785PObservational study of the peritoneal washing cytology positive gastric cancer without gross peritoneal metastasis underwent radical D2 gastrectomy

Abstract Background Clinical features and therapeutic strategies for peritoneal washing cytology- positive (CY+) gastric cancer without gross peritoneal metastasis have not yet been defined. The aim of the study was to evaluate the clinical prognostic impacts of postoperative chemotherapy for treating gastric cancer patients with CY+ without peritoneal metastasis. Methods Intraoperative peritoneal washing cytology was performed in 285 patients who underwent curative D2 gastrectomy between April 2004 and May 2016. Of them, 88 patients with CY+ without peritoneal metastasis were included in the study. 64 patients received postoperative chemotherapy, whereas 24 patients underwent surgery only. We combined CY+64 patients who received postoperative chemotherapy with another cohort of stage II/III gastric cancer patients (n=819) who received adjuvant chemotherapy, for survival comparison. Results The Disease-free survival (DFS) and overall survival (OS) curves were well separated according to stage and CY+ in combined cohort (both, P Conclusions The prognosis of gastric cancer with CY+ without gross peritoneal metastasis is somewhat different from gastric cancer with overt peritoneal metastasis, and postoperative chemotherapy improves survival outcome in this patient group. Legal entity responsible for the study The authors. Funding Has not received any funding. Disclosure All authors have declared no conflicts of interest.