Doubts cast on digital detection rates

Digital mammography provides no clear-cut improvements over traditional film X-rays in the ability to detect cases of breast cancer, says a new technology assessment report. The technology does, however, offer other benefits, including slightly lower radiation doses for patients, which may prompt its increasing use despite its much higher costs.

Known as "full-field digital mammography," the high-tech equipment records images of the breast electronically instead of on X-ray film. The pictures are stored directly in a computer system, where they can be enhanced, magnified or shared. The digital devices were first approved for marketing in the United States in 2000.

Three large trials of the technology have been completed, with several thousand women receiving digital mammograms in each. No statistically significant differences in detection rates were observed between the x-ray and the new digital technology. The patients in each group experienced identical positioning and compression of the breast.

"The studies that have been done so far haven't provided a 'slam-dunk' for full-field digital mammography," says Robert Maliff, associate director of the Health Systems Group at ECRI, whose Technology Assessment Group published the report. ECRI is a non-profit health services research agency that produces systematic evidence reviews on medical devices, drugs, biotechnologies, procedures, and behavioural health services.