Dense breasts riskier in younger women
Dense breasts riskier in younger women
4/12/2013
CHICAGO -- The increased risk of cancer for women with denser breasts may be stronger in younger women, researchers reported here.
In a single-center study, breast cancer patients had higher breast density than healthy controls through the age of 50, but the relationship became unclear after that age, Nicholas Perry, MBBS, of the London Breast Institute in England, and colleagues reported at the Radiological Society of North America meeting here.
Perry said this suggests that there's "some form of different biological density mechanism" for women with normal breasts compared with those who get cancer, and it "appears most obvious for younger women."
Perry noted that density "doesn't have to do with size. It's about the amount of fibrous and glandular tissue" -- which does make it hard to predict which women are more likely to have denser breasts.
Debra Copit, MD, of Albert Einstein Medical Center in Philadelphia, who wasn't involved in the study, said breast density may have to do with hormonal effects.
Perry agreed, speculating that some women may be more sensitive to the effects of estrogen and for them, density may be a type of protective mechanism that changes as they age and lose estrogen.
"It's interesting assuming that breast density is a risk factor in and of itself, and that it is not just masking tumors," Copit said.
Perry said it is difficult to tell, but noted it's "not the first time someone has shown that younger women are more vulnerable" to the risks of breast density.
Density is widely accepted to be an independent predictor of breast cancer risk: 13 states have even passed legislation that radiologists must inform women if they have dense breasts and explain their increased risk for cancer.
To clarify the relationship between breast density and cancer risk, Perry and colleagues looked at digital mammograms from 317 women who had breast cancer and compared them with mammograms of 317 healthy controls.
A total of 282 of these pairs also had fully automated breast density readings, which involved an algorithm that differentiated dense tissue from fat and calculated the percentage of dense breast tissue.
Perry noted that the automated density reading may be better than a radiologist's subjective read of a scan: "We're not very good at it, that's the problem," he said.
Using the automated system, the researchers found that cancer cases showed higher breast density than normal controls – but only up to age 50. After that point, there was a non-linear relationship between density and cancer, they reported.
Over the entire course of the study, healthy controls had a significant decline in density with age that followed a linear pattern.
Thus, Perry said, the risk associated with breast density appears to be more relevant to younger women.
He noted that these findings shouldn't "diminish the current American Cancer Society guidelines in any way, but it might add a new facet regarding the possibility of an early mammogram to establish an obvious risk factor, which may then lead to enhanced screening for those women with the densest breasts."
Some women could have a baseline density exam around age 35, Perry said, and those with denser breasts could be followed more closely.
Source: MedPage Today: http://www.medpagetoday.com/MeetingCoverage/RSNA/43244