Distribution pattern and penetration depth of doxorubicin after pressurized intraperitoneal aerosol chemotherapy (PIPAC) in a postmortem swine model

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.

Anatomical Targeting of Anticancer Drugs to Solid Tumors Using Specific Administration Routes: Review

Despite remarkable recent progress in developing anti-cancer agents, outcomes of patients with solid tumors remain unsatisfactory. In general, anti-cancer drugs are systemically administered through peripheral veins and delivered throughout the body. The major problem with systemic chemotherapy is insufficient uptake of intravenous (IV) drugs by targeted tumor tissue. Although dose escalation and treatment intensification have been attempted in order to increase regional concentrations of anti-tumor drugs, these approaches have produced only marginal benefits in terms of patient outcomes, while often damaging healthy organs. To overcome this problem, local administration of anti-cancer agents can yield markedly higher drug concentrations in tumor tissue with less systemic toxicity. This strategy is most commonly used for liver and brain tumors, as well as pleural or peritoneal malignancies. Although the concept is theoretically reasonable, survival benefits are still limited. This review summarizes clinical results and problems and discusses future directions of regional cancer therapy with local administration of chemotherapeutants.

Triple-Therapy of Peritoneal Metastasis-Partial-Dehydration under Hyperthermic Condition Combined with Chemotherapy: The First Preliminary In-Vitro Results

A newly introduced combination of intraperitoneal dehydration and hyperthermia has recently been shown to be feasible and cytotoxic for colon cancer cells in vivo. For the first time, our study now aims to evaluate dehydration under hyperthermic conditions combined with chemotherapy for potential use in the clinical setting. In this study, in vitro colon cancer cells (HT-29) were subjected to single or several cycles of partial dehydration under hyperthermic conditions (45 °C), followed by chemotherapy (triple exposure) with oxaliplatin or doxorubicin in various configurations. The viability, cytotoxicity, and proliferation of cells after the proposed protocols were assessed. Intracellular doxorubicin uptake was measured via flow cytometry. After one cycle of triple exposure, the viability of HT-29 cells was significantly reduced versus the untreated control (65.11 ± 5%, p < 0.0001) and versus only chemotherapy (61.2 ± 7%, p < 0.0001). An increased chemotherapeutic inflow into the cells after triple exposure was detected (53.4 ± 11%) when compared to cells treated with chemotherapy alone (34.23 ± 10%) (p < 0.001). Partial dehydration in a hyperthermic condition combined with chemotherapy increases the overall cytotoxicity of colon cancer cells significantly compared to chemotherapy alone. This could possibly be related to enhanced intracellular uptake of chemotherapeutic agents after partial dehydration. Further studies are required for the further evaluation of this new concept.

Feasibility and Safety of Laparoscopic D2 Gastrectomy in Combination with Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC) in Patients with Gastric Cancer at High Risk of Recurrence-The PIPAC-OPC4 Study

BACKGROUND

Patients with gastric adenocarcinoma (GAC) are at high risk of peritoneal recurrence despite perioperative chemotherapy and radical resection. This study evaluated feasibility and safety of laparoscopic D2 gastrectomy in combination with pressurized intraperitoneal aerosol chemotherapy (PIPAC).

METHODS

This was a prospective, controlled bi-institutional study in patients with GAC at high risk of recurrence treated with PIPAC with cisplatin and doxorubicin (PIPAC C/D) after laparoscopic D2 gastrectomy. High risk was defined as a poorly cohesive subtype with predominance of signet-ring cells, clinical stage ≥ T3 and/or ≥ N2, or positive peritoneal cytology. Peritoneal lavage fluid was collected before and after resection. Cisplatin (10.5 mg/m²) and doxorubicin (2.1 mg/m²) were aerosolized after anastomosis (flow 0.5-0.8 ml/s, maximum pressure 300 PSI). Treatment was feasible and safe if ≤ 20% had Dindo-Clavien ≥ 3b surgical complications or CTCAE ≥ 4 medical adverse events within 30 days. Secondary outcomes were length of stay (LOS), peritoneal lavage cytology, and completion of postoperative systemic chemotherapy.

RESULTS

Twenty-one patients were treated with a D2 gastrectomy and PIPAC C/D. The median age was 61 years (range 24-76), there were eleven female patients, and 20 patients had preoperative chemotherapy. There was no mortality. Two patients had grade 3b complications that were potentially related to PIPAC C/D (one anastomotic leakage, and one late duodenal blow-out). One patient had severe neutropenia, and nine patients had moderate pain. The LOS was 6 days (4-26). One patient had positive peritoneal lavage cytology before resection, and none were positive after. Fifteen patients had postoperative chemotherapy.

CONCLUSIONS

Laparoscopic D2 gastrectomy in combination with PIPAC C/D is feasible and safe.

Intraperitoneal Chemotherapy for Unresectable Peritoneal Surface Malignancies

Malignancies of the peritoneal cavity are associated with a dismal prognosis. Systemic chemotherapy is the gold standard for patients with unresectable peritoneal disease, but its intraperitoneal effect is hampered by the peritoneal-plasma barrier. Intraperitoneal chemotherapy, which is administered repeatedly into the peritoneal cavity through a peritoneal implanted port, could provide a novel treatment modality for this patient population. This review provides a systematic overview of intraperitoneal used drugs, the performed clinical studies so far, and the complications of the peritoneal implemental ports. Several anticancer drugs have been studied for intraperitoneal application, with the taxanes paclitaxel and docetaxel as the most commonly used drug. Repeated intraperitoneal chemotherapy, mostly in combination with systemic chemotherapy, has shown promising results in Phase I and Phase II studies for several tumor types, such as gastric cancer, ovarian cancer, colorectal cancer, and pancreatic cancer. Two Phase III studies for intraperitoneal chemotherapy in gastric cancer have been performed so far, but the results regarding the superiority over standard systemic chemotherapy alone, are contradictory. Pressurized intraperitoneal administration, known as PIPAC, is an alternative way of administering intraperitoneal chemotherapy, and the first prospective studies have shown a tolerable safety profile. Although intraperitoneal chemotherapy might be a standard treatment option for patients with unresectable peritoneal disease, more Phase II and Phase III studies focusing on tolerability profiles, survival rates, and quality of life are warranted in order to establish optimal treatment schedules and to establish a potential role for intraperitoneal chemotherapy in the approach to unresectable peritoneal disease.

Optimal Nozzle Position and Patient's Posture to Enhance Drug Delivery into the Peritoneum during Rotational Intraperitoneal Pressurized Aerosol Chemotherapy in a Swine Model

Even though rotational intraperitoneal pressurized aerosol chemotherapy (RIPAC) has been developed to improve the distribution and penetration depth of anti-cancer agents by pressurized intraperitoneal aerosol chemotherapy (PIPAC), the optimal nozzle position and patient's posture have not been investigated. Thus, we used nine pigs weighing 50-60 kg, and sprayed 150 mL of 1% methylene blue as an aerosol through the nozzle, DreamPen^® (Dreampac Corp., Wonju, Republic of Korea), with a flow rate of 0.6 ml/min under a pressure of 140 to 150 psi for RIPAC in six and three pigs with supine and Trendelenburg positions, respectively. When we evaluated its distribution and penetration depth, even distribution among 13 regions of the abdomen was observed in three pigs with Trendelenburg position regardless of the depth of the nozzle. Regarding penetration depth, the numbers of regions with maximal penetration depth were high in the 2 cm depth of the nozzle with supine position (n = 5) and the 4 cm depth with Trendelenburg position (n = 3). Conclusively, even distribution and maximal penetration of anti-cancer agents can be expected during RIPAC in the medium depth (4 cm) between the nozzle inlet and the visceral peritoneum located on the opposite side of it and the Trendelenburg position.

Feasibility and Safety of Taxane-PIPAC in Patients with Peritoneal Malignancies-a Retrospective Bi-institutional Study

Taxanes have a favorable pharmacokinetic profile for intraperitoneal application. We report our initial experience with taxane-PIPAC (pressurized intraperitoneal chemotherapy) for unresectable peritoneal metastases from different primary sites in terms of safety, feasibility, response rate, and conversion to resectability. In this retrospective study, PIPAC was performed alone or in combination with systemic chemotherapy. Paclitaxel was used as a single agent, whereas docetaxel was used in combination with cisplatin-adriamycin or oxaliplatin-adriamycin. From December 2019 to December 2021, 47 patients underwent 82 PIPAC procedures (1 PIPAC in 55.3%, 2 in 29.7%, 3 in 14.8%). The most common primary sites were ovarian cancer (31.9%), gastric cancer (23.4%), and colorectal cancer (21.2%). Docetaxel-cisplatin-adriamycin was used in 33 (70.2%) patients, docetaxel-oxaliplatin-adriamycin in 12 (25.5%), and paclitaxel alone in 2 (4.2%) patients. Grade 1-2 complications were observed in 24 (51%) and grade 3-4 complications in 6 (12.7%) patients (8.5% of 82 PIPACs). 16/47 (34.0%) patients had a clinical response to PIPAC. The mean PCI was 25.9 ± 9.2 for the first PIPACs and 22.4 ± 9 for the subsequent PIPACs with an average reduction of 3.6 points [change in PCI ranged from - 14 to + 8]. The PRGS was 1/2 in 4/47 (8.5%) patients (19.0% patients with > 1 PIPAC). A reduction in ascites was observed in 35.4% presenting with ascites. Nine (19.1%) patients had conversion to operability leading to a subsequent cytoreductive surgery in 8 (17%) patients. PIPAC with docetaxel is feasible and safe. The role of PIPAC with both docetaxel and paclitaxel either alone or in combination with other drugs should be investigated in prospective studies.

Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC): The First Reported Case in Brazil Using Standardized Technique with the Capnopen® Nebulizer Device

BACKGROUND Peritoneal metastasis is a common progression of abdominal-pelvic cancers, and it is associated with poorer oncological prognosis when compared to other metastasis sites. Its treatment has limited results, mainly because of poor bioavailability of chemotherapy within the abdominal cavity after systemic administration. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) has been proposed as a novel method to deliver chemotherapy directly into the peritoneal surface; it combines the effectiveness and response of an intraperitoneal therapy with benefits of a minimally invasive approach. The laparoscopic capnoperitoneum is used to instill chemotherapy particles in a more efficient way for distribution and penetration when compared to peritoneal lavage. In the present study, we describe the first PIPAC performed in Brazil, according to the standard technique previously described with the Capnopen® nebulizer device, as well as technique details based on our literature review. CASE REPORT A 67-year-old man with pancreatic adenocarcinoma metastatic to the liver at first diagnosis underwent systemic treatment with the FOLFIRINOX protocol. After a major clinical response due to systemic treatment, pancreaticoduodenectomy was performed with resection and radiofrequency ablation of hepatic nodules. After 7 months of follow-up, the patient's condition evolved with symptomatic relapse in the peritoneum. Aiming at better control of this site, multiple PIPAC procedures were performed, showing excellent control of the peritoneal cavity disease. The patient had a sustained response in the peritoneal cavity and showed systemic disease progression 6 months after the first PIPAC procedure, which deceased at 20 months after the first PIPAC procedure and 42 months after the primary diagnosis. CONCLUSIONS This report shows that the PIPAC procedure is reproducible elsewhere, with safety and good functional results.

HIPEC Methodology and Regimens: The Need for an Expert Consensus

BACKGROUND

Hyperthermic intraperitoneal chemotherapy (HIPEC) is performed with a wide variation in methodology, drugs, and other elements vital to the procedure. Adoption of a limited number of regimens could increase the collective experience of peritoneal oncologists, make comparison between studies more meaningful, and lead to a greater acceptance of results from randomized trials. This study aimed to determine the possibility of standardizing HIPEC methodology and regimens and to identify the best method of performing such a standardization.

METHODS

A critical review of preclinical and clinical studies evaluating the pharmacokinetic aspects of different HIPEC drugs and drug regimens, the impact of hyperthermia, and the efficacy of various HIPEC regimens as well as studies comparing different regimens was performed.

RESULTS

The preclinical and clinical data were limited, and studies comparing different regimens were scarce. Many of the regimens were neither supported by preclinical rationale or data nor validated by a dose-escalating formal phase 1 trial. All the regimens were based on pharmacokinetic data and did not take chemosensitivity of peritoneal metastases into account. Personalized medicine approaches such as patient-derived tumor organoids could offer a solution to this problem, although clinical validation is likely to be challenging.

CONCLUSIONS

Apart from randomized trials, more translational research and phases 1 and 2 studies are needed. While waiting for better preclinical and clinical evidence, the best way to minimize heterogeneity is by an expert consensus that aims to identify and define a limited number of regimens for each indication and primary site. The choice of regimen then can be tailored to the patient profile and its expected toxicity and the methodology according regional factors.

Development of rotational intraperitoneal pressurized aerosol chemotherapy to enhance drug delivery into the peritoneum

This study aims to evaluate the drug distribution, tissue concentrations, penetration depth, pharmacokinetic properties, and toxicities after rotational intraperitoneal pressurized aerosol chemotherapy (RIPAC) in pigs. Because relevant medical devices have not been introduced, we developed our prototype of pressurized intraperitoneal aerosol chemotherapy (PIPAC) and RIPAC by adding a conical pendulum motion device for rotating the nozzle. RIPAC and PIPAC were conducted using 150 ml of 1% methylene blue to evaluate the drug distribution and 3.5 mg of doxorubicin in 50 ml of 0.9% NaCl to evaluate the tissue concentrations and penetration depth, pharmacokinetic properties, and toxicities. All agents were sprayed as aerosols via the nozzle, DreamPen^® (Dalim Biotech, Gangwon, South Korea), with a velocity of 5 km/h at a flow rate of 30 ml/min under a pressure of 7 bars, and capnoperitoneum of 12 mmHg was maintained for 30 min. As a result, RIPAC showed a wider distribution and stronger intensity than PIPAC. Compared with PIPAC, RIPAC demonstrated high values of the tissue concentration in the central, right upper, epigastrium, left upper, left lower, right lower, and right flank regions (median, 375.5-2124.9 vs. 161.7-1240 ng/ml; p ≤ .05), and higher values of the depth of concentrated diffusion and depth of maximal diffusion (median, 232.5-392.7 vs. 116.9-240.1 μm; 291.2-551.2 vs. 250.5-362.4 μm; p ≤ .05) in all regions except for bowels. In RIPAC, the pharmacokinetic properties reflected hemodynamic changes during capnoperitoneum, and there were no related toxicities. Conclusively, RIPAC may have the potential to enhance drug delivery into the peritoneum compared to PIPAC.

Pressurized intra-peritoneal aerosol chemotherapy (PIPAC): increased intraperitoneal pressure does not affect distribution patterns but leads to deeper penetration depth of doxorubicin in a sheep model

BACKGROUND

Pressurized Intra-Peritoneal Aerosol Chemotherapy (PIPAC) is an innovative treatment against peritoneal carcinomatosis. Doxorubicin is a common intra-venous chemotherapy used for peritoneal carcinomatosis and for PIPAC. This study evaluated the impact of increased PIPAC intraperitoneal pressure on the distribution and cell penetration of doxorubicin in a sheep model.

METHODS

Doxorubicin was aerosolized using PIPAC into the peritoneal cavity of 6 ewes (pre-alpes breed): N = 3 with 12 mmHg intraperitoneal pressure ("group 12") and N = 3 with 20 mmHg ("group 20"). Samples from peritoneum (N = 6), ovarian (N = 1), omentum (N = 1) and caecum (N = 1) were collected for each ewe. The number of doxorubicin positive cells was determined using the ratio between doxorubicine fluorescence-positive cell nuclei (DOXO+) over total number of DAPI positive cell nuclei (DAPI+). Penetration depth (μm) was defined as the distance between the luminal surface and the location of the deepest DOXO+ nuclei over the total number of cell nuclei that were stained with DAPI. Penetration depth (μm) was defined as the distance between the luminal surface and the location of the deepest DOXO+ nuclei.

RESULTS

DOXO+ nuclei were identified in 87% of samples. All omental samples, directly localized in front of the nebulizer head, had 100% DOXO+ nuclei whereas very few nuclei were DOXO+ for caecum. Distribution patterns were not different between the two groups but penetration depth in ovary and caecum samples was significantly deeper in group 20.

CONCLUSIONS

This study showed that applying a higher intra-peritoneal pressure during PIPAC treatment leads to a deeper penetration of doxorubicin in ovarian and caecum but does not affect distribution patterns.

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.

Rotational intraperitoneal pressurized aerosol chemotherapy in a porcine model

Peritoneal carcinomatosis (PC) commonly represent drug resistance to intravenous (IV) chemotherapy in advanced or recurrent disease of solid tumors. For improving the prognosis of PC, intraperitoneal (IP) chemotherapy has been introduced in the clinical setting, and phase III trials proved the superiority of IP chemotherapy to IV chemotherapy, in particular, in advanced ovarian cancer. However, increased toxicities by IP chemotherapy lead to reduced cycles of chemotherapy, which does not guarantee its effectiveness. Moreover, hyperthermic IP chemotherapy after cytoreductive surgery also showed improved survival compared to IV chemotherapy in advanced ovarian cancer. Nevertheless, limited distribution and diffusion of drugs, and grade 3 or 4 renal and hepatic toxicity of 20% preclude the expansion of its application. On the other hand, pressurized intraperitoneal aerosol chemotherapy (PIPAC) is known to show the effect by delivering drugs to the parietal and visceral peritoneum in the form of aerosol under the abdominal pressure of 12 mmHg induced by laparoscopic system. Although low dose equivalent to about 1% dose of resistant drugs for IV chemotherapy and normothermia are used in PIPAC, it may improve tumor response and quality of life by repetitive application of PIPAC due to the increased distribution and penetration depth of drugs. However, the heterogeneous distribution of drugs is still the major limitation of PIPAC because the nozzle is placed at the possible outlying position to the tumor-bearing tissues during laparoscopic surgery. Therefore, we developed a novel prototype for PIPAC, rotational intraperitoneal pressurized aerosol chemotherapy (RIPAC) system because rotation of the nozzle and change of spray direction can contribute to homogenous distribution of drugs, and compared the distribution of drugs between PIPAC and RIPAC in a porcine model mimicking human body. As a result, RIPAC was more effective than PIPAC in terms of the distribution of drugs into the visceral and parietal peritoneum.

Pressurized intraperitoneal aerosol chemotherapy for recurrent ovarian, fallopian or primary peritoneal cancer with peritoneal carcinomatosis: a narrative review

For recurrent ovarian, fallopian or primary peritoneal cancer with peritoneal carcinomatosis (PC), it is challenging to resect tumors completely or to get complete remission by intravenous (IV) chemotherapy, and many patients show the resistance to various chemotherapeutic agents for IV chemotherapy ultimately. As an alternative, pressurized intraperitoneal aerosol chemotherapy (PIPAC) has been introduced for treating the disease, which delivers chemotherapeutic agents as an aerosol form while maintaining high intraperitoneal (IP) pressure. Based on preclinical studies, PIPAC showed better penetration depth and distribution of drugs into the peritoneum in comparison to conventional IP chemotherapy. Tumor regression on histology and peritoneal carcinomatosis index (PCI) has also been shown in relevant studies. In addition, most of the PIPAC procedures were completed successfully with acceptable toxicity due to the use of a low dose of chemotherapeutic agents. For considering these advantages of PIPAC, we review the current status of PIPAC for treating recurrent ovarian, fallopian or primary peritoneal cancer through literature review.

Role of Epithelial-Mesenchymal Plasticity in Pseudomyxoma Peritonei: Implications for Locoregional Treatments

The mechanisms by which neoplastic cells disseminate from the primary tumor to metastatic sites, so-called metastatic organotropism, remain poorly understood. Epithelial-mesenchymal transition (EMT) plays a role in cancer development and progression by converting static epithelial cells into the migratory and microenvironment-interacting mesenchymal cells, and by the modulation of chemoresistance and stemness of tumor cells. Several findings highlight that pathways involved in EMT and its reverse process (mesenchymal-epithelial transition, MET), now collectively called epithelial-mesenchymal plasticity (EMP), play a role in peritoneal metastases. So far, the relevance of factors linked to EMP in a unique peritoneal malignancy such as pseudomyxoma peritonei (PMP) has not been fully elucidated. In this review, we focus on the role of epithelial-mesenchymal dynamics in the metastatic process involving mucinous neoplastic dissemination in the peritoneum. In particular, we discuss the role of expression profiles and phenotypic transitions found in PMP in light of the recent concept of EMP. A better understanding of EMP-associated mechanisms driving peritoneal metastasis will help to provide a more targeted approach for PMP patients selected for locoregional interventions involving cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) for rare gynecologic indications: peritoneal metastases from breast and endometrial cancer

BACKGROUND

Peritoneal metastasis (PM) in patients with breast (BC) and endometrial cancer (EC) is rare and treatment options are limited. Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC) has demonstrated efficacy against PM from various cancers, but its efficacy in BC/EC patients is unknown.

METHODS

Retrospective cohort study of patients with PM from BC/EC undergoing PIPAC with doxorubicin 1.5 mg/m² and cisplatin 7.5 mg/m². Data were collected within an international prospective PIPAC registry. Study outcomes were microscopic tumor regression grade (TRG), survival, adverse events (CTCAE), and quality of life (QoL).

RESULTS

150 PIPAC procedures in 44 patients (BC/EC = 28/16; mean age 58.8 ± 10.1 and 63.2 ± 10.1 years, respectively) were analyzed. The mean number of PIPACs per patient was 3 (range 0-9) and 3.5 (range 0-10), respectively. Primary/secondary non-access occurred in 4/3 of 150 (5%) procedures. PIPAC induced objective tumor regression as demonstrated by repetitive PM biopsies in 73% (32/44) of patients. Peri- and postoperative CTCAE grade 3 and 4 complications were observed in 12/150 (8%) of procedures. No grade 5 event was observed. After a median follow up of 5.7 (IQR 2.7-13.0) months, overall median survival was 19.6 (95% CI: 7.8-31.5) months (from first PIPAC). QoL indicators (general health, nausea, fatigue, constipation, pain, dyspnea, social, cognitive, emotional, and physical functioning) all improved or were maintained throughout PIPAC treatments.

CONCLUSIONS

Repetitive intraperitoneal chemotherapy with PIPAC is feasible and safe in patients with PM from BC and EC. PIPAC induces significant histological regression of PM while maintaining QoL.

Intraperitoneal chemotherapy of the peritoneal surface using high-intensity ultrasound (HIUS): investigation of technical feasibility, safety and possible limitations

Introduction: The penetration of chemotherapeutic drugs into peritoneal nodules remains at levels well below 1 mm, thus significantly limiting the antitumor effect of intraperitoneal chemotherapy (IPC). Recently, high-Intensity ultrasound (HIUS) has been discovered as a potential tool to significantly improve peritoneal diffusion rates. Despite promising preliminary data, basic aspects regarding its technical feasibility, safety and possible limitations remain unclear. This study aims to enhance our current understanding of HIUS and test its applicability using an ex-vivo swine model. Methods: Three postmortem swine were subject to laparotomy and consecutive lavage with 0.9%NaCl saline and HIUS application. For this purpose, a large HIUS radiating pen was introduced into the abdominal cavity and HIUS was applied on two of the four abdominal quadrants for 300 seconds each at an output power of 70 W, 50 % amplitude and 20 kHz frequency. Following the procedure, small intestinal tissue samples were retrieved for further analyses. Results: Peritoneal and subperitoneal layers showed structural changes only visible on a microscopic level. The peritoneal layer was transformed into a mesh-like structure while the subperitoneal layer (depth of 142 +/- 28 µm) exhibited microcavities and vascular detachment from surrounding tissues. No bowel rupture or vascular perforations were observed. Conclusions: Our data indicate that HIUS is a technically feasible and safe add-on procedure for intraperitoneal chemotherapy (IPC) with measurable microscopic changes on the peritoneal surface. Pretreatment of the abdominal cavity with HIUS could significantly improve IPC efficacy. Further studies are required to optimize and evaluate this novel approach.

PIPAC versus HIPEC: cisplatin spatial distribution and diffusion in a swine model

Purpose: Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a novel approach for delivering intraperitoneal chemotherapy and offers perspective in the treatment of peritoneal carcinomatosis. Concept is based on a 12 mmHg capnoperitoneum loaded with drug changed in microdoplets. It was postulated to guarantee a more homogeneous drug distribution and tissular uptake than hyperthermic intraperitoneal chemotherapy (HIPEC). The aim of this study was to compare cisplatin peritoneal distribution and pharmacokinetic between HIPEC and PIPAC procedures in a healthy swine model.Methods: Two groups of eight pigs underwent either HIPEC with cisplatin (70 mg/m²) at 43 °C for 60 min, or PIPAC with cisplatin (7.5 mg/m²) for 30 min. Postoperatively, peritoneal areas were biopsied allowing peritoneal cavity cartography. Tissular and plasmatic cisplatin concentrations were analyzed.Results: Cisplatin distribution was heterogeneous in both the groups with higher concentrations obtained closed to the delivery sites. Median total platinum peritoneal concentration by pig was higher in the HIPEC group than in the PIPAC group (18.0 μg/g versus 4.3 μg/g, p < .001) but the yield was 2.2 times better with PIPAC. Platinum concentrations were higher in the HIPEC group in all stations. At each time-point, cisplatin plasmatic concentrations were higher in the HIPEC group (p < .001) but beneath the toxicity threshold.Conclusions: With doses used in clinical practice, HIPEC guaranteed a higher cisplatin peritoneal uptake than PIPAC in this swine model. Spatial drug distribution was heterogeneous with both technics, with hotspots closed to the drug delivery sites. Nevertheless, considering the dose ratio, IP drug uptake yield was better with PIPAC.

Initial Single-center Experience of PIPAC in Patients With Unresectable Peritoneal Metastasis

INTRODUCTION

Peritoneal carcinomatosis remains a condition with poor prognosis and limited therapeutic options. Pressurized Intrapertioneal Aerosol Chemotherapy (PIPAC) has been developed as a new tool for delivering intraperitoneal chemotherapy with low morbidity. The aim of this study was to evaluate the initial experience of PIPAC in patients with peritoneal carcinomatosis at our hospital.

METHODS

A prospective study between January 2019 and February 2020 was carried at a tertiary public hospital. Primary tumor, ascites volume, PCI, chemotherapy regimen, operative time, morbidity, length of hospital stay and mortality were recorded for analysis.

RESULTS

We analyzed 9 PIPAC procedures performed in 5patients. Median PCI was 27.6 (24-35). Median surgical time was 93minutes (70-125). Only one adverse event occurred out of 9 procedures (Clavien-DindoII). Median length of hospital stay was 2days (1-4). Mortality was 0%.

CONCLUSION

PIPAC seems to be a feasible and safe procedure to treat peritoneal carcinomatosis, with low morbidity and short hospital stay.

Anaesthesia in a Toxic Environment: Pressurised Intraperitoneal Aerosol Chemotherapy: A Retrospective Analysis

OBJECTIVE

Pressurised intraperitoneal aerosol chemotherapy (PIPAC) is a new type of intraperitoneal chemotherapy for peritoneal carcinosis via minimally invasive surgery. This technique's specificity is the remote application of the therapy because of the potential risk of exposure to toxic products. The present paper summarises the important aspects of PIPAC and analyses the anaesthetic outcomes.

METHODS

This retrospective study included all patients undergoing PIPAC treatment between January 2015 and February 2018. Data on protocol adherence and perioperative anaesthetic complications and postoperative nausea and vomiting (PONV) and pain levels (visual analogue scale 0-10) from recovery room to 72 h were analysed.

RESULTS

The overall analysis included 193 PIPAC procedures on 87 patients. Protocol adherence was high as regards the use of propofol (100%), rocuronium (98%), antiemetic prophylaxis (99%) and lidocaine intravenous (i.v.) (87%). No accidental exposure to chemotherapy occurred during the study period. Of the 87 patients, 6.3% suffered delayed recovery, 58% due to hypothermia and 42% due to excessive sedation or curarisation. In the recovery room, 16% of patients suffered moderate to severe pain, requiring >8 mg of morphine i.v., with average doses of 13.7 mg. Median postoperative pain scores were 1 and 3 at 12 h and 0 and 0 at 72 h at rest and mobilisation, respectively. PONV was observed in <10% of patients during the first 12 h, but in 40% at 72 h.

CONCLUSION

A dedicated anaesthetic protocol and intraoperative safety checklist facilitates safe, well-tolerated anaesthesia for PIPAC treatments.

Synergy between Intraperitoneal Aerosolization (PIPAC) and Cancer Nanomedicine: Cisplatin-Loaded Polyarginine-Hyaluronic Acid Nanocarriers Efficiently Eradicate Peritoneal Metastasis of Advanced Human Ovarian Cancer

Intra-abdominal dissemination of peritoneal nodules, a condition known as peritoneal carcinomatosis (PC), is typically diagnosed in ovarian cancer patients at the advanced stages. The current treatment of PC consists of perioperative systemic chemotherapy and cytoreductive surgery, followed by intra-abdominal flushing with solutions of chemotherapeutics such as cisplatin and oxaliplatin. In this study, we developed cisplatin-loaded polyarginine-hyaluronic acid nanoscale particles (Cis-pARG-HA NPs) with high colloidal stability, marked drug loading efficiency, unimpaired biological activity, and tumor-targeting ability. Injected Cis-pARG-HA NPs showed enhanced antitumor activity in a rat model of PC, compared to injection of the free cisplatin drug. The activity of Cis-pARG-HA NPs could even be further improved when administered by an intra-abdominal aerosol therapy, referred to as pressurized intraperitoneal aerosol chemotherapy (PIPAC). PIPAC is hypothesized to ensure a more homogeneous drug distribution together with a deeper drug penetration into peritoneal tumor nodules within the abdominal cavity. Using fluorescent pARG-HA NPs, this enhanced nanoparticle deposit on tumors could indeed be observed in regions opposite the aerosolization nozzle. Therefore, this study demonstrates that nanoparticles carrying chemotherapeutics can be synergistically combined with the PIPAC technique for IP therapy of disseminated advanced ovarian tumors, while this synergistic effect was not observed for the administration of free cisplatin.

The concept of foam as a drug carrier for intraperitoneal chemotherapy, feasibility, cytotoxicity and characteristics

For decades, intraperitoneal chemotherapy (IPC) was delivered into the abdominal cavity as a liquid solution. This preliminary study aims to evaluate foam as a potential new drug carrier for IPC delivery. Foam-based intraperitoneal chemotherapy (FBIC) was produced with taurolidine, hydrogen peroxide, human serum, potassium iodide and doxorubicin/ oxaliplatin for both ex vivo and in vitro experiments. Analysis of FBIC efficacy included evaluation of cytotoxicity, tissue penetration, foam stability, temperature changes and total foam volume per time evaluation. FBIC showed penetration rates of about 275 ± 87 µm and higher cytotoxicity compared to controls and to conventional liquid IPC (p < 0.005). The volume of the generated foam was approximately 50-times higher than the initial liquid solution and temporarily stable. Foam core temperature was measured and increased to 47 °C after 9 min. Foam ingredients (total protein content) were evenly distributed within different locations. Our preliminary results are quite encouraging and indicate that FBIC is a feasible approach. However, in order to discuss a possible superior effect over conventional liquid or aerosolized chemo applications, further studies are required to investigate pharmacologic, pharmacodynamic and physical properties of FBIC.

Pressurised intraperitoneal aerosol chemotherapy: rationale, evidence, and potential indications

Pressurised intraperitoneal aerosol chemotherapy (PIPAC) was introduced as a new treatment for patients with peritoneal metastases in November, 2011. Reports of its feasibility, tolerance, and efficacy have encouraged centres worldwide to adopt PIPAC as a novel drug delivery technique. In this Review, we detail the technique and rationale of PIPAC and critically assess its evidence and potential indications. A systematic search was done to identify all relevant literature on PIPAC published between Jan 1, 2011, and Jan 31, 2019. A total of 106 articles or reports on PIPAC were identified, and 45 clinical studies on 1810 PIPAC procedures in 838 patients were included for analysis. Repeated PIPAC delivery was feasible in 64% of patients with few intraoperative and postoperative surgical complications (3% for each in prospective studies). Adverse events (Common Terminology Criteria for Adverse Events greater than grade 2) occurred after 12-15% of procedures, and commonly included bowel obstruction, bleeding, and abdominal pain. Repeated PIPAC did not have a negative effect on quality of life. Using PIPAC, an objective clinical response of 62-88% was reported for patients with ovarian cancer (median survival of 11-14 months), 50-91% for gastric cancer (median survival of 8-15 months), 71-86% for colorectal cancer (median survival of 16 months), and 67-75% (median survival of 27 months) for peritoneal mesothelioma. From our findings, PIPAC has been shown to be feasible and safe. Data on objective response and quality of life were encouraging. Therefore, PIPAC can be considered as a treatment option for refractory, isolated peritoneal metastasis of various origins. However, its use in further indications needs to be validated by prospective studies.

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) for unresectable peritoneal metastasis from gastric cancer

BACKGROUND

PIPAC is a recent approach with promising results for patients with peritoneal metastasis (PM). We aimed to evaluate survival and postoperative outcome of patients with unresectable PM from gastric origin treated with chemotherapy and PIPAC.

METHODS

A retrospective analysis of a prospective maintained PIPAC database was queried for all patients diagnosed with unresectable PM from gastric cancer who underwent PIPAC before 2018. PIPAC with Cisplatin 7.5 mg/m2 and doxorubicin 1.5 mg/m2 were given for 30 min at 6-week intervals. Outcome criteria were overall survival and adverse events according to (CTCAE) version4.0.

RESULTS

One hundred Sixty-three PIPAC were done in 42 consecutive patients. Twenty-two (52%) of the patients were female. Signet-ring cells were observed in 33/42 patients (78.6%). At the first PIPAC, median age was 51.5 years (32-74). Median PCI was 17 (1-39). Twenty (47.6%) patients underwent more than 2 lines of pre-PIPAC chemotherapy. All patients had systemic chemotherapy alternating with PIPAC. Median consecutive PIPAC procedures were 3 (1-12). Overall and major complications (CTCAE - III, IV) occurred in 10 (6.1%) and 5 procedures (3.1%), respectively. Two patients (4.7%) died within 30 days of a PIPAC procedure, one related to small bowel obstruction and a pulmonary embolism for the other. Overall Survival was 19.1 months. Six (14.3%) patients became resectable during treatment and underwent curative intent CRS and HIPEC.

CONCLUSIONS

PIPAC with low-dose cisplatin and doxorubicin is safe and feasible in association with systemic chemotherapy for gastric PM. Survival data are encouraging and justify further clinical studies in this indication.

Systemic chemotherapy and pressurized intraperitoneal aerosol chemotherapy (PIPAC): A bidirectional approach for gastric cancer peritoneal metastasis

BACKGROUND

Few patients affected by gastric cancer peritoneal metastasis (GCPM) are offered locoregional treatment, despite several proof-of-efficacy trials. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) has emerged in recent years as a promising tool to control peritoneal carcinomatosis. The combination of PIPAC with systemic chemotherapy may offer a greater clinical benefit than standard treatment alone.

METHODS

A single-center cohort of 28 consecutive patients affected by GCPM was scheduled for bidirectional treatment, comprising PIPAC and systemic chemotherapy, from September 2017 to September 2019. Data recorded included safety, efficacy and survival outcomes. Ascite volumes, the Peritoneal Cancer Index (PCI) and pathological response through the Peritoneal Regression Grading Score (PRGS) were compared in those patients who underwent more than one PIPAC procedure.

RESULTS

Forty-six PIPAC procedures were administered, with a mean of 1.7 PIPAC procedures per patient. The median time to resume systemic chemotherapy after PIPAC was 6 days (range 4-7). Concerning safety, two grade 3-4 CTCAE (Common Terminology Criteria for Adverse Events v4.0) toxicity events and one intraoperative complication were recorded. Thirteen patients repeated PIPAC. A pathological response was recorded in 61.5% of patients (one with complete and seven with partial regression). The median overall survival was 12.3 months in the overall population and 15.0 months in patients undergoing more than one PIPAC procedure.

CONCLUSIONS

A bidirectional approach for GCPM was feasible and safe, as the PIPAC procedure integrates well with several systemic chemotherapy regimens. The pathological response demonstrated the antitumoral efficacy of PIPAC. The proposed bidirectional approach may be further investigated in the first-line treatment of metastatic gastric cancer.

Recent Advances in Intra-peritoneal Chemotherapy for Gastric Cancer

Peritoneal metastasis (PM) frequently occurs in patients with gastric cancer (GC) and confers a dismal prognosis despite advances in systemic chemotherapy. While systemic chemotherapy has poor peritoneal penetration, intraperitoneal (IP) chemotherapy remains sequestered, resulting in high peritoneal drug concentrations with less systemic side-effects. The first application of IP treatment was hyperthermic intraperitoneal chemotherapy (HIPEC) with cytoreductive surgery (CRS) for gastric cancer peritoneal metastasis (GCPM); but was associated with an increased morbidity and mortality rate without significantly improving overall survival (OS). While CRS confers limited benefit, the potential role of prophylactic HIPEC and laparoscopic neoadjuvant HIPEC are currently being evaluated. Combination systemic and IP chemotherapy (SIPC) gained popularity in the 1990s, since it provided the benefits of IP treatment while reducing surgical morbidity, demonstrating promising early results in multiple Phase II trials. Unfortunately, these findings were not confirmed in the recent PHOENIX-GC randomized controlled trial; therefore, the appropriate treatment for GCPM remains controversial. Small observational studies from Japan and Singapore have reported successful downstaging of PM in GC patients receiving SIPC who subsequently underwent conversion gastrectomy with a median OS of 21.6–34.6 months. Recently, the most significant development in IP-directed therapy is pressurized IP aerosol chemotherapy (PIPAC). Given that aerosol chemotherapy achieves a wider distribution and deeper penetration, the outcomes of multiple ongoing trials assessing its efficacy are eagerly awaited. Indeed, IP-directed therapy has evolved rapidly in the last 3 decades, with an encouraging trend toward improved outcomes in GCPM, and may offer some hope for an otherwise fatal disease.

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.

Intrathoracic aerosol chemotherapy via spray-catheter

Pressurized intrathoracic aerosol chemotherapy (PITAC) has been introduced to the clinical setting as a novel treatment option for pleural metastasis (PM). For decades the therapeutic application of aerosols was limited to intrabronchial delivery. However, present studies suggest performing PITAC on patients with PM and malignant pleural effusion. Using an established ex vivo swine model, the present study aimed to introduce a facilitated intrathoracic chemoaerosol application via spray-catheter. Using an ex-vivo model of 3 postmortem swine, the feasibility of intrathoracic aerosol chemotherapy (ITC) with doxorubicin using a spray-catheter was evaluated in a normal pressure environment. Following thoracotomy, the spray-catheter was inserted via trocar. Tissue samples were retrieved and further analyzed by fluorescence microscopy to detect doxorubicin contact. Our data demonstrated that the application of ITC was technically feasible and did not exhibit any significant obstacles. By making a minimally invasive thoracotomy incision it was possible to create an adequate pneumothorax without the need of a double-lumen tube or intubation. ITC did not require the creation of a pressurized environment. Tissue samples revealed doxorubicin contact within the pleura. In conclusion, ITC is a fast and feasible procedure that could possibly be administered via bedside application, therefore eliminating the need of an operating room and surgical staff. However, further studies are required to evaluate the safety of patients and physicians regarding this novel applicational modality. Nevertheless, the present study demonstrated that ITC may potentially be applied at bedside, an option that is particularly important for patients who do not qualify for PITAC procedures.

Bidirectional treatment of peritoneal metastasis with Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC) and systemic chemotherapy: a systematic review

Background

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is used in the palliative treatment of peritoneal metastasis. The combination of intraperitoneal and systemic chemotherapy seems rational, and the aim of this systematic review was to compare PIPAC directed monotherapy with a bidirectional treatment approach (PIPAC in combination with systemic chemotherapy). Main outcomes were survival and quality of life.

Methods

A systematic literature search in Medline, Embase, Cochrane and the “Pleura and Peritoneum” was conducted and analyzed according to PRISMA guidelines. Studies in English reporting on bidirectional treatment with PIPAC and systemic chemotherapy and published before April 2019 were included.

Results

Twelve studies with a total of 386 patients were included. None were specifically designed to compare mono- versus bidirectional treatment, but 44% of the patients received bidirectional treatment. This was more frequent in women (non-gynecological cancers) and one-third of the bidirectional treated patients had received no prior chemotherapy. Data from the included studies provided no conclusions regarding survival or quality of life.

Conclusion

Bidirectional treatment with PIPAC and systemic chemotherapy is practised and feasible, and some patients are enrolled having received no prior systemic chemotherapy for their PM.

The difficulty in drawing any conclusions based on this systematic review has highlighted the urgent need to improve and standardize reports on PIPAC directed therapy. We have, therefore, constructed a list of items to be considered when reporting on clinical PIPAC research.

Trial registration

International Prospective Register of Systematic Reviews, PROSPERO. Registration number: 90352, March 5, 2018.

Pressurized Intraperitoneal Aerosol Chemotherapy, a Palliative Treatment Approach for Patients With Peritoneal Carcinomatosis: Description of Method and Systematic Review of Literature

BACKGROUND

Peritoneal metastases arise in patients with a variety of primary cancers, and are associated with a poor prognosis. Systemic chemotherapy is the mainstay of treatment; however, the morbidity is considerable and the survival benefit is modest. Cytoreductive surgery and heated intraperitoneal chemotherapy is a potentially curative treatment available to a minority of patients; however, most develop recurrent disease. A novel palliative treatment for peritoneal metastases, pressurized intraperitoneal aerosol chemotherapy, has recently been introduced. Pressurized intraperitoneal aerosol chemotherapy utilizes an aerosol of chemotherapy in carbon dioxide gas. It is instilled into the abdomen under pressure via laparoscopic ports. No cytoreduction is performed. Pressurized intraperitoneal aerosol chemotherapy can be repeated at 6-week intervals. Oxaliplatin or cis-platinum and doxorubicin have been used to date.

OBJECTIVE

This study aims to systematically review and evaluate the method, and the preclinical and early clinical results of pressurized intraperitoneal aerosol chemotherapy.

DATA SOURCES

Medline and the Cochrane Library were the data sources for the study.

STUDY SELECTION

Peer-reviewed series of greater than 10 patients, with sufficient patient data, through April 2019, were selected.

INTERVENTION

Patients with peritoneal metastases underwent pressurized intraperitoneal aerosol chemotherapy.

MAIN OUTCOME MEASURES

Patient dropout, histologic tumor response, adverse events, and 30-day mortality were the primary outcomes measured.

RESULTS

A total of 921 patients with peritoneal metastases were brought to the operating room for pressurized intraperitoneal aerosol chemotherapy. The number of pressurized intraperitoneal aerosol chemotherapy treatments administered was as follows: 1 treatment, 862 (94%); 2 treatments, 645 (70%); and 3 treatments, 390 patients (42%). Initial laparoscopic access was not possible in 59 patients (6.4%). Common Terminology Criteria for Adverse Events grade 3 or higher were noted in 13.7% of the patients who, collectively, underwent a total of 2116 treatments. The 30-day mortality was 2.4% (22/921).

LIMITATIONS

This study was limited by the heterogeneity of reported data and primary tumor types and by the lack of long-term survival data.

CONCLUSIONS

Early clinical results are encouraging, but tumor-specific, prospective, randomized trials are needed to compare pressurized intraperitoneal aerosol chemotherapy to systemic chemotherapy. This method has yet to be introduced to the United States. It is another therapeutic option for patients with peritoneal metastases and will broaden the patient base for future clinical trials.

Creating nanocrystallized chemotherapy: the differences in pressurized aerosol chemotherapy (PAC) via intracavitary (IAG) and extracavitary aerosol generation (EAG) regarding particle generation, morphology and structure

Background: Nanocrystallization is a promising field for the development of new drugs. This study aims to present the use of nanocrystallization via intraperitoneal nanoaerosol therapy (INAT) for the treatment of peritoneal metastases.

Methods: A continuous aerosol generation device was used to aerosolize a highly concentrated doxorubicin solution within a dry CO₂ environment. The produced nanoaerosol was directed into an ex vivo abdominal model and collision of aerosol particles with placed samples was subject to further analysis via scanning-electron microscopy (SEM). SEM detected structural changes of particles caused by migration to different locations.

Results: It was possible to visualize the contact of doxorubicin aerosol particles with the surface. Larger particles as well as particles closer to the aerosol generation chamber collided with the glass sample creating liquid drops, while smaller particles with more distance to the aerosol chamber collided as highly concentrated nanocrystals. The amount of nanocrystal particles outweighed the amount of fluid aerosol particles by far.

Conclusions: Under optimal conditions, the formation of nanocrystals via aerosol creation device is possible. While a wide range of possible applications of nanocrystals is conceivable, surface coating with drug particles is especially interesting as it may serve as an alternative to conventional liquid intraperitoneal chemotherapy. Further studies are required to investigate nanocrystallization of chemotherapeutic solutions as well as its physical and pharmacological properties and side effects.

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.

Increased Tissue Penetration of Doxorubicin in Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC) after High-Intensity Ultrasound (HIUS)

BACKGROUND

High-intensity ultrasound (HIUS) has been studied for the past two decades as a new therapeutic option for solid tumor direct treatment and a method for better chemotherapy delivery and perfusion. This treatment approach has not been tested to our knowledge in peritoneal metastatic therapy, where limited tissue penetration of intraperitoneal chemotherapy has been a main problem. Both liquid instillations and pressurized aerosols are affected by this limitation. This study was performed to evaluate whether HIUS improves chemotherapy penetration rates.

METHODS

High-intensity ultrasound (HIUS) was applied for 0, 5, 30, 60, 120, and 300 seconds on the peritoneal tissue samples from fresh postmortem swine. Samples were then treated with doxorubicin via pressurized intraperitoneal aerosol chemotherapy (PIPAC) under 12 mmHg and 37°C temperature. Tissue penetration of doxorubicin was measured using fluorescence microscopy on frozen thin sections.

RESULTS

Macroscopic structural changes, identified by swelling of the superficial layer of the peritoneal surface, were observed after 120 seconds of HIUS. Maximum doxorubicin penetration was significantly higher in peritoneum treated with HIUS for 300 seconds, with a depth of 962.88 ± 161.4 μm (p < 0.05). Samples without HIUS had a penetration depth of 252.25 ± 60.41. Tissue penetration was significantly increased with longer HIUS duration, with up to 3.8-fold increased penetration after 300 sec of HIUS treatment.

CONCLUSION

Our data indicate that HIUS may be used as a method to prepare the peritoneal tissue for intraperitoneal chemotherapy. Higher tissue penetration rates can be achieved without increasing chemotherapy concentrations and preventing structural damage to tissue using short time intervals. More studies need to be performed to analyze the effect of HIUS in combination with intraperitoneal chemotherapy.

Release of doxorubicin from its liposomal coating via high intensity ultrasound

The present ex vivo study was performed to analyze the impact of high intensity ultrasound (HIUS) on penetration depth and particle stability of liposomal doxorubicin (LD) on the peritoneal surface. Fresh post mortem swine peritoneum was cut into proportional sections and subjected to a previously established ex vivo model of pressurized intraperitoneal aerosol chemotherapy (PIPAC). Samples were treated with 50 ml NaCl (0.9%) containing 3 mg LD via PIPAC or lavage. In both groups, half of the samples received additional HIUS treatment. Samples treated via PIPAC were covered with a 30-mm-thick abdominal muscle wall tissue, fatty tissue and skin, followed by transcutaneous HIUS. Samples administered with LD via lavage received close-range contact HIUS. Doxorubicin tissue penetration was measured using fluorescence microscopy on frozen sections. Liposomal integrity on peritoneal surfaces was measured via electron microscopy (EM). Mean penetration rates of doxorubicin were significantly higher with HIUS in combination with PIPAC or lavage compared with PIPAC alone (P<0.001) or lavage alone (P<0.00001). LD was not detected on the peritoneal surface via EM analysis in either group following HIUS. The present data suggested that HIUS may be a feasible application that can facilitate the release of doxorubicin from its liposomal envelope. HIUS was effective in both close-range, in contact with the samples, and through the abdominal wall. The present approach may be used in the future for both endoscopic and open lavage of the peritoneal cavity with LD in intraperitoneal chemotherapeutic applications such as hyperthermic intraperitoneal chemotherapy or PIPAC.

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 with one minute of electrostatic precipitation (ePIPAC) is feasible, but the histological tumor response in peritoneal metastasis is insufficient

INTRODUCTION

Electrostatic precipitation Pressurized IntraPeritoneal Aerosol Chemotherapy (ePIPAC) has shown superior penetration depth and tissue uptake compared to standard PIPAC. We investigated the feasibility and objective tumor response to ePIPAC with 1 min of precipitation in patients with peritoneal metastasis (PM).

MATERIALS AND METHODS

Patients with PM from various abdominal cancers were included in an amendment to the ongoing prospective PIPAC-OPC2 trial. Colorectal and appendiceal PM were treated with oxaliplatin, patients with PM from other primaries were treated with a combination of cisplatin and doxorubicin. Three ePIPAC procedures were planned in each patient including repeated peritoneal biopsies for response evaluation. After emission to the peritoneal cavity, the aerosolized chemotherapeutics were precipitated for 1 min followed by immediate exsufflation and abdominal closure. Histological regression from the first to the third ePIPAC was evaluated according to the Peritoneal Regression Grading Score (PRGS) and compared to data from the PIPAC-OPC1 trial. Complications and toxicities were recorded according to Dindo-Clavien and CTCAE.

RESULTS

Sixty-five ePIPAC procedures were performed in 33 patients (median 2, range 1-6). Ten patients were eligible for response evaluation based on biopsies from the first and third ePIPAC procedure. Four patients had disease progression, four patients had regressive disease, and two patients had stable disease according to PRGS. No life threatening adverse reactions and no mortality was observed following ePIPAC.

CONCLUSION

One minute ePIPAC was feasible and safe, but the histological tumor response was insufficient compared to standard PIPAC directed therapy with 30 min passive diffusion time.

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.

Exploring the Use of Pegylated Liposomal Doxorubicin (Caelyx®) as Pressurized Intraperitoneal Aerosol Chemotherapy

Background: Peritoneal carcinomatosis is a common metastatic pattern in ovarian, gastric, colorectal, and appendiceal cancer; systemic chemotherapy is the current standard of care for peritoneal metastatic disease; however, in a subset of patients its beneficial effect remains questionable. More effective perioperative chemotherapy is needed.

Materials and methods: Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a new treatment that applies chemotherapeutic drugs into the peritoneal cavity as an aerosol under pressure. It’s a safe and feasible approach that improves local bioavailability of chemotherapeutic drugs as compared with conventional intraperitoneal chemotherapy. Till now the drugs used in PIPAC for the treatment of the peritoneal carcinomatosis (PC) are cisplatin, doxorubicin, and oxaliplatin; as of yet, there are no in vivo data comparing different drug formulations and dosage schedules of PIPAC. Pegylated liposomal doxorubicin 1.5 mg/sm was aerosolized in PIPAC procedures.

Results: Pharmacokinetics analysis of 10 procedures performed with conventional doxorubicin solution at the dose of 1.5 mg/m² were compared to 15 procedures with the same dose of pegylated liposomal doxorubicin (PLD).

Significant differences between experimental groups were detected by one-way ANOVA followed by Bonferroni correction; a p value < 0.05 was considered statistically significant. A statistically different doxorubicin tissue concentration was observed for the doxorubicin solution compared to pegylated liposomal doxorubicin in the right parietal peritoneum and right diaphragm. In the Caelyx^® series a mean tissue concentration of 1.27 ± 1.33 mg/g was reported, while in the second one we registered a mean concentration of 3.1 ± 3.7 mg/g.

Conclusions: The delivery of nano-particles in PIPAC was feasible, but pegylated liposomal concentrations are lower than standard doxorubicin formulation. Probably mechanical and physical properties of pressurized aerosol chemotherapy might alter their stability and cause structural disintegration.

Establishment of a rat ovarian peritoneal metastasis model to study pressurized intraperitoneal aerosol chemotherapy (PIPAC)

BACKGROUND

pressurized intraperitoneal aerosol chemotherapy (PIPAC), with or without electrostatic precipitation (ePIPAC), was recently introduced in the treatment of peritoneal metastases (PM) from ovarian cancer (OC). Preliminary clinical data are promising, but several methodological issues as well the anticancer efficacy of PIPAC remain unaddressed. Here, we propose a rat ePIPAC model that allows to study these issues in a clinically relevant, reproducible, and high throughput model.

METHODS

laparoscopy and PIPAC were established in healthy Wistar rats. Aerosol properties were measured using laser diffraction spectrometry based granulometric analyses. Electrostatic precipitation was accomplished using a commercially available generator (Ultravision™). A xenograft model of ovarian PM was created in athymic rats using intraperitoneal (IP) injection of SKOV-3 luciferase positive cells. Tumor growth was monitored weekly by in vivo bioluminescence imaging.

RESULTS

PIPAC and electrostatic precipitation were well tolerated using a capnoperitoneum of 8 mmHg. All rats survived the (e)PIPAC procedure and no gas or aerosol leakage was observed over the entire procedure. With an injection pressure of 20 bar, granulometry showed a mean droplet diameter (D(v,0.5)) of 47 μm with a flow rate of 0.5 mL/s, and a significantly lower diameter (30 μm) when a flow rate of 0.8 mL/s was used. Experiments using IP injection of SKOV-3 luciferase positive cells showed that after IP injection of 20 × 10⁶ cells, miliary PM was observed in all animals. PIPAC was feasible and well supported in these tumor bearing animals.

CONCLUSIONS

we propose a reproducible and efficient rodent model to study PIPAC and ePIPAC in OC xenografts with widespread PM. This model allows to characterize and optimize pharmacokinetic and biophysical parameters, and to evaluate the anti-cancer efficacy of (e)PIPAC treatment.

Colorectal Peritoneal Metastases: A Systematic Review of Current and Emerging Trends in Clinical and Translational Research

Colorectal peritoneal metastases (CPM) are associated with abbreviated survival and significantly impaired quality of life. In patients with CPM, radical multimodality treatment consisting of cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) has demonstrated oncological superiority over systemic chemotherapy alone. In highly selected patients undergoing CRS + HIPEC, overall survival of over 60% has been reported in some series. These are patients in whom the disease burden is limited and where the diagnosis is made at an early stage in the disease course. Early diagnosis and a deeper understanding of the biological mechanisms that regulate CPM are critical to refining patient selection for radical treatment, personalising therapeutic approaches, enhancing prognostication, and ultimately improving long-term survivorship. In the present study, we outline three broad themes which represent critical future research targets in CPM: (1) enhanced radiological strategies for early detection and staging; (2) identification and validation of translational biomarkers for diagnostic, prognostic, and therapeutic deployment; and (3) development of optimized approaches for surgical cytoreduction as well as more precise strategies for intraperitoneal drug selection and delivery. Herein, we provide a contemporary narrative review of the state of the art in these three areas. A systematic review in accordance with PRISMA guidelines was undertaken on all English language studies published between 2007 and 2017. In vitro and animal model studies were deemed eligible for inclusion in the sections pertaining to biomarkers and therapeutic optimisation, as these areas of research currently remain in the early stages of development. Acquired data were then divided into hierarchical thematic categories (imaging modalities, translational biomarkers (diagnostic/prognostic/therapeutic), and delivery techniques) and subcategories. An interactive sunburst figure is provided for intuitive interrogation of the CPM research landscape.

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.

Feasibility, Safety, and Efficacy of Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC) for Peritoneal Metastasis: A Registry Study

INTRODUCTION

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a novel drug delivery system with superior pharmacological properties for treating peritoneal metastasis (PM). Safety and efficacy results of PIPAC with cisplatin/doxorubicin or oxaliplatin from a registry cohort are presented.

METHODS

IRB-approved registry study. Retrospective analysis. No predefined inclusion criteria, individual therapeutic recommendation by the interdisciplinary tumor board. Safety assessment with CTCAE 4.0. Histological assessment of tumor response by an independent pathologist using the 4-tied peritoneal regression grading system (PRGS). Mean PRGS and ascites volume were assessed at each PIPAC.

RESULTS

A total of 142 PIPAC procedures were scheduled in 71 consecutive patients with PM from gastric (n = 26), colorectal (n = 17), hepatobiliary/pancreatic (n = 9), ovarian (n = 6), appendiceal (n = 5) origin, pseudomyxoma peritonei (n = 4), and other tumors (n = 3). Mean age was 58 ± 13 years. Patients were heavily pretreated. Mean PCI was 19 ± 13. Laparoscopic nonaccess rate was 11/142 procedures (7.7%). Mean number of PIPAC/patient was 2. All patients were eligible for safety analysis. There was no procedure-related mortality. There were 2.8% intraoperative and 4.9% postoperative complications. 39 patients underwent more than one PIPAC and were eligible for efficacy analysis, and PRGS could be assessed in 36 of them. In 24 patients (67%), PRGS improved or remained unchanged at PIPAC#2, reflecting tumor regression or stable disease. Ascites was present in 24 patients and diminished significantly under therapy. Median survival was 11.8 months (95% CI: 7.45-16.2 months) from PIPAC#1.

CONCLUSION

PIPAC is feasible, safe, and well-tolerated and can induce histological regression in a significant proportion of pretreated PM patients. This trial is registered with NCT03210298.

Effect of Liposomal Doxorubicin in Pressurized Intra-Peritoneal Aerosol Chemotherapy (PIPAC)

Background: This ex-vivo study was performed to compare the impact of doxorubicin vs. liposomal doxorubicin on penetration depth in peritoneal tissue during Pressurized Intra-Peritoneal Aerosol Chemotherapy (PIPAC) via microcatheter (MC). Methods: Fresh post mortem swine peritoneum was cut into proportional sections. One group of samples was treated with PIPAC with Doxorubicin (D), and the other was treated with PIPAC with liposomal doxorubicin (LD). Tissue specimens were placed as follows: at the bottom of the plastic box (1), at the side wall (2), at the top cover (3) and the side of the box covered by a plastic tunnel (4). In-tissue doxorubicin penetration was measured using fluorescence microscopy on frozen thin sections. Results: Medium penetration levels with D were 325 µm (1), 152 µm (2), 84 µm (3) and 71 µm (4), respectively. Medium penetration levels with LD were significantly lower with 10 µm (1), 2 µm (2), 0 µm (3) and 0 µm (4), respectively. In most samples that were treated with LD no doxorubicin could be detected at all. Conclusion: Our data indicate that liposomal coating of doxorubicin and possibly other chemotherapeutical drugs might inhibit their interaction with the peritoneal surface. This inhibition appears to be relatively strong, since doxorubicin is partially undetectable due to liposomal coating. Further studies are warranted to investigate this interaction and its potential benefit in peritoneal applications.

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.

Concentrations of cisplatin and doxorubicin in ascites and peritoneal tumor nodules before and after pressurized intraperitoneal aerosol chemotherapy (PIPAC) in patients with peritoneal metastasis

INTRODUCTION

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a new means of delivering chemotherapy into the abdomen of patients with peritoneal carcinomatosis (PC). The amount of drug uptake in ascites and peritoneum after PIPAC is unknown.

METHODS

Retrospective cohort study of women with PC from gynecological tumors comparing the concentrations of cisplatin and doxorubicin in ascites and peritoneum before and after PIPAC. Concentrations were measured using gas chromatography. Peritoneal tumor samples were assessed for histological tumor regression.

RESULTS

59 PIPAC procedures were performed in 32 women with PC. The concentrations of doxorubicin and cisplatin in ascites significantly increased after PIPAC (140.2 ± 671.5 vs 9035.7 ± 5328.6 ng/ml; p < 0.0001 and 95.2 ± 106.4 vs 24,770.8 ± 11,710.8 ng/ml; p < 0.0001, respectively). Concentrations of doxorubicin and cisplatin in peritoneal tissue also significantly increased after PIPAC (5.1 ± 0.7 vs 19.2 ± 38.6 ng/g; p = 0.007, and 81.9 ± 7.8 vs 131.5 ± 134.4 ng/g; p = 0.005, respectively). On an individual patient level, a significant uptake (>2-fold) of doxorubicin and cisplatin was observed in 57/59 (97%) and 58/59 (98%) of cases in ascites and in 23/59 (39%) and 13/59 (22%) of cases in the peritoneum. Uptake of cisplatin and doxorubicin were significantly correlated (Spearman correlation coefficient: 0.33; p = 0.011). After repeated PIPACs, doxorubicin uptake increased in peritoneal tumor tissue (p = 0.008).

CONCLUSIONS

PIPAC leads to a significant chemotherapy uptake in both ascites and peritoneum, suggesting a bimodal cytotoxic effect of PIPAC via direct tissue uptake into peritoneal tumor nodules and via ascites. Consecutive PIPAC applications lead to peritoneal accumulation of doxorubicin, suggesting a cumulative cytotoxic effect of doxorubicin after repeated PIPACs.