The Digital Mammographic Imaging Screening Trial (DMIST), involving 49,500 women in the United States and Canada, will compare digital mammography to standard film mammography to determine how this new technique compares to the traditional method of screening for breast cancer. Digital mammography uses computers and specially designed detectors to produce a digital image of the breast that can be displayed on high-resolution monitors.

Daniel Sullivan, M.D., who is coordinating the trial for the NCI, said that "digital mammography has the potential to provide better detection of early breast cancer, but a large study is needed to really determine whether digital mammography is better than conventional mammography and, if it is better, how large the difference is."

ACRIN is an NCI-sponsored network of physicians, scientists, and medical institutions that have joined together to conduct clinical trials of new medical imaging technologies. The total cost of the digital mammography trial will be $26.3 million.

"This study represents ACRIN's most ambitious undertaking, and certainly the most important," according to Bruce J. Hillman, M.D., ACRIN network chair. "The results of this trial will guide women's breast care into the future."

"Standard mammography has been the most studied screening technology over the past 40 years," said the study's Principal Investigator Etta D. Pisano, M.D. "What we have here is a well-proven technology, film mammography, and one that is in its infancy, not as well studied yet, digital mammography. We want to make sure that digital mammography is at least as good as standard mammography at finding early breast cancer before it is widely used."

Dr. Pisano, with the department of radiology, University of North Carolina Hospital, Chapel Hill, said experts suspect that the difference between digital and film mammography may not be large, but they believe a large study is needed to compare the two techniques when used in screening women without symptoms.

One possible advantage of digital mammography, she said, is that it may be more effective in detecting cancers in women with dense breasts because it has improved contrast resolution. In addition, Dr. Pisano said, two smaller previous studies have indicated that digital mammography may result in fewer women called back for work-up of suspicious breast lesions.

"If this is true, we also want to learn how important this would be to women," she said. Secondary aims of the study address the impact of false positives on health-related quality of life and the cost-effectiveness of digital mammography Although the equipment for digital costs more than film mammography, there may be fewer call-backs or additional office visits with the new technique and this would save money as well as lessen patients' concerns, Dr. Pisano said. The ACRIN digital mammography image database will be an important resource for developers of computer-aided diagnosis (CAD) and image processing software, she added.

A total of 19 institutions in the United States and Canada will take part in the study. The investigators plan to accrue 49,500 women volunteers into the study in the next 18 months. Women will only be entered into the study at the time of their regular screening mammogram. Each woman will then be followed for several years after receiving both digital and conventional mammograms.

R. Edward Hendrick, Ph.D., with the department of radiology, Northwestern University, Chicago, Ill., is co-principal investigator of the study and Martin Yaffe, Ph.D., department of imaging research, University of Toronto, Ontario, Canada, is lead physicist. The Center for Statistical Sciences at Brown University, Providence, R.I. will provide statistical coordination for the study under the direction of Constantine Gatsonis, Ph.D. Dennis Fryback, Ph.D., at the University of Wisconsin at Madison will direct the health-related quality of life analysis and Anna Tosteson, Sc.D., at Dartmouth Medical School, Hanover, N.H. will direct the cost-effectiveness evaluation. Data/image collection and study coordination is being performed at the American College of Radiology, ACRIN headquarters, located in Philadelphia, Pa.

For a list of institutions participating in the study and contact information, check the study Web site, http://www.dmist.org The study will open to enrollment at many of the centers on Monday, October 15. Interested women may contact the centers now, directly, to learn how to participate in this study. At present, GE Medical Systems, Fuji Medical Systems, Fischer Imaging, and LORAD have developed digital mammography systems that will be tested in the trial. The Food and Drug Administration currently has approved only the GE system for clinical use.

To read a detailed interview with Dr. Etta Pisano about this study, please go to http://newscenter.cancer.gov/behindnews/digitmamm.html.

Backgrounders and downloadable images related to mammography are also available at http://newscenter.cancer.gov/behindnews.

For more information about cancer, visit the NCI's Web site at http://www.cancer.gov.