissue and has been demonstrated to reflect variations in estrogen-mediated vascular permeability. Lower BPE in TNBC may reflect the fact that these tumors are not hormonally sensitive. This may also have implications for radiogenomics, which aims to correlate imaging characteristics with gene expression and genome-related characteristics in tumor biology. Further studies are warranted in looking at these imaging biomarkers and TNBC.
Citation Format: Chun J, Schnabel F, Gooch J, Lee J, Jubas T, Goodgal J, Guth A, Moy L. The relationship of breast density in mammography and magnetic resonance imaging (MRI) in women with triple negative breast cancer (TNBC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-02-01.