Study Shows Certain Groups of Women May Benefit from Digital Mammography

Study Shows Certain Groups of Women May Benefit from Digital Mammography

September 20, 2005 - Digital mammography may be more accurate than conventional film mammography for women younger than 50, women who have dense breasts and women who are pre- or peri-menopausal (meaning they have had at least one menstrual period within the last year), according to a study released online on September 16, 2005 by the New England Journal of Medicine. However, for women overall there was no difference in accuracy between the standard film-based mammography procedure and digital mammography.

Digital Mammographic Imaging Screening Trial
In the Digital Mammographic Imaging Screening Trial (DMIST), 42,760 women in 33 sites in Canada and the United States who did not initially have a breast cancer diagnosis were followed over 15 months. They were evaluated with both digital and film mammography.

The procedure for both standard film mammography and digital mammography is the same. Breast compression is done for both processes.

Digital mammography
Digital mammography captures images in a computer, eliminating the need for actual film storage and allowing for on-screen viewing. These images can then be enlarged, made lighter or darker to see areas of concern better, be studied from different views, and enhanced by computer-assisted detection (CAD) programs. CAD software can analyze the images and highlight any areas of concern that should be studied in more detail.

The DMIST study reports that digital mammograms were more accurate compared to film mammograms in women under 50 years old, in women with dense breasts on mammography, and in women who were pre-menopausal and peri-menopausal.

Mammography is less accurate for women ages 40 to 49 than for women older than 50. In the 40 to 49 age group, regular mammography can often detect breast cancer early and lower their risk of dying from breast cancer by 15 percent to 20 percent. That percentage increases to 25 percent to 30 percent lower risk seen in women ages 50 to 69.

Film mammograms vs. digital mammograms
One of the reasons for that difference is attributed to differences in breast density. Younger women have denser, less fatty breast tissue. Tumors are harder to detect in dense breast tissue when standard film mammography is used. A higher number of false positive readings for breast tumors are reported in standard film mammograms for younger women. After menopause, fatty tissue usually replaces the breast tissue, making breasts less dense and lesions more visible on film mammograms.

Currently, digital mammography is available in only 8 percent of U.S. breast centers. Digital systems cost from 1.5 to 4 times more than film systems - a factor that might delay its widespread availability to patients. While Medicare does cover digital mammograms, digital mammograms are more expensive than film mammograms. Additional training is required for radiologists who use digital mammography.

The ability to easily transmit digital mammography images between institutions across the country and around the world means that health care providers can communicate more easily. Smaller institutions, for example, could benefit from input from larger centers of excellence in the interpretation of images, for example.

Additional Points
It is important to note again that digital and film mammography results were similar for the overall group of women in this trial. The digital mammography showed a benefit for only those women who had very dense breasts, who were under 50 years old, and who were pre- and peri-menopausal. A prior mammogram is needed to determine if you have very dense breasts, and a discussion with your doctor about your mammogram results can help you to understand about your personal breast density.

If you fall into any of these groups, there is still the issue of availability and cost. Film mammography is still an excellent screening tool and should be continued on schedule rather than delaying it to get a digital mammogram. And finally, even if you do fall into these subgroups, you shouldn't need additional screening before your next scheduled mammogram unless you have noticed a change in your breasts or are having a problem. Talk to your doctor about the timing of your next mammogram and the need for scheduling a digital mammogram for your next screening appointment.

These and other points were addressed in a question and answer document from the NCI. Read more

If you have changes in your breast or concerns, you should contact your doctor to discuss the need for additional evaluation.

Comments from the Komen Foundation
Cheryl Perkins, M.D., senior clinical advisor for the Susan G. Komen Breast Cancer Foundation said, "We know that mammography can help to detect breast cancer in its early stages, when there are more treatment options and the chances for survival are better. As a result of the findings in this study, digital mammography may offer the potential to offer younger women and pre- and peri-menopausal women a better opportunity for earlier detection of breast cancer."

This study supports the fact that mammography remains the gold standard for breast cancer screening for most women. Women in the sub-groups identified in this study should discuss their screening options and recommendations with their health care providers.

Recommendations from the Komen Foundation
The Susan G. Komen Breast Cancer Foundation recommends a three-step approach to breast cancer screening that includes, depending upon a woman's age, a combination of mammography, clinical breast exams and breast self-exams.

• Annual mammograms beginning at age 40.
• Clinical breast exam at least every three years beginning at age 20, and annually from age 40 on.
• Monthly breast self-examination beginning by age 20.

Women with a family history of breast cancer or other concerns about their personal risk for breast cancer should consult with a health care provider. Screening tests may need to be done more often and/or started earlier than the Komen Foundation's stated recommendations.

As part of a total approach to breast health, it is also important that women become familiar with their own bodies, play an active role in their own health, and develop a close partnership with their health care providers.

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Sources:

NCI:

Digital Mammographic Imaging Screening Trial

Digital vs. Film Mammography in the Digital Mammographic Imaging Screening Trial (DMIST): Questions and Answers

The Susan G. Komen Breast Cancer Foundation:

Early Detection and screening: Mammography