AbstractBackgroundPeritoneal carcinomatosis (PC) is a common endpoint in both gastrointestinal and non-gastrointestinal cancers, and PC is treated as other systemic metastases – unfortunately with disappointing results and considerable side-effects. Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC) is a new method of applying traditional chemotherapy, and preliminary data indicate that PIPAC is safe, able to stabilize or improve quality of life, and can induce an objectively measurable reduction in disease burden in PC.MethodsPIPAC-OPC2 is a prospectively controlled Phase II, single center, one-arm, open-label clinical trial investigating the treatment effect of PIPAC in patients with histological or cytological proven PC from gastrointestinal, ovarian or primary peritoneal cancer. Eligible patients will receive PIPAC in series of three using a combination of doxorubicin (1.5 mg/m²) and cisplatin (7.5 mg/m²) for non-colorectal cancer patients (PIPAC C/D), and oxaliplatin (92 mg/m²) in patients with PC of colorectal origin (PIPAC OX). Patients are monitored by: (1) repeated measurements of the Peritoneal Regression Grading Score (PRGS) in biopsies obtained from metal clips marked areas, (2) Quality-of-Life (QoL) questionnaires, (3) Magnetic Resonance Imaging (MRI) and (4) Prognostic Nutritional Index (PNI). Adverse events and surgical complications will be recorded according to the 30 days definition.ResultsThe primary outcome of PIPAC-OPC2 is to evaluate if PIPAC can induce major or complete response (PRGS 1 or 2) within a series of three PIPAC procedures. Secondarily this study investigates changes in QoL and MRI as a staging and response evaluation tool. The secondary outcomes will be used to create a model that may predict which of the patients will benefit from PIPAC treatment.ConclusionsIt is expected that PIPAC directed therapy can induce major or complete response in 50 % of patients with PC of colorectal origin and in 30 % of patients with PC of non-colorectal origin – and at the same time stabilize or even improve quality of life. This trial may provide data regarding the utility of MRI as a staging and response evaluation tool in patients with PC.Trial registrationThe study is registered with ClinicalTrials.gov Identifier NCT03287375 and the European Clinical Trials Database (EudraCT) number 2016-003394-18.