Phase I/II trial of concurrent use of S-1 and radiation therapy for T2 glottic cancer

Abstract

Objective: A Phase I/II study of S-1 combined radiation therapy was conducted in patients with Stage II (T2N0) glottic cancer. The purpose of the Phase I study was to identify the maximum tolerated dose, the recommended dose and the dose limiting toxicity. The objectives in the phase II study were to estimate the local control and the overall survival, and the incidence of adverse events. Methods: In Phase I, S-1 was administered orally in a split-course fashion as two doses of 40 mg/m. 2, for a total daily dose of 80 mg/m.2. The course involved a 2-week rest after a 2-week administration (Level 1) and a 1-week rest after a 3-week administration (Level 2). Radiation therapy was administered in 2-Gy daily (total 60-Gy) standard fractionation. Results: Seven patients were enrolled in the Phase I, and 19 in the Phase II study. Mucositis was the most common toxicity encountered. All 26 patients completed radiation therapy without delay. The overall response rate was 100% (26/26) with all patients showing a complete response. One patient developed a local recurrence 28 months after the treatment. The 3-year local control and overall survival rates were 94.7 and 85.4%, respectively (limited to 22 patients from Level 2). Conclusions: The use of S-1 at 80 mg/m. 2 per day in a split-course with 1-week rest during the course of radiation therapy was safe and effective for Stage II glottic cancer. The treatment strategy employing orally available S-1 proved to be beneficial over the conventional injection of antitumor agents for maintaining the patients' quality of life. © The Author (2010). Published by Oxford University Press. All rights reserved.