Efficacy of S-1 and concurrent intensity-modulated radiotherapy for locally advanced gastric cancer: an interim study of phase II clinical trial

Abstract

Objective To observe the incidence of adverse reactions and short-term efficacy of S-1 and concurrent intensity-modulated radiotherapy (IMRT) for locally advanced gastric cancer in a phase Ⅱ clinical trial based on the phase I clinical trial. Methods Patients pathologically diagnosed with stage TN (+) gastric adenocarcinoma with local or distal metastasis after R0 resection were enrolled as subjects. IMRT was delivered 5 times per week with a total dose of 45 Gy in 25 fractions. S-1 was orally administered on the day of radiotherapy at a dose of 80 mg/m2. Results A total of 40 patients, consisting of 6 patients from the phase I trial and 34 patients from the phase Ⅱ trial, were enrolled in this study. In those patients, the age ranged between 27 and 73 years (median age 50 years) and the male-to-female ratio was 3: 1. Thirty-nine (98%) out of the forty patients completed radiotherapy and thirty-five (88%) completed concurrent chemotherapy. The most common grade 3-4 adverse reactions were nausea/anorexia (13%), leukopenia (10%), vomiting (8%), radiation esophagitis (5%), and neutropenia (5%). There was no perioperative death. The 2-year overall survival and disease-free survival rates were 74% and 77%, respectively. Conclusions Postoperative S-1 and concurrent IMRT achieve satisfactory outcomes and tolerable toxicity in patients with locally advanced gastric cancer. Key words: S-1; Gastric neoplasms/concurrent chemoradiotherapy; Radiotherapy, intensity-modulated; Treament outcome