Dual Anti-HER2 Combination with Chemotherapy as First-line Treatment for HER2-positive Metastatic Breast Cancer.

HER2-positive metastatic breast cancer is an aggressive subtype of breast cancer associated with poor prognosis due to high recurrence and mortality rates. The introduction of dual anti-HER2 therapy combined with chemotherapy has significantly improved treatment outcomes. A 50-year-old woman with a history of left mastectomy in 2019 who initially declined adjuvant chemotherapy and radiotherapy. Three years later, she presented to the clinic with erythematous skin changes, a nodule at the mastectomy site, and left-arm lymphedema. A biopsy confirmed recurrent HER2-positive breast cancer with metastases to lymph nodes, liver, and bones (cT4cN3cM1 ER-, PR-, HER2+). She received initial treatment with dual anti-HER2 (Pertuzumab, Trastuzumab) and Docetaxel every 3 weeks for six cycles, followed by maintenance therapy with Pertuzumab and Trastuzumab. PET scan evaluations showed an excellent response, with complete resolution of the primary lesion and substantial regression of metastases. The CLEOPATRA trial supports the efficacy of a combination of dual anti-HER2 and Docetaxel, showing prolonged progression-free and overall survival. The combination of dual anti-HER2 enhanced antitumor efficacy by providing dual inhibition of HER2. This case highlights the pivotal role of dual anti-HER2 therapy combined with chemotherapy in improving survival outcomes of patients with metastatic HER2-positive breast cancer.