A new study that enrolled nearly 50,000 women has revealed that digital mammography can detect breast cancer better than conventional film-based mammography in certain groups of women.
Overall, the study showed that conventional film mammography and digital mammography were equally effective.
However, digital mammography performed better for the following groups: Women under 50, women who are premenopausal and perimenopausal and women with dense breasts.
The total of these groups represents at least 50 percent of the general population of women.
Physicians from 33 sites in the United States and Canada participated in the DMIST (Digital Mammographic Imaging Screening Trial).
School of Medicine investigators screened the largest cohort of volunteers in the study, enrolling more than 3,300 patients at the Joanne Knight Breast Health Center.
Scientists announced the results of DMIST at the fall meeting of the American College of Radiology Imaging Network. The study is simultaneously being published online by The New England Journal of Medicine.
The National Cancer Institute funded the DMIST trial.
“From the patient’s perspective, the digital mammogram experience is the same as a conventional mammogram,” said Dione Farria, M.D., assistant professor of radiology and principal investigator for the DMIST study site at the Medical Campus. Both technologies require X-rays and breast compression to obtain an image.
“Unlike conventional film mammography, digital mammography stores a digital image of the breast in a computer,” Farria said. “This allows radiologists to use computer software to manipulate the images in order to optimize their ability to evaluate the breast tissue.”
Farria said the DMIST results do not mean that women who have had conventional mammograms need to go back to their doctors immediately and request a digital mammogram.
“Since only 8 percent of mammography units in the United States are digital units, it will not be possible for all women to receive digital mammograms in the near future,” she said.
“Furthermore, the study showed that digital mammograms did not offer an advantage to all women.”
Researchers emphasize that it is important for women to continue having routine screening mammograms because it has been scientifically proven that conventional mammography saves lives by detecting breast cancers earlier.
“Whether a facility has digital or conventional film mammography is only one factor to consider when choosing a mammography facility,” Farria said.
“The expertise of the radiologists who read the mammograms and the skill of the technologists are probably equally, if not more, important.
While it is highly likely that we are going to see a transition from film to digital mammography, several factors will influence the speed of this change.”
Cost is a potential limiting factor in expanding the use of digital mammography. While a traditional mammography unit typically costs about $75,000-$100,000, digital units with the required computer workstation may costs 3-5 times more.
Since digital mammography is significantly more expensive than conventional mammography, DMIST investigators plan to conduct an analysis of the new technology in the context of its cost-effectiveness.
Researchers are also concerned about the ability of small mammography facilities to raise the capital necessary to convert to digital technology.
In women, breast cancer is the most common malignancy and the second-leading cause of cancer death.
Last year, there were more than 215,000 new cases of invasive breast cancer and over 40,000 breast cancer-related deaths in the United States.
The American Cancer Society estimated that in Missouri in 2004, 4,680 women were diagnosed with breast cancer and 870 women died from it.
More information about the results of the DMIST study may be obtained by calling the Siteman Cancer Center at 747-7222 or (800) 600-3606.