This isn't your mother's mammogram.
It seems we live in a time when everything's going digital – televisions, cell phones, pagers – even mammograms.
Clearly, women would appreciate an alternative to traditional mammograms, which compress and then x-ray the breast.
“It's not everybody's favorite,” said Barbara Croft, director of the biomedical imaging program at the National Cancer Institute. “It's a real issue that everybody would like to get around.”
Although no new technology is set to replace film mammography as the prime tool in detecting breast cancer, new devices including digital mammography, known as DM, are promising to serve as important complements.
DMs are faster than film mammograms and doctors can manipulate the images. By magnifying the images, doctors can better view possible calcifications, or the tiny calcium deposits that may indicate a small tumor. Without that tool, doctors suspicious of a possible tumor are more likely to call back patients, including women without breast cancer. DM promises to cut the rate of false-positives, now estimated between five and 20 percent.
The new technology also lets doctors store images in a computer so the files can be copied or sent electronically to radiologists thousands of miles away. And without film, doctors don't have to worry about scratched or misplaced negatives.
In a joint study of nearly 7,000 women by the University of Colorado and the University of Massachusetts, DM was found to detect cancer in nine women missed by traditional film mammography. However, 16 cancers detected by film mammography were missed by DM and eight were missed by both. The study showed a slightly lower call-back rate for DM, 12 percent compared to 15 percent.
At last week's annual meeting of the Radiological Society of North America's in Chicago, where the joint study was unveiled, doctors also released a study on DM and computer-aided detection, known as CAD. In its first clinical test of nearly 13,000 women, CAD increased breast cancer detection in asymptomatic women by 20 percent, according to the study.
“The challenge in diagnosing early breast cancer is detecting very subtle abnormalities on the mammogram,” said Timothy W. Freer, director of the Women's Diagnostic and Breast Health Center in Plano, Texas, and head of the CAD study. “CAD simply enhances our ability to detect these abnormalities at the earliest possible time.”
“While digital has not yet proven to be better than film mammography in detecting cancers, it is likely to improve rapidly,” said John Lewin, director of breast imaging research at the University of Colorado Health Sciences Center.
Since January, when the Federal Drug Administration approved the first and only DM machine, General Electric has installed about 100 units for clinical and commercial use worldwide, including 60 in the United States. So why aren't more hospitals and clinics biting? The machine's cost, at $500,000, is about five times the cost of traditional mammography machines.
“There's no question digital mammography is a very good tool but the problem right now is it's very expensive,” said Robert Smith, director of cancer screening at the American Cancer Society in Atlanta.
But GE points out that over five years, using DMs can be cost-effective. DM cuts exam time in half, allowing increased volume, and because it doesn't require the use of film, chemicals or storage space, it reduces costs.
Although DM is not the only new breast cancer detection technology being tested, it has the most promise, doctors say. Magnetic resonance imaging or MRIs, nuclear injections and ultrasounds – they are all being studied as the wave of the future in breast cancer detection. Even the heat seeking technology responsible for the Star Wars' program has found its way into clinical trials at prestigious cancer institutes.
MRIs and ultrasounds are now tapped as a second exam for women with questionable mammogram results. And although they might be better at detecting differences between benign and malignant tumors, they cannot detect microcalicifications. And they are expensive. The tests themselves cost $300 to $400, six times as much as mammograms, and it's doubtful whether medical facilities could afford to replace $85,000 mammogram machines with $1 million MRI equipment.
In 1997, a Long Island company acquired rights to heat-seeking technology invented by California's Jet Propulsion Laboratory and used for the Star Wars program to use as a breast cancer detection tool. The technology created to spot Soviet missile launches uses infrared sensors and a camera to detect changes in blood flow in the breast and the presence of nitric oxide, two hallmarks of cancer. The FDA approved the device, known as the BioScan System, for marketing in December. Since the summer, there have been small trials at three cancer institutes.
“This device might find its role as an add-on to mammography,” said Terry Button, a metaphysicist at Stoneybrook, where 30 pre-biopsy patients have taken part in a clinical trials. But it's still too early to tell exactly how effective the screening is and when it will be available, he added.
Although some of the new methods in detecting cancer might hold water in the future, there's skepticism in the medical community since the procedures are still in the experimental phase. In the meantime, doctors say traditional mammography is the best method – and the only proven one – for detecting breast cancer.
“When the first one is pretty good, it's hard to show something better,” said Croft.