What is the prevalence of false-positive and false-negative mammography results in breast cancer screening?

Updated: Apr 10, 2019
  • Author: Erin V Newton, MD; Chief Editor: Marie Catherine Lee, MD, FACS  more...
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False-positive results may arise when benign microcalcifications are regarded as malignant. Tissue summation shadows may appear as local parenchymal distortion; this may erroneously be called malignant tissue. A benign, circumscribed lesion may show signs suggestive of malignancy, along with other findings, such as an irregular border and no halo sign.

According to data from the Breast Cancer Detection Demonstration Project (BCDDP), the false-negative rate of mammography is approximately 8-10%. About 1-3% of women with a clinically suspicious abnormality, a negative mammogram, and a negative sonogram may still have breast cancer.

Possible causes for missed breast cancers include dense parenchyma obscuring a lesion, poor positioning or technique, perception error, incorrect interpretation of a suspect finding, subtle features of malignancy, and slow growth of a lesion.

Birdwell et al performed a multicenter study and found that on previous mammograms with missed cancers, 30% of the 115 lesions were calcifications, with 49% (17 of 35) clustered or pleomorphic. [13] Approximately 70% were mass lesions, with 40% spiculated or irregular. For calcifications and masses, the most frequently suggested reasons for possible miss were dense breasts (34%) and distracting lesions (44%).

Some cancers (eg, mucinous carcinomas) may have well-defined borders and mammographic features suggestive of a benign lesion.

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