[A case of mandibular gingival cancer (T4) responding to concurrent chemoradiotherapy with TS-1].

We report here a patient with advanced oral cancer in which concurrent chemoradiotherapy with TS-1 was performed. The patient was an 82-year-old male who had a 41 x 22 mm tumor mass around the left lower gingiva, whose X-ray showed a bone resorption image reaching the mandibular canal. We carried out concurrent chemoradiotherapy with TS-1. After 4 weeks, severe side effects, i.e., stomatitis and diarrhea, force us to discontinue the treatment. However, the tumor had begun to shrink from the 2nd week of treatment, and had clinically disappeared by the 8th week. The histopathological examination also indicated a complete response (CR). Thus, this treatment was very effective and may be useful for advanced cases.