Long-term survival in patients with peritoneal metastasized gastric cancer treated with cytoreductive surgery and HIPEC: A multi-institutional cohort from PSOGI.

390 Background: Peritoneal metastasis of gastric cancer is relatively common (17%) and is associated with poor survival. Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) is still controversially discussed, as it has proven an increase in median survival in selected patients, but only a small subgroup reached long-term survival. The aim of this study was to collect and analyze a worldwide cohort of patients treated with CRS and HIPEC with long-term survival in order to explore relevant patient characteristics. Methods: We conducted a questionnaire, which was distributed to all collaborators of the Peritoneal Surface Oncology Group International (PSOGI). Inclusion criteria were: histopathologic proven peritoneal metastasis of gastric cancer, treated with CRS and HIPEC, and overall survival > 5 years. Patient, tumor, and therapeutic details were collected and analyzed. Results: A total of 29 patients with a mean age of 52.5 years and a mean PCI of 3.2 were included. The overall median survival was 11.0 years (min 5.0; max 27.9). The predictors completeness of cytoreduction (CC-0) and low PCI (PCI < 6) were present in 23/29 patients. 13/29 patients developed at a median of 82.2 months tumor recurrence. Tumor recurrence was associated with inferior median overall survival compared to patients without tumor recurrence (8.8 years vs. not reached; p = 0.002). Conclusions: Long-term survival and even cure are possible in patients with peritoneal metastasis of gastric cancer treated with CRS and HIPEC. Completeness of cytoreduction (CC-0) and low PCI seemed to be crucial. Further studies are needed in order to improve existing selection criteria.