Feasibility of hyperthermic pressurized intraperitoneal aerosol chemotherapy in a porcine model

Hyperthermic pressurized intraperitoneal aerosol drug delivery system in a large animal model: a feasibility and safety study

BACKGROUND

We developed a novel drug delivery system called hyperthermic pressurized intraperitoneal aerosol chemotherapy (HPIPAC) that hybridized Hyperthermic intraperitoneal chemotherapy (HIPEC) and pressurized intraperitoneal aerosol chemotherapy (PIPAC). The present study aims to assess the feasibility and safety of HPIPAC system in a large animal survival model.

METHODS

Eleven pigs (eight non-survival models and three survival models) were used in the experiment. The heat module in the HPIPAC controller circulates hyperthermic CO2 in a closed-loop circuit and creates gas-based dry intraperitoneal hyperthermia. Three 12 mm trocars were placed on the abdomen. The afferent CO2 tube wound with heat generating coil was inserted into a trocar, and the efferent tube was inserted into another trocar. Heated CO2 was insufflated and circulated in a closed circuit until the intra-abdominal and peritoneal surface temperature reached 42 °C. 100 ml of 5% dextrose in water was nebulized for 5 min and the closed-loop circulation was resumed for 60 min at 42 °C. Tissue biopsies were taken from several sites from the pigs in the survival model.

RESULTS

The average change in core temperature of the pigs was 2.5 ± 0.08 °C. All three pigs displayed no signs of distress, and their vital signs remained stable, with no changes in their diet. In autopsy, inflammatory and fibrotic responses at the biopsy sites were observed without serious pathologic findings.

CONCLUSIONS

We successfully proved the feasibility and safety of our novel HPIPAC system in an in-vivo swine survival model.

Effects of Hyperthermia and Hyperthermic Intraperitoneal Chemoperfusion on the Peritoneal and Tumor Immune Contexture

Hyperthermia combined with intraperitoneal (IP) drug delivery is increasingly used in the treatment of peritoneal metastases (PM). Hyperthermia enhances tumor perfusion and increases drug penetration after IP delivery. The peritoneum is increasingly recognized as an immune-privileged organ with its own distinct immune microenvironment. Here, we review the immune landscape of the healthy peritoneal cavity and immune contexture of peritoneal metastases. Next, we review the potential benefits and unwanted tumor-promoting effects of hyperthermia and the associated heat shock response on the tumor immune microenvironment. We highlight the potential modulating effect of hyperthermia on the biomechanical properties of tumor tissue and the consequences for immune cell infiltration. Data from translational and clinical studies are reviewed. We conclude that (mild) hyperthermia and HIPEC have the potential to enhance antitumor immunity, but detailed further studies are required to distinguish beneficial from tumor-promoting effects.

Advances in Treatment Models of Advanced Gastric Cancer

The prognosis of advanced gastric cancer (AGC) is extremely poor, and the therapeutic effect of traditional palliative chemotherapy is far from satisfactory. To overcome this bottleneck, palliative surgery resection, perioperative chemotherapy combined with surgical resection, hyperthermic intraperitoneal chemotherapy (HIPEC), pressurized intraperitoneal aerosol chemotherapy (PIPAC), radiation therapy, molecular-targeted therapy have been explored in AGC. Although considerable progress has been achieved, there is still no overwhelming therapeutic method. Due to the high heterogeneity of AGC, it is particularly vital to reshaped the paradigm of gastric cancer therapy according to the characteristics of clinical classifications and molecular subtypes.

Establishment of an Experimental System for Intraperitoneal Chemotherapy in a Rat Model

AIM

To establish an experimental system for comparing different methods of intraperitoneal chemotherapy in a rat model.

MATERIALS AND METHODS

We used six-week-old Sprague-Dawley rats, and created an early postoperative intraperitoneal chemotherapy (EPIC) system using 18-gauge syringes and evacuators, and a hyperthermic intraperitoneal chemotherapy (HIPEC) system using two peristaltic pumps which controlled the flow rate and temperature. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) was achieved using a nozzle for dispersing aerosols at a flow rate up to 41.5 ml/min. The distribution and intensity of 0.2% trypan blue dye was compared among three methods.

RESULTS

The distribution was limited and the intensity was weak after EPIC, and the dye stained moderately in gravity-dependent regions after HIPEC. On the other hand, the distribution was the most comprehensive, and the intensity was the greatest after PIPAC.

CONCLUSION

This experimental system in a rat model may reflect the comparative effect among EPIC, HIPEC and PIPAC in humans.

Technology development of hyperthermic pressurized intraperitoneal aerosol chemotherapy (hPIPAC)

Background

Optimized drug delivery systems are needed for intraperitoneal chemotherapy. The aim of this study was to develop a technology for applying pressurized intraperitoneal aerosol chemotherapy (PIPAC) under hyperthermic conditions (hPIPAC).

Methods

This is an ex-vivo study in an inverted bovine urinary bladder (IBUB). Hyperthermia was established using a modified industry-standard device (Humigard). Two entry and one exit ports were placed. Warm-humid CO₂ was insufflated in the IBUB placed in a normothermic bath to simulate body thermal inertia. The temperature of the aerosol, tissue, and water bath was measured in real-time.

Results

Therapeutic hyperthermia (target tissue temperature 41–43 °C) could be established and maintained over 30 min. In the first phase (insufflation phase), tissue hyperthermia was created by insufflating continuously warm-humid CO₂. In the second phase (aerosolization phase), chemotherapeutic drugs were heated up and aerosolized into the IBUB. In a third phase (application phase), hyperthermia was maintained within the therapeutic range using an endoscopic infrared heating device. In a fourth phase, the toxic aerosol was discarded using a closed aerosol waste system (CAWS).

Discussion

We introduce a simple and effective technology for hPIPAC. hPIPAC is feasible in an ex-vivo model by using a combination of industry-standard medical devices after modification. Potential pharmacological and biological advantages of hPIPAC over PIPAC should now be evaluated.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00464-021-08567-y.

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.

Overcoming Drug Resistance by Taking Advantage of Physical Principles: Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC)

Theoretical considerations as well as comprehensive preclinical and clinical data suggest that optimizing physical parameters of intraperitoneal drug delivery might help to circumvent initial or acquired resistance of peritoneal metastasis (PM) to chemotherapy. Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC) is a novel minimally invasive drug delivery system systematically addressing the current limitations of intraperitoneal chemotherapy. The rationale behind PIPAC is: (1) optimizing homogeneity of drug distribution by applying an aerosol rather than a liquid solution; (2) applying increased intraperitoneal hydrostatic pressure to counteract elevated intratumoral interstitial fluid pressure; (3) limiting blood outflow during drug application; (4) steering environmental parameters (temperature, pH, electrostatic charge etc.) in the peritoneal cavity for best tissue target effect. In addition, PIPAC allows repeated application and objective assessment of tumor response by comparing biopsies between chemotherapy cycles. Although incompletely understood, the reasons that allow PIPAC to overcome established chemoresistance are probably linked to local dose intensification. All pharmacological data published so far show a superior therapeutic ratio (tissue concentration/dose applied) of PIPAC vs. systemic administration, of PIPAC vs. intraperitoneal liquid chemotherapy, of PIPAC vs. Hyperthermic Intraperitoneal Chemotherapy (HIPEC) or PIPAC vs. laparoscopic HIPEC. In the initial introduction phase, PIPAC has been used in patients who were quite ill and had already failed multiple treatment regimes, but it may not be limited to that group of patients in the future. Rapid diffusion of PIPAC in clinical practice worldwide supports its potential to become a game changer in the treatment of chemoresistant isolated PM of various origins.

A real-time ex vivo model (eIBUB) for optimizing intraperitoneal drug delivery as an alternative to living animal models

BACKGROUND

Optimization of intraperitoneal drug delivery systems requires functional models. We proposed the Inverted Bovine Urinary Bladder Model (IBUB), but IBUB does not allow repeated measurements over time and there is a significant biological variability between organs.

METHODS

A further development of IBUB is presented, based on the physical principle of communicating vessels. Fresh bovine bladders were inverted so that the peritoneum lines up the inner surface. The IBUB and a second vessel were then interconnected under the same CO2 pressure and placed on two scales. The therapeutic solution (Doxorubicin 2.7 mg and Cisplatin 13.5 mg) was delivered via an aerosolizer. All experiments were in triplicate and blinded to the origin of samples, measurements in a GLP-certified laboratory.

RESULTS

The enhanced IBUB (eIBUB) model allows measurements of tissue drug concentration, depth of tissue penetration and spatial distribution. The homogeneous morphology of the peritoneum enables standardized, multiple tissue sampling. eIBUB minimizes biological variability between different bladders and eliminates the bias caused by the liquid collecting at the bottom of the model. Concentration of doxorubicin in the eIBUB (mean ± STDV: 18.5 ± 22.6 ng/mg) were comparable to clinical peritoneal biopsies (19.2 ± 38.6 ng/mg), as was depth of drug penetration (eIBUB: mean (min-max) 433 (381-486) µm, clinical ~ 500 µm).

CONCLUSIONS

The eIBUB model is a simple and powerful ex vivo model for optimizing intraperitoneal drug delivery and represents an attractive alternative to animal models. Results obtained are similar to those obtained in the human patient.

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) might increase the risk of anastomotic leakage compared to HIPEC: an experimental study

BACKGROUND

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) and hyperthermic intraperitoneal chemotherapy (HIPEC) are technics proposed to treat patients with peritoneal carcinomatosis, in different settings. There is some concern about an over-risk of anastomotic leakage (AL) with PIPAC jeopardizing a combination with cytoreductive surgery. This study used a healthy swine model to compare the postoperative AL rate between PIPAC and HIPEC with digestive resection and to analyze macrocirculation and microcirculation parameters.

METHODS

Segmental colonic resection with a handsewn anastomosis was performed on 16 healthy pigs; 8 pigs had a PIPAC procedure with 7.5 mg/m² cisplatin (PIPAC group), and 8 pigs had a closed HIPEC procedure with 70 mg/m² cisplatin and 42 °C as the target intraperitoneal temperature (HIPEC group). Pigs were kept alive for 8 days, then sacrificed and autopsied to look for AL, which was defined as local abscess or digestive fluid leakage when pressure was applied to the anastomosis. Food intake, weight, and core temperature were monitored postoperatively. Macrocirculation (heart rate, systolic blood pressure) and microcirculation parameters (percentage of perfused vessels, perfused vessels density, DeBacker score) were evaluated intraoperatively at five timepoints. Results were compared between pigs with AL and those without.

RESULTS

The HIPEC group had no AL, but 3 of 8 pigs (37.5%) had AL in the PIPAC group (p = 0.20). Heart rate and core temperature showed perioperative increases in the HIPEC group. Intraoperatively, heart rate was higher in the HIPEC group at the two last timepoints (123 vs. 93 bpm, p = 0.031, and 110 vs. 85 bpm, p = 0.010, at timepoints 3 and 4, respectively). Other macrocirculatory and microcirculatory parameters showed no significant differences.

CONCLUSION

In this healthy swine model, PIPAC might have increased AL incidence compared to HIPEC. This potential over-risk did not seem to be related to changes in the microcirculation. PIPAC should probably not be used with digestive resection and should be avoided in cases of perioperative serosal injury.

Aerosolization of Nanotherapeutics as a Newly Emerging Treatment Regimen for Peritoneal Carcinomatosis

Recent advances in locoregional chemotherapy have opened the door to new approaches for the clinical management of peritoneal carcinomatosis (PC) by facilitating the delivery of anti-neoplastic agents directly to the tumor site, while mitigating adverse effects typically associated with systemic administration. In particular, an innovative intra-abdominal chemotherapeutic approach, known as Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC), was recently introduced to the intraperitoneal (IP) therapy regimens as a palliative therapeutic option in patients with PC, presumably providing a better drug distribution pattern together with deeper drug penetration into tumor nodules within the peritoneal space. Furthermore, the progress of nanotechnology in the past few decades has prompted the application of different nanomaterials in IP cancer therapy, offering new possibilities in this field ranging from an extended retention time to sustained drug release in the peritoneal cavity. This review highlights the progress, challenges, and opportunities in utilizing cancer nanotherapeutics for locoregional drug delivery, with a special emphasis on the aerosolization approach for intraperitoneal therapies.

Pressurized intraperitoneal aerosol chemotherapy and its effect on gastric-cancer-derived peritoneal metastases: an overview

This manuscript aspires to portray a review of the current literature focusing on manifest peritoneal metastasis (PM) derived from gastric cancer and its treatment options. Despite the development of chemotherapy and multimodal treatment options during the last decades, mortality remains high worldwide. After refreshing important epidemiological considerations, the molecular mechanisms currently accepted through which PM occurs are revised. Palliative chemotherapy is the only recommended treatment option for patients with PM of gastric cancer according to the National Comprehensive Cancer Network guidelines, although cytoreductive surgery in combination with hyperthermic intraperitoneal chemotherapy demonstrated promising results in selected patients with regional PM and localized intraabdominal tumor spread. A novel treatment named pressurized intraperitoneal aerosol chemotherapy may have a promising future in improving overall survival with an acceptable postoperative complication rate and stabilizing quality of life during treatment. Additionally, the procedure has been proved to be safe for the patient and medical personnel and a feasible, repeatable method to deter metastatic proliferation. This overview comprehensively addresses this novel and promising treatment in the context of a scientifically and clinically challenging disease.

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) for peritoneal carcinomatosis: systematic review of clinical and experimental evidence with special emphasis on ovarian cancer

BACKGROUND

Systemic chemotherapy is not effective in patients with peritoneal carcinomatosis (PC) and only a minority of affected patients is eligible for cytoreductive surgery. Intraperitoneal chemotherapy may provide a therapy alternative for these patients.

METHODS

We performed a systematic review of clinical and experimental evidence on the safety and efficacy of pressurized intraperitoneal aerosol chemotherapy (PIPAC) in patients with PC and provide clinical recommendations based on the available evidence.

RESULTS

Fifty-eight reports were identified, categorized as experimental (18 reports), clinical (28 reports), and other articles (14 reports). Experimental studies demonstrated improved tissue penetration and peritoneal coverage. The 28 clinical studies reported on 3515 procedures in 1547 patients with PC of various primary tumors with 16 of these studies reporting on patients with ovarian cancer. Toxicity was manageable. Based on 1197 patients in 22 studies, adverse events CTCAE grades 1, 2, 3, 4, and 5 were observed in 537 (45%), 167 (14%), 83 (7%), 10 (0.8%), and 19 (1.6%) cases, respectively. In a pooled analysis, the objective tumor response rate was 69% and the mean overall survival duration was 13.7 months. No significant hepatic, renal, or hematologic toxicity was described. PIPAC maintained and/or improved quality of life, as reported in 10 studies with 396 patients.

CONCLUSIONS

Available evidence from controlled trials (phase I and phase II) and retrospective cohort studies in > 1500 patients unequivocally demonstrates that PIPAC is feasible, safe, and effective. PIPAC maintains quality of life in patients with recurrent cancer and PC. PIPAC is as evidence-based as any other treatment in women with ovarian cancer and PC beyond the third line of systemic chemotherapy and can be recommended in this indication.

The use of PIPAC (pressurized intraperitoneal aerosol chemotherapy) in gynecological oncology: a statement by the "Arbeitsgemeinschaft Gynaekologische Onkologie Studiengruppe Ovarialkarzinom (AGO-OVAR)", the Swiss and Austrian AGO, and the North-Eastern German Society of Gynaecologic Oncology

BACKGROUND

Ovarian, tubal, and peritoneal carcinomas primarily affect the peritoneal cavity, and they are typically diagnosed at an advanced tumor stage (Foley, Rauh-Hain, del Carmen in Oncology (Williston Park) 27:288-294, 2013). In the course of primary surgery, postoperative tumor residuals are, apart from the tumor stage, the strongest independent factors of prognosis (du Bois, Reuss, Pujade-Lauraine, Harter, Ray-Coquard, Pfisterer in Cancer 115:1234-1244, 2009). Due to improved surgical techniques, including the use of multi-visceral procedures, macroscopic tumor clearance can be achieved in oncological centers, in most cases (Harter, Muallem, Buhrmann et al in Gynecol Oncol 121:615-619, 2011). However, to date, it has not been shown that peritoneal carcinomatosis is, per se, an independent factor of prognosis or that it excludes the achievement of tumor clearance. Several studies have shown that a preceding drug therapy in peritoneal carcinomatosis could positively influence the overall prognosis (Trimbos, Trimbos, Vergote et al in J Natl Cancer Inst 95:105-112, 2003). In relapses of ovarian carcinoma, studies have shown that peritoneal carcinomatosis is a negative predictor of complete tumor resection; however, when it is possible to resect the tumor completely, peritoneal carcinomatosis does not play a role in the prognosis (Harter, Hahmann, Lueck et al in Ann Surg Oncol 16:1324-1330, 2009).

RESULTS

PIPAC is a highly experimental method for treating patients with ovarian, tubal, and peritoneal cancer. To date, only three studies have investigated a total of 184 patients with peritoneal carcinomatosis (Grass, Vuagniaux, Teixeira-Farinha, Lehmann, Demartines, Hubner in Br J Surg 104:669-678, 2017). Only some of those studies were phase I/II studies that included PIPAC for patients with different indications and different cancer entities. It is important to keep in mind that the PIPAC approach is associated with relatively high toxicity. To date, no systematic dose-finding studies have been reported. Moreover, no studies have reported improvements in progression-free or overall survival associated with PIPAC therapy.

CONCLUSIONS

Randomized phase III studies are required to evaluate the effect of this therapy compared to other standard treatments (sequential or simultaneous applications with systemic chemotherapy). In cases of ovarian, tubal, and peritoneal cancer, PIPAC should not be performed outside the framework of prospective, controlled studies.

Systematic review of pressurized intraperitoneal aerosol chemotherapy for the treatment of advanced peritoneal carcinomatosis

BACKGROUND

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a minimally invasive approach under investigation as a novel treatment for patients with peritoneal carcinomatosis of various origins. The aim was to review the available evidence on mechanisms, clinical effects and risks.

METHODS

This was a systematic review of the literature on pressurized intraperitoneal chemotherapy published between January 2000 and October 2016. All types of scientific report were included.

RESULTS

Twenty-nine relevant papers were identified; 16 were preclinical studies and 13 were clinical reports. The overall quality of the clinical studies was modest; five studies were prospective and there was no randomized trial. Preclinical data suggested better distribution and higher tissue concentrations of chemotherapy agents in PIPAC compared with conventional intraperitoneal chemotherapy by lavage. Regarding technical feasibility, laparoscopic access and repeatability rates were 83-100 and 38-82 per cent. Surgery-related complications occurred in up to 12 per cent. Postoperative morbidity was low (Common Terminology Criteria for Adverse Events grade 3-5 events reported in 0-37 per cent), and hospital stay was about 3 days. No negative impact on quality of life was reported. Histological response rates for therapy-resistant carcinomatosis of ovarian, colorectal and gastric origin were 62-88, 71-86 and 70-100 per cent respectively.

CONCLUSION

PIPAC is feasible, safe and well tolerated. Preliminary good response rates call for prospective analysis of oncological efficacy.

Feasibility and Safety of Pressurized Intraperitoneal Aerosol Chemotherapy for Peritoneal Carcinomatosis: A Retrospective Cohort Study

Background. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) has been introduced as a novel repeatable treatment for peritoneal carcinomatosis. The available evidence from the pioneer center suggests good tolerance and high response rates, but independent confirmation is needed. A single-center cohort was analyzed one year after implementation for feasibility and safety. Methods. PIPAC was started in January 2015, and every patient was entered into a prospective database. This retrospective analysis included all consecutive patients operated until April 2016 with emphasis on surgical feasibility and early postoperative outcomes. Results. Forty-two patients (M : F = 8 : 34, median age 66 (59–73) years) with 91 PIPAC procedures in total (4×: 1,  3×: 17,  2×: 12, and  1×: 12) were analyzed. Abdominal accessibility rate was 95% (42/44); laparoscopic access was not feasible in 2 patients with previous HIPEC. Median initial peritoneal carcinomatosis index (PCI) was 10 (IQR 5–17). Median operation time was 94 min (89–108) with no learning curve observed. One PIPAC application was postponed due to intraoperative intestinal lesion. Overall morbidity was 9% with 7 minor complications (Clavien I-II) and one PIPAC-unrelated postoperative mortality. Median postoperative hospital stay was 3 days (2-3). Conclusion. Repetitive PIPAC is feasible in most patients with refractory carcinomatosis of various origins. Intraoperative complications and postoperative morbidity rates were low. This encourages prospective studies assessing oncological efficacy.

Inhibition of peritoneal dissemination of colon cancer by hyperthermic CO2 insufflation: A novel approach to prevent intraperitoneal tumor spread

BACKGROUND

The increasing use of laparoscopic surgery for advanced gastrointestinal cancer raises concerns about intra-peritoneal tumor spread. Prevention of peritoneal dissemination is extremely important but a preventive modality is lacking. The aim of this study was to examine a novel approach (hyperthermic CO2 insufflation, HT-CO2) for preventing peritoneal dissemination during laparoscopic surgery.

METHODS

A peritoneal dissemination model was established in Balb/c nu/nu mice by intraperitoneal injection of human colon cancer cells (SW1116, 1×106). The mice (n = 48) were subsequently randomized into two groups and subjected to hyperthermic CO2 (43°C, >95% humidity, HT-CO2 group) or standard normothermic CO2 (21°C, <1% relative humidity, NT-CO2 group) insufflation for 3 hours. The mice were sacrificed 28 days later. The peritoneal dissemination was quantitatively analyzed by counting and weighing the peritoneal nodules. The port sites and ascites volume were measured. The peritoneal damage of HT-CO2 was histologically examined with light microscopy and scanning electron microscopy. Intra-abdominal adhesions were evaluated 4 weeks later.

RESULTS

The number of peritoneal nodules in the HT-CO2 group was significantly less than that in the NT-CO2 group (10.21±3.72 vs. 67.12±5.49, P<0.01). The mean weight of metastatic tumors in the HT-CO2 group was significantly lower than that in the NT-CO2 group (0.31±0.10g vs. 2.16±0.31g, P<0.01). Massive ascites were found in the NT-CO2 group while significantly less ascites developed in HT-CO2- treated mice (8.26±0.31ml vs. 1.27±0.28ml, P<0.01). No port-site metastases were detected in the HT-CO2 group while the incidence of the NT-CO2 group was 12.5% (3/24). HT-CO2 subjection resulted in slight peritoneal damage; the peritoneum returned to normal within five days. No adhesions formed after HT-CO2 treatment.

CONCLUSIONS

HT-CO2 can suppress peritoneal dissemination of colon cancer cells and only causes slight and transient peritoneal damage. HT-CO2 may serve as a promising adjuvant treatment for preventing peritoneal dissemination in laparoscopic resection of advanced colorectal cancer.

Cytotoxic effect of different treatment parameters in pressurized intraperitoneal aerosol chemotherapy (PIPAC) on the in vitro proliferation of human colonic cancer cells

Background

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) has been recently reported as a new approach for intraperitoneal chemotherapy (IPC). By means of a patented micropump, the liquid chemotherapy is delivered into the peritoneal cavity as an aerosol which is supposed to achieve “gas-like” distribution. However, recent data report that the fraction of the submicron aerosol (gas-like) is less than 3 vol% of the total amount of aerosolized chemotherapy. Until today, possible modifications of treatment parameters during PIPAC with the aim of improving therapeutic outcomes have not been studied yet.

This study aims to establish an in vitro PIPAC model to explore the cytotoxic effect of the submicron aerosol fraction and to investigate the impact of different application parameters on the cytotoxic effect of PIPAC on human colonic cancer cells.

Methods

An in vitro model using HCT8 colon adenocarcinoma wild-type cells (HCT8^WT) and multi-chemotherapy refractory subline (HCT8^RT) was established. Different experimental parameters such as pressure, drug dosage, time exposure, and system temperature were monitored in order to search for the conditions with a higher impact on cell toxicity. Cell proliferation was determined by means of colorimetric MTT assay 48 h following PIPAC exposures.

Results

Standard operational parameters applied for PIPAC therapy depicted a cytotoxic effect of the submicron aerosol fraction generated by the PIPAC micropump. We also observed that increasing pressure significantly enhanced tumor cell toxicity in both wild-type and chemotherapy-resistant cells. A maximum of cytotoxicity was observed at 15 mmHg. Pressure >15 mmHg did not show additional cytotoxic effect on cells. Increased oxaliplatin dosage resulted in progressively higher cell toxicity as expected. However, in resistant cells, a significant effect was only found at higher drug concentrations. Neither an extension of exposure time nor an increase in temperature of the aerosolized chemotherapy solution added an improvement in cytotoxicity.

Conclusions

In this in vitro PIPAC model, the gas-like PIPAC aerosol fraction showed a cytotoxic effect which was enhanced by higher intra-abdominal pressure with a maximum at 15 mmHg. Similar findings were observed for drug dose escalation. A phase I dose escalation study is currently performed at our institution. However, increasing the intra-abdominal pressure might be a first and simple way to enhance the cytotoxic effect of PIPAC therapy which needs further clinical investigations.

Electronic supplementary material

The online version of this article (doi:10.1186/s12957-017-1109-4) contains supplementary material, which is available to authorized users.

Pharmacokinetic problems in peritoneal drug administration: an update after 20 years

Intraperitoneal chemotherapy has demonstrated significant pharmacologic and clinical advantage over traditional intravenous administration for cancers that are restricted to the peritoneal cavity. The combination of cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC) has become the standard technique used to fight ovarian and gastrointestinal cancers in many centers. However, challenges remain for HIPEC to contact the entire peritoneal surface, penetrate the tumor tissue, and transport to the lymphatics and other metastatic sites. New innovations in delivery technique, such as heated aerosol, and in delivery molecules, such as microparticles, nanoparticles, nanogels, and tumor-penetrating peptides are being tested in animal models and will likely soon be in human trials. Improvements in overall care, such as the recent clinical trial of an oral agent for maintenance therapy in ovarian carcinoma, will continue in this field for the next 20 years.

Environmental safety during the administration of Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC)

Background

Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC) is an innovative technique for intraperitoneal drug delivery. This study investigates the efficacy of the occupational health safety measures taken to prevent exposition of healthcare workers to the toxic chemotherapy aerosol.

Methods

Air samples were taken at the working place of the surgeon and of the anesthetist during 2 PIPAC procedures and analyzed for content of platinum by inductively coupled plasma mass spectrometry (ICP-MS). Airborne particles were quantified in real time. Biological monitoring was performed in two surgeons after 50 PIPAC by examining blood samples for possible traces of platinum. Analysis was performed by an independent company.

Results

Safety measures included tightly closed abdomen, operating room (OR), ventilation meeting requirements of ISO norm 14644-1 class 5, closed aerosol waste system and remote control of PIPAC administration. No traces of platinum were found in the air of the OR (detection limit of 0.0001 mg/filter). No specific rise in particle concentration was detected in the air during the PIPAC procedure, patient closure and removal of the sterile drapes. Blood samples of the surgeons showed no traces of platinum.

Conclusions

After implementation of adequate safety measures, no signs of environmental contamination or biological exposure of the surgeons were detected during PIPAC.

Functional vascular anatomy of the peritoneum in health and disease

The peritoneum consists of a layer of mesothelial cells on a connective tissue base which is perfused with circulatory and lymphatic vessels. Total effective blood flow to the human peritoneum is estimated between 60 and 100 mL/min, representing 1-2 % of the cardiac outflow. The parietal peritoneum accounts for about 30 % of the peritoneal surface (anterior abdominal wall 4 %) and is vascularized from the circumflex, iliac, lumbar, intercostal, and epigastric arteries, giving rise to a quadrangular network of large, parallel blood vessels and their perpendicular offshoots. Parietal vessels drain into the inferior vena cava. The visceral peritoneum accounts for 70 % of the peritoneal surface and derives its blood supply from the three major arteries that supply the splanchnic organs, celiac and superior and inferior mesenteric. These vessels give rise to smaller arteries that anastomose extensively. The visceral peritoneum drains into the portal vein. Drugs absorbed are subject to first-pass hepatic metabolism. Peritoneal inflammation and cancer invasion induce neoangiogenesis, leading to the development of an important microvascular network. Anatomy of neovessels is abnormal and characterized by large size, varying diameter, convolution and blood extravasation. Neovessels have a defective ultrastructure: formation of large "mother vessels" requires degradation of venular and capillary basement membranes. Mother vessels give birth to numerous "daughter vessels". Diffuse neoangiogenesis can be observed before appearance of macroscopic peritoneal metastasis. Multiplication of the peritoneal capillary surface by neoangiogenesis surface increases the part of cardiac outflow directed to the peritoneum.

Electrostatic precipitation Pressurized IntraPeritoneal Aerosol Chemotherapy (ePIPAC): first in-human application

Background: Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC) is a drug delivery technique with superior pharmacological properties for treating peritoneal metastasis (PM). Adding electrostatic loading (ePIPAC) as an adjunct to aerosol and artificial hydrostatic pressure improved tissue uptake in a preclinical model. Methods: We report the first ePIPAC use in 3 patients with PM of hepatobiliary-pancreatic (HBP) origin. All 3 patients received concomitant palliative systemic chemotherapy that was discontinued in two patients. PIPAC with cisplatin 7.5 mg/m2 and doxorubicin 1.5 mg/m2 was applied intraperitoneally at a pressure of 12 mmHg and a temperature of 37% °C for 30 min. Additionally, a voltage 7,500-9,500 V and a current≤10 µA were applied over a stainless steel brush electrode emitting a stream of electrons. Results: ePIPAC was technically feasible. No intraoperative complication was noted. The procedures were well tolerated with no adverse event CTCAE > 2. Patient 1 with PM of unknown origin (CUP with HBP phenotype) showed an objective histological and radiological response and survived 11 months. Patient 2 with ductal pancreatic cancer underwent secondary resection after ePIPAC with no residual PM; however, tumor recurred 5 months later. Patient 3 with adenocarcinoma of the gallbladder showed a radiological regression of liver infiltration and is alive after 22 months without histological evidence of PM. Conclusion: ePIPAC is technically feasible, is well tolerated and can induce tumor regression of PM in HBP cancers with and without concomitant systemic chemotherapy. These preliminary results justify prospective clinical studies with ePIPAC.