Search

Background: The advent of Deep Learning initiated a new era in which neural networks relying solely on Whole-Slide Images can estimate the survival time of cancer patients. Remarkably, despite deep learning’s potential in this domain, no prior research has been conducted on image-based survival analysis specifically for peritoneal mesothelioma. Prior studies performed statistical analysis to identify disease factors impacting patients’ survival time. Methods: Therefore, we introduce MPeMSupervisedSurv, a Convolutional Neural Network designed to predict the survival time of patients diagnosed with this disease. We subsequently perform patient stratification based on factors such as their Peritoneal Cancer Index and on whether patients received chemotherapy treatment. Results: MPeMSupervisedSurv demonstrates improvements over comparable methods. Using our proposed model, we performed patient stratification to assess the impact of clinical variables on survival time. Notably, the inclusion of information regarding adjuvant chemotherapy significantly enhances the model’s predictive prowess. Conversely, repeating the process for other factors did not yield significant performance improvements. Conclusions: Overall, MPeMSupervisedSurv is an effective neural network which can predict the survival time of peritoneal mesothelioma patients. Our findings also indicate that treatment by adjuvant chemotherapy could be a factor affecting survival time.

Summary: About 500,000 patients with rare adult solid cancers (RASC) are diagnosed yearly in Europe. Delays and unequal quality of management impact negatively their survival. Since 2017, European reference networks (ERN) aim to improve the quality of care of patients with rare disease. The steering committee of EURACAN, including physicians, researchers and patients review here the previous actions, present objectives of the ERN EURACAN dedicated to RASC. EURACAN promoted management in reference centres, and equal implementation of excellence and innovation in Europe and developed 22 clinical practice guidelines (CPGs). Additionally, fourteen information brochures translated in 24 EU languages were developed in collaboration with patient advocacy groups (ePAGs) and seventeen training session were organized. Nevertheless, connections to national networks in the 26 participating countries (106 centres), simplification of cross-border healthcare, international multidisciplinary tumour boards, registries and monitoring of the quality of care are still required. In this Health Policy, evaluation criteria of the performances of the network and of health care providers are proposed.

Abstract The peritoneal surface malignancy (PSM) is an advanced disease, the prognosis of which has been radically improved since the development of cytoreductive surgery (CRS) with or without hyperthermic intraperitoneal chemotherapy (HIPEC). These procedures are associated with many complications. However, very few data are available regarding the psychiatric morbidities that might occur. The present study assessed the epidemiology of depressive mood and anxiety during the 6 months following the procedure. The analysis of a prospective cohort that included patients who underwent CRS with or without HIPEC between December 2016 and December 2019 was performed. A total of 115 patients were included. During the 6-months follow-up, the mean (SD) Hospital Anxiety and Depression Scale –D (HADS-D) score was 7.8 (48) and a significant increase compared with the pre-operative period (t(49) = − 4.36, p

IntroductionOvarian cancer (OC) is the primary cause of mortality in women diagnosed with gynecological cancer. Our study assessed pressurized intraperitoneal aerosol chemotherapy (PIPAC) as treatment for peritoneal surface metastases (PSM) from recurrent or progressive OC and conducted survival analyses to identify prognostic factors.Material and methodsThis retrospective cohort study, conducted across 18 international centers, analyzed the clinical practices of patients receiving palliative treatment for PSM from OC who underwent PIPAC. All patients were initially treated appropriately outside any clinical trial setting. Feasibility, safety, and morbidity were evaluated along with objective endpoints of oncological response. Multivariate analysis identified prognostic factors for OS and PFS.ResultsFrom 2015-2020, 234 consecutive patients were studied, from which 192 patients were included and stratified by platinum sensitivity for analysis. Patients with early recurrence, within one postoperative month, were excluded. Baseline characteristics were similar between the groups regarding platinum sensitivity (platinum sensitive (PS) and resistant (PR)), but chemotherapy frequency differed, as did PCI before PIPAC. Median PCI decreased in both groups after three cycles of PIPAC (PS 16 vs. 12, p < 0.001; PR 24 vs. 20, p = 0.009). Overall morbidity was 22%, with few severe complications (4-8%) or mortality (0-3%). Higher pathological response and longer OS (22 vs. 11m, p = 0.012) and PFS (12 vs. 7m, p = 0.033) were observed in the PS group. Multivariate analysis (OS/PFS) identified ascites (HR 4.02, p < 0.001/5.22, p < 0.001), positive cytology at first PIPAC (HR 3.91, p = 0.002/1.96, p = 0.035), and ≥ 3 PIPACs (HR 0.30, p = 0.002/0.48, p = 0.017) as independent prognostic factors of overall survival/progression-free survival.ConclusionsWith low morbidity and mortality rates, PIPAC is a safe option for palliative treatment of advanced ovarian cancer. Promising results were observed after 3 PIPAC, which did improve the peritoneal burden. However, further research is needed to evaluate the potential role of PIPAC as an independent prognostic factor.

Abstract Background Advanced cancer patients often experience multiple symptoms at a same time. This might lead to polypharmacy and increase adverse events representing major threats to the quality of health care, especially in palliative care situations. Mirtazapine, an antidepressant agent, has been suggested as a potential relevant drug to alleviate multiple cancer-related symptoms at a same time. Therefore, the present study aims to assess the effectiveness of mirtazapine in alleviating multiple symptoms at a same time in advanced cancer patients suffering from a major depressive episode compared to a group receiving escitalopram, another antidepressant agent. Methods Multicentre, prospective, randomized, controlled trial in 12 palliative care services in France. The study will be based on a mixed-method methodology using parallel groups, of oral mirtazapine compared with oral escitalopram, with a 56 day follow-up. The primary outcome will be an improvement of the Global health Status (issued from the EORTC-QLQ-C30) on day 56. 418 participants will be clinically followed-up on day 7 and 56 and will have a telephonic assessment on days 14 and 28. A sub-sample of participants will be invited to take part in semi-structured qualitative interviews at baseline and day 56. For the qualitative part, purposeful sampling will be used. Discussion This study will provide evidence for the pharmaceutics management of poly-symptomatology in advanced cancer patients. This could lead to important changes in the management of those patients by using a single molecule to alleviate multiple symptoms at a same time, potentially improving medication adherence, symptoms’ control, and reducing the risk of medications adverse events. Trial registration Trial registration: NCT04763135 . Registered 18 March 2021.

Abstract Objective To investigate the benefit of cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) for the treatment of endometrial peritoneal carcinomatosis compared to CRS alone. Methods We conducted a retrospective multicentre study of patients from experienced centres in treating peritoneal malignancies from 2002 to 2015. Patients who underwent surgery for peritoneal evolution of endometrial cancer (EC) were included. Two groups of 30 women were matched and compared: “CRS + HIPEC” which used HIPEC after CRS, and “CRS only” which did not use HIPEC. We analysed clinical, pathologic and treatment data for patients with peritoneal metastases from EC. The outcome measures were morbidity, overall survival (OS), and progression-free survival (PFS). Results In “CRS plus HIPEC” group, 96.7% of women were treated for recurrence, while in “CRS only” 83.3 were treated for primary disease. There was no significant difference between Peritoneal Carcinomatosis Index at laparotomy or Completeness of Cytoreduction score. Grade III and IV complications rates did not significantly differ between “CRS plus HIPEC” group and “CRS only” group (20.7% vs 20.7%, p = 0.739). Survival analysis showed no statistical difference between both groups. Median OS time was 19.2 months in “CRS plus HIPEC” group and 29.7 months in “CRS only” group (p = 0.606). Median PFS survival time was 10.7 months in “CRS plus HIPEC” group and 13.1 months in “CRS only” group (p = 0.511). Conclusion The use of HIPEC combined to CRS did not have any significance as regard the DFS and OS over CRS alone in patients with primary or recurrent peritoneal metastasis of endometrial cancer.

Introduction: Intra-arterial hepatic (IAH) treatment has shown promising results in the management of patients with unresectable colorectal liver metastases (CRLM) the prognosis of which is poor. Bevacizumab adjunction to standard chemotherapy has been shown to improve survival of this patient population. This prospective study was conducted to assess the efficacy and safety of IAH bevacizumab combined to systemic chemotherapy after first-line treatment failure in patients with CRLM. Methods: Included patients had dominant or isolated unresectable CRLM progressing after standard first-line treatment for metastases of colorectal cancer. Three patients had less than 30% liver invasion, three patients between 30 and 50%, two more than 50% and data was missing in two patients. An intra-hepatic catheter was implanted surgically or percutaneously. Bevacizumab 7.5 mg/kg was administered once every 3 weeks in combination with capecitabine 2000 mg/m² per day for 2 weeks and oxaliplatin 130 mg/m² or irinotecan 200 mg/m² once every 3 weeks. The primary end-point was the objective response rate. Results: Between June 2013 and February 2015, 10 patients were included. The trial was prematurely closed because of the lack of financial support and poor accrual. The patients had a median of 6 [1–9] cycles of treatment. Partial response was achieved in 2 patients (20%) and a R0 liver metastases resection in one another. All patients died of disease progression. The median overall and progression-free survival rates were respectively 14.0 (95% IC [4.8 – 25.8] and 5.4 months (95% IC [1.6 – 6.2]). Four patients had severe side effects but no toxic death occurred. Conclusion: IAH bevacizumab combined to systemic chemotherapy is feasible and safe in patients with unresectable isolated or dominant CRLM progressing after a first-line systemic treatment. Based on the low number of patients included in our study, our results suggest that this treatment does not increase dramatically the response rate versus an adapted systemic treatment. However, considering the safety data provided in this study, arterial infusion of bevacizumab in adjunction to chemotherapeutic agents could be evaluated in the future.

Summary: Background: There is a paucity of studies evaluating perioperative systemic chemotherapy in conjunction with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) in patients with colorectal cancer peritoneal metastases (CRCPM). The aim was to evaluate neoadjuvant and/or adjuvant systemic therapy in CRCPM. Methods: Patients with CRCPM from 39 treatment centres globally from January 1, 1991, to December 31, 2018, who underwent CRS+HIPEC were identified and stratified according to neoadjuvant/adjuvant use. Crude data analysis, propensity score matching (PSM) and Cox-proportional hazard modelling was performed. Findings: Of 2093 patients, 1613 were included in neoadjuvant crude evaluation with 708 in the PSM cohort (354 patients/arm). In the adjuvant evaluation, 1176 patients were included in the crude cohort with 778 in the PSM cohort (389 patients/arm). The median overall survival (OS) in the PSM cohort receiving no neoadjuvant vs neoadjuvant therapy was 37.0 months (95% CI: 32.6–42.7) vs 34.7 months (95% CI: 31.2–38.8, HR 1.08 95% CI: 0.88–1.32, p = 0.46). The median OS in the PSM cohort receiving no adjuvant therapy vs adjuvant therapy was 37.0 months (95% CI: 32.9–41.8) vs 45.7 months (95% CI: 38.8–56.2, HR 0.79 95% CI: 0.64–0.97, p = 0.022). Recurrence-free survival did not differ in the neoadjuvant evaluation but differed in the adjuvant evaluation – HR 1.04 (95% CI: 0.87–1.25, p = 0.66) and 0.83 (95% CI: 0.70–0.98, p = 0.03), respectively. Multivariable Cox-proportional hazard modelling in the crude cohorts showed hazard ratio 1.08 (95% CI: 0.92–1.26, p = 0.37) for administering neoadjuvant therapy and 0.86 (95% CI: 0.72–1.03, p = 0.095) for administering adjuvant therapy. Interpretation: Neoadjuvant therapy did not confer a benefit to patients undergoing CRS+HIPEC for CRCPM, whereas adjuvant therapy was associated with a benefit in this retrospective setting. Funding: None.

BackgroundAggressive locoregional therapies like hyperthemic intraperitoneal chemotherapy(HIPEC) and total parietal peritonectomy(TPP) have been used to delay recurrence in patients with advanced ovarian cancer undergoing interval cytoreductive surgery(CRS). The aim of this retrospective study was to evaluate the incidence of platinum resistant recurrence (PRR) and early recurrence (ER)(recurrence within 6 months and 1 year of the last dose of platinum based therapy, respectively) in patients undergoing interval CRS. The secondary goal was to study impact of each of these therapies on PRR and ER.MethodsOne-hundred and fifty-three patients undergoing interval CRS from July 2018 to June 2020 were included. The surgical strategy was to perform a TPP in which the entire parietal peritoneum is resected irrespective of the disease extent or a selective parietal peritonectomy (SPP) in which only the peritoneum bearing visible residual disease is resected. The use of HIPEC was at the discretion of the treating oncologists.ResultsThe median surgical PCI was 15 [range, 0-37]. A CC-0 resection was obtained in 119 (77.7%) and CC-1 in 29 (18.9%) patients. Eighty-one (53%) patients had a TPP and 72 (47%) had SPP. HIPEC was performed in 98(64%) patients. Bevacizumab maintenance was administered to 31(19.6%) patients. No patients received PARP inhibitors during first-line therapy. PRR was observed in 8(5.2%) patients and ER in 30(19.6%). The respective incidences of PRR and ER were 4.9% and 16% in the TPP group, 4.1% and 23.6% in the SPP group, 9% and 20% in the no-HIPEC group and 3% and 19.3% in the HIPEC groups. On multivariate analysis, CC-0(p=0.014) resection and HIPEC(p=0.030) were independent predictors of a low ER. All patients with PR and 70% with ER had peritoneal recurrence with or without extra-peritoneal sites of recurrence.ConclusionsThe incidence of PRR and ER in this cohort was low as compared to historical data. This low incidence could be attributed to the use of aggressive locoregional therapies like TPP and HIPEC. In future, studies should be conducted to confirm these findings and evaluate the potential additive benefit of TPP and HIPEC coupled together as well as their combination with maintenance therapies.

The airway exposure to Aspergillus fumigatus spores (AFsp) is associated with an inflammatory response, potentially leading to allergic and/or chronic pulmonary aspergillosis. The aim of our study is to better understand the host response, first in vitro, then in vivo, following the chronic exposure of mice to AFsp. We investigated the inflammatory response to AFsp in cell mono- and co-culture systems with murine macrophages and alveolar epithelial cells. The mice were subjected to two intranasal instillations using 105 AFsp. Their lungs were processed for inflammatory and histopathological analyses. In cell culture, the gene expressions significantly increased for TNF-α, CXCL-1, CXCL-2, IL-1β, IL-1α and GM-CSF in macrophages, with these increases being limited for TNF-α, CXCL-1 and IL-1α in epithelial cells. In co-culture, increases in the TNF-α, CXCL-2 and CXCL-1 gene expressions were observed to be associated with increased protein levels. The in vivo lung histological analyses of mice challenged by AFsp showed cellular infiltrates in the peribronchial and/or alveolar spaces. A Bio-Plex approach on the bronchoalveolar lavage revealed significant increases in the protein secretion of selected mediators of the challenged mice compared to the unchallenged mice. In conclusion, the exposure to AFsp resulted in a marked inflammatory response of macrophages and epithelial cells. These inflammatory findings were confirmed in mouse models associated with lung histologic changes.

Background Multicystic peritoneal mesothelioma (MCPM) is a rare, slowly growing, condition prone to recur after surgery. The role of hyperthermic intraperitoneal chemotherapy (HIPEC) added to complete cytoreductive surgery (CRS) remains controversial and difficult to assess. As patients are mostly reproductive age women, surgical approach, and fertility considerations are important aspects of the management. This observational retrospective review aimed to accurate treatment strategy reflections. Methods The RENAPE database (French expert centers network) was analyzed over a 1999–2019 period. MCPM patients treated with CRS were included. A special focus on HIPEC, mini-invasive approach, and fertility considerations was performed. Results Overall 60 patients (50 women) were included with a median PCI of 10 (4–14) allowing 97% of complete surgery, followed by HIPEC in 82% of patients. A quarter of patients had a laparoscopic approach. Twelve patients (20%) recurred with a 3-year recurrence free survival of 84.2% (95% confidence interval 74.7–95.0). The hazard of recurrence was numerically reduced among patients receiving HIPEC, however, not statistically significant (hazard ratio 0.41, 0.12–1.42, p = 0.200). A severe post-operative adverse event occurred in 22% of patients with five patients submitted to a subsequent reoperation. Among four patients with a childbearing desire, three were successful (two had a laparoscopic-CRS-HIPEC and one a conventional CRS without HIPEC). Conclusion MCPM patients treatment should aim at a complete CRS. The intraoperative treatment options as laparoscopic approach, fertility function sparing and HIPEC should be discussed in expert centers to propose the most appropriate strategy.

BackgroundThe utility of heated intraperitoneal chemotherapy (HIPEC) in the management of epithelial ovarian cancer (EOC) has been assessed in several randomised clinical trials and meta-analyses, and it is still a subject of controversy. Therefore, we performed an umbrella review of existing meta-analyses to summarise the outcomes of HIPEC and cytoreductive surgery (CRS) association in ovarian cancer.MethodsWe examined the MEDLINE, Cochrane Library, Scopus, Prospero, Web of Science and Science Direct from inception to May 30, 2020, for meta-analyses of randomised controlled trials and observational studies. Analyses of overall survival, disease free survival and progression survival were performed separately for primary and recurrent ovarian cancers.ResultsWe identified 6 meta-analyses investigating the association of HIPEC with CRS in the management of ovarian cancer. Three year overall survival was significantly improved by the association of CRS and HIPEC for primary (HR: 0.66, 95%CI:0.56-0.78) and recurrent ovarian cancers (HR:0.50, 95%CI:0.38-0.64). This benefit was also demonstrated on disease-free survival for primary (HR: 0.54, 95%CI:0.48-0.61) and recurrent ovarian cancer (HR: 0.60, 95%CI:0.46-0.78). The pooled hazard ratios confirmed the advantage of HIPEC and CRS association with respect to CRS alone on progression free survival for primary and recurrent ovarian cancer respectively with HR: 0.50, 95%CI: 0.43-0.58 and HR: 0.59, 95%CI: 0.41-0.85.ConclusionWhile waiting for the results of the current prospective studies, the present umbrella study suggests that HIPEC performed at the end of CRS may be a complementary effective asset for ovarian cancer patient management.

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

Introduction Despite optimal patient selection and surgical effort, recurrence is seen in over 70% of patients undergoing cytoreductive surgery (CRS) for peritoneal metastases (PM). Apart from the Peritoneal Cancer Index (PCI), completeness of cytoreduction and tumour grade, there are other factors like disease distribution in the peritoneal cavity, pathological response to systemic chemotherapy (SC), lymph node metastases and morphology of PM which may have prognostic value. One reason for the underutilisation of these factors is that they are known only after surgery. Identifying clinical predictors, specifically radiological predictors, could lead to better utilisation of these factors in clinical decision making and the extent of peritoneal resection performed for different tumours. This study aims to study these factors, their impact on survival and identify clinical and radiological predictors.Methods and analysis There is no therapeutic intervention in the study. All patients with biopsy-proven PM from colorectal, appendiceal, gastric and ovarian cancer and peritoneal mesothelioma undergoing CRS will be included. The demographic, clinical, radiological, surgical and pathological details will be collected according to a prespecified format that includes details regarding distribution of disease, morphology of PM, regional node involvement and pathological response to SC. In addition to the absolute value of PCI, the structures bearing the largest tumour nodules and a description of the morphology in each region will be recorded. A correlation between the surgical, radiological and pathological findings will be performed and the impact of these potential prognostic factors on progression-free and overall survival determined. The practices pertaining to radiological and pathological reporting at different centres will be studied.Ethics and dissemination The study protocol has been approved by the Zydus Hospital ethics committee (27 July, 2020) and Lyon-Sud ethics committee (A15-128).Trial registration number CTRI/2020/09/027709; Pre-results.

Background: Complete cytoreduction is acknowledged to be an effective way to achieve macroscopic tumor clearance for a variety of tumors confined to the peritoneal cavity. Recent trials have shown that surgery respecting anatomical planes results in excellent outcomes and even the chance of cure for some from what was once thought to be life-limiting disease. Objective: To describe peritonectomy procedures in the current era. Method: A thorough and systematic method for cytoreductive surgery aimed at complete surgical resection of peritoneal metastases (PMs) was described. Results: The general principles of cytoreductive surgery were set out including preoperative preparation, patient positioning and incision. Strategies for assessing disease extent and planning surgical steps were outlined and established peritonectomy procedures such as Glisson’s capsulectomy, omentectomy, left and right diaphragmatic peritonectomy, lesser omentectomy, stripping of the omental bursa, and pelvic peritonectomy were described. Novel techniques such as anterior pancreatic peritonectomy, small bowel mesenteric peritonectomy and cardiophrenic lymph node dissection were explained, and illustrated with accompanying video. Conclusion: Peritoneal metastases present a challenge to the surgeon which calls for a unique skill set if optimal outcomes are to be achieved. Attempts to standardize the surgical techniques described will allow further refinement as new technological advances occur.

Background: In colorectal cancer, hPG80 (progastrin) is released from tumor cells, promotes cancer stem cells (CSC) self-renewal and is detected in the blood of patients. Because the gene GAST that encodes hPG80 is a target gene of oncogenic pathways that are activated in many tumor types, we hypothesized that hPG80 could be expressed by tumors from various origins other than colorectal cancers, be a drug target and be detectable in the blood of these patients. Methods: hPG80 expression was monitored by fluorescent immunohistochemistry and mRNA expression in tumors from various origins. Cancer cell lines were used in sphere forming assay to analyze CSC self-renewal. Blood samples were obtained from 1546 patients with 11 different cancer origins and from two retrospective kinetic studies in patients with peritoneal carcinomatosis or hepatocellular carcinomas. These patients were regularly sampled during treatments and assayed for hPG80. Findings: We showed that hPG80 was present in the 11 tumor types tested. In cell lines originating from these tumor types, hPG80 neutralization decreased significantly CSC self-renewal by 28 to 54%. hPG80 was detected in the blood of patients at significantly higher concentration than in healthy blood donors (median hPG80: 4.88 pM versus 1.05 pM; p

Abstract Background To investigate the relationship between hospital volume activities and the survival for Epithelial Ovarian Carcinoma (EOC) patients in France. Methods This retrospective study using prospectively implemented databases was conducted on an exhaustive cohort of 267 patients undergoing first-line therapy during 2012 in the Rhone-Alpes Region of France. We compared Progression-Free Survival for Epithelial Ovarian Carcinoma patients receiving first-line therapy in high- (i.e. ≥ 12 cases/year) vs. low-volume hospitals. To control for selection bias, multivariate analysis and propensity scores were used. An adjusted Kaplan-Meier estimator and a univariate Cox model weighted by the propensity score were applied. Results Patients treated in the low-volume hospitals had a probability of relapse (including death) that was almost two times (i.e. 1.94) higher than for patients treated in the high-volume hospitals (p

Abstract Purpose: To evaluate the technical feasibility and homogeneity of drug distribution of pressurized intraperitoneal aerosol chemotherapy (PIPAC) based on a novel process of intraperitoneal drug application (multidirectional aerosolization). Methods: This was an in vivo experimental study in pigs. A single-port device was manufactured at the smallest diameter possible for multidirectional aerosolization of the chemotherapeutic drug under positive intraperitoneal pressure. Four domestic pigs were used in the study, one control animal that received multidirectional microjets of 9 mL/sec for 30 min and three animals that received multidirectional aerosolization (pig 02: 9 mL/sec for 30 min; pigs 03 and 04: 3 mL/sec for 15 min). Aerosolized silver nitrate solution was applied for anatomopathological evaluation of intraperitoneal drug distribution. Results: Injection time was able to maintain the pneumoperitoneum pressure below 20 mmHg. The rate of moderate silver nitrate staining was 45.4% for pig 01, 36.3% for pig 02, 36.3% for pig 03, and 72.7% for pig 04. Conclusions: Intra-abdominal drug distribution had a broad pattern, especially in animals exposed to the drug for 30 min. Our sample of only four animals was not large enough to demonstrate an association between aerosolization and a higher silver nitrate concentration in the stained abdominal regions.