Real-world data on Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC)-directed therapy in patients with peritoneal metastases; Third annual report from the ISSPP PIPAC database

Objectives: In 2020, the International Society for the Study of the Pleura and Peritoneum (ISSPP) launched a database monitoring real-world data on Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC)-directed therapy in patients with peritoneal metastases (PM). This study covers data from the third annual report on the ISSPP PIPAC database. Methods: Systematic analysis of all data reported to the ISSPP PIPAC database between June 15th, 2020, and November 1st, 2024. We hypothesize that ISSPP PIPAC data align with existing literature. Results: Seventeen PIPAC centers reported 3224 PIPAC treatments in 1126 patients with PM (median number of treatments 2, range 1-33). The median peritoneal cancer index (PCI) at PIPAC 1 was 19 and remained unchanged during subsequent treatments. The number of patients with >500 mL ascites significantly decreased from the first three PIPAC treatments to PIPAC 4+ (p<0.01). Major complications (Dindo-Clavien ≥3b) occurred in 0.7 % of the treatments, while Common. Terminology Criteria for Adverse Events (CTCAE) grades ≥3 were reported in 5.2 %. Peritoneal regression grading score (PRGS) was performed in 2306 (72 %) of the treatments. At PIPAC 1, 2, and 3, complete or major response (mean PRGS ≤2) was achieved in 57 %, 72 %, and 75 % of the patients, respectively. Median overall survival from PIPAC 1 was 12.5 months. Patients with complete/major response (mean PRGS ≤2) at PIPAC 1-3 had a longer overall survival compared to patients with minimal/no response (mean PRGS >2). Conclusions: This study from the ISSPP PIPAC database provides substantial real-world data demonstrating the feasibility, safety, and potential effect of PIPAC-directed therapy in patients with PM.