False-Negative Review from the Mammography Audit: Refining Breast Imaging Practice

Annual review of false-negative (FN) mammograms is a mandatory and critical component of the Mammography Quality Standards Act (MQSA) annual mammography audit. FN review can help hone reading skills and improve the ability to detect cancers at mammography. Subtle architectural distortion, asymmetries (seen only on one view), small lesions, lesions with probably benign appearance (circum-scribed regular borders), isolated mi-crocalcifications, and skin thickening are the most common mammographic findings when the malignancy is visible at retrospective review of FN mam-mograms. Most FN mammograms are not due to radiologist error. There are common and predictable settings in which FN mammograms occur. Patient factors associated with elevated FN mammograms include dense breasts, elevated lifetime risk of breast cancer, and personal history of breast cancer treated with lumpectomy and radiation therapy. About half of FN cancers are detected by supplemental screening examinations and half manifest clinically. The most common manifesting symptoms for interval cancers are a palpable abnormality, nipple discharge, and skin changes. Interval cancers can have more aggressive pathologic features and higher rates of node positivity. The FN review includes Breast Imaging Reporting and Data System (BI-RADS) 3 cases that develop a cancer diagnosis during surveillance. Nonbreast malignancies diagnosed as interval cancers (most commonly lymphoma and metastatic disease) do not need to be counted as FNs for audit purposes. The FN review and annual audit are confidential processes that protect patient and radiologist information while allowing meaningful quality control and improvement. Although FN mammograms are rare, review of these cases is a valuable educational tool.