The Researchers call for breast density a cancer risk ignored

Currently, most women learn that they have a lot of dense breast tissue only because it can be difficult for radiologists to see trouble spots on their mammograms, sometimes requiring a second round of the breast-squashing X-rays. Dense tissues appear light on X- ray film, the same color as a tumor, creating a problem radiologists liken to "looking for a black cat on a dark night." By contrast, fat appears dark on the X- ray film, making tumors or precancerous lesions easier to see.

It's difficult for a woman to determine on her own whether she has a lot of dense tissue in her breasts. Women under 50 generally have a higher percentage of dense tissue than women over 60, and leaner women tend to have denser breasts than overweight women, but there is significant variation among individuals. The only reliable way to find out is to undergo a mammogram, and even that isn't foolproof: Radiologists estimate the percentage of dense tissue from looking at a two-dimensional picture, but the estimate is both imprecise and not commonly shared with patients.

Diane Balma seemingly had little reason to worry about breast cancer. She was just 30 - 10 years too young for a routine mammogram - with no family history of the disease. When she discovered a lump in her breast 12 years ago, the radiologist reassured her that it was probably nothing and "I wouldn't lose any sleep over it."

But a biopsy revealed Balma had an aggressive form of cancer, forcing her to undergo six rounds of chemotherapy and the removal of both breasts before she regained her health. "If I had taken a wait and watch approach, I would be dead," said Balma, now public policy director for Susan G. Komen for the Cure, a Dallas-based breast cancer advocacy group.

It turns out Balma did have a crucial cancer risk that most women and their doctors seldom discuss: Her breasts were loaded with ligaments, milk duct lining, and other tissues that are more prone to developing tumors than the fat that predominates in many women's breasts. Researchers at the Ontario Cancer Institute reported last month that women with dense breasts are nearly three times more likely to get breast cancer than other women, accounting for a quarter of all breast cancers in women under 56.

Woman and doctors need to pay more attention to breast density, said Dr.Karla Kerlikowske of the Veterans Affairs Medical Center in San Francisco, a leading authority on dense breast tissue. She and her colleagues are developing an easy-to-use test to accurately gauge women's breast density so that those with large volumes of dense tissue can get more frequent screening, perhaps using sophisticated digital mammograms in which potentially cancerous cells are easier to see.

"The time has come to acknowledge breast density as a major risk factor for breast cancer," Kerlikowske wrote in an editorial accompanying the Canadian study in the New England Journal of Medicine.

In truth, researchers have known since the 1970s that dense breast tissue was linked to cancer, but that has had little impact on the way doctors discussed cancer with their patients. A widely used questionnaire that estimates breast cancer risk, called the Gail model, didn't even include breast density until recently.

"Even though we've kind of known that breast density is a risk factor, nobody has really used it" to estimate individual women's risk, said Dr.

Elsie Levin, medical director of the Faulkner-Sagoff Breast Imaging and Diagnostic Center at Boston's Faulkner Hospital.

Partly, that's because doctors have been unsure what to do for women who have dense breasts but have not been diagnosed with cancer. Most women under age 40 have dense breasts, but statistically, they are expected to account for only about 5 percent of the 178,000 people who will be diagnosed with breast cancer this year. As a result, insurance companies would never pay for a vast expansion of mammograms for such a low-risk group. Some doctors, based on a physical exam, do urge women who seem to have exceptionally dense breasts to get mammograms before they turn 40.

For women 40 and older, until recently, doctors didn't have an alternative to the film mammogram if the dense tissue made tumors invisible in large sections of the breast. Finally, in October 2005, a large-scale study called DMIST showed that tumors are easier to spot in dense breasts using digital mammograms - a computerized system that allows the radiologist to zoom in on spots much the way a digital camera does. However, the study wasn't large enough to tell doctors at what age women with dense breast tissue should get digital mammograms.

Source: www.iht.com