Outcomes of intraperitoneal chemotherapy for the treatment of gastric cancer with peritoneal metastasis: A comprehensive systematic review and meta-analysis

BACKGROUND: Peritoneal metastasis is common in gastric cancer and linked to poor survival. Treatment of peritoneal metastasis with intraperitoneal chemotherapy has become an accepted practice in some centres. This systematic review and meta-analysis intends to provide a comprehensive evaluation of published evidence for the use of intraperitoneal chemotherapy is gastric cancer patients with peritoneal metastasis. METHODS: A systematic literature search for studies reporting the use of intraperitoneal chemotherapy for the treatment gastric cancer with macroscopic peritoneal metastasis was performed up until June 2024. Studies were not eligible for inclusion if they described the use of intraperitoneal chemotherapy solely as an adjunct to gastrectomy or cytoreductive surgery. Pooled- and meta-analysis was used to summarise study outcomes. RESULTS: Fifty-three studies reporting the outcomes of 2446 gastric cancer patients who received intraperitoneal chemotherapy for the treatment of peritoneal metastasis, were included. Three principal methods of intraperitoneal chemotherapy administration were described: catheter based (normothermic) intraperitoneal chemotherapy (n = 28); pressurised intraperitoneal aerosolised chemotherapy (n = 14), and; hyperthermic intraperitoneal chemotherapy (n = 11). The proportion of patients with complete peritoneal disease regression after receiving intraperitoneal chemotherapy was 27 % (95%CI, 14-41). Median overall survival determined was 16.4 months (95%CI, 14.4-18.4). Meta-analysis of data from eight studies comparing combined intraperitoneal and systemic chemotherapy with systemic chemotherapy alone identified a survival benefit for patients receiving intraperitoneal chemotherapy (Hazard ratio 0.57 [95%CI, 0.48-0.67],P < 0.001). CONCLUSION: Despite variation in published treatment approaches and a lack of evidence from well-designed clinical trials, intraperitoneal chemotherapy may be considered safe and in selected circumstances efficacious.