Systemic chemotherapy and pressurized intraperitoneal aerosol chemotherapy (PIPAC): A bidirectional approach for gastric cancer peritoneal metastasis.

Background: Few patients affected by gastric cancer peritoneal metastasis (GCPM) are offered locoregional treatment, despite several proof-of-efficacy trials. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) has emerged in recent years as a promising tool to control peritoneal carcinomatosis. The combination of PIPAC with systemic chemotherapy may offer a greater clinical benefit than standard treatment alone.

Methods: A single-center cohort of 28 consecutive patients affected by GCPM was scheduled for bidirectional treatment, comprising PIPAC and systemic chemotherapy, from September 2017 to September 2019. Data recorded included safety, efficacy and survival outcomes. Ascite volumes, the Peritoneal Cancer Index (PCI) and pathological response through the Peritoneal Regression Grading Score (PRGS) were compared in those patients who underwent more than one PIPAC procedure.

Results: Forty-six PIPAC procedures were administered, with a mean of 1.7 PIPAC procedures per patient. The median time to resume systemic chemotherapy after PIPAC was 6 days (range 4-7). Concerning safety, two grade 3-4 CTCAE (Common Terminology Criteria for Adverse Events v4.0) toxicity events and one intraoperative complication were recorded. Thirteen patients repeated PIPAC. A pathological response was recorded in 61.5% of patients (one with complete and seven with partial regression). The median overall survival was 12.3 months in the overall population and 15.0 months in patients undergoing more than one PIPAC procedure.

Conclusions: A bidirectional approach for GCPM was feasible and safe, as the PIPAC procedure integrates well with several systemic chemotherapy regimens. The pathological response demonstrated the antitumoral efficacy of PIPAC. The proposed bidirectional approach may be further investigated in the first-line treatment of metastatic gastric cancer.