Clinical management issues in percutaneous core breast biopsy.

Percutaneous imaging-guided core biopsy is a less invasive and less expensive alternative to surgical biopsy for the evaluation of breast lesions. Percutaneous core biopsy is most often used for evaluation of BI-RADS category 4 lesions, but may also be helpful in the evaluation of some BI-RADS category 5 lesions. Stereotactic guidance is particularly useful for calcifications; for masses that can be seen with ultrasound, ultrasound guidance may be preferable because of the absence of radiation and lower cost. The automated core biopsy needle is excellent for mass lesions, but directional vacuum-assisted biopsy is superior for calcifications. Directional vacuum-assisted biopsy may also be preferable for small lesions that may require placement of a localizing clip and lesions that are superficial or in thin breasts. The more expensive ABBI device has substantial limitations, and its role in percutaneous breast biopsy has not been demonstrated. Complete removal of the mammographic target can occur at percutaneous biopsy, and is a more frequent event when the larger tissue acquisition devices are used. Complete removal of the mammographic target does not ensure complete excision of the histologic process. Further investigation is necessary to determine in which lesions, if any, complete removal of the target is advantageous. Epithelial displacement can occur during all breast needling procedures, but may be less frequent at directional vacuum-assisted biopsy than at fine-needle aspiration or automated core biopsy. There is no evidence that displaced cells are of biologic significance, but displaced DCIS can mimic infiltrating carcinoma. The pathologist should be aware of the findings of epithelial displacement, to avoid misdiagnosing DCIS as infiltrating ductal carcinoma. Some lesions warrant repeat biopsy or surgical excision after percutaneous core biopsy. Repeat biopsy is warranted if histologic findings and imaging findings are discordant. Surgical excision is warranted for lesions yielding a percutaneous diagnosis of ADH or possible phyllodes tumor. Controversy exists regarding the need for surgical excision after percutaneous diagnosis of radial scar, papillary lesion, ALH, or LCIS. Follow-up is necessary if percutaneous biopsy yields benign findings concordant with imaging characteristics. Follow-up protocols vary, but all require substantial commitment of time and resources. We have an embarassment of riches for performing percutaneous core biopsy of the breast. It can be estimated that approximately 1 million breast biopsies will be performed this year to diagnose approximately 200,000 breast cancers. Percutaneous core biopsy may spare many of these women the need for a more deforming, invasive, and expensive surgical biopsy. Further work is necessary to optimize criteria for patient selection, develop and define the role of new technologies for tissue acquisition, refine protocols for management after percutaneous breast biopsy, and assess long-term outcome, so that more women can benefit from this minimally invasive approach to breast diagnosis.