A new study in the journal Cancer says that women who have been treated for breast cancer have a higher chance of recurrence if they have “dense” breast tissue. And in fact, those with the densest tissue are four times more likely to relapse than those with less dense tissue, the study says.
The research suggest that treatment might be changed for those in the densest group to include radiation, but that those in the less dense group may not need it. More studies are needed before anything would happen, however.
The researchers, from Women’s College Hospital in Toronto, Canada, studied medical records and mammograms of 335 women who had lumpectomies for invasive breast cancer tumors. They categorized the women’s breasts as low, intermediate or high density (using the accepted Wolfe scale, which categorizes breasts with less than 25% dense tissue as low, 25-50% dense tissue as intermediate, and more than 50% dense tissue as high).
Over 10 years, the women in the highest density group had a 21% risk of breast cancer recurrence, vs. a 5% risk for those in the low density group.
Among those who did not have radiation in addition to surgery, the rate of recurrence went up to 40% in women with the highest density breasts.
The researchers are not sure why the densest tissue has the higher rate of recurrence. Several factors may be a part of it: younger women generally have dense breast tissue, and also more often have estrogen-fed cancers. Tumors may be