NEJM: Single CAD reading could replace double mammo readings
Fiona J. Gilbert, FRCR, from the Aberdeen Biomedical Imaging Centre in Aberdeen, Scotland, and colleagues conducted a trial to determine whether the performance of a single reader using CAD would match the performance achieved by two readers.
The researchers randomly assigned 31,057 women undergoing routine screening by film mammography at three centers in England to double reading, single reading with CAD, or both double reading and single reading with CAD, at a ratio of 1:1:28. The primary outcome measures of the equivalence trial were the proportion of cancers detected according to regimen and the recall rates within the group receiving both reading regimens.
They found that the proportion of cancers detected was 87.7 percent for double reading and 87.2 percent for single reading with CAD. The overall recall rates were 3.4 percent for double reading and 3.9 percent for single reading with CAD—the difference between the rates was small but significant, according to the authors.
Gilbert and colleagues found that the estimated sensitivity, specificity and positive predictive value for single reading with CAD were 87.2 percent, 96.9 percent and 18 percent, respectively; while the corresponding values for double reading were 87.7 percent, 97.4 percent and 21.1 percent. There were no significant differences between the pathological attributes of tumors detected by single reading with CAD alone and those of tumors detected by double reading alone, the researchers said.
The authors said that their “results suggest that single reading with CAD is an alternative to double reading; whether to adopt this technology is a question of cost-effectiveness.”
They added that “the results of this study are applicable to programs in which double reading is standard practice. Where single reading is standard practice, CAD has the potential to improve cancer-detection rates to the level achieved by double reading.”
“Double reading is a method for increasing cancer detection commonly used in European screening programs. However, it is used by few practices in the United States because it is time-consuming and because of a shortage of radiologists focused on breast imaging,” commented Ronald A. Castellino, MD, chief medical officer for the Bedford, Mass-based Hologic.