Outcome of breast lesions detected at screening ultrasonography

Objective

To assess the final outcome of breast lesions detected during screening ultrasonography (US) and categorized by BI-RADS final assessment.

Materials and methods

During a 1-year period, 3817 consecutive asymptomatic women with negative findings at both clinical breast examinations and mammography underwent bilateral whole breast US and BI-RADS categories were provided for US-detected breast lesions. The reference standard was a combination of histology and US follow-up (≥12 months), and the final outcomes of 1192 US-detected lesions were analyzed.

Results

Of 904 category 2 lesions, 890 remained stable for 12–60 months. Biopsies of 14 lesions revealed no malignancies (NPV = 100%). Of 247 category 3 lesions, 232 remained stable for 12–60 months. Biopsies of 15 lesions revealed 2 malignancies, which were diagnosed within 6 months of the index examination and were node negative (NPV = 99.2%). Of 41 category 4 lesions, biopsies of 38 lesions revealed 5 malignancies (PPV = 12.2%), and 3 remained stable for 37–51 months. No US-detected lesion was classified as category 5.

Conclusion

The rates of malignancy for US-detected BI-RADS categories 2, 3, and 4 lesions were 0%, 0.8%, and 12.2%, respectively. The final assessment of US BI-RADS categorization showed it to be an appropriate predictor of malignancy for screening US-detected breast lesions.