Missed Breast Cancer: What Can We Learn?

Multiple studies have shown that screening mammography helps to reduce mortality and morbidity from advanced breast cancer. However mammography does have its own limitations, and unfortunately, there are a fair number of false-negative mammograms. We are all aware that the sensitivity of mammography is inversely proportional to the breast density. With many states passing mandatory breast density reporting legislation, there has been an emphasis on using additional and alternative screening methods such as whole breast ultrasound and screening magnetic resonance imaging. Many cancers are simply not detected on mammography, even in retrospect. However, many of the breast cancers are actually visible retrospectively on the prior mammogram. It is these small and often subtle cancers that are perceptible but often missed, that provide a valuable learning opportunity. Studying the imaging findings of cancers that went undetected is a good learning exercise for the radiologist to identify common patterns and mistakes that lead to a missed cancer. This allows the radiologist to improve mammographic sensitivity and overall diagnostic accuracy. This article discusses some of the limitations of mammography, common sources of error which may lead to an undetected cancer, and also discuss a few pearls to prevent these common errors.