Abstract
Background/objectives: Despite the incremental improvement of survival with systemic therapy in metastatic gastric cancer (GC), the outcomes of patients with peritoneal carcinomatosis (PC) remain poor. The limited effectiveness of systemic therapy is attributed to the blood-peritoneal barrier and anarchic intra-tumoral circulation, which reduce the penetration of systemic therapy. Approaches that incorporate intraperitoneal (IP) chemotherapy, in addition to systemic therapies, may be a viable alternate strategy. Therefore, we provide a review of biology of gastric cancer peritoneal metastasis and evidence for bidirectional iterative IP chemotherapy in GCPC. Methods: A comprehensive search in PubMed, Scopus, Embase, Web of Science, Google Scholar, and ClinicalTrials.gov was performed to find the relevant articles and ongoing phase II/III clinical trials in iterative IP chemotherapy in GCPC. Results: Intraperitoneal (IP) chemotherapy leverages the blood-peritoneal barrier to allow for the administration of high concentrations of chemotherapy directly to the peritoneal metastases, with a significant reduction in the systemic toxicity and enhanced drug efficacy against peritoneal metastasis. This pharmacokinetic advantage of IP chemotherapy can be further enhanced by additional measures such as heat or aerosolization. There are three IP chemotherapy approaches, namely, heated intraperitoneal chemotherapy (HIPEC), pressurized intraperitoneal aerosolized chemotherapy (PIPAC), and normothermic intraperitoneal chemotherapy (NIPEC). Recent evidence suggests that iterative IP chemotherapy combined with systemic therapy may offer significant survival benefits for patients with peritoneal metastasis. Furthermore, bidirectional treatment approaches may also increase the chances of surgical resection and survival. Conclusions: IP chemotherapy plays a pivotal role in the management of gastric carcinomatosis, particularly in combination with cytoreduction in highly selected patients. The combination of systemic and regional control may increase the chances of surgical resection and may ultimately lead to significant survival benefits.