Feasibility of neoadjuvant S-1 and oxaliplatin followed by surgery for resectable advanced gastric adenocarcinoma

Abstract

In Japan, the administration of S-1 following D2 gastrectomy is a standard treatment for stage II/III gastric cancer (GC). However, the survival of stage IIIB/IIIC GC remains unsatisfactory. To improve this, we conducted a multicenter phase II study to evaluate the safety and efficacy of a neoadjuvant S-1 and oxaliplatin regimen (SOX) followed by surgery targeted at stage III GC. Oxaliplatin was administered intravenously (130mg/m(2)) on day 1, and S-1 was administered orally (40mg/m(2), twice a day) for 14days followed by a seven-day rest period. After three cycles of therapy, D2 gastrectomy was performed. A total of 14 patients were enrolled and completed the protocol treatment. Grade 3/4 toxicities included thrombocytopenia (21.4%), anorexia (14.3%), and diarrhea (7.1%). Seven patients (50%) underwent total gastrectomy, and seven patients underwent distal gastrectomy. Grade 3/4 surgical complications included pancreatic fistula (21.4%) and lung infection (7.1%). The pathological response rate was 85.7%. Although our data are limited and preliminary, neoadjuvant SOX followed by surgery can be performed safely with a high pathological response rate in patients with resectable advanced GC. Further investigation of this neoadjuvant approach is warranted.