Preoperative concurrent chemotherapy with S-1 and radiotherapy for locally advanced squamous cell carcinoma of the oral cavity: Phase I trial

BACKGROUND: This study was conducted to identify a recommended dose for S-1, used in combination with 40-Gy radiation. METHODS: Thirty patients, 15 each with stage III and IVA oral carcinoma, were enrolled. All patients received a total dose of 40-Gy. For the S-1 treatment, patients were given either the standard Japanese dose, calculated according to body surface area, or a reduced dose. Groups consisting of at least three patients were given S-1 according to one of 8 regimens. RESULTS: Hematologic toxicity was mild and reversible. The most common nonhematologic toxicity was mucositis. At level 8 that was the standard S-1 dose for 5 days per week for 4 weeks, dose-limiting toxicity was observed when 2 patients had grade 4 mucositis. This level was thus deemed the maximum tolerated dose for the regimen. CONCLUSIONS: The recommended dose of S-1 with concurrent radiotherapy was the reduced dose of S-1 given for 5 days per week, for 4 consecutive weeks. Preoperative S-1 and concurrent radiotherapy was well tolerate and feasible and warrants a phase II study.