Risk of peritoneal carcinomatosis in localized gastric adenocarcinoma patients who undergo preoperative therapy and attempted surgery.

104Background: Positive peritoneal cytology (+PCyt) or gross peritoneal carcinomatosis (GPC) carries a poor prognosis. Laparoscopic staging to detect +PCyt/GPC is recommended for all ≥T1b GACs. The natural history of GAC patients who have baseline –PCyt and then undergo multimodality therapy is not well documented, particularly for the risk of subsequent GPC. Methods: We analyzed 178 GAC patients with -PCyt at baseline who were followed postoperatively. Results: Of 178 patients who went to surgery after preoperative therapy, surgery in 14 patients (7.9%) was aborted due to GPC in 13 patients, and liver metastases in 1. We then analyzed 164 patients who had an R0 resection. The median follow-up duration was 3.4 (0.6-18) years. The rate of subsequent GPC was 13.4%, (22/164 patients) and the median time to GPC was 15.6 months. The median overall survival (OS) after GPC was only 7.1 months (95% CI: 0.4-17.9 months). Various clinical variables were related with GPC after an R0 resection (Table 1). The 5-year O...