Mammographic density - a useful biomarker for breast cancer risk in epidemiologic studies

Abstract

We describe mammographic density and how it is associated with breast cancer risk, what mammographic density represents biologically, as well as evidence that it is associated with breast cancer risk factors and is modifiable. Mammographic density has a large unused potential in mammographic screening programs. Currently mammographic density is being used as a biomarker or surrogate endpoint for breast cancer risk in a number of studies, and we discuss the rationale for doing this, as well as the challenges involved. A major challenge is the need for an automated method that can yield an even more precise estimate of the dense areas in the breast. Currently the most widely used methods are various computer-assisted methods. These are reader intensive, but so far the methods that yield the highest estimates for breast cancer risk. Once a robust automated method for assessing mammographic density or breast density is developed, this measure will probably become even more widely used, not just in epidemiology, but also in screening programs and in clinical practice.