Digital mammograms are 15 percent to 28 percent more effective at detecting breast tumors in women under 50, those with dense breast tissue, and women entering menopause, according to a landmark study comparing the techniques.
Those three groups, which substantially overlap, account for about 55 percent of all U.S. women. Women in those groups are more likely to have fast-growing, aggressive tumors for which early detection and treatment are crucial for a cure.
“These are cancers that kill women and (many) were missed on film,” said Dr. Etta Pisano of the University of North Carolina, Chapel Hill, who led the study of nearly 50,000 women.
Wider use of the digital technique, which now accounts for only about 8 percent of all mammograms, “should save more lives,” she said.
“There is no question in my mind that this will be the mammography of the future,” said Dr. Lawrence Bassett, a breast-imaging expert at the University of California, Los Angeles’ Jonsson Comprehensive Cancer Center.
Mammography is the most important way of detecting breast tumors, which affect an estimated 211,000 American women each year, killing 40,000.
Conventional mammograms detect about 70 percent of tumors in older women, but only about 55 percent in younger women and those with dense breast tissue.
As women age, their breasts generally acquire a higher proportion of less-dense, fatty tissue that makes detection of tumors easier.
Pisano presented the results Friday at a meeting of the American College of Radiology Imaging Network in Arlington, Va., and they were published online the same day by the New England Journal of Medicine.
For the remaining 45 percent of women, primarily post-menopausal women, digital mammography was about as effective as the conventional form, the study found.
But Dr. Yuri Parisky, the senior mammographer for the University of Southern California School of Medicine, cautioned that the study was performed with first-generation digital equipment and “the advances since this study have been pretty profound.”
Improvements have been made in software, digital detectors for recording X-rays, workstations for displaying data, and in the production of three-dimensional images like those produced by CT scans of other body parts.
“I wish I could afford to have all my units replaced with digital mammography,” he said.
Digital mammography presents a variety of other advantages as well, according to experts such as Dr. Phil Evans of the University of Texas Southwestern Center for Breast Care in Dallas.
Digital images can be enhanced by changing contrasts and magnified to view isolated areas. They require less radiation and are easier to produce, store and transmit.