Intraperitoneal Paclitaxel and Systemic Therapy Versus Systemic Therapy Alone in Gastric Cancer Patients With Peritoneal Metastasis

Inclusion Criteria: * Gastric or gastro-oesophageal junction Siewert type II or III adenocarcinoma verified by biopsy or cytology from the primary tumour * Peritoneal metastasis verified by biopsy, or cytology from ascites or peritoneal wash fluid * Staging laparoscopy with assessment of peritoneal cancer index (PCI) performed less than four weeks before enrolment. * Patients with tumour positive cytology (CYT+) without clinically manifest peritoneal metastases at baseline (PCI 0) staging laparoscopy can be included if they persist to be CYT+ after at least four cycles of systemic chemotherapy. * Adequate hematology assessment and serum chemistry * Eastern Cooperative Oncology Group (ECOG) performance status 0-1. * Age of at least 18 years * Life expectancy of at least three months * Assurance that adequate anti-reproductive measures will be taken during study interventions when applicable Exclusion Criteria: * Comorbidity that does not allow treatment with ST or IP paclitaxel * Confirmed or suspected severe abdominal adhesions * Severe coagulation disorder which precludes surgical interventions * Distant metastases (including M1 lymph node metastases) other than peritoneal, with the specific exception of ovarian metastases * Symptomatic ascites already requiring drainage for palliation, or expected to require drainage in the short term * Peritoneal recurrence of gastric cancer diagnosed within 6 months after curative intent surgery * Previously received more than 2 cycles…