21% Breast Cancers Missed on Mammogram

The ability to detect breast cancer by mammogram readings misses 21% of cancers even when the radiologist were dealing with a known lump according to a recent study.

Diana Migloretti, a researcher at the Group Health Center for Health Studies in Seattle reported the findings of her team recently in the Journal of the National Cancer Institute.

The study evaluated 123 radiologists who looked at 36,000 diagnostic mammograms from 1996 through 2003 at 72 US facilities. These were diagnostic rather than screening mammograms, meaning that in each case the radiologist was dealing with a known lump. Earlier studies had found variation in the reading of screening mammograms but the new research found inconsistencies even when a lump was known to be present.

“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” Miglioretti said in a telephone interview reported by Reuters.