Jung Lim Yoo MD, Presenter: Nothing to Disclose

Joo Hee Cha, Abstract Co-Author: Nothing to Disclose

Eun Young Chae, Abstract Co-Author: Nothing to Disclose

Hak Hee Kim MD, Abstract Co-Author: Nothing to Disclose

Hee Jung Shin MD, Abstract Co-Author: Nothing to Disclose

Hyunji Kim MD, Abstract Co-Author: Nothing to Disclose

To determine the frequency and the malignancy rate of BI-RADS category 3 lesions detected on screening breast ultrasound and reassess whether they satisfied the ACRIN 6666 protocol.

During two years, 28,796 asymptomatic women underwent screening mammography. Among them, 8359 women underwent additional breast ultrasound as part of a screening examination. Radiologists analyzed US lesion features and provided a final BI-RADS assessment. We retrospectively reviewed the initial US images with BI-RADS category 3 lesions and their mammography as well. We also investigated the outcome of these lesions. The reference standard was a combination of pathology and clinical follow-up for at least 24 months.

The frequency of category 3 lesions detected on breast US was 16.8% (1403/8359). Of 941 patients with follow up for at least 24 months or biopsy, six eventually proved to be malignant (0.6%). The malignancy rate was 1.5% (4/805) for patients with abnormal mammogram and 0.5% (2/136) for those with negative mammogram. When the ACRIN (American College of Radiology Imaging Network) 6666 protocol were strictly applied, 147 (15.6%) were retrospectively recategorized as BI-RADS 4 (n=7) or BI-RADS 2 (n=140).

The malignancy rate of BI-RADS category 3 lesions is very low, especially with negative mammogram.

With BI-RADS category 3, careful assessment is needed to avoid unnecessary biopsy or short-interval follow-up.

Yoo, J, Cha, J, Chae, E, Kim, H, Shin, H, Kim, H, Reassessment and Follow-up Results of BI-RADS Category 3 Lesions Detected on Screening Breast US.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13012929.html