e15113 Background: The prognosis for patients with unresectable advanced gastric cancer treated with chemotherapy alone is extremely poor. We have evaluated the safety and efficacy of salvage gastrectomy following chemotherapy with docetaxel, cisplatin, and S-1 (DCS) in patients with unresectable advanced gastric cancer. Methods: We evaluated 30 patients with unresectable advanced gastric adenocarcinoma whose lesions were down-staged by DCS chemotherapy and who underwent salvage gastrectomy with lymph node dissection from 2006 to 2012, when visible lesions were judged resectable. We retrospectively reviewed their medical records to identify factors that would influence overall survival. Results: Of the 30 patients, 17 had extra-regional lymph node metastases, 5 had liver metastases, 9 had peritoneal dissemination and 6 had pancreatic head invasion prior to DCS chemotherapy. Of the 30 patients, 23, 3, and 4 underwent R0, R1, and R2 resection, respectively. No in-hospital deaths or reoperations occurred. Pathological evaluation of primary tumors revealed grades 3, 2, 1b, 1a, and 0 tumor regression in 4, 9, 7, 7, and 2 patients, respectively. Median progression-free survival was 19 months.Two-year progression-free survival and overall survival rates were 45% and 65%, respectively. Of 17 patients with target tumors, 15 had partial responses, making the overall response rate 88%. The most common grade 3/4 hematologic toxicity was neutropenia (56%); all treatment-related toxicities were resolved, and no patient died of toxicity-related causes. Univariate analysis showed that R1/2 surgery (p<0.001), diffuse type histology (p=0.054), histological grade 0/1a/1b following chemotherapy (p<0.033), ypN3 (p<0.001) and yply2/3 (p=0.003), were significantly prognostic of reduced overall survival. A multivariate proportional hazard model found that ypN3 (p=0.003) was the sole independent prognostic factor. Conclusions: Salvage gastrectomy after DCS chemotherapy was safe and effective in patients with unresectable advanced gastric cancer. Lymph node metastasis after chemotherapy was significantly prognostic of poor prognosis, suggesting the need for further treatment.