When Sandra Beckwith, 51, had her recent annual mammogram at the Elizabeth Wende Breast Center in Rochester, New York, she held her breath and gritted her teeth while the technician adjusted the plastic device that squeezes one breast and then the other, spreading its dense glandular tissue apart to get better pictures. For Beckwith, the exam felt exactly the same as usual, but there was one big difference. This time, she didn't have to wait anxiously for results because within seconds, high-quality digital images of Beckwith's breasts were on her doctor's desktop computer so they could be carefully examined for any signs of cancer.

If you are a woman under the age of 50, pre- or peri-menopausal or, like Beckwith, have dense breasts, you may want to opt for this newer type of computerized mammography for your next breast cancer screening, according to a $26 million landmark study of mammography techniques funded by the National Cancer Institute (NCI) and conducted by the American College of Radiology Imaging Network (ACRIN).
"The findings show that digital mammography is better than films at finding breast cancer in these three groups, particularly in women with dense breasts," say Etta Pisano, M.D., a radiologist and breast imaging specialist at the University of North Carolina - Chapel Hill, who was the lead study investigator. Researchers also concluded that for the general population of women, there is no diagnostic advantage of one technique over another.

Increased Accuracy

In the ACRIN study, almost 50,000 women who had no signs of breast cancer were given both digital and conventional mammography exams in 33 sites across the United States and Canada. Each of the exams was interpreted by two radiologists. Some 335 breast cancers were diagnosed. Follow-up exams a year later showed that the sensitivity of digital mammography (its ability to tell if cancer was present) was 15% more accurate than standard film x-rays for women with dense breasts. "More than 65% of the study population fit into one or more of the three groups that showed a benefit with digital mammography," says Pisano.

Experts say there is no way a woman can know if her breasts are dense unless she has had a prior mammogram and was told so. Breast density tends to decrease with age, with younger women having denser breasts. "There is no correlation between size and density," says Melissa Scheer, M.D., a radiologist with Women's Imaging of Northern Westchester, located in Mount Kisco, New York. "If anything, young and thin women tend to have dense breasts, but not all the time," she says.

"Fatty and dense are both normal variants of women's breasts," explains Dr. Ellen Mendelson, Director of Breast Imaging at Chicago's Northwestern Memorial Hospital, one of the ACRIN study sites. "Just like different shoes sizes and eye colors are all normal, these variations are individual signatures that distinguish us as human beings," she says. "Fatty breasts are fine for mammography, but dense breasts can cause problems so supplementation with other imaging techniques is often worthwhile." If they haven't been told so in the past, Mendelson advises women to ask their doctors about the density of their breasts. Another ongoing ACRIN study is examining the use of breast sonograms for women with dense tissue.

Facilitating Second Opinions

It is easier to interpret scans of fatty breasts because the dark background forms a contrast against a mass that is small and white, says Scheer. "It's like looking at a star against a sky at night," she says. In the case of dense breasts, the milk-producing glandular tissue forms a white background, making it more challenging for the radiologist to detect an abnormality. The image quality of digital mammography, in my opinion, is much sharper than film, says Scheer. "I am better able to visualize hard-to-see areas of the breast and provide the most thorough examination possible," she says.

Digital mammography also offers some practical advantages to women and their doctors. Images can be enhanced, magnified or manipulated by the doctor to look more closely at suspicious findings, and they can be sent electronically over the Internet from one office to another with less risk of getting lost. This allows for the possibility of more timely second opinions from other doctors. The new machines also emit slightly less radiation.

According to Scheer, digital mammography cuts the exam time in half for the patient. With conventional film x-rays, it takes at least several minutes to develop the pictures; when multiple images are required, it can take longer. For an anxious woman waiting for results, the minutes feel like hours. "When it was a 'do-over' with film, I always made the leap of worrying about whether I should tell my mother about my breast cancer before or after the surgery," says Beckwith, whose sister has breast cancer.

Because digital mammography only came to market in 2001 and the new machines are significantly more costly (almost one and a half to four times the price of the older ones), only 8% of breast imaging units across the country are digital. This cost is often passed on to the consumer although the amount varies by insurer. In 2005, reimbursement by Medicare for film mammography was $85 compared to $135 for digital mammography. Pisano and her colleagues are still analyzing cost-effectiveness data from the ACRIN study.

According to a spokesman from GE Healthcare, one of several manufacturers making the new machines, units have been installed in more than 40 countries around the world including the Americas, Europe, and Asia. Some countries haven't yet adopted the new technology because they were waiting for more evidence of their greater effectiveness, says Pisano.

"No woman should delay getting a mammogram because digital equipment isn't available," cautions James P. Borgestede, M.D., a radiologist in Colorado Springs, Colorado who chairs the Board of Chancellors of the American College of Radiology (ACR). "That would be the worst thing they could do," he says. "It's important for women who can't get a digital exam to understand that we have been screening successfully with analog for 35 years and they need to be screened," says Pisano.

"The use of mammography over the last 30 years has been associated with a decrease in mortality through its use over the long term, not just one mammogram," says Mendelson. "It is the mainstay of breast cancer screening." But its limitations, she says, have been greatest in women with dense breasts. "Medical imaging and diagnostic radiology is moving toward a digital mode like everything else. We've seen this happen with medical records moving away from paper and film toward electronic modalities in every area of medicine. There isn't any going back," she says.

According to NCI, breast cancer is the most common non-skin cancer in women and the second leading cause of cancer-related death in the United States. An estimated 211,240 women will be diagnosed with breast cancer this year. The U.S. Preventive Services Task Force recommends that all women over the age of 40 receive a screening mammogram every one to two years. According to the American Cancer Society, women below the poverty level are less likely to have had a mammogram within the last two years than those living above it.