MESOTIP: Phase II multicenter randomized trial evaluating the association of PIPAC and systemic chemotherapy vs. systemic chemotherapy alone as 1st-line treatment of malignant peritoneal mesothelioma

Standardizing eligibility and patient selection for Pressurized Intraperitoneal Aerosol Chemotherapy: A Delphi consensus statement

INTRODUCTION

Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC) is a procedure for minimally invasive drug administration in patients with peritoneal metastasis. Previous studies have emphasized the importance of uniformity in treatment protocols and standardization of this practice. This study aimed to reach a consensus on eligibility, patient selection, and choice of chemotherapy for PIPAC.

METHODS

A three-round modified Delphi study was conducted. A steering group formulated a list of baseline statements, addressing the objectives. The steering group consisted of seven expert surgical and medical oncologists. Available evidence and published key opinions were critically reviewed. An international expert panel scored those statements on a 4-point Likert scale. The statements were submitted electronically and anonymously. Consensus was reached if the agreement rate was ≥75%. A minimum Cronbach's alpha of >0.8 was set.

RESULTS

Forty-five (45/58; 77.6%) experts participated and completed all rounds. Experts were digestive surgeons (n = 28), surgical oncologists (n = 7), gynecologists (n = 5), medical oncologists (n = 4), and one clinical researcher. Their assessment of 81 preliminary statements in the first round resulted in 41 consolidated statements. In round two, consensus was reached on 40 statements (40/41; 97.6%) with a consensus of ≥80% for each individual statement. In the third round, 40 statements were unanimously approved as definitive. The choice of first- and second-line chemotherapy remained controversial and could not reach consensus.

CONCLUSIONS

This International Delphi study provides practical guidance on eligibility and patient selection for PIPAC. Ongoing trial data and long-term results that could contribute to the further standardization of PIPAC are eagerly awaited.

The effect of electrostatic high pressure nebulization on the stability, activity and ex vivo distribution of ionic self-assembled nanomedicines

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is applied to treat unresectable peritoneal metastasis (PM), an advanced, end-stage disease with a poor prognosis. Electrostatic precipitation of the aerosol (ePIPAC) is aimed at improving the intraperitoneal (IP) drug distribution and tumor penetration. Also, the combination of nanoparticles (NPs) as drug delivery vehicles and IP aerosolization as administration method has been proposed as a promising tool to treat PM. There is currently limited knowledge on how electrostatic precipitation (ePIPAC) and high pressure nebulization (PIPAC) affects the performance of electrostatically formed complexes. Therefore, the stability, in vitro activity and ex vivo distribution and tissue penetration of negatively charged cisPt-pArg-HA NPs and positively charged siRNA-RNAiMAX NPs was evaluated following PIPAC and ePIPAC. Additionally, a multidirectional Medspray® nozzle was developed and compared with the currently used Capnopen® nozzle. For both NP types, PIPAC and ePIPAC did not negatively influence the in vitro activity, although limited aggregation of siRNA-RNAiMAX NPs was observed following nebulization with the Capnopen®. Importantly, ePIPAC was linked to a more uniform distribution and higher tissue penetration of the NPs aerosolized by both nozzles, independent on the NPs charge. Finally, compared to the Capnopen®, an increased NP deposition was observed at the top of the ex vivo model following aerosolization with the Medspray® nozzle, which indicates that this device possesses great potential for IP drug delivery purposes. STATEMENT OF SIGNIFICANCE: Aerosolized drug delivery in the peritoneal cavity holds great promise to treat peritoneal cancer. In addition, electrostatic precipitation of the aerosol to the peritoneal tissue is aimed at improving the drug distribution and tumor penetration. The combination of nanoparticles (NPs), which are nano-sized drug delivery vehicles, and aerosolization has been proposed as a promising tool to treat peritoneal cancer. However, there is currently limited knowledge on how electrostatic precipitation and aerosolization affect the performance of electrostatically formed NPs. Therefore, the stability, activity, distribution and penetration of negatively and positively charged NPs was evaluated after aerosolization and electrostatic precipitation. Additionally, to further optimize the local drug distribution, a multidirectional spray nozzle was developed and compared with the currently used nozzle.

Smart hydrogels delivered by high pressure aerosolization can prevent peritoneal adhesions

Postoperative peritoneal adhesions occur in the majority of patients undergoing intra-abdominal surgery and are one of the leading causes of hospital re-admission. There is an unmet clinical need for effective anti-adhesive biomaterials, which can be applied evenly across the damaged tissues. We examined three different responsive hydrogel types, i.e. a thermosensitive PLGA-PEG-PLGA, a pH responsive UPy-PEG and a shear-thinning hexapeptide for this purpose. More specifically, their potential to be homogeneously distributed in the peritoneal cavity by high pressure nebulization and prevent peritoneal adhesions was evaluated. Solutions of each polymer type could be successfully nebulized while retaining their responsive gelation behavior in vitro and in vivo. Furthermore, none of the polymers caused in vitro toxicity on SKOV3-IP2 cells. Following intraperitoneal administration, both the PLGA-PEG-PLGA and the hexapeptide hydrogels resulted in local inflammation and fibrosis and failed in preventing peritoneal adhesions 7 days after adhesion induction. In contrast, the pH sensitive UPy-PEG formulation was well tolerated and could significantly reduce the formation of peritoneal adhesions, even outperforming the commercially available Hyalobarrier® as positive control. To conclude, local nebulization of the bioresponsive UPy-PEG hydrogel can be considered as a promising approach to prevent postsurgical peritoneal adhesions.

Peritoneal Mesothelioma in a High Volume Peritoneal Surface Malignancies Unit

Diffuse malignant peritoneal mesothelioma (PM) is a rare neoplasm, traditionally associated with a poor prognosis. There are other varieties of PM that are even less frequent and of uncertain malignancy. Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) has achieved prolonged survival in selected patients. The aim of this study is to analyze the patients with PM assessed in our center. Clinicopathological characteristics, diagnostic procedures and survival results from patients with PM appraised at our unit, according to the applied treatment, were analyzed. Seventeen patients were assessed between 2007 and 2019. Three cases had multicystic PM that were treated with complete CRS + HIPEC; all patients are alive and free of disease after a long follow-up. Three other cases had biphasic PM; a curative treatment could be performed in none of them, and their survival was minimal (<6 moths). Lastly, 11 cases with epithelioid PM were treated. Two cases were considered unresectable at laparoscopy (PCI 39); one of them had a long survival (67 months) with three iterative laparoscopic palliatives HIPECs for refractory ascites. The other nine cases were treated with curative CRS + HIPEC, with a median PCI of 14 (range 4–25), and a median overall survival (OS) of 58 months, with a 5-year OS of 47.4%. In conclusion, CRS + HIPEC, when possible, appears to be the optimal treatment for patients with PM. Knowledge of this therapeutic option is crucial, both to offer it to patients and to avoid delays in their referral to appropriate centers for treatment.

Advances in the management of peritoneal malignancies

Peritoneal surface malignancies (PSMs) are usually associated with a poor prognosis. Nonetheless, in line with advances in the management of most abdominopelvic metastatic diseases, considerable progress has been made over the past decade. An improved understanding of disease biology has led to the more accurate prediction of neoplasia aggressiveness and the treatment response and has been reflected in the proposal of new classification systems. Achieving complete cytoreductive surgery remains the cornerstone of curative-intent treatment of PSMs. Alongside centralization in expert centres, enabling the delivery of multimodal and multidisciplinary strategies, preoperative management is a crucial step in order to select patients who are most likely to benefit from surgery. Depending on the specific PSM, the role of intraperitoneal chemotherapy and of perioperative systemic chemotherapy, in particular, in the neoadjuvant setting, is established in certain scenarios but questioned in several others, although more prospective data are required. In this Review, we describe advances in all aspects of the management of PSMs including disease biology, assessment and improvement of disease resectability, perioperative management, systemic therapy and pre-emptive management, and we speculate on future research directions.

Primary and metastatic peritoneal surface malignancies

Peritoneal surface malignancies comprise a heterogeneous group of primary tumours, including peritoneal mesothelioma, and peritoneal metastases of other tumours, including ovarian, gastric, colorectal, appendicular or pancreatic cancers. The pathophysiology of peritoneal malignancy is complex and not fully understood. The two main hypotheses are the transformation of mesothelial cells (peritoneal primary tumour) and shedding of cells from a primary tumour with implantation of cells in the peritoneal cavity (peritoneal metastasis). Diagnosis is challenging and often requires modern imaging and interventional techniques, including surgical exploration. In the past decade, new treatments and multimodal strategies helped to improve patient survival and quality of life and the premise that peritoneal malignancies are fatal diseases has been dismissed as management strategies, including complete cytoreductive surgery embedded in perioperative systemic chemotherapy, can provide cure in selected patients. Furthermore, intraperitoneal chemotherapy has become an important part of combination treatments. Improving locoregional treatment delivery to enhance penetration to tumour nodules and reduce systemic uptake is one of the most active research areas. The current main challenges involve not only offering the best treatment option and developing intraperitoneal therapies that are equivalent to current systemic therapies but also defining the optimal treatment sequence according to primary tumour, disease extent and patient preferences. New imaging modalities, less invasive surgery, nanomedicines and targeted therapies are the basis for a new era of intraperitoneal therapy and are beginning to show encouraging outcomes.

Consensus guidelines for pressurized intraperitoneal aerosol chemotherapy: Technical aspects and treatment protocols

BACKGROUND

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is increasingly used to treat patients with peritoneal cancer. A recent survey demonstrated considerable diversification of current practice of PIPAC raising issues of concern also regarding safety and efficacy. The study aim was to reach consensus on best practice of PIPAC treatment.

METHODS

Current practice was critically discussed during an expert meeting and the available evidence was scrutinized to elaborate a 33-item closed-ended questionnaire. All active PIPAC centers were then invited to participate in an online two-round Delphi process with 3 reminders at least. Consensus was defined a priori as >70% agreement for a minimal response rate of 70%.

RESULTS

Forty-nine out of 57 invited PIPAC centers participated in Delphi 1 and 2 (86%). Overall, there was agreement for 21/33 items. Consensus was reached for important aspects like advanced OR ventilation system (91.8%), remote monitoring (95.9%), use of the PRGS (85.7%) and use of a safety checklist (98%). The drug regimens oxaliplatin (87.8%) and cisplatin/doxorubicin (81.6%) were both confirmed by the expert panel. Important controversies included number and location of Biopsies during repeated PIPAC and the combination of PIPAC with additional surgical procedures.

CONCLUSION

This consensus statement aims to allow for safe and efficacious PIPAC treatment and to facilitate multi-center analyses of the results. Additional preclinical and clinical studies are needed to resolve the remaining controversies.

Non-resectable Malignant Peritoneal Mesothelioma Treated with Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC) Plus Systemic Chemotherapy Could Lead to Secondary Complete Cytoreductive Surgery: A Cohort Study

BACKGROUND

Diffuse malignant peritoneal mesothelioma (DMPM) is an aggressive primary peritoneal neoplasia. At diagnosis, few patients are eligible for a recommended cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Among neoadjuvant strategies, pressurized intraperitoneal aerosol chemotherapy (PIPAC) combined with systemic chemotherapy has been recently proposed. This study evaluated this strategy in a cohort of DMPM patients.

METHODS

Patients with DMPM and primary or recurrent non-resectable diseases who received at least one PIPAC procedure in alternation with systemic chemotherapy were included in this retrospective study to analyze oncologic outcomes.

RESULTS

Overall, 26 DMPM patients were treated with at least one PIPAC, including 20 patients with no previous CRS. Of 22 patients (85%) who had symptoms, 9 had perceptible ascites. Overall, 79 PIPAC procedures were performed, with half of the patients receiving three PIPAC procedures or more. Among eight patients (31%), 10 adverse events (13% of procedures) were reported, including two severe complications, both corresponding to digestive perforations. Improvement of symptoms was reported for 32% of the patients, whereas control of ascites was noted in 46%. All but one procedure among 14 patients (54%) secondarily treated by CRS-HIPEC were considered complete resections. After a median follow-up period of 29.6 months (95% confidence interval [CI], 17.6-not reached [NR]), the median overall survival period was 12 months (95% CI 11.1-NR). The median progression-free survival (PFS) was significantly better among the patients who underwent resection than among those who did not (33.5 vs 7.4 months; hazard ratio [HR], 0.18; 95% CI 0.06-0.755; p < 0.001).

CONCLUSIONS

For patients with initially non-resectable DMPM, PIPAC is feasible for treatment with neoadjuvant intent and could facilitate complete secondary resection.

The ISSPP PIPAC database: design, process, access, and first interim analysis

Objectives

Several trials have documented the favorable safety profile, and promising clinical results of pressurized intraperitoneal aerosol chemotherapy (PIPAC) directed treatment in different types of peritoneal malignancies. However, until the results of randomized trials are available, the quality of documentation and acceptance by the users may be improved through a worldwide registry. The International Society for the Study of Pleura and Peritoneum (www.ISSPP.org) facilitated this process by creating a dedicated focus group and providing the funding needed for the creation and implementation of an international database. This article describes the design and the journey of establishing this international database and the first, preliminary results from the ISSPP PIPAC online database.

Methods

In 2019 the ISSPP PIPAC Registry Group started to create a database with a minimal dataset relevant to many diseases and applicable in different framework conditions. The task was divided into three phases including design, testing, implementation, protocol, handbook, legal requirements, as well as registry rules and bylaws for the registry group.

Results

The ISSPP PIPAC online database has six key elements (patient, consent, treatment, complications, response evaluation and follow-up). Following design, testing and implementation the database was successfully launched in June 2020. Ten institutions reported on 459 PIPAC procedures in 181 patients during the first 6 months, and the recorded data were comparable to the present literature.

Conclusions

A new international multicenter PIPAC database has been developed, tested and implemented under the auspices of ISSPP. The database is accessible through the ISSPP website (www.ISSPP.org), and PIPAC institutions worldwide are highly encouraged to participate.

Exploring High Pressure Nebulization of Pluronic F127 Hydrogels for Intraperitoneal Drug Delivery

Peritoneal metastasis is an advanced cancer type which can be treated with pressurized intraperitoneal aerosol chemotherapy (PIPAC). Here, chemotherapeutics are nebulized under high pressure in the intraperitoneal (IP) cavity to obtain a better biodistribution and tumor penetration. To prevent the fast leakage of chemotherapeutics from the IP cavity, however, nebulization of controlled release formulations is of interest. In this study, the potential of the thermosensitive hydrogel Pluronic F127 to be applied by high pressure nebulization is evaluated. Therefore, aerosol formation is experimentally examined by laser diffraction and theoretically simulated by computational fluid dynamics (CFD) modelling. Furthermore, Pluronic F127 hydrogels are subjected to rheological characterization after which the release of fluorescent model nanoparticles from the hydrogels is determined. A delicate equilibrium is observed between controlled release properties and suitability for aerosolization, where denser hydrogels (20% and 25% w/v Pluronic F127) are able to sustain nanoparticle release up to 30 hours, but cannot effectively be nebulized and vice versa. This is demonstrated by a growing aerosol droplet size and exponentially decreasing aerosol cone angle when Pluronic F127 concentration and viscosity increase. Novel nozzle designs or alternative controlled release formulations could move intraperitoneal drug delivery by high pressure nebulization forward.

Pressurized Intraperitoneal Aerosol Chemotherapy-Related Clinical Trials in the Treatment of Peritoneal Metastases

INTRODUCTION

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a treatment option for patients with peritoneal metastases. We evaluated the current status of ongoing prospective clinical trials investigating PIPAC to provide an overview and predict trends in this field.

METHODS

All 367,494 records of clinical trials registered at ClinicalTrials.gov were searched for trials dealing with PIPAC. Active or unpublished trials were further analyzed.

RESULTS

In total, 22 clinical trials were identified and selected for further analyses. Most trials had a single-arm design and were phase I or II. No phase III trials were registered. Academic centers were recorded as primary sponsors in the majority of trials (63.6%). Every year, between 2 and 5 new trials were initiated. In 17 trials (81.8%), PIPAC was used in a palliative setting only, 2 trials performed PIPAC in a neoadjuvant setting, and 2 trials performed PIPAC in an adjuvant setting. Six different drugs (doxorubicin, cisplatin, oxaliplatin, nab-paclitaxel, 5-fluorouracil, and docetaxel) were used in these clinical trials. Most trials investigated the efficacy (n = 15) or safety (n = 7) of PIPAC therapies.

CONCLUSIONS

The results of ongoing clinical trials will bring specific information on indications for PIPAC as well as the impact of PIPAC on quality of life and overall survival.

Systemic Chemotherapy Including Ramucirumab in Combination With Pressurized Intra-Peritoneal Aerosol Chemotherapy Is a Safe Treatment Option for Peritoneal Metastasis of Gastric Cancer

Background

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a laparoscopic technique for local chemotherapy. It has been used for treatment of peritoneal metastasis of gastric cancer (PM GC) in combination with systemic therapy. VEGFR2 antagonist ramucirumab is a second-line therapy for GC, and has been suspected to cause wound healing disorders.

Methods

This is a retrospective single center cohort study of patients with PM GC, who received PIPAC treatment in combination with systemic chemotherapy with and without ramucirumab. Data on patients’ characteristics and their perioperative courses were collected and complication rates were compared with regard to preoperative use of ramucirumab and time between last dose of systemic therapy and PIPAC treatment.

Results

Fifty patients underwent 90 PIPAC treatments for PM GC in 3 years. Overall postoperative morbidity was 11% with 6% severe complications. The mean interval between systemic therapy and PIPAC was 20 days. Neither the length of interval nor the use of ramucirumab had an effect on complication rates.

Conclusion

Our study suggests that addition of ramucirumab to pre-PIPAC systemic therapy, irrespective of the length of the treatment-free interval before PIPAC, does not increase the risk of postoperative complications and is therefore a safe option for treatment of PM GC.

The emergence of pressurized intraperitoneal aerosol chemotherapy as a palliative treatment option for patients with diffuse peritoneal metastases: a narrative review

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is an emerging palliative treatment for patients with unresectable peritoneal metastases. Potential advantages of PIPAC over current treatment options are a homogeneous intraperitoneal distribution, low local and systemic toxicity, and enhanced tumour penetration. Given these possible benefits, PIPAC is increasingly implemented in many centres worldwide. Scientific research into PIPAC is currently available from in vitro/in vivo/in animal studies, retrospective cohorts in humans, and phase I and II studies in humans. There are no results from randomised trials comparing PIPAC with conventional treatment, such as palliative systemic therapy. This narrative review aimed to provide an overview of the currently available literature on PIPAC. In general, repetitive PIPAC was feasible and safe for patients and operating room personnel. Primary and secondary non-access rates varied from 0-17% and 0-15%, respectively. Iatrogenic bowel injury was observed in 0-3% of PIPAC procedures. CTCAE grade 1-2 complications were common, mostly consisting of abdominal pain, nausea, vomiting, and fatigue. CTCAE grade 3-4 complications were uncommon, occurring on 0-15% of PIPAC procedures. Post-operative mortality rates of 0-2% were reported. The risk of occupational exposure to cytotoxic drugs was very low when strict safety guidelines were followed. Clinical heterogeneity was high in most studies, since, in general, patients with unresectable peritoneal metastases from a variety of primary tumours were included. Also, patients received either PIPAC monotherapy or PIPAC combined with concomitant systemic therapy, and were able to receive PIPAC in any line of palliative treatment. Since the results were generally not stratified for these three important factors, this severely complicates the interpretation of results. Based on the current literature, PIPAC may be regarded as a promising palliative treatment option in patients with diffuse peritoneal metastases. Initial results show that it is feasible and safe. However, well designed and (ideally) randomized controlled trials are urgently needed to determine the additional value of PIPAC in this setting. Until then, PIPAC should preferably be performed in the setting of clinical trials.

Intraperitoneal Chemotherapy for Peritoneal Metastases: Technical Innovations, Preclinical and Clinical Advances and Future Perspectives

(1) Background: Tumors of the peritoneal serosa are called peritoneal carcinosis. Their origin may be primary by primitive involvement of the peritoneum (peritoneal pseudomyxoma, peritoneal mesothelioma, etc.). This damage to the peritoneum can also be a consequence of the dissipation of cancers-in particular, digestive (stomach, pancreas, colorectal, appendix) and gynecological (ovaries) ones in the form of metastases. The aim of the treatment is a maximal reduction of the macroscopic disease called "cytoreduction" in combination with hyperthermic intra-abdominal chemotherapy to treat residual microscopic lesions. (2) Methods: In this narrative review, we fundamentally synthetize the evolution of this process over time and its impact on clinical applications. (3) Results: Over the last past decade, different evolutions concerning both delivery modes and conditions concerning hyperthermic intra-abdominal chemotherapy have been realized. (4) Conclusion: The final objective of these evolutions is the improvement of the global and recurrence-free survival of primary and secondary malignant peritoneal pathologies. However, more large randomized controlled trials are needed to demonstrate the efficacy of such treatments with the help of molecular biology and genetics.

Current practice of pressurized intraperitoneal aerosol chemotherapy (PIPAC): Still standardized or on the verge of diversification?

BACKGROUND

PIPAC is a new treatment modality for peritoneal cancer which has been practiced and evaluated until very recently by few academic centers in a highly standardized manner. Encouraging oncological outcomes and the safety profile have led to widespread adoption. The aim of this study was to assess current PIPAC practice in terms of technique, treatment and safety protocol, and indications.

METHODS

A standardized survey with 82 closed-ended questions was sent online to active PIPAC centers which were identified by help of PIPAC training centers and the regional distributors of the PIPAC-specific nebulizer. The survey inquired about center demographics (n = 8), technique (n = 34), treatment and safety protocol (n = 34), and indications (n = 6).

RESULTS

Overall, 62 out of 66 contacted PIPAC centers answered the survey (response rate 93%). 27 centers had performed >60 PIPAC procedures. A consensus higher than 70% was reached for 37 items (50%), and higher than 80% for 28 items (37.8%). The topics with the highest degree of consensus were safety and installation issues (93.5% and 80.65%) while chemotherapy and response evaluation were the least consensual topics (63.7 and 59.6%). The attitudes were not influenced by volume, PIPAC starting year, type of activity, or presence of peritoneal metastases program.

CONCLUSION

Homogeneous treatment standards of new techniques are important to guarantee safe implementation and practice but also to allow comparison between cohorts and multi-center analysis of merged data including registries. Efforts to avoid diversification of PIPAC practice include regular update of the PIPAC training curriculum, targeted research and a consensus statement.

Pressurized intraperitoneal aerosol chemotherapy with cisplatin and doxorubicin or oxaliplatin for peritoneal metastasis from pancreatic adenocarcinoma and cholangiocarcinoma

Background

Systemic chemotherapy for pancreatic adenocarcinoma (PDAC) and cholangiocarcinoma (CC) with peritoneal metastases (PM) is affected by several pharmacological shortcomings and low clinical efficacy. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is expected to maximize exposure of peritoneal nodules to antiblastic agents. This study aims to evaluate safety and efficacy of PIPAC for PM of PDAC and CC origin.

Methods

This is a retrospective analysis of consecutive PDAC and CC cases with PM treated with PIPAC at two European referral centers for peritoneal disease. We prospectively recorded from August 2016 to May 2019 demographic, clinical, surgical, and oncological data. We performed a feasibility and safety assessment and an efficacy analysis based on clinical and pathological regression.

Results

Twenty patients with PM from PDAC (14) and CC (six) underwent 45 PIPAC administrations. Cisplatin-doxorubicin or oxaliplatin were administered to eight and 12 patients, respectively. We experienced one intraoperative complication (small bowel perforation) and 18 grade 1-2 postoperative adverse events according to Common Terminology Criteria for Adverse Events version 4.0. A pathological regression was recorded in 50% of patients (62% in the cisplatin-doxorubicin cohort and 42% in the oxaliplatin one). Median survival from the first PIPAC was 9.7 and 10.9 months for PDAC and CC, respectively.

Conclusion

PIPAC resulted feasible and safe without relevant toxicity issues, with both cisplatin-doxorubicin and oxaliplatin. The pathological response observed supports the evidence of antitumoral activity. Despite the study limitations, these outcomes are encouraging, recommending PIPAC in prospective, controlled trials in the palliative setting or the first line chemotherapy for PM from PDAC and CC.

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.