BETHESDA, MarylandThe first large, multicenter study to compare
digital vs standard film mammography has begun enrolling patients. The Digital
Mammographic Imaging Screening Trial (DMIST) will study 49,500 women at 18
centers in the United States and one center in Canada.
"We want to make sure digital mammography is at least as good as
standard mammography at finding early breast cancer," said principal
investigator Etta D. Pisano, MD, professor of radiology, University of North
Carolina, Chapel Hill. "We expect there will be an advantage, but none of
the early studies has shown a real benefit of digital over film."
The American College of Radiology Imaging Network, a National Cancer
Institute-supported clinical trials group, will conduct the $26.3 million
study. Women will be enrolled at the time of their regular screening mammogram.
Researchers expect to complete patient accrual in 18 months, and participants
will be followed for at least 1 year.
Each woman will receive a two-view digital mammogram and a two-view film
mammogram of each breast. Each of the two screenings will be interpreted
independently, and patients will undergo workups based on abnormal findings
from either exam. One year later, researchers will repeat the screenings using
the same protocol.
"Truth regarding breast cancer status for all patients will be
determined either through the results of breast biopsy, if that occurs, or as a
result of 1 year of follow-up without clinical evidence of disease," NCI
said. "All pathologic specimens will be reread by an expert breast
pathologist."
The radiation dose will be the same for both digital and standard mammograms in the study. "We can certainly get the same information out
of a digital mammogram at a lower dose than film, but we might be able to get
more information at a higher dose," Dr. Pisano said.
In addition to the primary endpoint of efficacy, researchers will seek to
determine the effect of breast density on the diagnostic accuracy of digital
mammography. Other secondary objectives of DMIST include:
- Determining the effects of patient characteristics (such as age,
lesion type, pathologic diagnosis, hormonal status, and family history) on the
diagnostic accuracy of digital mammography. - Assessing the effect of the reduced false-positive tests that are
expected with digital mammography on participants’ health-related quality of
life and personal anxiety. - Comparing the diagnostic accuracy of soft copy vs printed film
display for digital mammography. - Comparing the image quality and breast radiation dose in digital vs
screen-film mammography. - Determining the temporal variations in image quality, breast
radiation dose, and other quality-control parameters in the participating study
centers.