Borderline breast lesions: comparison of malignancy underestimation rates with 14-gauge core needle biopsy versus 11-gauge vacuum-assisted device.

Objective: To compare malignancy underestimation rates in the case of percutaneous diagnosis of borderline breast lesions(B3) at 14-g core-needle-biopsy (CNB) and at 11-g vacuum-assisted-biopsy (VAB).

Methods: The histological results of 4764 image-guided breast biopsies were retrospectively reviewed. 300 B3, 151 benign papillomas, 88 radial sclerosing lesions, 46 lobular neoplasia, 15 atypical ductal hyperplasia diagnosed at ultrasound-guided 14-g CNB (76%) or stereotactically-guided 11-g VAB (24%) were identified. On average, 5 cores were obtained with CNB and 12 with VAB. Biopsy variables were reviewed and correlated with surgical excision or follow-up (>24 months). Lesion- and device-specific underestimation rates of malignancy were calculated.

Results: Surgical excision was performed on 237 lesions: 178 were benign, 21 atypical, 38 cancers. The remaining 63 lesions were unchanged at follow-up. Overall malignancy underestimation rate was 12.7% at 14-g CNB and 12.5% at 11-g VAB. Based on excision histology or follow-up, lesion-specific underestimation rates were: benign papillomas: 14-g CNB 11%, 11-g VAB 0%; RSL: 14-g CNB 6%, 11-g VAB 4%; LN: 14-g CNB 40%, 11-g VAB 23%; ADH: 14-g CNB 33%; 11-g VAB 22%.

Conclusions: In the case of percutaneous diagnosis of B3 lesions, underestimation of malignancy occurs regardless of the biopsy method.