A phase II study of neoadjuvant docetaxel, oxaliplatin, and S-1 (DOS) chemotherapy followed by surgery and adjuvant S-1 chemotherapy in potentially resectable gastric or gastroesophageal junction adenocarcinoma

Adjuvant chemotherapy trial of TS-1 for gastric cancer study demonstrated that postoperative S-1 chemotherapy for 1 year improved overall survival of locally advanced gastric cancer (LAGC) patients. The goals of this study were to evaluate the feasibility and efficacy of neoadjuvant docetaxel, oxaliplatin, and S-1 (DOS) chemotherapy followed by surgery and adjuvant S-1 chemotherapy. In this single-center, open-label, phase II study, patients with potentially resectable adenocarcinoma of the stomach or gastroesophageal junction were eligible. For neoadjuvant chemotherapy, docetaxel 50 mg/m(2) on day (D) 1, oxaliplatin 100 mg/m(2) on D1, and S-1 40 mg/m(2) bid orally on D1-14 were administrated every 3 weeks for three cycles. After DOS chemotherapy, gastrectomy was performed, and then, adjuvant S-1 40 mg/m(2) bid was given on D1-28 every 6 weeks for 1 year. The primary endpoints were the proportion of patients who did not experience grade 3 or 4 toxicities (except grade 3 neutropenia) and R0 resection rates. A total of 41 patients were enrolled. All patients completed three planned cycles of neoadjuvant chemotherapy without disease progression. Eighteen patients (43.9 %) did not experience any grade 3-4 toxicity (except grade 3 neutropenia) during the neoadjuvant chemotherapy. All patients underwent surgery, and R0 resection was achieved in 40 patients (97.6 %). Neoadjuvant DOS chemotherapy could be performed safely with a high R0 resection rate in LAGC patients. A phase III trial is currently underway.