[A Case of an Elderly with Locoregional Recurrence of ER-Negative HER2-Positive Breast Cancer Successfully Treated with Local Therapy].

An 80-year-old woman who received on anticoagulant therapy for atrial fibrillation was diagnosed with ER-negative HER2-positive breast cancer(cT4bcN1M0, Stage ⅢB). She underwent mastectomy with skin graft and lymphadenectomy, but was evaluated to be too old for standard chemotherapy and HER2-directed therapy. Four months after the operation, she was diagnosed with regional lymph node metastasis and underwent radiotherapy. Moreover, 9 months later, other recurrent sites were revealed in the parasternal lymph node and thoracic wall without distant metastasis. Radiotherapy could be performed around these secondary recurrent sites while avoiding overlap. After 2 years, solitary contralateral axillary lymph node metastasis was diagnosed by PET-CT. She underwent Lt axillary lymphadenectomy. The intrinsic breast cancer subtype did not change. Patient performance status was kept to achieve a good quality of daily life. Eight months later, she diagnosed with primary pancreatic cancer and received 13 cycles of chemotherapy until her death from pancreatic cancer 14 months later. During chemotherapy, no recurrence of breast cancer was observed.