BREAST DENSITY AND WHY IT MATTERS

“How can that be?”

An understandable lament when a woman, often young, would be diagnosed with a large breast cancer within months of a “normal” mammogram. We now know most of these women have “dense” breasts, and density would mask an early cancer even with the most advanced mammogram technique. This density has nothing to do with the way the breast looks or feels, so cannot be diagnosed on examination. It has to do with the concentration of fibro-glandular tissue which is only seen on a mammogram. Density has several features, some alarming: First of all, it is a gradient, from virtually none to virtually all fibroglandular. It is divided into four categories for easy management— fatty, scattered, heterogenous and extreme. It cannot be changed by any medical treatment. Nearly half of all women are in the top two categories where increased density makes early diagnosis difficult and unreliable. And as if that were not bad enough, increased density also increases the risk of getting breast cancer. Starting this year Iowa law requires that the radiologist tell the patient her density category in the mammogram letter, along with information, or how to obtain information, on density. For those in the two highest categories it must also inform them of their increased risk of cancer and the masking effect on early diagnosis. So, what should these women do? First of all, continue mammograms on schedule—the cancer may be diagnosed later and larger than most, but it will be diagnosed eventually, perhaps still in time to save your life. Secondly, maintain awareness of your breast anatomy—report any   change to your doctor and insist upon further investigation, even if your mammogram was “normal”. All women regardless of density should talk to their doctor about other risk factors they may be able to change (obesity, inactivity and alcohol). For those in the extreme category additional testing (ultrasound, MRI) can see through the density and provide an early diagnosis. Visit www.densebreast-info.org for updated breast density information. User-friendly and evidence based, it is appropriate for both patients and physicians.