[A Case of Surgical and Chemotherapeutic Treatment for Ipsilateral Breast Tumor Recurrence during Pregnancy].

A 40-year-old woman was diagnosed with ipsilateral breast tumor recurrence in the conserved breast 1.5 years after undergoing partial mastectomy for right breast cancer at another hospital. She was referred to our hospital at 19 weeks of gestation. At 21 weeks, total mastectomy of the conserved breast with sentinel lymph node biopsy was performed. The postoperative pathological diagnosis was invasive ductal carcinoma mixed with squamous cell carcinoma. AC chemotherapy was initiated at 33 weeks, and she gave birth by cesarean section at 39 weeks. Postpartum, EC therapy followed by paclitaxel therapy were administered. Currently, she is on endocrine therapy, with no new recurrence observed for 3 years after surgery. Pregnancy-associated breast cancer is rare, accounting for approximately 1% of all breast cancers, and there are few reports on the treatment of local recurrence or distant metastasis during pregnancy. This case, involving breast-conserving surgery recurrence during pregnancy, highlights the importance of careful decision-making and treatment strategies tailored to individual cases, considering the safety of both mother and fetus through multidisciplinary collaboration.