Can We Reboot the Role of Intraperitoneal Chemotherapy in the Treatment for Gastric Cancer with Peritoneal Carcinomatosis?: A Retrospective Cohort Study Regarding Minimally Invasive Surgery Conjoined with Intraperitoneal plus Systemic Chemotherapy

SIMPLE SUMMARY: The prognosis of gastric cancer (GC) patients with peritoneal carcinomatosis (PC) remains poor, in spite of the recent evolution of systemic chemotherapy for patients with GC. Nowadays, as intraperitoneal (IP) chemotherapy has been applied in the treatment for GC patients with PC, several promising data have been suggested. Inspired by the known characteristics of minimally invasive surgery (MIS), we have recently applied MIS concept in IP and systemic chemotherapy for GC patients with PC. We retrospectively compared the clinical outcomes between the patients underwent MIS conjoined IP plus systemic chemotherapy and patients underwent systemic chemotherapy only, to show the promising potential of the new treatment strategy combining MIS concept with IP plus systemic chemotherapy for GC patients with PC. ABSTRACT: Background: Peritoneal carcinomatosis (PC) is the most common form of metastasis in gastric cancer (GC) and is related with a poor prognosis. Several treatment modalities including systemic chemotherapy and intraperitoneal chemotherapy have been studied and adopted in treatment of GC patients with PC. Nevertheless, few studies have reported the comparison of the oncologic outcomes between minimally invasive surgery (MIS) with intraperitoneal (IP) chemotherapy and conventional chemotherapy for GC with PC. Methods: We retrospectively reviewed the clinical records of 74 patients who had been diagnosed as GC with PC via either intra-abdominal exploration or abdominopelvic computed tomography between January 2011 and April 2021. After performing propensity score-matching for this retrospective data, we compared the outcomes of 26 patients who underwent MIS followed by IP combined systemic chemotherapy (MIS-IP group) and 26 patients who underwent systemic chemotherapy only (SC-only group). Results: The 2-year progression free survival rate of the MIS-IP group was significantly higher than the SC-only groups (36.4% and 10.5%, respectively; p = 0.010). In multivariate analysis to detect relevant factors on PFS, IP chemotherapy (HR 0.213; p < 0.001), Eastern Cooperative Oncology Group performance status (HR 3.689; p = 0.002), and the amount of ascites (p = 0.011) were significant prognostic factors. Conclusions: This study demonstrated the therapeutic potential of MIS conjoined IP plus systemic chemotherapy for GC patients with PC. MIS conjoined by IP plus systemic chemotherapy can be adopted as a treatment option to reboot the role of IP chemotherapy in GC patients with PC.