Breast-conserving surgery after vacuum-assisted biopsy in patients with unexpected breast cancer: is it reliable? A 5-year follow-up study.

Background: Vacuum-assisted breast biopsy (VABB) is commonly used for complete resection of benign tumors and diagnostic biopsy of suspected malignant tumors in China. Post-procedural hematoma formation may potentially facilitate tumor cell dissemination into surrounding tissues. When pathological analysis confirms malignancy, does subsequent breast-conserving surgery (BCS) affect long-term prognosis? This study aims to use five-year follow-up data to investigate these issues. Methods: All patients diagnosed with malignancy following VABB between January 2016 and January 2020 were included in this study. These patients were subsequently stratified into two cohorts based on their selected surgical approach (BCS vs. mastectomy). Clinical and pathological characteristics, comprehensive treatment regimens, and recurrence rates were systematically compared between the groups. Results: A cohort of 124 patients with BI-RADS category 3 or 4a lesions, diagnosed with incidental breast malignancies, was enrolled. The breast-conserving surgery (BCS) group comprised 64 patients (51.6%), of whom 6 demonstrated positive resection margins (9.4%) and 2 ultimately underwent conversion to total mastectomy. Preoperative clinical parameters showed no significant intergroup differences except for tumor location. During follow-up, 8 patients developed ipsilateral recurrence or contralateral new primaries, with 3 subsequent cancer-related deaths; however, no statistically significant differences were observed between the surgical groups. Conclusions: Hematoma and residual cavities may appear after VABB in unexpected breast cancer, potentially affecting surgical visualization and raising concerns about tumor cell extravasation. However, as long as the cavity is completely removed to ensure negative surgical margins, further BCS does not adversely affect patient prognosis.