I have dense breasts. And ever since the surgeon who performed my breast reduction surgery more than 10 years ago told me about the composition of my breast tissue, I have been a bit obsessed with how my breasts feel. Good thing -- because I ended up with breast cancer two years ago as a result of my own at-home monitoring. And now I wonder if my cancer was influenced by the density characterizing the tissue that fills my breasts.Canadian researchers are reporting in a groundbreaking study that women with dense breasts, like me, are five times more likely to develop breast cancer than whose whose breasts have a lot of fatty tissue. It's long been knows that dense breasts inhibit the effectiveness of X-ray mammograms -- and perhaps delay diagnosis -- but now it's clear that breast density is a risk factor all on its own.
"Breast density is an 'extremely important' factor that accounts for up to one-third of all cases," says lead investigator Norman Boyd of the Campbell Family Institute for Breast Cancer Research at Princess Margaret Hospital in Toronto
Dr. Boyd says breast size has no bearing on density, and women cannot determine their degree of density on their own.
Density is the percentage of breast tissue not clearly visible on X-ray mammography. While fat shows up dark on mammograms, dense tissue appears light -- making it difficult to spot tumors.This is not all bad news, say the authors of the study who report that density decreases with age. This research opens up a whole new avenue of prevention because the factors that affect density -- hormones, diet, exercise, environmental exposures -- can hopefully be altered. Also, this is very important news for women because it provides them with new and better information. And now, women who know they have dense breasts can insist on more frequent screening.
This research is published in Thursday's edition of the New England Journal of Medicine.
