The scientific report from the first pressurized intraperitoneal aerosol chemotherapy (PIPAC) procedures performed in the eastern part of Central Europe

Restricted access to innovative surgical technique related to a specific training, is it ethical? Example of the PIPAC procedure. A systematic review and an experts survey

OBJECTIVE

Using the example of Pressurized Intra Peritoneal Aerosol Chemotherapy (PIPAC), we analyse the development model of this procedure and provide an ethical analysis of the involvement of the industry in a new development.

SUMMARY BACKGROUND DATA

In the case of breakthrough innovation, medical training is essential for safe use of the new procedure. In some cases, pharmaceutical companies decide to organise this training. But when it becomes the only training opportunity to use the device, scientists and clinicians could be exposed to a conflict of interest?

METHODS

We performed a literature review of PIPAC publications using the STROBE criteria. Then, we conducted interviews with an expert panel to analyse the ethical impact of involvement of the industry in the development of the PIPAC procedure.

RESULTS

The number of publications has increased every year since the first publication in Germany, where the technology was developed in 2013. The scientific production was of good quality, with a mean STROBE score of 18.2 ± 2.4 out of 22 points. Ten of the 33 included studies declared a conflict of interest. From the interviews, the main axe concerning the implication of the industry was the training model. The company had decided that only trained and approval surgeon could perform the PIPAC procedure. All four interviewed practitioners agreed that it was initially a good way to implement the procedure safely, but later they felt uncomfortable about the control and validation by the industry.

CONCLUSION

Based on the growing number of published papers from a growing number of international centres, the controlled training model is not limiting. However, the different levels of conflict of interest complicate transparency, and we postulated that this development model is limited to the beginning of the procedure diffusion. CLINICALTRIAL.

GOV REGISTRATION

NCT04341337.

Pressurized intraperitoneal aerosol chemotherapy: a review of the introduction of a new surgical technology using the IDEAL framework

BACKGROUND

The IDEAL (Idea, Development, Evaluation, Assessment, Long-term study) framework is a scheme of investigation for innovative surgical therapeutic interventions. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a procedure based on laparoscopy to deliver intraperitoneal chemotherapy for peritoneal metastases, introduced in 2011. The aim of this article was to review literature on PIPAC and assess whether development of the technique has followed the IDEAL framework.

METHODS

A search of MEDLINE and Embase was carried out to identify scientific reports on PIPAC published between January 2000 and February 2019. The studies were categorized according to the IDEAL stages.

RESULTS

Eighty-six original research papers on PIPAC were identified. There were 23 stage 0, 18 stage 1, 25 stage 2a and six stage 2b studies. Protocol papers for stage 1, 2b and 3 studies, and trial registrations for stage 2a studies, were also identified. The number of centres publishing reports and the number of publications has increased each year. Overall, there has been progression through the IDEAL stages; however, about 60 per cent of clinical reports published in 2018 were stage 1 Idea-type studies.

CONCLUSION

Since its introduction, studies investigating PIPAC have progressed in line with the IDEAL framework. However, the majority of studies reported recently were stage 0 and 1 studies.

Colorectal peritoneal metastases: pathogenesis, diagnosis and treatment options - an evidence-based update

Peritoneal metastases confer the worst survival among all sites in patients with metastatic colorectal cancer. They develop largely through transcoelomic spread, with a sequence of events that allow cells to first detach from primary tumours, survive in the peritoneal environment, attach to the peritoneal surface of organs and migrate into the submesothelial space to create a microenvironment conducive to metastatic growth. Diagnostic challenges have previously hindered early identification of peritoneal metastases. While advances in diagnostic modalities have improved our ability to identify peritoneal metastases, lesions under 0.5 cm remain challenging to detect. The advent of cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC) can offer selected patients with colorectal peritoneal metastases a favourable long-term survival. Recent trials, however, have cast doubts on the efficacy of HIPEC, with the recent PRODIGE 7 trial showing no benefit from oxaliplatin based HIPEC in addition to good quality cytoreductive surgery in resectable disease. While peritoneal recurrence can be reliably predicted from high-risk features in primary tumours such as a perforated cancer, ovarian metastases or T4a cancers, the use of prophylactic second look surgery with HIPEC or adjuvant HIPEC failed to demonstrate any survival benefit in high-risk cases in recent clinical trials, raising further questions about the efficacy of HIPEC. With high failure rates from systemic chemotherapy in unresectable disease, novel surgical techniques such as pressurized intraperitoneal aerolized chemotherapy are being investigated in clinical trials worldwide. Further collaborative research is needed to explore newer avenues of treatment for this poor prognostic cohort.

Particle stability and structure on the peritoneal surface in pressurized intra-peritoneal aerosol chemotherapy (PIPAC) analysed by electron microscopy: First evidence of a new physical concept for PIPAC

Pressurized intra-peritoneal aerosol chemotherapy (PIPAC) has been introduced to the clinical setting as a novel approach for the treatment of peritoneal metastasis. The local interaction of chemoaerosol droplets with the peritoneal surface as well as their distribution pattern is considered the main advantage over conventional liquid intraperitoneal chemotherapy. The aim of the present study was to investigate the behavior of these aerosol particles during PIPAC application via electron microscopy. Solutions of doxycycline, liposomal doxorubicin and macrophage cells were aerosolized using an established ex-vivo model. PIPAC was performed on peritoneum samples via microcatheter (MC) at a pressure of 12 mmHg C02 at 27°C. Following PIPAC the surface structure of applied particles was measured via electron microscopy. The aerosol particle contact of doxycyclin created a nanofilm of ~200 nm height on the peritoneal surface, and this height was revealed to be independent of the size of the initial particle hitting. These nanofilm blocks of 'cylinders' are of different diameters depending on the initial aerosol particle hitting that spot. Diameters of these 'cylinders' are far wider than the original diameter of the initial aerosol particle. However, coated particles such as liposomal doxorubicin and macrophages remained intact following contact with the peritoneal surface. Based on this and other data, the concept that aerosol particles exhibit a gas-like behavior in the abdomen creating a therapeutic capnoperitoneum should be revised. Fluid aerosol particles collide with the peritoneum creating a nanofilm. The interaction of pressurized intraperitoneal aerosol on the peritoneum is therefore closer to the distribution of a liquid film than to that of a gas. Further studies are required to further analyze the interaction of this nanofilm on the peritoneum.