摘要Objective The peritoneal cancer index (PCI) has been used for the detailed evaluation of the peritoneal spread in tumors of a gynecologic origin and has been found to be a prognostic indicator of survival. The aim of this study was to identify the significance of the PCI in advanced gastric cancer (AGC) with peritoneal carcinomatosis (PC).Methods From 2010 to 2018, a retrospective analysis was carried out of 60 AGC patients with PC, including 21 patients with a PCI ≤ 13 and 39 with a PCI > 13. All patients were treated with both surgery and intraoperative peritoneal hyperthermic chemotherapy (IPHC). The performance status (Karnofsky performance status), age, sex, Borromann's classification, differentiation, depth of invasion, lymph node metastasis, PCI, extent of gastrectomy, extent of lymph node dissection, and residual tumor volume were retrospectively evaluated and correlated to survival. Results The overall 5-year survival rate was 43％ and mean survival was (54.47 ± 4.53) months. The favorable clinical prognostic indicators of survival were Borromann's classification, differentiation, depth of invasion, PCI, and residual tumor volume on univariate analyses (P < 0.05). The Cox proportional regression hazard model showed that only the volume of residual tumor and PCI were associated with postoperative survival. The median survival time was 69.76 months for patients with a PCI ≤ 13 and 39.96 months for patients with a PCI > 13. There was a significant difference in survival rate between the two group (P = 0.004). Postoperative major morbidity and mortality rates were 23.81％ and 4.76％ in the PCI ≤ 13 group and 43.59％ and 5.12％ in the PCI > 13 group, respectively. Conclusion The peritoneal spread in advanced gastric cancer with peritoneal carcinomatosis can be assessed in detail using the PCI. It is also a significant prognostic factor of survival and is useful in identifying subgroups.