Román M, et al. - Using data from the Breast Cancer Screening Program in Spain (1996–2015), researchers investigated how the risk of breast cancer is influenced by alterations in mammographic density over time. From 117,388 women first screened at age 50–54 and underwent at least two screening tests, individual level data were obtained and analyzed. An increased breast cancer risk was noted in relation to an increase in density category, and the decreased risk was seen in relation to a decrease in density, compared with women who continued to be in the same BI-RADS (breast imaging reporting and data system) category. Findings revealed a shift in BI-RADS density category in a modest proportion of women. The risk of breast cancer was modulated by alterations in mammographic density. Women at a differential risk were also identified by mammographic density changes. For risk-based screening strategies, women could be targeted by using two longitudinal measures of BI-RADS density.