Abstract P1-01-02: Mammographic breast density and magnetic resonance (MR) imaging in women with mammographically occult breast cancer
Authors: Jennifer Chun , Schnabel Freya , Schwartz Shira , Billig Jessica , Gillman Jennifer , Moy Linda 
Published: May 2015

Abstract
Background: Recent data suggests a correlation between mammographically-occult breast cancer (MOBC) and increasing breast density. There is a dearth of information on the assessment of the amount of fibroglandular tissue (FGT) with contiguous MR images through both breasts and background parenchymal enhancement (BPE) in women with MOBC. The purpose of this study was to evaluate the relationship between mammographic breast density (BD), BPE, and FGT in women with MOBC and mammographically evident breast cancer (MEBC).
Methods: The Breast Cancer Database at our medical center was queried for all women who were newly diagnosed with breast cancer between 2010 and 2014. Variables included age, BD, BPE, FGT, tumor characteristics. Statistical analyses included Pearson’s Chi Square Tests.
Results: Out of a total of 1781 women, there were 110 (6%) with MOBC and 1671 (94%) with MEBC. The median age of the cohort was 59 years. Majority of the patients had early stage disease (72%) and invasive ductal carcinoma (61%). There was a higher proportion of women with DCIS with MEBC (22%) compared to women with MOBC (16%) and a higher proportion of invasive lobular carcinoma in women with MOBC (17%) compared to the women with MEBC (10%). Increased mammographic BD was significantly associated with mammographically occult breast cancer (p&lt;0.001). However, BPE (p=0.29) and FGT (p=0.28) were not associated with MOBC. In the MOBC group, there was a higher proportion of women with dense breasts on mammography (74%) compared to women with dense breasts on MRI (48%).
Conclusions: For women who develop mammographically occult breast cancer, there are currently no guidelines regarding recommendations for future screening. Increased breast density reduces the sensitivity of mammography, which compromises the ability to detect meaningful findings. Our study shows that MRI may be less affected by obstacles of sensitivity that is usually associated with mammography. Our results support the use of MRI in women with dense breasts who are at higher risk of developing MOBC. By better understanding the patient population who are more likely to be diagnosed with mammographically-occult breast cancer, we can more effectively select patients who should be screened with breast MRI.
Table 1. Mammographic breast density, BPE, and FGT in study populationVARIABLESTOTAL (N=1781)%MOBC (N=110)%MEBC (N=1671)%P-VALUESMAMMOGRAPHIC BREAST DENSITYPredominantly fatty94633916p&lt;0.001Scattered fibroglandular58738252356240 Heterogeneously dense71547676164846 Extremely dense135914131219 BACKGROUND PARENCHYMAL ENHANCEMENTMinimal741615245915p=0.29Mild22549304819549 Moderate11625132110326 Marked4710584211 FIBROGLANDULAR TISSUEPredominantly fatty91217128423p=0.28Scattered fibroglandular16037244113637 Heterogeneously dense12128203410127 Extremely dense57138144913
Citation Format: Chun Jennifer, Freya Schnabel, Shira Schwartz, Jessica Billig, Jennifer Gillman, Linda Moy. Mammographic breast density and magnetic resonance (MR) imaging in women with mammographically occult breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-01-02.