[A case of advanced upper gingival carcinoma responding completely to concurrent chemoradiotherapy with S-1].

We report a case of advanced upper gingival carcinoma with a contralateral metastatic lymph node invading the maxillary sinus (T4aN2cM0). An 83-year-old man was treated concurrently with chemoradiotherapy and S-1. S-1 (80 mg/body/day) was administered for 2 weeks followed by a 1-week rest period as one course. Radiation therapy involved a total of 60 Gy (2 Gy/day; 5 days/week). There were side effects of mild leucopenia and a grade 2 stomatitis. After the completion of 2 courses and radiation therapy, the primary tumor disappeared, and the patient achieved a pathologically complete response. The metastatic lymph node also completely disappeared. S-1 was then administered in the same regimen for 1 year. Neither local recurrence nor distant metastasis has been detected 2 years after the completion of the concurrent chemoradiotherapy with S-1.