These findings, culled from the real-world setting, bolster evidence from earlier studies that examined radiologist variability using test sets of mammograms. In this study, Joann G. Elmore, M.D., of the University of Washington School of Medicine, Harborview Medical Center, and her coworkers examined results from 24 community radiologists' interpretations of 8,734 screening mammograms from 2,169 women over an eight-and-a-half year period.
The authors found wide variation in how frequently different radiologists noted masses, calcifications, and other suspicious lesions. For example, one radiologist did not observe any calcifications, while another radiologist noted calcifications in more than 20% of the films read. The radiologists also varied widely in their diagnostic interpretations and recommendations for additional screens and biopsies.
The rate of false-positive readings among the radiologists ranged from 2.6% to 15.9%. However, after adjustment for differences in patient, radiologist, and testing characteristics, the range of false-positive rates narrowed to 3.5% to 7.9%. Women who were younger, were premenopausal, were using hormone replacement therapy at the time of the mammogram, had a family history of breast cancer, or had had a previous biopsy were more likely to have a false-positive result.
A false-positive result was also more likely for women who had mammograms in the 1990s than women who had mammograms in the 1980s. "This increase in false-positive rates may be related to the fear of malpractice litigation, given the prominence in North America of malpractice litigat
Contact: Linda Wang
Journal of the National Cancer Institute