[Effective chemotherapy with S-1 alone in a patient with lung metastases of breast cancer].

We report a 50-year-old female with pulmonary metastases from breast cancer who responded to S-1. In September 2003, she underwent surgery for breast cancer. Four years 8 months after the operation, lung relapse was detected. After the treatment failure of FEC60 (5-FU 500 mg/m², epirubicin 60 mg/m², cyclophosphamide 500 mg/m²) and taxane antitumor drugs, oral administration of S-1 80 mg/body/day was initiated. At the end of three courses, thoracic CT revealed the disappearance of the lung metastasis. Advanced reactions during the administration period were mild. After 14 courses of S-1 therapy (during 11 months), a complete response was clinically maintained. S-1 showed a good antitumor effect and tolerance, and it might be useful for treating metastatic and recurrent breast cancers.