Computer-Aided Breast Screens Lacking
More Mammography False Positives Seen
April 4, 2007 -- Radiologists are increasingly relying on computers to help them read screening mammograms, but the practice has not improved the detection of invasive breast cancer, a new study shows.
Researchers concluded that computer-aided detection (CAD) is far from enhancing breast cancer detection and has led to increases in what they termed “potential harms,” including false positives and unnecessary biopsies.
The study was the most comprehensive analysis of computer-aided detection ever conducted, including more than 429,000 mammograms read at 43 screening centers located in New Hampshire, Colorado, and the state of Washington.
“We found that, among large numbers of diverse facilities and radiologists, the use of computer software designed to improve the interpretation of mammograms was associated with significantly higher false positive rates, recall rates, and biopsy rates and with significantly lower overall accuracy in screening mammography,” researcher Joshua Fenton, MD, MPH, and colleagues write in the April 5 New England Journal of Medicine.
The promise behind computer-aided detection was that the computer programs would help radiologists find cancers.
The computer programs read digitized versions of screening mammograms and identify areas of concern for review by the radiologist.
One study showed that within three years of approval by the FDA in 1998, roughly 10% of the mammography facilities in the United States were using CAD.
In an effort to better understand the benefits and risks associated with CAD, Fenton and colleagues assessed mammography data for 222,135 women screened between 1998 and 2002, including 2,351 women who were diagnosed with breast cancer within one year after screening.
Seven of the 43 screening facilities included in the study began using CAD during the study period, and outcomes from these centers after they implemented CAD were compared with outcomes prior to its use.
The researchers concluded that CAD did not result in significant improvements in cancer detection rates, but it did increase the number of false-positive mammograms, resulting in significantly more patient callbacks and biopsies.
More Experience Needed
Robert Smith, PhD, who is director of screening for the American Cancer Society, tells WebMD that while there are problems with CAD, “we don’t want to throw the baby out with the bathwater.”