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Digital mammography may detect breast cancer more accurately than
standard film-based mammography in certain women, according to
preliminary results of a study funded by the U.S. National Cancer Institute (NCI). The study found that women with
dense breasts, those who are pre- or perimenopausal (women who had a last menstrual period within 12 months of their mammograms),
or those who are younger than age 50 may benefit from having a digital rather than a film mammogram. However, digital
mammography does not appear to be more effective in other women.
"These results will give clinicians better guidance and greater choice in deciding which women would
benefit most from various forms of mammography," said senior author, Etta Pisano, MD, of the University of
North Carolina at Chapel Hill, in an NCI news release.
To conduct the Digital Mammographic Imaging Screening Trial (DMIST), Dr. Pisano and her colleagues gave 49,528
American and Canadian women with no signs or symptoms of breast cancer both digital mammography and film
mammography examinations. Two different radiologists independently reviewed each of the examinations. Confirmation of
breast cancer or absence of the disease was determined through available
breast biopsy information within 15 months of a woman's
entry into the study or through follow-up mammography ten months or later after study entry.
According to the study results, digital and standard film mammography had similar accuracy rates for
many women. However, digital mammography was significantly better at screening women in any
of the following categories:
- under age 50, regardless of what level of breast tissue density they had
- of any age with very dense or extremely dense breasts
- pre- or perimenopausal women of any age (defined as women who had a last menstrual period within 12 months of their mammograms)
The study showed no benefit for post-menopausal women over age 50 who did not have dense breast tissue.
Study results were announced in September 2005 at a meeting of the American College of Radiology Imaging Network (ACRIN) in
Pentagon City, Virginia, and were available in the September 16, 2005 online edition of The New England
Journal of Medicine. The study will appear in the October 27, 2005 print edition of the journal.
Digital (computerized) mammography is similar to standard mammography in that x-rays are used to produce
detailed images of the breast. While x-ray films are produced with standard mammography, with digital
mammography, the breast image is captured using a special electronic x-ray detector, which converts the
image into a digital picture for review on a computer monitor. The digital mammogram is then stored on a
computer. With digital mammography, the magnification, orientation, brightness, and contrast of the image
may be altered after the exam is completed to help the radiologist more clearly see certain areas.
Standard film mammography detects about 85% of all breast cancers. However, mammography can be more difficult on
women with dense breast tissue, which can obscure breast cancer on traditional mammogram films. With digital
mammography, physicians are able to manipulate breast images, and as the current study suggests, this could
lead to the more accurate detection of breast cancer in women with dense breast tissue. Younger women are more
likely than older women to have dense breast tissue.
"This digital mammography study demonstrates how new technologies are expanding our ability to detect breast cancer
earlier in more women. The study corroborates NCI's commitment to exploring advanced technologies in a wide range
of clinical applications and the critical role they can play in making cancer a manageable disease," said NCI
Director Andrew C. von Eschenbach, MD, in the NCI news release.
According to the NCI, General Electric Medical Systems, Fuji Medical Systems, Fischer Imaging, and Hologic digital mammography
systems were each tested in the study. All systems except for the Fuji system are approved by the U.S.
Food and Drug Administration and are available for clinical use in the United States.
Additional Resources and References
- The study, Diagnostic Performance of Digital versus Film Mammography for Breast Cancer Screening - The Results of the
American College of Radiology Imaging Network (ACRIN) Digital Mammographic Imaging Screening Trial (DMIST) was published
in the September 16, 2005 online edition of The New England Journal of Medicine and will appear in the October 27,
2005 print edition.
- This article references the National Cancer Institute news release, "Digital Mammography Trial Results
Announced: Women with Dense Breasts, Women Younger than 50, and Those Who are Perimenopausal May Benefit
from Digital Mammograms," http://www.cancer.gov/
- To learn more about digital mammography, please visit http://www.imaginis.com/breasthealth/digital_mammo.asp
- For general information on mammography, please visit http://www.imaginis.com/breasthealth/mammography.asp
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