Background: Stereotactic breast biopsy using the Mammotome system allows minimal invasive tissue sampling of suspicious lesions of the breast cancer, e.g. clustered microcalcifications BI-RADS type 3 and 4, and has widely replaced open surgical biopsies. The aim of this retrospective study was to review the results of these biopsies in regard of technical feasibility and complications as well as to correlate initial BI-RADS assessment with histopathology.
Methods: One hundred thirty-five vacuum-assisted breast biopsies in 124 patients were evaluated. Before biopsy, the mammograms were classified according to the Breast Imaging Reporting and Data System (BI-RADS). All mammograms were reviewed with knowledge of the final histologic diagnosis. Patients with benign diagnoses underwent mammographic follow-up. Excisional biopsy was recommended for diagnoses of in-situ or invasive carcinoma.
Results: No serious complications of the biopsies were observed. Histopathology revealed 105 (78%) benign lesions. Benign lesions were classified as BI-RADS 3 in 49 (36%) and as suspicious (BI-RADS 4) in 56 (41%). Thirty lesions (22%) were malignant, of which 26 (87%) were classified BI-RADS 4 or 5. The frequency of malignancy in BI-RADS 4 and 5 was 19 of 75 (25%) and 7 of 7 (100%), respectively. Of the 53 BI-RADS 3 lesions, 4 (8%) were malignant.
Conclusions: Mammotome biopsy was shown to be a safe and well-tolerated technique for the work-up of mammographic lesions. The frequency of malignant histopathologic findings in BI-RADS 3 lesions was higher than expected, reflecting the difficulties in the mammographic differentiation of benign and malignant clustered microcalcifications.