Re-evaluating the necessity of removing residual calcifications detected after surgery in HR-/HER2+ breast cancer with pathologic complete response

Purpose: Neoadjuvant chemotherapy(NAC) is now widely used in breast cancer to reduce tumor burden and potentially achieve pathologic complete response (pCR). However, when planning breast conserving surgery (BCS) after NAC, considerable debates remain regarding the appropriate extent of surgery. Therefore, this study was designed to comprehensively analyze residual calcifications in patients undergoing BCS following NAC, particularly regarding residual calcifications. Materials and methods: This retrospective observational study included hormone receptor-negative (HR-) and human epidermal growth factor receptor 2-positive (HER2+) breast cancer patients treated with NAC followed by BCS from 2015 to 2020. Patients were grouped by the presence of residual calcifications. Imaging (including mammography and magnetic resonance imaging (MRI)), pathology, and clinical data were reviewed. Survival outcomes were analyzed using Kaplan-Meier curves and statistical tests appropriate to variable types. Results: Among 150 HR-/HER2+ breast cancer patients who achieved pCR after NAC following BCS, 34 patients (22.7 %) showed residual calcifications on postoperative mammography. No statistically significant differences were observed in baseline characteristics or survival outcomes according to the presence of postoperative residual calcifications, including local recurrence free survival, disease free survival, distant metastasis free survival and overall survival. Subgroup analyses by yp T stage showed consistent results. Conclusion: In HR-/HER2+ breast cancer patients achieving pCR after NAC, residual calcifications on postoperative imaging were not associated with worse survival outcomes. Close observation may be a reasonable option compared to additional surgery when negative margins and pCR are confirmed.