[A Case of HER2-Positive Breast Cancer with Liver Metastases Showing Three Years of Complete Response to Combination Therapy with Trastuzumabplus Pertuzumab].

A 48-year-old woman with severe interstitial pneumonitis was diagnosed with right breast cancer(invasive ductal carcinoma, T1aN1M0, ER+, PgR-, HER2 3+)and underwent modified radical mastectomy.The patient was administered tamoxifen as adjuvant therapy.However, 1 year after the mastectomy, multiple liver metastases were found and the patient received 2 anti-HER2 agents, trastuzumab and pertuzumab.A complete response(CR)was observed with the disappearance of the liver metastases in 7 months.CR was maintained for 2 years after the initiation of treatment, and then, we started trastuzumab monotherapy, which has resulted in long-term disease control.