Does Mammotome biopsy affect surgery option and margin status of breast conserving surgery in breast cancer?

The Mammotome, an image-guided, usually ultrasound-guided vacuum-assisted breast biopsy (US-VABB) system, has been widely used in the early diagnosis of breast disease and the complete excision of benign lesions. However, in some malignant lesions underestimated by U.S., whether Mammotome biopsy would affect the surgery option, especially the margin status in breast-conserving surgery (BCS), has never been studied.

Between 2015 and 2019, 198 patients with 200 lesions who have been diagnosed with breast cancer by Mammotome elsewhere received surgery by pathological confirmation in our center. The clinicopathological characteristics, surgery options, therapies, and the details of the specimen, such as margin status of BCS, tumor residual after VABB, and hematoma were reviewed.

Among 200 lesions, 90% were evaluated below US-BIRADS 4b before Mammotome biopsy and 94.5% with a tumor size ≤3 cm. 131 patients received mastectomy (66.2%) and 67 received BCS (33.8%). Hematoma and tumor residual were observed in 37.5% and 71.5% of all lesions, respectively. There is a higher incidence of hematoma in the mastectomy group than in the BCS group (44.4% vs. 23.9%, P=0.005). In BCS group, the positive margin was found in 7 patients at first examination including four focals with re-excision, two extensive with mastectomy and one focal but refusing further surgery. The ultimate success rate of BCS was 95.5%. Margin positivity correlated with tumor residual (P=0.044) but not with hematoma.

Mammotome biopsy might lead to hematoma and tumor residual; however, it is not the determinant factor for a surgery option, and BCS is feasible through a complete excision of tumor residual to acquire negative margin.