Assessing the Relationship of Mammographic Breast Density and Proliferative Breast Disease

Increased breast density and a history of benign breast biopsy are both considered risk factors for developing breast cancer. Understanding the specifics of these risk factors and their relationship to each other can lead to a better understanding of a patient's propensity for breast cancer development and improved surveillance strategies. We included 245 women who underwent a benign breast biopsy without atypia between October 2011 and June 2013. Biopsies were performed for suspicious calcifications as well as masses and architectural distortion. Lesions biopsied were divided into two groups: calcified and noncalcified lesions. The patient's breast density was assessed on most recent mammogram and was classified using the American College of Radiology BI-RADS density categories. Based on histologic diagnosis, each case was classified as proliferative or nonproliferative breast disease. The median age of the cohort (n = 245) was 55 years (range, 40-84 years). There were 162 (66%) postmenopausal women in the study. A core biopsy was performed for calcifications in 33.5% cases and for noncalcified lesions in 58% cases. In patients with dense breast tissue, an underlying proliferative histology was found significantly more frequently with calcifications (66.7%) as opposed to noncalcified lesions (35.9%) (RR = 2.3 (1.3-4.0); χ(2) = 8.7; p = 0.003). In nondense breast patients, there was no significant difference (RR = 1.1 (0.7-1.8); χ(2) = 0.1; p = 0.738). In the postmenopausal group, women with dense breasts had proliferative histology significantly more frequently than women with nondense breasts (55.3% versus 38.3%; p < 0.05), regardless of the underlying lesion type. Postmenopausal women with dense breasts who underwent a breast biopsy with benign histology had a significantly higher likelihood of having proliferative breast disease, regardless of underlying lesion type. Women with dense breasts also showed proliferative histology significantly more often for calcifications as opposed to noncalcified lesions.