After a long delay, the Food and Drug Administration is on the verge of issuing revised guidelines that could enable a new generation of mammography devices to come to the market. The devices rely on digital imaging, a technique experts say offers clearer, more detailed pictures of some breast tissue than traditional X-ray film.
Proponents of digital mammography say that it is particularly effective in viewing dense portions of the breast. Dense breast tissue occurs in women of all ages but is more frequent in younger women. ''With a digital image, you can magnify an area and adjust the contrast at a computer workstation so that dense tissue that appears virtually white on film reveals more detail,'' said Dr. Robert Smith, director of cancer screening for the American Cancer Society.
But companies seeking to market the devices which X-ray the entire breast have been delayed by a bottleneck in the Food and Drug Administration, which has not approved any digital mammography systems even though it issued an initial set of guidelines to the manufacturers in July 1996. Manufacturers must comply with the guidelines in order to receive the agency's approval to market their devices.
Some are critical of the way the agency is handling the matter.
''They have moved excessively slowly, dampening enthusiasm for a development that could be helpful to women,'' said Dr. Martin Yaffe, a professor of medical biophysics and medical imaging at the University of Toronto and an expert in new techniques for breast imaging. Dr. Yaffe's research has contributed to the development of the new systems, but he says he has no financial connection to any manufacturers of the devices.
''It's just a mammogram -- not a vastly new procedure,'' Dr. Yaffe said. ''The new systems just replace film with an electronic detector.''Continue reading the main story
In August, the agency conceded that its original guidelines were flawed. ''The F.D.A.'s guidance did not take into account the variability in the way radiologists read mammograms,'' said Brian Casey, editor of Diagnostic Imaging Scan, a medical-imaging industry newsletter. ''It wasn't possible for manufacturers to comply, as the agency more or less admitted when it decided to revise the criteria in August.''
Robert J. Doyle, a reviewer at the agency, said officials there were responding to critics and hoped to release new guidelines in about a month.
Dr. Susan Alpert, director of the F.D.A.'s office of device evaluation, disagreed that the agency had been slow to act. ''This is a high-impact decision,'' she said. ''It divides the women who go away for a year from the women who need follow-up. We have to be sure digital mammography provides a reliable assessment before we let those women leave for 12 months.''
Dr. Alpert said she is particularly concerned about the skills of those who will read the digital mammograms. ''How do we train people to use this new information so we don't lose the gain we have from film-screen mammograms,'' she said. ''As a woman, patient, doctor and regulator, I think this question is critically important.''
Dr. Edward Sickles, a professor of radiology at the University of California School of Medicine in San Francisco, who participated in the August panel convened by the agency to discuss guideline revisions, disputed Dr. Alpert's contention. ''Radiologists know what mammograms look like, and they can learn to read new ones,'' he said. ''The problem is not radiologists; it's the F.D.A. They are dragging their heels.''
Breast cancer is the most commonly diagnosed cancer in women in the United States. About 180,000 new cases have been discovered this year, said Dr. Smith of the cancer society. Though he would like to see digital mammography approved, he said he believed that the agency was being duly cautious. ''The F.D.A. needs to satisfy itself that the accuracy of the new method is as good as conventional methods,'' Dr. Smith said. ''Based on conversations I've had, I suspect that the F.D.A. and manufacturers will soon sort out their differences, and that companies will then be able to bring products to market.'' He predicted that several systems would come out in 2000.
Dr. Smith also cautioned that, although the new technology offers many benefits, the devices were not revolutionary: ''It's still mammography, however improved.''
Fran Visco, president of the National Breast Cancer Coalition, a patient-advocate group in Washington, expressed reservations about the new systems' costs, expected to be about four times those of traditional mammography units. ''We think they are a step forward,'' Ms. Visco said, ''but we'd prefer an inexpensive global alternative -- a low-tech, low-cost blood test that all women could use.''Continue reading the main story