To make matters worse, breast density isn't one of those things a woman or her physician can guess at on the basis of a woman's size, shape or medical history. Women with dense breasts -- meaning that their breasts have lots of ductal and connecting tissue that shows up as opaque on a mammogram -- appear to be evenly distributed throughout the female population. And so are women with "non-dense" breasts, which are largely made up of fatty tissue. These women's breasts appear filled with fine, transparent filaments on a mammogram.
UCLA breast cancer specialist Dr. Patricia Ganz says that as scientists debate how to recalibrate the Gail Model and how best to measure breast density, some physicians have already begun to use the new research findings in guiding women who are fearful of developing the disease and pondering their options. For these physicians and their patients, the remaining uncertainty makes little difference: Patients, who make the final decision, often rely on their gut instincts, rather than hard numbers, in making their decision, Ganz says. And physicians, armed with a broad reading of a woman's breast density, already know enough to add that bit of information to the mix.