Safety and Feasibility of High-Pressure/High-Dose Pressurized Intraperitoneal Aerosol Chemotherapy (HP/HD-PIPAC) for Primary and Metastatic Peritoneal Surface Malignancies.

OBJECTIVE: The aim of this study was to evaluate the feasibility and perioperative safety of high-pressure/high-dose pressurized intraperitoneal aerosol chemotherapy (HP/HD-PIPAC) to manage peritoneal surface malignancies (PSM). METHODS: Retrospective analysis of a prospective database of about 130 consecutive patients scheduled for HP/HD-PIPACs for PSM. Doxorubicin plus cisplatin (PIPAC-C/D) or oxaliplatin (PIPAC-Ox) were nebulized into a constant capnoperitoneum of 20 mmHg at doses of 6, 30, or 120 mg/m2 of body surface area (BSA). Outcome criteria were perioperative complications (Clavien-Dindo). RESULTS: The median age of patients was 62 years (range 9-82), and the primary tumor site was of colorectal (CRC), upper gastrointestinal tract (UGI), unknown primary (CUP), malignant epithelioid mesothelioma of the peritoneum (MPM), hepato-pancreatic-biliary tract (HPB), and other origin in 30 (23.1%), 27 (20.8%), 16 (12.3%), 16 (12.3%), 6 (4.6%), and 35 (26.9%) patients, respectively. Abdominal access failed for a first, second, third, and fourth or more HP/HD-PIPAC in 12/130 (9.2%), 4/64 (6.3%), 6/40 (15.0%), and 2/33 (6.1%) patients. A total of 243 procedures were performed in 118 patients. No intraoperative complications related to increased capnoperitoneal pressure occurred, but an intraoperative bleeding complication was observed in 1/243 (0.4%) patients. The overall rate of postoperative procedure-related complications was 19.3% (47/243), while 15.3% (37/243), 1.6% (6/243), 1.6% (1/243), 0.4% (1/243), and 0.4% (1/243) were Grade I, II, III, IV, and V complications, respectively. CONCLUSIONS: Perioperative complications of HP/HD-PIPAC are comparable with standard pressure/dose PIPAC treatment protocols. Prospective studies are warranted to examine potential improvement in therapy outcomes.

Clinical Outcome for Patients Managed with Low-Dose Cisplatin and Doxorubicin Delivered as Pressurized Intraperitoneal Aerosol Chemotherapy for Unresectable Peritoneal Metastases of Gastric Cancer.

BACKGROUND: Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is increasingly used to manage gastric cancer peritoneal metastasis (GCPM). METHODS: This study analyzed a prospective database of GCPM patients treated with cisplatin and doxorubicin PIPAC (PIPAC-C/D). The outcome criteria were adverse events, pathologic response [peritoneal regression grading score (PRGS)], and overall survival (OS). RESULTS: The PIPAC-C/D procedure was scheduled for 144 patients with a median age of 57 years (range 22-88 years). Access to the abdominal cavity for the first PIPAC failed in 11 patients (7.7 %). A total of 296 procedures were performed for 131 patients. Of the 144 patients, 52 (36.1%) underwent one PIPAC, 32 (22.2%) underwent two PIPACs, 24 (16.7%) underwent three PIPACs, and 21 (14.6%) underwent four or more PIPACs. The overall morbidity/mortality was grade 1 for 22 patients (15.3%), grade 2 for 32 patients (22.2%), grade 3 for 7 patients (4.9%), grade 4 for no patients (0%), and grade 5 for 2 patients (1.4%). Of the 37 patients who had three or more PIPACs eligible for histopathologic response analysis, 27 (73%) had major or complete regression (PRGS 1/2). A median OS of 11 months (range 0-61 months) for the total study population and 16 months (range 2-61 months) for the patients with three or more PIPACs was observed. For 10 patients (7%) who underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy, the median OS was 15 months (minimum, 4 months; maximum, 27 months). Multivariate analysis showed three or more PIPACs to be an independent prognostic factor for improved OS (hazard ratio, 0.36; p < 0.0001). CONCLUSIONS: Repetitive PIPAC-C/D ± systemic chemotherapy is associated with low morbidity and mortality rates. Prospective randomized trials are needed to confirm whether three or more PIPAC-C/Ds improve clinical outcome.

Development and technical validation of an ultrasound nebulizer to deliver intraperitoneal pressurized aerosols in a rat colon cancer peritoneal metastases model.

BACKGROUND/AIM: To develop and validate a nebulizer device for anti-cancer research on pressurized intraperitoneal aerosol supply in a preclinical peritoneal metastases (PM) rat model. MATERIAL AND METHODS: For aerosol generation, an ultrasonic nebulizer (USN) was modified. Aerosol analyses were performed ex-vivo by laser diffraction spectrometry (LDS). Intraperitoneal (IP) 99mtechnetium sodium pertechnetate (99mTc) aerosol distribution and deposition were quantified by in-vivo single photon emission computed tomography (SPECT/CT) and compared to liquid IP instillation of equivalent volume/doses of 99mTc with and without capnoperitoneum. PM was induced by IP injection of HCT116-Luc2 human colon cancer cells in immunosuppressed RNU rats. Tumor growth was monitored by bioluminescence imaging (BLI), 18F-FDG positron emission tomography (PET) and tissues examination at necropsy. RESULTS: The USN was able to establish a stable and reproducible capnoperitoneum at a pressure of 8 to 10 mmHg. LDS showed that the USN provides a polydisperse and monomodal aerosol with a volume-weighted diameter of 2.6 µm. At a CO2 flow rate of 2 L/min with an IP residence time of 3.9 s, the highest drug deposition efficiency was found to be 15 wt.-%. In comparison to liquid instillation, nebulization showed the most homogeneous IP spatial drug deposition. Compared to BLI, 18F-FDG-PET was more sensitive to detect smaller PM nodules measuring only 1-2 mm in diameter. BLI, 18F-FDG PET and necropsy analyses showed relevant PM in all animals. CONCLUSIONS: The USN together with the PM rat model are suitable for robust and species-specific preclinical pharmacological studies regarding intraperitoneal delivery of pressurized aerosolized drugs and cancer research.

Available prediction scores of conversion for laparoscopic rectal cancer surgery seem to be unsuitable for nowadays rectal cancer management.

INTRODUCTION: This study aimed to externally evaluate the accuracy of four predictive scores for conversion to open surgery after rectal laparoscopic resection. None of the four scores achieved external validation previously. METHODS: This was a retrospective analysis of two prospectively maintained databases from two academic centers in France and Morocco. All consecutive patients who underwent laparoscopic resection for rectal adenocarcinoma between 2005 and 2020 were included. Logistic regression was used to assess the association between the factors present in the four scores and conversion. The accuracy of each score was assessed using the area under the curve (AUC). Observed and predicted conversion rates were compared for each score using the Chi-square goodness-of-fit test. RESULTS: Four hundred patients were included. There were 264 men (66%) with a mean age of 65.95 years (standard deviation 12.2). The median tumor height was 7 cm (quartiles 4-11) and 29% of patients had low rectal tumors. Conversion rate was 21.75%. The accuracy to predict conversion was low with an AUC lower than 0,62 for the four models. The observed conversion rates were significantly different from the predicted rates, except for one score. CONCLUSIONS: The four models had low accuracy in predicting the conversion to open surgery for laparoscopic rectal resection. There is a need for new well-designed studies, analyzing more specific variables, in a multicentric design to ensure generalizability of the results for daily surgical practice.

Pressurized Intraperitoneal Aerosol Chemotherapy for Colorectal Peritoneal Metastases.

BACKGROUND: The benefit of repetitive PIPAC specifically in CPM patients has yet to be demonstrated in terms of oncological and functional outcomes. OBJECTIVE: The aim of this study was to evaluate the outcome of patients with non-resectable colorectal peritoneal metastases (CPM) treated with pressurized intraperitoneal aerosol chemotherapy (PIPAC). METHODS: We conducted an analysis of a prospective single-center database of all CPM patients who underwent PIPAC with oxaliplatin 92 mg/m2 body surface (PIPAC-Ox). The outcome criteria were adverse events (Common Terminology Criteria for Adverse Events version 4.0), Peritoneal Regression Grading Score (PRGS), and survival. RESULTS: Overall, 102 patients with a median age of 64 years (33-88) were scheduled for PIPAC-Ox. Access to the abdominal cavity for the first application failed in 22/102 (21.6%) patients. A total of 185 PIPACs were performed, with 26/102 (25.5%), 20/102 (19.6%), 17/102 (16.7%), and 17/102 (16.7%) patients undergoing one, two, three, and four or more PIPACs, respectively. Perioperative overall morbidity/mortality Grade I-V occurred in 14 (7.6%), 29 (15.8%), 6 (3.2%), 1 (0.5%), and 1 (0.5%) patient without significant differences between each cycle. Of 27 patients who underwent three or more PIPACs, 20/102 (19.6%) had major/complete CPM regression (PRGS 1-2). In a multivariate analysis, independent predictive factors for > 12 months' survival following the first PIPAC-Ox administration were three or more PIPACs (odds ratio [OR] 4.5, 95% confidence interval [CI] 1.35-15.2; p = 0.014) and younger patient age (OR 1.058, 95% CI 1.00-1.12; p = 0.039). CONCLUSIONS: Repetitive PIPAC-Ox for CPM patients, alone or combined with perioperative systemic chemotherapy, is feasible. Our data suggest that three or more consecutive PIPAC-Ox cycles for advanced CPM can improve survival.

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.

Long term outcome of anastomotic leakage in patients undergoing low anterior resection for rectal cancer.

BACKGROUND: The influence of anastomotic leakage (AL) on local recurrence rates and survival in rectal cancer remains controversial. The aim of this study was to analyze the effect of asymptomatic anastomotic leakage (AAL) and symptomatic anastomotic leakage (SAL) on short- and long-term outcome after curative rectal cancer resection. METHODS: All patients who underwent surgical resection of non-metastatic rectal cancer with curative intent from January 2005 to December 2017 were retrospectively analyzed. Short-term morbidity, long-term functional and oncological outcomes were compared between patients with SAL, AAL and without AL (WAL). RESULTS: Overall, 200 patients were included and AL was observed in 39 (19.5%) patients (10 AAL and 29 SAL) with a median follow-up of 38.5 months. Rectal cancer location and preoperative neoadjuvant treatment was similar between the three groups. Postoperative 30-day mortality rate was nil. The permanent stoma rate was higher in patients with SAL or AAL compared to WAL patients (44.8 and 30% vs 9.3%, p < 0.001). The mean wexner continence grading scale was significantly different between AAL (11,4 ± 3,8), SAL (10,3 ± 0,6) and WAL (6,4 ± 4,7) groups (p = 0.049). The 3 and 5-year overall and disease-free survival rates were similar between the 3 groups (86.6% /84% vs 100%/100% vs 76%/70 and 82.9%/77% vs 100%/100% vs 94.7%/88.3% for patients with SAL, AAL, and WAL, p = 0.480 and p = 0.527). CONCLUSION: The permanent stoma rate was significant higher in patients with SAL or AAL compared to WAL patients. AL did not impair long-term oncological outcome.

Comparison of Tissue and Blood Concentrations of Oxaliplatin Administrated by Different Modalities of Intraperitoneal Chemotherapy.

BACKGROUND: Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a new technology for delivering intraperitoneal chemotherapy. It is generally assumed that with PIPAC, the ratio of peritoneal to systemic drug concentration is superior to liquid hyperthermic intraperitoneal chemotherapy (HIPEC). To date, no direct comparative data are available supporting such an assumption. MATERIALS AND METHODS: Twelve 65-day-old pigs were randomly separated into three groups of four pigs each, all of which received intraperitoneal chemotherapy using the following administration methods: PIPAC with oxaliplatin 92 mg in 150 ml dextrose 5% (Group 1); PIPAC with electrostatic aerosol precipitation (ePIPAC; Group 2); or laparoscopic HIPEC (L-HIPEC) with oxaliplatin 400 mg in 4 L dextrose 5% at 42 °C (Group 3). Serial blood and peritoneal tissue concentrations of oxaliplatin were determined by spectrometry. RESULTS: In all three groups, the maximum concentration of oxaliplatin in blood was detected 50-60 min after onset of the chemotherapy experiments, with no significant differences among the three groups (p = 0.7994). Blood oxaliplatin concentrations (0-30 min) were significantly higher in the L-HIPEC group compared with the ePIPAC group (p < 0.05). No difference was found for the overall systemic oxaliplatin absorption (area under the curve). Overall concentrations in the peritoneum were not different among the three groups (p = 0.4725), but were significantly higher in the visceral peritoneum in the PIPAC group (p = 0.0242). CONCLUSIONS: Blood and tissue concentrations were comparable between all groups; however, depending on the intraperitoneal area examined and the time points of drug delivery, the concentrations differed significantly between the three groups.

Long-term hospital mortality due to small bowel obstruction after major colorectal surgery in a national cohort database.

PURPOSE: Adhesions following major colorectal surgery can be responsible for bowel obstruction, mostly occurring in the small intestine. Published data for long-term survival following major colorectal surgery complicated with intestinal obstruction are limited. The aim of this study was to identify the mortality rates and mortality risk factors in patients with primary colorectal surgery (PMCS) complicated with surgical small bowel obstruction (SBO). METHODS: This was a retrospective analysis of a prospective national registry of patients who underwent PMCS in 2008. RESULTS: Of 15,640 patients who underwent PMCS, 2900 required further surgery for SBO with a median follow-up of 42 months (until the end of 2014). Re-hospitalization mortality rate was 10.1%, and 65% of deaths were obstruction-related. No differences were found in SBO incidence between patients who had undergone laparoscopic or open procedures. Hospital mortality was significantly higher in patients who underwent open PMCS compared with those who underwent a laparoscopic procedure (11% vs. 2%, p = 0.0006). Overall 1- and 5-year survival rates in patients who underwent surgical SBO treatment were significantly lower when the initial surgery was an open procedure compared with a laparoscopy (96.8% vs. 99.4% and 86.6% vs. 95.1%, respectively, p = 0.0016). Multivariate analysis revealed that age, sex, a history of diabetes, cancer, and heart disease were mortality risk factors. CONCLUSIONS: The surgical incidence and mortality rate of PMCS complicated with SBO were elevated. Laparoscopy clearly reduced long-term postoperative mortality in patients with and without abdominal adhesions.

Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC) for the treatment of malignant mesothelioma.

BACKGROUND: Patients with recurrent malignant epithelioid mesothelioma (MM) after surgery and standard chemotherapy with cisplatin and pemetrexed have limited treatment options. METHODS: We performed a retrospective cohort study of patients with recurrent MM undergoing Pressurized IntraPeritoneal/Thoracal Aerosol Chemotherapy (PIPAC/PITAC) with doxorubicin 1.5 mg/m2 and cisplatin 7.5 mg/m2. Data were retrospectively collected in a prospective registry of patients undergoing PIPAC/PITAC. Study outcomes were microscopic tumor regression grade (TRG), survival and adverse events (v4.0 CTCAE). RESULTS: A total of 29 patients (m/f = 17/12) with MM with a mean age of 62.4 (range: 42 to 84) years were analyzed. A total of 74 PIPAC and 5 PITAC procedures were performed. The mean number of PIPAC applications was 2.5 (range: 0 to 10) per patient. Twenty patients (69%) had > 2 PIPAC procedure and were eligible for TRG analysis. TRG 1 to 4 was observed in 75% (15/20) of patients. Major regression (TRG 3) or complete regression (TRG 4) was observed in 20% and 10%, respectively. PIPAC induced significant tumor regression in 51.7% (15/29) of patients with a cumulative effect after repetitive PIPACs (PIPAC #1 vs. PIPAC #2: p = 0.001; PIPAC #1 vs. PIPAC #3: p = 0.001; PIPAC #1 vs. PIPAC #4: p = 0.001). Postoperative CTCAE grade 4 complications were observed in two patients (6.9%) who had cytoreductive surgery (CC2) and intraoperative PIPAC. One patient (3.4%) died due to postoperative kidney insufficiency. After a follow up of 14.4 (95% CI: 8.1 to 20.7) months after the last PIPAC/PITAC application, median overall survival was 26.6 (95% CI: 9.5 to 43.7) months (from the first application). CONCLUSION: After prior abdominal surgery and systemic chemotherapy, repetitive PIPAC applications are feasible and safe for patients with end-stage MM. Furthermore, PIPAC induces significant histological regression of malignant mesothelioma in the majority of patients. PITAC is feasible, but its safety and efficacy to control malignant pleural effusion remain unclear.

A phase I, single-arm, open-label, dose escalation study of intraperitoneal cisplatin and doxorubicin in patients with recurrent ovarian cancer and peritoneal carcinomatosis.

OBJECTIVE: We performed a phase I, single-arm, non-randomized, open-label, dose-escalation trial to determine the dose-limiting toxicity of intraperitoneal cisplatin and doxorubicin applied as pressurized intraperitoneal aerosol chemotherapy (PIPAC) in women with recurrent ovarian cancer. METHODS: We used a standard 3 + 3 dose-escalation design with doxorubicin 1.5 mg/m2, cisplatin 7.5 mg/m2 q 4 to 6 weeks for 3 cycles and subsequent dose escalation steps (20% increment per step) in patients with recurrent ovarian cancer and peritoneal carcinomatosis. Toxicity and clinical efficacy were monitored. The primary endpoint was the maximum-tolerable dose. Secondary endpoints included histologic tumor regression and serum parameters. RESULTS: 15 evaluable patients (3, 7, and 5 in cohorts 1, 2, and 3, respectively) on average received 2.3 PIPAC cycles. No dose limiting toxicities were found. Adverse side effects were 1 grade 3 event (colon perforation) and 85 grade 1/2 events including fatigue (n = 19), abdominal pain (n = 18), nausea/vomiting (n = 14), sleep disorder (n = 8), diarrhea (n = 5), and fever (n = 2). Liver and renal toxicity was not observed in any of the 3 cohorts (AST 19.1 ±â€¯3.2, 25.8 ±â€¯6.5, and 22.1 ±â€¯4.5 IU/L, respectively; ALT 14.7 ±â€¯3.5, 18.5 ±â€¯5.6, and 23.3 ±â€¯13.0 IU/L, respectively; GGT 45.7 ±â€¯35.1, 25.2 ±â€¯10.3, and 43.9 ±â€¯26.4 IU/L, respectively; serum creatinine 1.06 ±â€¯0.23, 0.80 ±â€¯0.17, and 0.89 ±â€¯0.35 mg/dL, respectively). No systemic hematologic toxicity, alopecia, or neurotoxicity was noted. The maximum tolerable dose was not reached. Histologic tumor regression was observed in 7/11 (64%) patients who underwent ≥2 PIPAC cycles. CONCLUSIONS: PIPAC with cisplatin and doxorubicin may be safely used at an intraperitoneal dose of 10.5 mg/m2 and 2.1 mg/m2, respectively. Systemic toxicity of this therapy is low.

Scintigraphic peritoneography reveals a non-uniform 99mTc-Pertechnetat aerosol distribution pattern for Pressurized Intra-Peritoneal Aerosol Chemotherapy (PIPAC) in a swine model.

BACKGROUND: Although recent data are contradictory, it is still claimed that Pressurized Intra-Peritoneal Aerosol Chemotherapy (PIPAC) would deliver an aerosol which distributes homogeneously throughout the entire abdominal cavity. METHODS: 99mTc-Pertechnetat was administered in four postmortem swine using either PIPAC or liquid intra-peritoneal chemotherapy (IPC). The animals were examined by planar scintigraphy and SPECT/CT. Planar distribution images were divided into four regions of interest (ROIs: right/left upper and lower abdominal quadrant). SPECT/CT slices were scanned for areas of intense nuclide accumulation ("hot spots"). The percentage of relative distribution for planar scintigraphy was calculated by dividing the summed individual counts of each ROI by total counts measured in the entire abdominal cavity. The relative distribution of the "hot spots" was analyzed by dividing the counts of the local volume of interest (VOI) by the summed volume counts measured in the entire abdominal cavity. RESULTS: In all four animals, planar scintigraphy showed inhomogeneous nuclide distribution. After PIPAC only 8-10% of the delivered nuclide was detected in one ROI with a mean deviation of 40% and 74% from a uniform nuclide distribution pattern. In all animals, SPECT/CT revealed "hot spots" beneath the PIPAC Micropump, catheter tip, and in the cul-de-sac region which comprise about 25% of the total amount of delivered nuclide in 2.5% of the volume of the entire abdominal cavity. CONCLUSIONS: Our present data indicate that the intra-abdominal aerosol distribution pattern of PIPAC therapy is non-homogeneous and that the currently applied technology has still not overcome the problem of inhomogeneous drug distribution of IPC.

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.

Technical description of the microinjection pump (MIP®) and granulometric characterization of the aerosol applied for pressurized intraperitoneal aerosol chemotherapy (PIPAC).

BACKGROUND: Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is gaining acceptance in clinical practice, but detailed information about the microinjection pump (MIP®), the generated aerosol and drug distribution is missing. ANALYTICAL METHODS: Ex vivo granulometric analyses by means of laser diffraction spectrometry were performed for MIP® aerosol characterization. Beside the standard operation conditions, the impact of the volumetric liquid flow rate on the aerosol characteristics was investigated with different liquids. Granulometric results as well as the local drug distribution were verified by ex vivo gravimetric analyses. On the basis of determined MIP® characteristics, the aerosol droplet size, which is necessary for a homogenous intra-abdominal drug distribution, was calculated. RESULTS: Granulometric analyses showed that the MIP® aerosol consists of a bimodal volume-weighted particle size distribution (PSD3) with a median droplet diameter of x 50,3 = 25 µm. Calculations reveal that the droplet size for a homogenous intra-abdominal drug distribution during PIPAC therapy should be below 1.2 µm. We show that >97.5 vol% of the aerosolized liquid is delivered as droplets with ≥3 µm in diameter, which are primarily deposited on the surface beneath the MIP® by gravitational settling and inertial impaction. These findings were confirmed by ex vivo gravimetric analyses, where more than 86.0 vol% of the aerosolized liquid was deposited within a circular area with a diameter of 15 cm. CONCLUSIONS: The granulometric aerosol properties, as well as the aerodynamic conditions achieved by standard MIP® operation, do not support the idea of widespread or homogenous drug distribution in the abdominal cavity.

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

BACKGROUND: Pressurized intraperitoneal aerosol chemotherapy (PIPAC) has been recently reported as a new approach for intraperitoneal chemotherapy (IPC). By means of a patented micropump, the liquid chemotherapy is delivered into the peritoneal cavity as an aerosol which is supposed to achieve "gas-like" distribution. However, recent data report that the fraction of the submicron aerosol (gas-like) is less than 3 vol% of the total amount of aerosolized chemotherapy. Until today, possible modifications of treatment parameters during PIPAC with the aim of improving therapeutic outcomes have not been studied yet. This study aims to establish an in vitro PIPAC model to explore the cytotoxic effect of the submicron aerosol fraction and to investigate the impact of different application parameters on the cytotoxic effect of PIPAC on human colonic cancer cells. METHODS: An in vitro model using HCT8 colon adenocarcinoma wild-type cells (HCT8WT) and multi-chemotherapy refractory subline (HCT8RT) was established. Different experimental parameters such as pressure, drug dosage, time exposure, and system temperature were monitored in order to search for the conditions with a higher impact on cell toxicity. Cell proliferation was determined by means of colorimetric MTT assay 48 h following PIPAC exposures. RESULTS: Standard operational parameters applied for PIPAC therapy depicted a cytotoxic effect of the submicron aerosol fraction generated by the PIPAC micropump. We also observed that increasing pressure significantly enhanced tumor cell toxicity in both wild-type and chemotherapy-resistant cells. A maximum of cytotoxicity was observed at 15 mmHg. Pressure >15 mmHg did not show additional cytotoxic effect on cells. Increased oxaliplatin dosage resulted in progressively higher cell toxicity as expected. However, in resistant cells, a significant effect was only found at higher drug concentrations. Neither an extension of exposure time nor an increase in temperature of the aerosolized chemotherapy solution added an improvement in cytotoxicity. CONCLUSIONS: In this in vitro PIPAC model, the gas-like PIPAC aerosol fraction showed a cytotoxic effect which was enhanced by higher intra-abdominal pressure with a maximum at 15 mmHg. Similar findings were observed for drug dose escalation. A phase I dose escalation study is currently performed at our institution. However, increasing the intra-abdominal pressure might be a first and simple way to enhance the cytotoxic effect of PIPAC therapy which needs further clinical investigations.

Exploring the Spatial Drug Distribution Pattern of Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC).

BACKGROUND: Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a novel approach to delivering intraperitoneal chemotherapy (IPC) as a pressurized aerosol. One of the assumed advantages is the homogeneous drug distribution in the intraperitoneal cavity compared with conventional liquid in situ chemotherapy. However, to date, the spatial drug distribution pattern of PIPAC has not been investigated in detail. METHODS: Doxorubicin was aerosolized in an ex vivo PIPAC model containing native fresh tissue samples of swine peritoneum at a pressure of 12 mmHg CO2 at 36 °C. In the center of the top cover of the PIPAC chamber, a PIPAC micropump was installed. Tissue specimens were placed as follows: (A) bottom of the plastic box, (B) margin of the aerosol jet covered with a bilaterally open tunnel, (C) side wall, and (D) top cover, respectively. In-tissue doxorubicin penetration was measured using fluorescence microscopy on frozen thin sections. RESULTS: The depth of doxorubicin penetration was found to be significantly higher in tissues directly exposed to the aerosol jet (A: 215 ± 79 µm) compared with the side wall (C: 77 ± 18 µm; p < 0.01) and the top of the box (D: 65 ± 17 µm; p < 0.01). The poorest penetration was observed for peritoneal tissue covered under a bilaterally open plastic tunnel (B: 34 ± 19 µm; p < 0.001). CONCLUSIONS: The study data suggest that the spatial drug distribution pattern of ex vivo PIPAC is heterogeneous.

Pressurized intraluminal aerosol chemotherapy with Dbait in the distal esophagus of swine.

BACKGROUND AND STUDY AIMS: A novel therapeutic concept, pressurized intraluminal aerosol chemotherapy (PILAC), and a corresponding device for distributing drugs to the mucosa and submucosa of the distal esophagus are presented. MATERIALS AND METHODS: The endoscopic device that was designed consisted of (i) a double-balloon catheter, similar to a Sengstaken-Blakemore tube; (ii) a carbon dioxide (CO2) line, used to create a gaseous, pressurized environment; and (iii) a micropump, used to generate a therapeutic aerosol. The device was inserted into the distal esophagus in three narcotized Landrace pigs. Dbait (short interfering DNA, or siDNA) was aerosolized under pressure (12 mmHg) in CO2 at 37 °C for 30 minutes. RESULTS: The procedure was well tolerated by all animals. At autopsy, no mucosal or muscular tear was observed. Fluorescence microscopy revealed a homogeneous intramural distribution of Dbait-cyanine 5 in the esophageal wall down to the circular muscular layer (400 - 600 µm). CONCLUSIONS: PILAC is feasible in a large animal model and appears to be safe. Therapy of the entire "tissue at risk" for the development of cancer in the distal esophagus is possible without the prior endoscopic identification of diseased tissue.

Pressurized intraperitoneal aerosol chemotherapy in women with recurrent ovarian cancer: A phase 2 study.

OBJECTIVE: Recurrent ovarian, fallopian or peritoneal cancer with peritoneal carcinomatosis (ROCPC) is resistant to systemic chemotherapy. We assessed the safety and activity of laparoscopic pressurized intraperitoneal aerosol chemotherapy (PIPAC) in women with this cancer. METHODS: In this open-label, single-arm phase 2 study, patients underwent 3 courses q 28-42 days of PIPAC with doxorubicin 1·5 mg/m(2) followed by cisplatin 7·5 mg/m(2). A pressure of 12 mm Hg and a temperature of 37 °C were applied for 30 min/course. The primary endpoint was the proportion of patients who had an objective tumor response (OTR) according to RECIST version 1.1 criteria. Analysis was by intention to treat. Secondary endpoints were tumor regression on histology, PC Index improvement on repeated video-laparoscopy, and quality of life measured with the EORTC QLQ-30 questionnaire. RESULTS: Sixty-four patients were enrolled. Laparoscopic non-access rate was 11/64 (17%). 53 patients were eligible for analyses. 33/53 (62%) patients had an OTR - three had a partial response and 30 patients had stable disease. Tumor regression on histology and PC Index improvement were observed in 26/34 (76%) and in 26/34 (76%) patients who underwent all 3 PIPACs. There were no treatment-related deaths. No grade 4 toxicity was observed. Grade 3 toxicities were trocar hernia (n=2), bowel obstruction (n=2), abdominal pain (n=2), hematoma (n=1), intraoperative bleeding (n=1), and cystitis with urosepsis (n=1). EORTC QLQ-30 global physical health scores, nausea/vomiting, appetite loss, diarrhea, and constipation improved during therapy. CONCLUSION: PIPAC is well tolerated and active in women with ROCPC and warrants further investigation in these patients.

Intraperitoneal chemotherapy of peritoneal carcinomatosis using pressurized aerosol as an alternative to liquid solution: first evidence for efficacy.

BACKGROUND: Peritoneal carcinomatosis (PC) is an unmet medical need. Despite recent improvements, systemic chemotherapy has limited efficacy. We report the first application of intraperitoneal chemotherapy as a pressurized aerosol in human patients. METHODS: Three end-stage patients with advanced PC from gastric, appendiceal, and ovarian origin were treated as a compassionate therapy. All patients had received previous systemic chemotherapy. A pressurized aerosol of CO2 loaded with doxorubicin 1.5 mg/m(2) and cisplatin 7.5 mg/m(2) (pressurized intraperitoneal aerosol chemotherapy, PIPAC) was applied into the abdomen for 30 min at a pressure of 12 mmHg and a temperature of 37 °C. RESULTS: No side-effects >2 CTCAE were observed, and the procedures were well tolerated. Early hospital discharge was possible (days 2-5). Nuclear presence of doxorubicin was documented throughout the peritoneum, reaching high local concentration (≤4.1 µmol/g) and plasma concentration was low (4.0-6.2 ng/ml). PIPAC created no significant adhesions, could be repeated, and was applied 6×, 4×, and 2×. Two patients showed a complete and one a partial histological remission. Mean survival after the first PIPAC was 288 days. One patient is alive after 567 days. CONCLUSIONS: PIPAC shows superior pharmacological properties with high local concentration and low systemic exposure. PIPAC can induce regression of PC in chemoresistant tumors, using 10% of a usual systemic dose.