Correlation of automated volumetric mammographic breast density with non-herditary risk factors for breast cancer – the future of personalised screening.

Mammographic breast density has recently been shown to be an independent risk factor for breast cancer. This study examines the association of breast density with more established demographic, reproductive and lifestyle risk factors. Asymptomatic women (N=617) who attended mammographic screening in our hospital between December 2015 and April 2017 and fulfilled the inclusion criteria were recruited. They completed a questionnaire regarding their demographics, reproductive history and lifestyle characteristics. Mammographic breast density was obtained using an automated volumetric breast density assessment software (QUANTRATM). The women were divided into pre-menopausal and post-menopausal groups. Pearson correlation coefficient was used to assess the relationship between breast density and continuous variables within the respective groups. The groups were further divided into high and low breast density categories using the median as threshold. The association between high and low density categories within each group and categorical variables were assessed with either Fisher’s exact or chi-square test; and the association with continuous variables was assessed with two-tailed t-test. Breast density was significantly correlated with parity (r=-0.12; p=0.046) and weight (r=-0.35; p<0.0001) for post-menopausal women. Post-menopausal women exhibited increased breast density when parity >0 (OR=2.0; p=0.012). Significant differences were demonstrated between high density (HD) and low density (LD) categories for age at menarche (HD=12.8; LD=12.4; p=0.041) within the pre-menopausal group and for age (HD=58.6; LD=60.5; p=0.011), weight (HD=54.8; LD=62.0; p<0.0001), parity (HD=2.1; LD=2.4; p=0.0036) and primipara age (HD=27.2; LD=25.9; p=0.016) within the post-menopausal group. Pre-menopausal women had higher breast density with later age of menarche. Post-menopausal women had higher breast density with younger age, lower parity and weight, having children and higher primapara age. These important associations are useful in developing breast cancer prevention and personalised screening strategies.