The research was led by a UCSF team and is published in the March 2 issue of the Journal of the National Cancer Institute.
Screening mammograms are the type most women get. These images are designed to discover any cancer that might be hidden in women with no breast symptoms. Women who have a history of breast cancer or other symptoms -- or who experience symptoms at the time of their exam -- receive diagnostic mammograms. After two to five asymptomic years, their physicians will usually revert to screening mammography.
Study findings showed that the more experienced physicians not only properly identified cancer, they also were 50 percent less likely to falsely characterize a mammogram as abnormal. In addition, the study found dramatic variability in physician accuracy. For example, physicians on average detected 77 percent of cancers, but for individual physicians the detection rate ranged from 29-97 percent. The average false positive rate was 10 percent, while the rate for individual physicians ranged from 1-29 percent.
According to the UCSF researchers, it has already been well documented in scientific literature that patient characteristics -- such as breast tissue density -- can be negatively associated with mammogram accuracy and those characteristics largely cannot be changed. They chose, therefore, to focus their study on what physician characteristics could be associated with accuracy. They studied more than 1.2 million mammograms paired with data from statewide cancer registries in four states.
The study found that physicians who read a greater number of mammograms identified cancers with
Contact: Eve Harris
University of California - San Francisco