A Case of Hormone-Positive, HER2-Negative Metastatic Recurrent Breast Cancer that Has Responded to XC Therapy for 8 Years

Abstract

A 39-year-old woman was diagnosed with right breast cancer (cT2N1M0, Stage IIB, luminal type) and underwent right partial mastectomy and axillary dissection. The postoperative diagnosis was pT2N2M0 Stage IIIA. Postoperative adjuvant therapy included AC (adriamycin + cyclophospamide), weekly PTX, and right breast irradiation followed by oral tamoxifen and LH-RH agonists. Four years after surgery, tumor marker levels were elevated, and CT showed multiple liver metastases. In accordance with the XC therapy dosage, capecitabine 4,200 mg/day (2-week oral administration, 1-week off) was initiated and cyclophosphamide 100 mg/day was added one month later. One month after co-administration, capecitabine was reduced to 3,600 mg/day (2-week oral administration, 2-week off) because of hand-foot syndrome. Three months after the start of XC therapy, the tumor marker levels were almost within the reference values, and CT revealed shrinkage of the liver metastases. The metastases continued to diminish thereafter, and the patient achieved a long SD without any significant changes in the liver metastases for four years, beginning four years after initiating the XC therapy. We believe that one of the factors contributing to the long SD in this case was the appropriate dose reduction at an early stage, allowing for the long-term use of XC therapy.