Study: More False Positives on Mammograms From Younger Radiologists

Young, recently trained radiologists reading mammogram X-rays are far more likely to erroneously tell women they might have breast cancer than older more experienced radiologists, according to researchers at the University of Washington School of Medicine.

In a study of interpretations of 8,734 mammograms from 2,169 women over an eight-year period, the younger radiologists gave two to four times more false-positive readings than the older radiologists, the researchers reported in the Journal of the National Cancer Institute.

The incidences of false-positive readings among the radiologists ranged from 2.6 percent to 15.9 percent. After adjustments were made for differences in patient, radiologist, and testing characteristics, the range of false-positive readings was 3.5 percent to 7.9 percent.

There was also a wide variation in how often different radiologists noted masses, calcifications, and other lesions. The radiologists also differed in their diagnoses and recommendations for additional screenings and biopsies.

Younger women who were menopausal and using hormone therapy were more likely to have a false-positive reading, reported the researchers. Also, false-positive readings were more likely for women who had mammograms in the 1990s than those 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 litigation for delayed detection of breast cancer," wrote the authors.

The differences in the rates of false-positive readings could be accounted for by the age of the radiologist, gender and number of years since graduating from medical school. Younger and more recently trained radiologists gave two to four times more false-positive readings than those who graduated more than 15 years prior to the study.

Researchers also found that false-positive readings were reduced by about 70 percent when radiologists compared current mammogram images with past images. This finding suggests that women benefit from returning to the same screening facility for their screenings.

Other sources: Journal of the National Cancer Institute