Evaluation of stereotactic core needle biopsy (SCNB) of the breast at a single institution

Stereotactic core needle biopsy (SCNB) has become a popular method for diag nosis of occult breast abnormalities. There are few large series of SCNB fr om a single institution. Data on patients undergoing SCNB for mammographic abnormalities were collected prospectively over 43 months at a university h ospital. Mammographic findings were categorized as benign, probably benign, indeterminate, suspicious or malignant. For lesions with SCNB pathology th at were non-diagnostic, showed atypical hyperplasia or malignancy (in situ or invasive), or were discordant with the pre-biopsy mammogram findings, su rgical excision was recommended. Subsequent surgical pathology was reviewed . All remaining lesions were followed mammographically after SCNB. SCNB was performed on 692 lesions in 607 patients. There were 79 malignancies, for a positive SCNB rate of 11.4%. The 349 SCNB performed for benign, probably benign and indeterminate lesions on mammography had a positive SCNB rate of only 4%. Surgery was recommended for 127 (18.3%) lesions, while 565 (81.6% ) were followed mammographically after SCNB. A compliance rate of 61% for a t least one follow-up mammogram was obtained, with a median follow-up of 17 .2 months and with no cancers found. The sensitivity for malignancy with SC NB was 93%. SCNB provides a minimally invasive method to assess mammographi c abnormalities. Abnormalities considered radiographically to be other than malignant or suspicious yielded few cancers. In this series a low positive SCNB rate resulted in no false negatives on mammographic follow-up. The op timal positive biopsy rate for SCNB is debatable.