The accuracy of mammograms is highly dependent on the radiologist reading them, not only in finding easy-to-miss tumors but in diagnosing visible lumps, reports Reuters. "On average, 21 percent of breast cancers were missed and 4.3 percent of women underwent a biopsy even though they didn't have breast cancer," said the lead researcher.
The study looked at the work of 123 radiologists over 7 years, at 72 different labs. They found a range in sensitivity—the ability to accurately detect cancer—of 27% to 100%. False positives ranged from 0 to 16%. "It's not necessarily the mammographer's fault," the researcher warned. "It's the limitation of the technology." The most accurate radiologists tended to be those at academic facilities or who specialize in breast imaging, which is rare in the US.