Validation of a new automated volumetric breast density measurement system as a marker of breast cancer risk

Abstract

Purpose To validate the predictive power for determining breast cancerrisk of an automated breast density measurement system with full-fielddigital mammography (FFDM). Materials and methods Two hundred cancersand 200 controls were imaged with FFDM. Density was measured separatelyon MLO and CC images using an integral automated volumetric breastdensity measurement system (Hologic, Quantra). For each cancer, thecontralateral mammogram was used. Each cancer was matched to a controlcase by date of birth, age at examination and laterality of mammogramused for density determination. Breast density (percentage of fibroglandular tissue) was analyzed by Quantra. Data were analyzedby conditional logistic regression to determine the effect on breastcancer risk. Results The percentage of breast density ranged from6% to 63%. Density declined signifi cantly with age (P <0.001). Overall,there was no significant association of density with risk of breastcancer (P = 0.4). There was a suggestive increase in risk with densevolume higher than 35% (OR = 1.80, 95% CI = 0.96 to 3.39, P = 0.07).There was significant heterogeneity by age in the eff ect of densityon risk (P = 0.04). In women aged <50, density was significantlyassociated with increased risk (P = 0.02), with odds ratios of 6.06,3.98 and 10.59 for density volumes of 15 to 24%, 25 to 34% and =35%respectively, relative to those with <15%. In women aged =50 yearsthere was no association of density with risk (P = 0.5). ConclusionsQuantra automated volumetric breast density measurement is stronglyassociated with breast cancer risk in women aged under 50, but notin women aged =50 years or over.