Investigating the relationship between mammographic breast density and triple negative breast cancer in Nova Scotia, Canada

Abstract

The study objectives were to estimate the association between mammographic breast density (MBD) and triple negative breast cancers (TNBC); as well as to estimate the discriminatory ability of MBD, alone and with clinical risk factors, in the screening population. This case-control study consisted of 121 TNBC cases with a full-field digital mammography (FFDM) screen in 2009-2015 in Nova Scotia. The 6807 controls were women with a prior negative FFDM screening mammogram episode. Odds ratios and areas under curves were reported for models generated using two measures of MBD, percent and BI-RADS categories (5th ed.), both separately and in combination. Aside from the two forms of MBD, other variables included self-reported risk factors (menopausal status, hormone replacement therapy use, parity, family history), biopsy history, and derived breast volume. A significant positive association was found between MBD and TNBC in this screening population. The addition of clinical factors to density improved the discriminatory ability of the prediction models.