More false-positives, less malignancy in supplemental breast ultrasound utilization

Care must be used when evaluating imaging results of supplemental breast ultrasound used in tandem with traditional mammography screening to avoid excessive false-positive rates and retain specificity, according to results of a new study published in the American Journal of Roentgenology.

With a continuing effort within healthcare to improve accuracy and sensitivity in breast cancer screening, the popularity of supplemental breast ultrasound imaging is on the rise as a readily available and easy-to-use screening tool.

While adding breast ultrasound to cancer screening strategies has been shown to aid in overall cancer detection, it can also reduce the accuracy of lesion assessments and result in unnecessary biopsies, said lead author Eun Young Chae, MD, and his colleagues from the University of Ulsan College of Medicine in Seoul, South Korea.

“Studies have shown that supplemental screening breast ultrasound provides an increased cancer detection yield of 2.3–4.6 cancers per 1,000 women,” they wrote. “However, the addition of screening breast ultrasound to mammography also causes an increase in false-positive biopsy rates and a decrease in specificity.”

Chae and his team conducted a study to assess BI-RADS category 3 lesions detected using breast ultrasound to determine malignancy and agreement with the American College of Radiology Imaging Network (ACRIN) 6666 protocol. To do so, they subjected 12,187 female patients who received mammography screening to additional breast ultrasound imaging. Those with BI-RADS category 3 lesions present on ultrasound were reviewed and the resulting clinical outcomes investigated using pathologic analysis and follow-up over a two-year time span.

Their results showed that after breast ultrasound exams, the frequency of BI-RADS category 3 lesion detection was 15 percent. A total of 1,164 patients had a follow-up duration of at least two years or a biopsy, with only eight lesions proven to be malignant. More than 19 percent of lesions were recategorized according to BI-RADS guidelines using ACRIN 6666 protocols.

“Although the frequency of ultrasound BI-RADS category 3 lesions is considerably high, the malignancy rate is very low, especially in patients with a normal mammogram,” the authors concluded. “Therefore, with BI-RADS category 3 assessment, careful evaluation is required to avoid unnecessary short-interval follow-up or biopsy.”