[A case of multi-drug resistant recurrent breast cancer with multiple bone metastasis responding to TS-1 and trastuzumab]

Abstract

We experienced a case of multi-drug resistant recurrent breast cancer with multiple bone metastases achieving a significant improvement by TS-1 and trastuzumab. The prior treatments including taxane or vinorelbine and trastuzumab were changed in the regimen to TS-1 and trastuzumab because of the progressive disease. TS-1 was administered orally at 100 mg/day everyday for 2 weeks, followed by a 1-week rest interval as 1 cycle, and trastuzumab was injected at 2 mg/kg/week for 4 weeks, followed by a 1-week rest interval as 1 cycle. After 3 cycles of the treatment, the level of tumor markers and tumor sizes of bone metastases became reduced. In conclusion, the combination treatment of TS-1 and trastuzumab is thought to be effective for multi-drug resistant recurrent breast cancer.