Stereotactic vacuum-assisted biopsy (SVAB) of nonpalpable breast microcalcifications: advantage of clip placement (prospective study)

Abstract

Purpose: The purposes were to evaluate the feasibility of an add-on stereotactic vacuum-assisted breast biopsy (SVAB) on lateral lying position, to predict which patients requiring clips and to compare two kinds of clips. Materials and Methods: 177 microcalcifications from 162 women (mean age, 62 ± 11.2; range 34 - 85 years) performed breast biopsy with an 11-gauge needle. One kind of clip, Gel Mark® Ultra or MicroMarkTM II, was deployed. Craniocaudal (CC) and mediolateral (ML) mammograms were obtained before and after biopsy. All lesions were classified into three mono-focal groups according to their diameter of < 10 mm (group 1), 10 - 20 mm (group 2), > 20 mm (group 3) and one multi-focal group (group 4). Results were considered statistically significant if the P < 0.05. Results: Histology showed benign in 135 (76.3 %), malignancy in 39 (22.0 %) and atypical ductal hyperplasia (ADH) in 3 (1.7 %) biopsies. The sensitivity, specificity, accuracy were 100 %, 92.9 % and 97.1 % respectively. In group 1 (n = 26), 23 lesions (88.5 %) and in group 2 (n = 22), 18 lesions (68.2 %) were completely removed, while in group 3 (n = 18), no lesion was completely removed. 57/123 (46.3 %) lesions were multi-focal microcalcifictions (group 4). 75 clips (69.4 %) were located within 10 mm distance from the biopsy site on both (CC, ML) projections. 33 (30.5 %) clips were dislocated on at least one projection and 84.8 % clips were dislocated only on CC projection. There was no significant difference between the two kinds of clips. Four patients developed hematomas. No inflammation and vasovagal reaction had occurred. Conclusions: An add-on SVAB is an effective diagnostic procedure for nonpalpable breast microcalcifications. Microcalcifications smaller than 20 mm and all the multi-focal microcalcifications are useful indicators to deploy clips. The major influent factor of clip displacement is the "accordion effect". There is no significant difference of the two kinds of clips as to accurate localization.