Pressurized intraperitoneal aerosol chemotherapy (PIPAC) in patients with peritoneal surface malignancies (PSM): a prospective single-center registry study

Pressurised Intraperitoneal Aerosolised Chemotherapy-Results from the First Hundred Consecutive Procedures

PIPAC is a new and promising technique for the intraperitoneal administration of chemotherapy. It can be used in patients with various peritoneal cancer metastases. It is mainly a palliative treatment, but there is some neoadjuvant treatment potential. We have operated on 41 patients with various intra-abdominal cancers. PIPAC was performed every 6 weeks. The indication was extension of peritoneal carcinomatosis beyond the criteria for cytoreductive surgery and HIPEC. The effect was evaluated according to the peritoneal cancer index, the peritoneal regression grading score and the amount of ascites. Complications were classified according to the Clavien-Dindo system. We have performed 100 PIPAC procedures. There were two major complications, classified as Clavien Dindo III (2%). The number of procedures varied from 1 to 6. Five patients switched to cytoreductive surgery and HIPEC, and one was indicated for the watch and wait strategy due to total regression according to PRGS. Three patients are still continuing treatment. The others stopped treatment mainly because of progression of the disease and loss of metastases. We observed a reduction in ascites production soon after PIPAC application. PIPAC is a safe and well-tolerated treatment modality. It is mainly a palliative treatment that can improve the quality of life by reducing the production of ascites, but in about 10% of cases, it can reduce the extent of the disease and allow for further radical treatment.

PIPAC for Gastrointestinal Malignancies

The peritoneum is a common site of metastases for gastrointestinal tumors that predicts a poor outcome. In addition to decreased survival, peritoneal metastases (PMs) can significantly impact quality of life from the resulting ascites and bowel obstructions. The peritoneum has been a target for regional therapies due to the unique properties of the blood-peritoneum barrier. Cytoreductive surgery (CRS) and heated intraperitoneal chemotherapy (HIPEC) have become accepted treatments for limited-volume peritoneal disease in appendiceal, ovarian, and colorectal malignancies, but there are limitations. Pressurized intraperitoneal aerosolized chemotherapy (PIPAC) improves drug distribution and tissue penetration, allowing for a minimally invasive application for patients who are not CRS/HIPEC candidates based on high disease burden. PIPAC is an emerging treatment that may convert the patient to resectable disease, and may increase survival without major morbidity, as indicated by many small studies. In this review, we discuss the rationale and benefits of PIPAC, as well as sentinel papers describing its application for gastric, colorectal, appendiceal, and pancreatobiliary PMs. While no PIPAC device has yet met FDA approval, we discuss next steps needed to incorporate PIPAC into neoadjuvant/adjuvant treatment paradigms, as well as palliative settings. Data on active clinical trials using PIPAC are provided.

Response Evaluation in Patients with Peritoneal Metastasis Treated with Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC)

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) directed therapy emerged as a treatment of peritoneal metastasis (PM) a decade ago. The response assessment of PIPAC is not uniform. This narrative review describes non-invasive and invasive methods for response evaluation of PIPAC and summarizes their current status. PubMed and clinicaltrials.gov were searched for eligible publications, and data were reported on an intention-to-treat basis. The peritoneal regression grading score (PRGS) showed a response in 18-58% of patients after two PIPACs. Five studies showed a cytological response in ascites or peritoneal lavage fluid in 6-15% of the patients. The proportion of patients with malignant cytology decreased between the first and third PIPAC. A computed tomography showed stable or regressive disease following PIPAC in 15-78% of patients. The peritoneal cancer index was mainly used as a demographic variable, but prospective studies reported a response to treatment in 57-72% of patients. The role of serum biomarkers of cancer or inflammation in the selection of candidates for and responders to PIPAC is not fully evaluated. In conclusion, response evaluation after PIPAC in patients with PM remains difficult, but PRGS seems to be the most promising response evaluation modality.