Accurate diagnoses are directly related to the number of mammograms interpreted by a physician, according to a UCSF study published in the March 6 issue of the Journal of the National Cancer Institute.

The study was done to understand factors that affect quality in mammography. The participants were each given a set of 60 mammograms to interpret. From the U.S., 60 radiologists were divided into three groups: low volume radiologists who read 100 or fewer mammograms per month, medium volume radiologists who read 101-300 mammograms per month, and high volume radiologists who read more than 300 mammograms per month. Joining them were 194 radiologists from the U.K, all high volume readers. The results of two Swedish radiologists were used to compare high volume results but not included in the data analyses.

Sensitivity, or the ability to detect cancer, was higher among the high volume readers than medium and low volume readers. Furthermore, the U.K. high volume readers were as accurate or more accurate than the high volume U.S. readers were. The high accuracy achieved by the U.K. readers is significant, said the authors, because mammograms are far more likely to be followed by biopsies in the U.S. than in the U.K. These results suggest that higher biopsy rates are not necessary to find more cancers, said lead author Laura Esserman, MD, MBA, UCSF assistant professor in residence and director of the Carol Franc Buck Breast Care Center at UCSF.

Overall, high volume readers were shown to have better accuracy they found more cancers and more often were correct in identifying non-malignant abnormalities. Low volume U.S. readers identified fewer abnormalities than any of the high volume readers. High volume U.S. readers were 76 percent and U.K. readers 79 percent accurate; medium volume U.S. readers were 70 percent and low volume U.S. readers 65 percent accurate.

The conditions under which physicians provide mammography vary widely. In both
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Contact: Eve Harris
eharris@pubaff.ucsf.edu
415-885-7277
University of California - San Francisco
5-Mar-2002