Stereotactic core needle biopsy of nonpalpable breast lesions using a conventional mammography unit with an add-on device

OBJECTIVE: The purpose of this prospective study was to assess the accuracy of an add-on stereotactic unit for core needle biopsy of mammographic lesions. SUBJECTS AND METHODS. Between September 1994 and February 2001, 506 stereotactic core needle biopsies of mammographic lesions in 492 patients were performed in our center on a mammography unit with add-on stereotactic equipment. Of the initial 92 patients, 80 underwent stereotactic core needle biopsy and surgical excision simultaneously. In subsequent cases, surgical biopsy was performed after core biopsy in patients who had malignant or atypical histologic results or discordance between mammographic and pathologic findings. Follow-up mammography was advised for all patients whose core biopsy results were diagnosed as benign lesions. RESULTS: Histologic results for 506 lesions undergoing stereotactic core needle biopsy were as follows: 113 (22.3%) were malignant; 369 (72.9%), benign; and 24 (4.7%), atypical. Of 113 malignant lesions identified at stereotactic core needle biopsy, 111 were confirmed as malignant, whereas two showed no evidence of malignancy at surgical excision. Of 369 lesions diagnosed as benign at stereotactic core needle biopsy, 172 (46.6%) showed no change on follow-up mammography, 114 (30.9%) were lost to follow-up, and 83 (22%) underwent surgical excision. Of 24 lesions with atypical histology, 23 had surgical follow-up, six were malignant, nine were benign, and eight were confirmed as showing atypical histology. Stereotactic core needle biopsy of the 506 lesions was complicated by five (1.0%) cases of vasovagal attack and four (0.8%) cases of bleeding. The resulting sensitivity, specificity, and positive and negative predictive values were 98.3%, 93.0%, 86.0%, and 99.2% respectively. CONCLUSION: Biopsy with an add-on unit is safe, reliable, accurate, and cost-effective with results comparable to those reported for dedicated prone biopsy devices.