An audit of the results of ultrasound-guided core needle biopsy of mammography versus ultrasound screen-detected breast lesions

Purpose: To analyze the malignancy rate of ultrasound-guided core needle biopsy (US-CNB) for screen-detected breast lesions and to evaluate the results according to the mode of detection of the target lesions. Methods: This is a retrospective review of 703 consecutive women who underwent US-CNB for screen-detected breast lesions at a single tertiary hospital. Breast Imaging Reporting and Data System (BI-RADS) categories and histopathological results of the target lesions were assessed. The cases were divided into two groups: the mammography-based detected lesions (M-group) and the US-based detected lesions (U-group). The biopsy performances of the two groups were compared using the χ² test. Results: The malignancy rate in the entire population was 22.0%: 0.8%, 12.3%, 65.2%, 89.3%, and 94.6% in BI-RADS categories 3, 4A, 4B, 4C, and 5, respectively. The malignancy rate was significantly higher in the M-group (54.1% [79/146]) than in the U-group (13.6% [76/557]) (p < 0.001). BI-RADS category 3 was the most common assessment overall that led to a US-CNB (362/703, 51.5%) and the rate of BI-RADS category 3 diagnoses that led to US-CNB was significantly higher in the U-group (p < 0.001). Conclusions: The malignancy rate associated with US-CNB for screen-detected breast lesions was 22.0%. The breast lesions detected by mammography have a higher malignancy rate than those detected by US.