Role of locoregional therapy in gastric cancer with peritoneal metastasis

The peritoneum is a common site of early dissemination of gastric cancer (GC) as well as a common site of recurrence after curative gastrectomy. Peritoneal metastasis (PM) is a major cause of morbidity and mortality in patients with GC and is associated with poor prognosis, making treatment of peritoneal disease is an important target for improving survival. The development of standardized methods to assess extent of peritoneal disease, an increased understanding of intraperitoneal chemotherapy, and improvements in systemic chemotherapy have renewed interest in the curative-intent treatment of GCPM. The different approaches of locoregional therapy for GCPM includes surgical resection, intraperitoneal chemotherapy, and a combination of the two. Surgical resection involves gastrectomy and/or a cytoreductive surgery (CRS) with removal of all visible disease. Intraperitoneal (IP) chemotherapy can involve administering heated chemotherapy usually at the time of surgery i.e., Hyperthermic Intraperitoneal Chemotherapy (HIPEC) or laparoscopically in the neoadjuvant setting i.e., NL-HIPEC, chemotherapy given immediately post-op i.e., Early Post-operative Intraperitoneal Chemotherapy (EPIC), multiple infusions of non-heated chemotherapy i.e. Normothermic Intraperitoneal Chemotherapy Long Term (NIPEC-LT) or the newer technique of Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC). This review provides an overview of these different locoregional treatment modalities and summarizes the evolution of the techniques, regimens, and applications of IP chemotherapy. It highlights the multitude of options available, the promising yet heterogenous existing literature and the exciting ongoing work that will hopefully help establish the role of locoregional therapy in GCPM.