Cavity Margins Sample Shaving as Part of Extended Vacuum-Assisted Breast Biopsy: A Potential Approach to Predict Percutaneous Breast Cancer Excision

BACKGROUND: Excision of small breast cancers has been reported by vacuum-assisted biopsy (VAB). Nevertheless, patients are submitted to surgery, because there is no way to predict excision. The purpose of this study was to evaluate extended vacuum-assisted biopsy (EVAB) associated with cavity margins sample shaving (CMSH) to predict breast cancer excision. METHODS: This is a retrospective database analysis of 120 cancers [both invasive breast cancers (IC) and ductal carcinoma in situ (DCIS)] diagnosed by EVAB-CMSH submitted to surgery with histological data from EVAB-CMSH and surgery. The CMSH was evaluated as a diagnostic test for excision compared to surgery as gold standard. Factors associated with residual tumor, gross residual tumor (GRD) (> 3 mm), and false-negative CMSH after EVAB-CMSH were evaluated. RESULTS: A total of 120 cases were analyzed. Media age was 57 (48.5-69); image tumor size (T) was 11 (8.6-15) mm; pathological tumor size (pT) was 6 (4-10) mm; most cases IC+DCIS 53 (44.2%), DCIS 46 (38.3%), and IC 15 (12.5%); 45 (37.5%) were excised by EVAB-CMSH. CMSH sensitivity 70.7%, specificity 66.7%, false-negative rate 18.33%, and accuracy 69.2%. In multivariate analysis, DCIS pT (p = 0.003, odds ratio [OR] 1.46, 95% confidence interval [CI]) was associated with residual tumor; DCIS pT (p = 0.001, OR 1.34, 95% CI) and the CMSH T (p = 0.001, OR 1.67, 95% CI) with GRD; surgical specimen DCIS T (p = 0.015, OR 1.12, 95% CI) with CMSH false negative. CONCLUSIONS: Cavity margins sample shaving is a potential approach to predict small breast cancer excision and should be added to vacuum-assisted excision in prospective trials. For DCIS, EVAB-CMSH should not be standard of care.