Response-adapted Surgery for Residual Calcifications in HER2-positive Breast Cancer after Neoadjuvant Chemotherapy

The clinical significance of residual mammographic microcalcifications after neoadjuvant systemic therapy in HER2-positive (HER2+) breast cancer remains unclear. Traditionally, persistent calcifications have prompted wide excisions or mastectomies under the assumption that they indicate residual disease. However, accumulating evidence suggests that calcifications may persist as treatment-related or biologically-attenuated changes, rather than as viable carcinomas, particularly in the era of dual HER2-directed therapy. Recent Korean studies demonstrate that patients with favorable radiologic response who achieve pathologic complete response maintain excellent local control after breast-conserving surgery, even when residual calcifications are present. A large multicenter cohort study reported a 5-year local recurrence-free survival rate of 97.4% and a validated prediction model showed strong discriminatory performance. This Brief Communication synthesizes emerging evidence on the biological basis and clinical implications of residual calcifications after neoadjuvant therapy, with emphasis on recent Korean data. Current evidence supports a response-adapted surgical approach in selected patients, emphasizing clip-guided excision of the invasive index lesion and consistent delivery of whole-breast irradiation rather than routine removal of the entire pretreatment calcification field in patients with HER2+ breast cancer. Prospective validation with a long-term follow-up is warranted to further refine patient selection and confirm the safety of this strategy in clinical practice.