Conversion Therapy for Gastric Cancer with Peritoneal Metastasis

Peritoneal metastasis in gastric cancer has a poor prognosis and is increasing in prevalence. Neoadjuvant chemotherapy is used for advanced tumors; however, surgery is generally not considered for metastatic and unresectable diseases. Recently, conversion surgery, a treatment which aims for an R0 resection following chemotherapy, has become a novel therapeutic option with better survival rates. In addition to surgery, hyperthermic intraperitoneal chemotherapy (HIPEC) leads to significant tumor reduction, but it is limited by its morbidity. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) delivers high concentrations of chemotherapy, but does not remove the tumor, making it useful mostly in palliative settings. Intraperitoneal (IP) therapy, known for its minimally invasive nature and repeatability, shows promise but requires further research. Ultimately, an integrated approach involving systemic chemotherapy, radical gastrectomy, HIPEC, PIPAC and IP chemotherapy can be used to optimize treatment outcomes of gastric cancer patients with peritoneal metastasis.