[A case report of tongue squamous cell carcinoma showing a complete response to TS-1].

A 75-year-old female with squamous cell carcinoma in the left margin of the tongue (T2N0M0) was referred to our hospital. She was treated with oral administration TS-1 80 mg/day as preoperative chemotherapy. After commencement of TS-1 administration, the tumor size was reduced at 1 week and had disappeared clinically at 4 weeks.