Interobserver variability in upgraded and non-upgraded BI-RADS 3 lesions

Abstract

To evaluate interobserver variability in the assessment of Breast Imaging-Reporting and Data System (BI-RADS) 3 mammographic lesions, and to determine if the initial evaluation of upgraded BI-RADS 3 lesions was appropriate. Retrospective review of the mammography database (1/1/2004-12/31/2008) identified 1,188 screen-detected BI-RADS 3 lesions, 60 (5.1%) were upgraded to BI-RADS 4/5 during surveillance (cases). Cases were matched to 60 non-upgraded BI-RADS 3 lesions (controls) by lesion type, laterality, and year. Available studies were assessed separately by two radiologists blinded to outcomes. Eighty-two studies were available (43 cases, eight malignancies, and 39 controls). Reader 1 assessed 18/82 (22%) as BI-RADS 0, 13 cases, five controls; 35/82 (42.7%) as BI-RADS 2, 11 cases, 24 controls; 7/82 (8.5%) BI-RADS 3, four cases, three controls; 22/82 BI-RADS 4, 15 cases, seven controls. Reader 2 assessed 8/82 (9.8%) as BI-RADS 0, four cases, four controls; 27 (32.9%) BI-RADS 2, 11 cases, 16 controls; 33 (40.2%) BI-RADS 3, 19 cases, 14 controls; 14 (17%) BI-RADS 4, nine cases, five controls. For cancers, reader 1 assessed two BI-RADS 0, one BI-RADS 2, one BI-RADS 3, and four BI-RADS 4; reader 2 assessed two BI-RADS 2, four BI-RADS 3, and two BI-RADS 4. Reasons for BI-RADS 0 assessment included incomplete mammographic views, lack of ultrasound, and failure to include the lesion on follow-up imaging. Reasons for BI-RADS 4 assessment included suspicious morphology or instability. There is much interobserver variability in the assessment of BI-RADS 3 lesions. Many BI-RADS 3 lesions were judged as incompletely evaluated on blinded review.