The median survival of patients with unresectable gastric cancer treated with systemic chemotherapy is about 12 months. In patients with histologically proven unresectable or recurrent gastric cancer limited to the peritoneum and/or cancer cells in peritoneal cytology, the combination of i.p. paclitaxel with systemic chemotherapy reported a median survival time of 23.6 months. However, a phase III trial (PHOENIX-GC trial) comparing IP regimen with systemic chemotherapy versus systemic therapy alone in Japan recently reported preliminary data which did not show any superiority of the IP regimen.PIPAC is an innovative intraperitoneal chemotherapy concept that enhances the efficacy by taking advantage of the physical properties of gas and pressure. This results in a superior distribution and depth of penetration of the drug. To date, most phase II trials utilising PIPAC involve the use of cisplatin and doxorubicin4-6. Only two prior trials have utilised oxaliplatin in PIPAC for peritoneal carcinomatosis. Oxaliplatin is an approved drug for systemic chemotherapy, with well documented use intraperitoneally via hyperthermic intraperitoneal chemotherapy (HIPEC) as well. This makes is a favourable agent for PIPAC in early phase studies. The dose of oxaliplatin utilised for PIPAC in the literature has thus far been arbitrarily set at 92 mg/m2, which is approximately 80% of the drug concentration used in HIPEC. Furthermore, these studies were performed on patients with a recent or concurrent administration of systemic chemotherapy, which may make interpretation of the side effects and safety profile difficult to interpret. In this study, we intend to determine the safety profile and tolerability of PIPAC with oxaliplatin by assessment of dose limiting toxicities and the adverse event profile.