Automated volumetric breast density measures: differential change between breasts in women with and without breast cancer

Kathleen R Brandt,Fang Fang Wu,Christopher G Scott,John A Shepherd,Steven R Cummings,Lin Ma,Diana L Miglioretti,Aaron D Norman,Karla Kerlikowske,Matthew R Jensen,Carrie Hruska,Stacey J Winham,Amir P Mahmoudzadeh,Natalie J Engmann,Celine M Vachon

doi:10.1186/s13058-019-1198-9

Abstract

BackgroundGiven that breast cancer and normal dense fibroglandular tissue have similar radiographic attenuation, we examine whether automated volumetric density measures identify a differential change between breasts in women with cancer and compare to healthy controls.MethodsEligible cases (n = 1160) had unilateral invasive breast cancer and bilateral full-field digital mammograms (FFDMs) at two time points: within 2 months and 1–5 years before diagnosis. Controls (n = 2360) were matched to cases on age and date of FFDMs. Dense volume (DV) and volumetric percent density (VPD) for each breast were assessed using Volpara™. Differences in DV and VPD between mammograms (median 3 years apart) were calculated per breast separately for cases and controls and their difference evaluated by using the Wilcoxon signed-rank test. To simulate clinical practice where cancer laterality is unknown, we examined whether the absolute difference between breasts can discriminate cases from controls using area under the ROC curve (AUC) analysis, adjusting for age, BMI, and time.ResultsAmong cases, the VPD and DV between mammograms of the cancerous breast decreased to a lesser degree (− 0.26% and − 2.10 cm3) than the normal breast (− 0.39% and − 2.74 cm3) for a difference of 0.13% (p value < 0.001) and 0.63 cm3 (p = 0.002), respectively. Among controls, the differences between breasts were nearly identical for VPD (− 0.02 [p = 0.92]) and DV (0.05 [p = 0.77]). The AUC for discriminating cases from controls using absolute difference between breasts was 0.54 (95% CI 0.52, 0.56) for VPD and 0.56 (95% CI, 0.54, 0.58) for DV.ConclusionThere is a small relative increase in volumetric density measures over time in the breast with cancer which is not found in the normal breast. However, the magnitude of this difference is small, and this measure alone does not appear to be a good discriminator between women with and without breast cancer.

Highlights

Given that breast cancer and normal dense fibroglandular tissue have similar radiographic attenuation, we examine whether automated volumetric density measures identify a differential change between breasts in women with cancer and compare to healthy controls
The breast density measure most widely used in clinical practice is the Breast Imaging Reporting and Data System (BI-RADS) [6], which consists of four categories of increasing density reflecting the risk of tumor masking and breast cancer [7, 8]
Study population The participating studies included two retrospective casecontrol studies nested within large breast screening facilities at Mayo Clinic Rochester (MCR) and in the Bay Area that participate in the San Francisco Mammography Registry (SFMR) [8]

Summary

Introduction

Given that breast cancer and normal dense fibroglandular tissue have similar radiographic attenuation, we examine whether automated volumetric density measures identify a differential change between breasts in women with cancer and compare to healthy controls. The breast density measure most widely used in clinical practice is the Breast Imaging Reporting and Data System (BI-RADS) [6], which consists of four categories of increasing density reflecting the risk of tumor masking and breast cancer [7, 8]. It is a subjective [9,10,11] woman-level assessment of overall density determined by the interpreting radiologist. This study investigates the potential for the automated density measures calculated for each breast separately to detect potentially relevant unilateral breast changes in density over time

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