[Phase I study of concurrent radiotherapy with S-1 for oral squamous cell carcinoma].

S-1 is a novel oral fluoropyrimidine inhibitory for dihydropyrimidine dehydrogenase (DPD). In the present study, we have examined the appropriate dose of S-1 in the combination with radiation and the safety and clinical efficacy. Radiation was given (2 Gy/day; 5 days/week) for a total of 60 Gy. S-1 was given orally every day for 2 weeks and then S-1 was stopped for 1 week. The levels were divided accordingly to the S-1 application as follows; level 0, 50 mg/m2/day; level 1, 65 mg/m2/day; level 2, 80 mg/m2/day. grade 3 toxicity of anorexia and the grade 3 toxicity increase in bilirubin level were observed in 2 cases of level 2. We decided that level 1 (65 mg/m2/day) was the recommended dose of the S-1 application as observed in compliance and efficacy. This therapy is a useful concurrent chemo-radiotherapy which may improve the response rate and quality of life (QOL) of patients with oral squamous cell carcinoma.