Digital mammography analysts adopt wait-and-see attitude

Studies have failed to provide a slam dunk for digital mammography over traditional film x-rays, according to a recent technology assessment report from the ECRI group.

ECRI, a nonprofit health services research agency based in Plymouth Meeting, PA, found that digital mammography's ability to detect breast cancer provides no significant improvement over film mammography.

The report reviewed three previously published screening trials that have compared the two technologies: the study by Lewin et al published in the September 2002 issue of the American Journal of Roentgenology as well as the Oslo I and Oslo II screening trials, said Robert Maliff, associate director of the Health Systems Group at ECRI. The group's technology assessment arm published the report in June.

A review of the three large trials indicated no statistically significant differences in detection rates between x-ray and digital mammography.

The technology report comes at an opportune time. Many hospitals, for marketing reasons, are lining up to offer top-of-the-line women's services and are contemplating investments in the new technology, Maliff said. Those investments could have steep price tags, as digital mammography systems can cost up to three times as much as film systems.

"While digital costs considerably more than film, there are a lot of people that point to digital's advantages such as the ease with which electronic images can be stored and retrieved," said Dr. Etta Pisano, chief of breast imaging at the University of North Carolina and principal investigator for the American College of Radiology Imaging Network protocol 6652 trial comparing digital versus film-screen mammography.

The ACRIN 6652 Digital Mammographic Imaging Screening Trial (DMIST) protocol is the most recent study to compare the two modalities, with nearly 50,000 participants. It was not included in the ECRI report.

While current research indicates that digital mammography may be able to reduce recall rates as well as follow-up procedures, possibly offsetting the high cost of the technology, more evidence is needed to confirm these benefits. Potential purchasers should wait for the published results of the DMIST Trial, according to Maliff.

ACRIN had announced in November of 2003 that the DMIST trial had reached its enrollment goal of 49,500 participants and was closed to further enrollment, according to the National Cancer Institute Web site. Publication of the study's first results had been expected by the end of 2004. Accrual is now complete, and results will be presented at the ACRIN meeting in Washington, DC, in mid-September, according to Pisano.

"I hope that before people jump to digital mammography that they would wait until results of the ACRIN DMIST trial are published. I hope that they get the evidence before they actually adopt new technology. The results will be coming out very soon, so they won't have to wait that long," Pisano said.