The American College of Radiology's BI-RADS 3 Classification in a Nationwide Screening Program: current assessment and comparison with earlier use.

The Breast Imaging Reporting and Data System allows radiologists to classify lesions as "probably benign-short interval follow-up suggested" (category 3). The purpose of this study is to evaluate the recent use of the category 3 designation in a national cancer detection program. We analyzed data from the National Breast and Cervical Cancer Early Detection Program, a nationwide collaboration between the Centers for Disease Control and Prevention (CDC) and local health agencies that provides cancer screening for low-income, uninsured women. The study population included all women at least 40 years old who had mammograms in the program through September 1999 (n = 826,424). Of the 826,424 mammograms, the percentage classified as category 3 in the initial phase (1991-1996, previously reported, n = 372,760) was 7.7%; of the most recent 453,664 mammograms (1996-1999), 6.0% were given this designation. During the same periods, the percentage of abnormal mammograms decreased from 2.6% to 2.1% and those needing "additional imaging" (category 0) increased from 5.0% to 6.9%. The percentage receiving a category 3, category 0, or abnormal designation decreased with increasing age for each classification. The percentage of category 3 mammograms varied by site from 1.1% to 12.2%. Overall the proportions of category 3 mammograms decreased over time, while requests for additional examinations increased. This suggests that patients were more likely than before to receive additional examinations prior to their final designation. The persistent wide variability in category 3 indicates further education and attention to the use of this category is warranted.