Under pressure: A phase I pilot trial evaluating pressurised intraperitoneal aerosol chemotherapy with oxaliplatin in resectable high-risk gastric cancer.

BACKGROUND: Gastric cancer was the fifth leading cause of cancer-related mortality worldwide in 2022. Peritoneal recurrence after gastrectomy and chemotherapy occurs in 40-60% of patients. This study evaluated the safety and feasibility of adding pressurised intraperitoneal aerosol chemotherapy with oxaliplatin (PIPAC-O+) to perioperative chemotherapy in patients with gastric cancer. METHODS: This prospective, single-centre, non-randomised, open-label pilot trial included patients with gastric adenocarcinoma treated with curative intent. High-risk features included: poorly cohesive subtype with signet cells, serosal involvement, positive peritoneal cytology, high nodal burden on imaging, age <50 years, or proximal tumour location. PIPAC-O+ (92 mg/m2) was administered 4 weeks after neoadjuvant FLOT chemotherapy, followed by gastrectomy with lymphadenectomy. The primary outcome was safety and feasibility. Secondary outcomes included length of stay, cytology conversion, progression-free survival, overall survival, and quality of life. RESULTS: Ten patients (median age 55, range 44-82) were enrolled between 2021 and 2025. All received neoadjuvant FLOT, and 90% completed adjuvant FLOT. PIPAC-O+ did not delay or interrupt treatment. No PIPAC-O+ related morbidity or mortality occurred. One patient experienced transient bloating, fatigue, and cold sensitivity; another had nausea. No other CTCAE-grade events were reported. Quality of life was maintained. CONCLUSION: PIPAC-O+ is a safe and feasible adjunct to perioperative therapy in high-risk resectable gastric cancer.