The Role of Additional Staining in the Assessment of the Peritoneal Regression Grading Score (PRGS) in Peritoneal Metastasis of Gastric Origin

INTRODUCTION

The Peritoneal Regression Grading Score (PRGS) is a 4-tied histologic regression grading score for determining the response of peritoneal metastasis to chemotherapy. Peritoneal biopsies in every abdominal quadrant are recommended. A positive therapy response is defined as a decreasing or stable mean PRGS between 2 therapy cycles. The added value of periodic acid satin (PAS) and Ber-EP4 staining over HE staining for diagnosing PRGS1 (the absence of vital tumor cells) is unclear.

MATERIALS AND METHODS

A total of 339 biopsies obtained during 76 laparoscopies in 33 patients with peritoneal metastasis of gastric cancer were analyzed. Biopsies classified as PRGS 1 (no residual tumor, n=95) or indefinite (n=50) were stained with PAS, and remaining indefinite or PRGS1 cases additionally stained with BerEP4.

RESULTS

After PAS-staining tumor cells were detected in 28 out of 145 biopsies (19%), the remaining 117 biopsies were immunostained with Ber-EP4. Tumor cells were detected in 22 biopsies (19%). In total, additional staining allowed the detection of residual tumor cells in 50 out of 339 biopsies (15%) and changed the therapy response assessment in 7 out of 33 (21%) patients.

CONCLUSIONS

In summary, 25% (24 out of 95) of initially tumor-free samples (PRGS1) showed residual tumor cells after additional staining with PAS and/or BerEp4. Immunohistochemistry provided important additional information (the presence of tumor cells) in 22 of all 339 biopsies (11.2%). Further staining reduced the instances of unclear diagnosis from 50 to 0 and changed the therapy response assessment in 7 out of 33 patients (21%). We recommend additional staining in PRGS1 or unclear cases.

Descriptive review of current practices and prognostic factors in patients with ovarian cancer treated by pressurized intraperitoneal aerosol chemotherapy (PIPAC): a multicentric, retrospective, cohort of 234 patients

Introduction

Ovarian 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 methods

This 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.

Results

From 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.

Conclusions

With 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.

Acidic ascites inhibits ovarian cancer cell proliferation and correlates with the metabolomic, lipidomic and inflammatory phenotype of human patients

BACKGROUND

The poor prognosis of ovarian cancer patients is strongly related to peritoneal metastasis with the production of malignant ascites. However, it remains largely unclear how ascites in the peritoneal cavity influences tumor metabolism and recurrence. This study is an explorative approach aimed at for a deeper molecular and physical-chemical characterization of malignant ascites and to investigate their effect on in vitro ovarian cancer cell proliferation.

METHODS

This study included 10 malignant ascites specimens from patients undergoing ovarian cancer resection. Ascites samples were deeply phenotyped by ¹H-NMR based metabolomics, blood-gas analyzer based gas flow analysis and flow cytomertry based a 13-plex cytokine panel. Characteristics of tumor cells were investigated in a 3D spheroid model by SEM and metabolic activity, adhesion, anti-apoptosis, migratory ability evaluated by MTT assay, adhesion assay, flowcytometry and scratch assay. The effect of different pH values was assessed by adding 10% malignant ascites to the test samples.

RESULTS

 The overall extracellular (peritoneal) environment was alkaline, with pH of ascites at stage II-III = 7.51 ± 0.16, and stage IV = 7.78 ± 0.16. Ovarian cancer spheroids grew rapidly in a slightly alkaline environment. Decreasing pH of the cell culture medium suppressed tumor features, metabolic activity, adhesion, anti-apoptosis, and migratory ability. However, 10% ascites could prevent tumor cells from being affected by acidic pH. Metabolomics analysis identified stage IV patients had significantly higher concentrations of alanine, isoleucine, phenylalanine, and glutamine than stage II-III patients, while stage II-III patients had significantly higher concentrations of 3-hydroxybutyrate. pH was positively correlated with acetate, and acetate positively correlated with lipid compounds. IL-8 was positively correlated with lipid metabolites and acetate. Glutathione and carnitine were negatively correlated with cytokines IL-6 and chemokines (IL-8 & MCP-1).

CONCLUSION

Alkaline malignant ascites facilitated ovarian cancer progression. Additionally, deep ascites phenotyping by metabolomics and cytokine investigations allows for a refined stratification of ovarian cancer patients. These findings contribute to the understanding of ascites pathology in ovarian cancer.

Peritoneal regression grading score (PRGS) in peritoneal metastasis: how many biopsies should be examined?

Objectives

The four-tied peritoneal regression grading score (PRGS) is increasingly used to evaluate the response of peritoneal metastases (PM) to chemotherapy. The minimal number of peritoneal biopsies needed for PRGS determination remains unclear.

Methods

A prospective cohort of 89 PM patients treated with 210 pressurized intraperitoneal aerosol chemotherapy (PIPAC) cycles was investigated. Four biopsies from every abdominal quadrant were recommended. Histological tumor response was defined as a stable or decreasing mean PRGS between therapy cycles, progression increasing. We compared the diagnostic uncertainty induced by missing biopsies to the histological response.

Results

A total of 49 patients had at least two PIPAC and were eligible for therapy response assessment. Mean PRGS decreased from 2.04 (CI 5-95% 1.85-2.27) to 1.79 (CI 5-95% 1.59-2.01), p=0.14, as a proof of therapy effectiveness. 35 (71.4%) patients had a stable or decreasing PRGS (therapy response), 14 (28.6%) a PRGS increase (disease progression). Histology showed agreement between four biopsies in 42/210 laparoscopies (20%), between ≥3 biopsies in 103 (49%), and between ≥2 biopsies in 169 laparoscopies (81%). Mean loss of information with one missing biopsy was 0.11 (95% CI=0.13) PRGS points, with two missing biopsies 0.18 (95% CI 0.21). In 9/49 patients (18.3%), the loss of information with one less biopsy exceeded the change in PRGS under therapy.

Conclusions

A minimum of three biopsies is needed to diagnose PM progression with an accuracy superior to 80%. Missing biopsies often result in a false diagnosis of tumor progression.

Multicenter dose-escalation Phase I trial of mitomycin C pressurized intraperitoneal aerosolized chemotherapy in combination with systemic chemotherapy for appendiceal and colorectal peritoneal metastases: rationale and design

Objectives

Peritoneal metastasis (PM) from appendiceal cancer or colorectal cancer (CRC) has significant morbidity and limited survival. Pressurized intraperitoneal aerosolized chemotherapy (PIPAC) is a minimally invasive approach to treat PM. We aim to conduct a dose-escalation trial of mitomycin C (MMC)-PIPAC combined with systemic chemotherapy (FOLFIRI) in patients with PM from appendiceal cancer or CRC.

Methods

This is a multicenter Phase I study of MMC-PIPAC (NCT04329494). Inclusion criteria include treatment with at least 4 months of first- or second-line systemic chemotherapy with ineligibility for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC). Exclusion criteria are: progression on chemotherapy; extraperitoneal metastases; systemic chemotherapy intolerance; bowel obstruction; or poor performance status (ECOG>2). Escalating MMC-PIPAC doses (7-25 mg/m2) will be administered in combination with standard dose systemic FOLFIRI. Safety evaluation will be performed on 15 patients (dose escalation) and six expansion patients: 21 evaluable patients total.

Results

The primary endpoints are recommended MMC dose and safety of MMC-PIPAC with FOLFIRI. Secondary endpoints are assessment of response (by peritoneal regression grade score; Response Evaluation Criteria in Solid Tumors [RECIST 1.1], and peritoneal carcinomatosis index), progression free survival, overall survival, technical failure rate, surgical complications, conversion to curative-intent CRS-HIPEC, patient-reported outcomes, and functional status. Longitudinal blood and tissue specimens will be collected for translational correlatives including pharmacokinetics, circulating biomarkers, immune profiling, and single-cell transcriptomics.

Conclusions

This Phase I trial will establish the recommended dose of MMC-PIPAC in combination with FOLFIRI. Additionally, we expect to detect an early efficacy signal for further development of this therapeutic combination.

Safety and efficacy of pressurized intraperitoneal aerosolized chemotherapy in appendiceal and colorectal cancer patients with peritoneal carcinomatosis: A first-in-US phase I study

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Background: Pressurized intraperitoneal aerosolized chemotherapy (PIPAC) is being evaluated as a novel minimally invasive palliative treatment of peritoneal metastases (PM). Prior studies have established the feasibility and safety of repeated PIPAC treatments in gastrointestinal and gynecologic cancers. The goal of the present phase 1 trial was to establish the safety and feasibility of PIPAC oxaliplatin in a highly chemotherapy refractory colorectal and appendiceal cancer patient population. Methods: Patients with biopsy-proven peritoneal metastases from colorectal or appendiceal cancer underwent up to three PIPAC treatments using oxaliplatin (92 mg/m2) with a six-week interval at two academic centers. Patients with bowel obstruction, extra-peritoneal metastases, or poor performance status (ECOG>2) were excluded. PIPAC was nebulized over 5 min with a 30 min aerosol dwell time. Apart from the first PIPAC cycle, the patients also received a sensitizing dose of 5FU/LV (400mg/m2) within 24 hours of the procedure. Primary end point was safety as assessed by dose limiting toxicities within 6 weeks of the first PIPAC. Secondary endpoints included safety with the addition of 5FU/LV, efficacy, surgical morbidity, technical failure rate, progression-free and overall survival, pharmacokinetics (PK), and quality of life assessment. Results: A total of 8 patients were included: 5 colorectal; and 3 appendiceal. Median number of prior chemotherapy cycles was 2 (Interquartile range – IQR; 1.5-3.5). All patients were refractory to systemic oxaliplatin-based chemotherapy. Median time from diagnosis to PIPAC was 16 months (IQR; 5.6, 17.5) and Peritoneal Carcinomatosis Index was 29 (IQR; 20.5, 31.5). Five (62.5%) patients completed 3 PIPAC cycles while in 3 (37.5%) patients PIPAC was discontinued due to disease progression within the peritoneal cavity. No surgical complication or dose limiting toxicity was observed. Only one patient developed grade 3 treatment-related toxicity after first PIPAC (anemia), and another patient after second PIPAC (abdominal pain and anemia). At the completion of PIPAC treatment 5 patients had stable disease and 3 had disease progression. Pharmacokinetic, histologic response and preliminary survival data will be presented at the meeting. Conclusions: PIPAC with oxaliplatin is safe and feasible in a highly chemotherapy refractory cohort of appendiceal and colorectal carcinomatosis patients with or without sensitizing 5-FU/ LV. Clinical trial information: NCT04329494.

Cost-effectiveness analysis of pressurized intraperitoneal aerosol chemotherapy (PIPAC) in patients with gastric cancer and peritoneal metastasis

OBJECTIVE

The aim of this study was to assess the cost-effectiveness of pressurized intraperitoneal aerosol chemotherapy with low-dose cisplatin and doxorubicin (PIPAC C/D) for the treatment of advanced gastric cancer.

METHODS

A Partitioned Survival Model followed by state transition Markov model was developed to estimate the costs and effectiveness of the use of PIPAC C/D versus palliative chemotherapy in the UK. The intervention was assessed at two different levels of care, including upfront therapy (PIPAC C/D plus Oxaliplatin in combination with Capecitabine (XELOX) chemotherapy versus first-line chemotherapy alone) and second-line therapy (PIPAC C/D alone versus second-line chemotherapy (ramucirumab monotherapy)). Data from multiple sources, including published literature and UK-based databases, were used to inform the economic model.

RESULTS

For the upfront therapy analysis, the estimated total costs in the intervention and comparator arms were £32,606 (SD: £3877) and £17,844 (SD: £920), respectively. PIPAC C/D plus XELOX led to an increase of 0.46 in quality-adjusted life-years (QALYs) gained. The incremental cost per QALY gained was £31,868. For the second-line therapy analysis, the use of PIPAC C/D led to an increase of 0.19 in QALYs and a £21,474 reduction in costs, meaning the intervention was a dominant strategy.

CONCLUSIONS

The cost-effectiveness results for the upfront therapy analysis indicate that PIPAC C/D plus chemotherapy is a cost-effective strategy. Additionally, PIPAC C/D alone as a second-line therapy has the potential to reduce costs and improve clinical outcomes for patients with advanced gastric cancer with peritoneal metastasis.

PIPAC for the Treatment of Gynecologic and Gastrointestinal Peritoneal Metastases: Technical and Logistic Considerations of a Phase 1 Trial

BACKGROUND

Peritoneal metastases (PM) from ovarian, gastric, appendiceal, or colorectal origin can be treated via cytoreductive surgery with or without the addition of hyperthermic intraperitoneal chemotherapy (HIPEC) for selected patients. Unfortunately, not all patients are candidates for aggressive surgical debulking. For these patients, pressurized intraperitoneal aerosolized chemotherapy (PIPAC) has emerged as an alternative method for intraperitoneal (IP) chemotherapy administration. This report presents the design and implementation of the first phase 1 trial to evaluate the safety and efficacy of PIPAC in the United States.

METHODS

This is an ongoing prospective phase 1 clinical trial of PIPAC for patients who have histologically confirmed ovarian, uterine, gastric, appendiceal, or colorectal cancer with PM and have progressed to at least one evidence-based chemotherapeutic regimen. The trial has two clinical arms. The patients in arm 1 have gynecologic and gastric malignancies treated with IP cisplatin and doxorubicin, and the arm 2 patients have colorectal and appendiceal malignancies treated with intravenous fluorouracil and leucovorin followed by IP oxaliplatin. All the patients are monitored for dose-limiting toxicities and adverse events.

RESULTS

Practical and technical considerations for the phase 1 PIPAC trial are presented. These considerations include patient selection, operating room setup, and technical details for successful aerosolized chemotherapy delivery. The phase 1 study results will be reported separately at completion of the trial.

CONCLUSIONS

The PIPAC treatment is a feasible, minimally invasive approach that permits IP delivery of chemotherapy. Once completed, the ongoing phase 1 trial will help to provide safety and initial efficacy data.

Current practice and perceptions of safety protocols for the use of intraperitoneal chemotherapy in the operating room: results of the IP-OR international survey

OBJECTIVES

To assess the risk perception and the uptake of measures preventing environment-related risks in the operating room (OR) during hyperthermic intraperitoneal chemotherapy (HIPEC) and pressurized intraperitoneal aerosol chemotherapy (PIPAC).

METHODS

A multicentric, international survey among OR teams in high-volume HIPEC and PIPAC centers: Surgeons (Surg), Scrub nurses (ScrubN), Anesthesiologists (Anest), Anesthesiology nurses (AnesthN), and OR Cleaning staff (CleanS). Scores extended from 0-10 (maximum).

RESULTS

Ten centers in six countries participated in the study (response rate 100%). Two hundred and eleven responses from 68 Surg (32%), 49 ScrubN (23%), 45 Anest (21%), 31 AnesthN (15%), and 18 CleanS (9%) were gathered. Individual uptake of protection measures was 51.4%, similar among professions and between HIPEC and PIPAC. Perceived levels of protection were 7.57 vs. 7.17 for PIPAC and HIPEC, respectively (p<0.05), with Anesth scoring the lowest (6.81). Perceived contamination risk was 4.19 for HIPEC vs. 3.5 for PIPAC (p<0.01). Information level was lower for CleanS and Anesth for HIPEC and PIPAC procedures compared to all other responders (6.48 vs. 4.86, and 6.48 vs. 5.67, p<0.01). Willingness to obtain more information was 86%, the highest among CleanS (94%).

CONCLUSIONS

Experience with the current practice of safety protocols was similar during HIPEC and PIPAC. The individual uptake of protection measures was rather low. The safety perception was better for PIPAC, but the perceived level of protection remained relatively low. The willingness to obtain more information was high. Intensified, standardized training of all OR team members involved in HIPEC and PIPAC is meaningful.

Cost-effectiveness analysis of pressurized intraperitoneal aerosol chemotherapy (PIPAC C/D) in patients with gastric cancer and peritoneal metastasis

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Background: The efficacy of systemic chemotherapy is still highly unsatisfactory for patients with gastric cancer and peritoneal metastases (PM). The aim of this study was to assess the costs effectiveness of pressurized intraperitoneal aerosol chemotherapy with low-dose cisplatin and doxorubicin (PIPAC C/D) for advanced gastric cancer. Methods: We developed a state transition Markov Model to estimate the costs and effectiveness of the use of PIPAC C/D versus palliative chemotherapy. Intervention was assessed in two different levels including upfront therapy (PIPAC C/D plus XELOX chemotherapy versus first-line chemotherapy alone) and second line therapy (PIPAC C/D only versus second-line chemotherapy (ramucirumab monotherapy)). Data from multiple sources such as published literature and UK-based databases were used to inform the economic model. Deterministic and probabilistic sensitivity analyses were conducted to explore the impact of key parameter variation on the results. Results: For the upfront therapy the estimated total costs in the intervention and comparator arms were £33,587(SD: £2,394) and £17,477 (£927) respectively. PIPAC C/D plus XELOX led to an increase of 0.56 in QALYs. Estimated incremental cost per quality adjusted life years (QALYs) was £28,879. Result from probabilistic sensitivity analysis showed that PIPAC C/D plus XELOX is cost effective in more than 50% of Monte Carlo simulations at £30,000 threshold. For the second-line therapy, the total costs for PIPAC C/D was £15,985 (£1,391) and for the second-line palliative chemotherapy was £36,319 (£3,673). PIPAC C/D led to an increase of 0.21 in QALYs and £20,222 reduction in costs, meaning the intervention is dominant strategy in the second line therapy as it is less costly and more effective. Conclusions: The cost effectiveness results for the upfront therapy indicate that PIPAC C/D plus chemotherapy intervention is more costly and more effective and a cost effective intervention. PIPAC C/D only intervention has the potential to reduce costs and improve clinical outcomes for patients with advanced gastric cancer with peritoneal metastasis and therefore a dominant strategy.

shRNA-mediated inhibition of PhosphoGlycerate Kinase 1 (PGK1) enhances cytotoxicity of intraperitoneal chemotherapy in peritoneal metastasis of gastric origin

BACKGROUND

Phosphoglycerate kinase 1 (PGK1) plays metabolic, kinase and translational roles in Peritoneal metastasis (PM) of gastric origin and is associated with chemoresistance. Silencing PGK1 might potentiate the effect of chemotherapy.

METHODS

In an orthoptic xenograft nude mice model, human gastric cancer cells (MKN45) were grown in 22 donor animals. Solid tumors were then grafted into the gastric subserosa of 102 recipient animals and allowed to grow for 10 days. Animals were randomized into 7 groups: Five test groups: 1) Mitomycin C (MMC), 2) MMC and small hairpin RNA silencing of PGK1 with an adenoviral vector (Adv-shPGK1), 3) 5-fluorouracil (5-FU), 4) 5-FU and Adv-shPGK1, 5) Adv-shPGK1 alone; two control groups: 1) Sham (NaCl 0.9%), 2) empty viral vector. Intraperitoneal therapy was administered on postoperative day (POD) 11 and 18. Animals were sacrificed at POD 21, analysis was blinded to therapy.

RESULTS

Adding Adv-shPGK1 to 5-FU reduced the number (0.23 ± 0.43 vs. 1.36 ± 1.00, p = 0.005) and weight (0,005 ± 0.012 mg vs. 0.05 ± 0.08 mg, p = 0.002) of PM as compared to 5-FU alone. The effect of adding Adv-shPGK1 to MMC did not reach statistical significance. Mortality was not increased by adding Adv-shPGK1 to chemotherapy but was increased by Adv-shPGK1 alone as compared to sham.

CONCLUSION

In this experimental model, combined therapy with chemotherapy and Adv-shPGK1 improves control of PM of gastric origin as compared to chemotherapy alone and might counteract chemoresistance of PM. A systemic toxicity of Adv-shPGK1 cannot be excluded.

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

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Pressurized intraperitoneal aerosol chemotherapy with low-dose cisplatin and doxorubicin (PIPAC C/D) in patients with gastric cancer and peritoneal metastasis: a phase II study

Background:

Efficacy of second-line systemic chemotherapy in recurrent gastric cancer with peritoneal metastasis (RGCPM) is limited. We assessed the feasibility, safety and possible efficacy of pressurized intraperitoneal aerosol chemotherapy (PIPAC) in patients with RGCPM after ⩾1 line of palliative intravenous chemotherapy.

Methods:

In this open-label, single-arm, monocentric phase II ICH-GCP clinical trial, patients were scheduled for three courses of PIPAC with cisplatin 7.5 mg/m² and doxorubicin 1.5 mg/m² (PIPAC C/D) every 6 weeks. Patients with bowel obstruction or extraperitoneal metastasis were ineligible. The primary endpoint was clinical benefit rate (CBR) by Response Evaluation Criteria in Solid Tumors based on clinical records. Secondary endpoints included overall survival (OS), median time to progression (TTP), peritoneal carcinomatosis index (PCI), histological regression and ascites volume. Safety and tolerability were assessed by Common Terminology Criteria for Adverse Events (CTCAE) version 4, quality of life (QoL) by EORTC-QLQ30 questionnaire.

Results:

A total of 25 patients were enrolled and available for the analysis of the primary endpoint. Of those 25 patients, 10 (40%) had a radiological complete, partial response or stable disease. Median OS [intention to treat (ITT)] was 6.7 months, median TTP was 2.7 months. Complete or major regression on histology were observed in 9/25 patients (36%, ITT) or 6/6 [100%, per protocol (PP)] patients. There were no suspected unexpected serious adverse reactions, no treatment-related deaths, no CTCAE grade 4 toxicity and three (12%) grade 3 toxicities. Changes in the QLQ-C30 scores during PIPAC C/D therapy were small and not significant.

Conclusions:

PIPAC C/D was well tolerated and active in patients with RGCPM. Survival was encouraging. Randomized controlled trials should now be designed in this indication.

Resistance to anoikis in transcoelomic shedding: the role of glycolytic enzymes

Detachment of cells from the extracellular matrix into the peritoneal cavity initiates a cascade of metabolic alterations, leading usually to cell death by apoptosis, so-called anoikis. Glycolytic enzymes enable the switch from oxidative phosphorylation to aerobic glycolysis and allow resistance to anoikis of shed tumour cells. These enzymes also have moonlighting activities as protein kinases and transcription factors. Phosphoglycerate kinase (PGK) and pyruvate kinase are the only glycolytic enzymes generating ATP in the hexokinase pathway. Hypoxia, EGFR activation, expression of K-Ras G12V and B-Raf V600E induce mitochondrial translocation of phosphoglycerate kinase 1 (PGK1). Mitochondrial PGK1 acts as a protein kinase to phosphorylate pyruvate dehydrogenase kinase 1 (PDHK1), reducing mitochondrial pyruvate utilization, suppressing reactive oxygen species production, increasing lactate production and promoting tumourigenesis. PGK1 also plays a role as a transcription factor once transported into the nucleus. Resistance to anoikis is also facilitated by metabolic support provided by cancer-associated fibroblasts (CAFs). Our series of experiments in-vitro and in the animal model showed that PGK1 knock-out or inhibition is effective in controlling development and growth of peritoneal metastasis (PM) of gastric origin, establishing a causal role of PGK1 in this development. PGK1 also increases CXCR4 and CXCL12 expression, which is associated with a metastatic phenotype and plays a role in the metastatic homing of malignant cells. Thus, PGK1, its modulators and target genes may be exploited as therapeutic targets for preventing development of PM and for enhancing cytotoxic effects of conventional systemic chemotherapy.

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.

Peritoneal innervation: embryology and functional anatomy

The parietal peritoneum (PP) is innervated by somatic and visceral afferent nerves. PP receives sensitive branches from the lower intercostal nerves and from the upper lumbar nerves. Microscopically, a dense network of unmyelinated and myelinated nerve fibers can be found all over the PP. The unmyelinated fibers are thin and are ending just underneath the PP. The myelinated fibers can penetrate the PP to reach the peritoneal cavity, where they lose their myelin sheath and are exposed to somatic and nociceptive stimuli. PP is sensitive to pain, pressure, touch, friction, cutting and temperature. Noxious stimuli are perceived as a localized, sharp pain. The visceral peritoneum (VP) itself is not innervated, but the sub-mesothelial tissue is innervated by the autonomous nerve system. In contrast to the PP, the visceral submesothelium also receives fibers from the vagal nerve, in addition to the spinal nerves. VP responds primarily to traction and pressure; not to cutting, burning or electrostimulation. Painful stimuli of the VP are poorly localized and dull. Pain in a foregut structure (stomach, duodenum or biliary tract) is referred to the epigastric region, pain in a midgut structure (appendix, jejunum, or ileum) to the periumbilical area and pain from a hindgut source (distal colon or rectum) is referred to the lower abdomen or suprapubic region. Peritoneal adhesions can contain nerve endings. Neurotransmitters are acetylcholine, VIP, serotonin, NO, encephalins, CGRP and substance P. Chronic peritoneal pain can be exacerbated by neurogenic inflammation, e.g. by endometriosis.

A new ex vivo model for optimizing distribution of therapeutic aerosols: the (inverted) bovine urinary bladder

Background

Development of Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC) requires adequate preclinical models.

Methods

The model should be easy to use, reproducible and cost-effective. It should have a volume similar to the human abdominal cavity, and an oval shape. The inner surface should be lined with serosa. The model should allow pharmacological and biological analysis, including histology. No living animals should be used.

Results

The fresh urinary bladder is explanted from an adult bovine in the slaughterhouse. A 4-cm incision is performed into the bladder neck. The bladder can be inverted through the incision, which allows exposition of the serosa on its inner side. A balloon trocar is inserted through the incision and a ligature placed, ensuring full tightness. The therapeutic capnoperitoneum is installed. The bovine bladder has a volume somewhat smaller (2-3 L) than the human abdominal cavity (3-5 L). Costs are minimal. There is no significant bacteriological contamination. Manipulation is simple.

Conclusions

The (inverted) bovine urinary bladder is an innovative and versatile ex vivo model for optimizing drug delivery with therapeutic aerosols both onto the mucosa or the serosa. This model can be used for pharmaceutical Quality-by-Design approaches and will replace a large number of experiments in the animal.

Pressurized intraperitoneal aerosol chemotherapy with low-dose cisplatin and doxorubicin (PIPAC C/D) in patients with gastric cancer and peritoneal metastasis (PIPAC-GA1)

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Background: Efficacy of 2nd and 3rdline chemotherapy in recurrent gastric cancer with peritoneal metastasis (RGCPM) is limited. We assessed the feasibility, safety and activity of intraperitoneal chemotherapy as PIPAC C/D in RGCPM after > 1 line of intravenous chemotherapy. Methods: Open-label, single-arm, Phase II ICH-GCP Clinical Trial (NCT01854255) Patients were scheduled for 3 courses q42 days of low-dose PIPAC with doxorubicin 1.5 mg/m2 and cisplatin 7.5 mg/m2. Primary endpoint was objective tumor response (RECIST 1.1). Secondary endpoints were safety (CTCAE 4.0), histological tumor regression (PRGS) and overall survival. Results: 25 patients were enrolled. 10/25 (40 %, ITT) patients had an OTR. Complete or major regression on histology was observed in 9/12 (75 %) patients who underwent at least 2 PIPAC cycles. Mean overall survival was 8.4 months (13.1 months in patients with PCI < 12). There were no treatment-related deaths, no grade 4 toxicity and four (16%) grade 3 toxicities. Conclusions: PIPAC C/D is well tolerated and active in patients with RGCPM. Survival is encouraging. Randomized controlled trials should now be designed. Clinical trial information: NCT01854255. [Table: see text]

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) as a neoadjuvant therapy before cytoreductive surgery and hyperthermic intraperitoneal chemotherapy

BACKGROUND

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a novel drug delivery system able to induce regression of peritoneal metastasis (PM) in the salvage situation. The aim of this study was to determine the clinical characteristics, tumor histology, and extent of disease of the patients having undergone cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) after "neoadjuvant" PIPAC.

METHODS

This study was performed at a single institution, tertiary center. In a prospective registry, retrospective analysis was done. PIPAC indication was restricted to patients in the salvage situation who were not eligible for cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC).

RESULTS

Nine-hundred sixty-one PIPAC sessions were successfully performed in 406 patients: 21 patients (5.2 %) were scheduled for CRS and HIPEC. Twelve of these patients had a low PCI (mean 5.8 ± 5.6). The remaining nine patients showed an advanced peritoneal disease (mean PCI 14.3 ± 5.3) at initial laparoscopy. After repeated PIPAC (mean number of cycles 3.5 ± 0.9), radiological tumor regression was observed in 7/9 patients and major histological regression was observed in 8/9 patients, so that secondary CRS and HIPEC became possible.

CONCLUSIONS

PIPAC might be used as a neoadjuvant therapy before CRS and HIPEC in order to improve the outcome of CRS and HIPEC, to select patients with chemosensitive, biologically favorable tumors, to extent the indications of CRS and HIPEC in the presence of diffuse small bowel involvement, and to reduce the extent of cytoreductive surgery.

In Vivo Feasibility of Electrostatic Precipitation as an Adjunct to Pressurized Intraperitoneal Aerosol Chemotherapy (ePIPAC)

Background

Intraperitoneal chemotherapy is limited by tissue penetration. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) has been shown to improve drug uptake by utilizing the physical properties of gas and pressure. This study investigated the effect of adding electrostatic precipitation to further enhance the pharmacologic properties of this technique.

Methods

A comparative study was performed using an in vivo porcine model. There were 3 cases in each group, PIPAC and electrostatic precipitation pressurized intraperitoneal aerosol chemotherapy (ePIPAC), plus 1 negative control comparing intraperitoneal distribution and tissue uptake of 2 tracer substances (toluidine blue and DT01). Tracer uptake was determined by measuring DT01 in tissue and peritoneal fluid at the end of each procedure.

Results

Electrostatic precipitation of the aerosol was technically feasible in all ePIPAC animals. The aerosol was cleared completely from the visual field within 15 s in the ePIPAC group versus 30 min in the PIPAC group. The peritoneal surface was homogeneously stained in both groups. After 30 min, 1.5 % remaining DT01 was measured in samples of ePIPAC-treated peritoneal fluid versus 15 % in PIPAC animals (p = 0.01). Tissue concentration was increased after ePIPAC versus PIPAC (p = 0.06).

Conclusions

ePIPAC is technically feasible and improves tissue uptake of 2 tracer substances compared to PIPAC by up to tenfold. Intraperitoneal distribution was homogeneous in both groups. ePIPAC has the potential to allow more efficient drug uptake, further dose reduction, a significant shortening of the time required for PIPAC application, and improved health and safety measures.

Electronic supplementary material

The online version of this article (doi:10.1245/s10434-016-5108-4) contains supplementary material, which is available to authorized users.

Quality of life of patients with end-stage peritoneal metastasis treated with Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC)

BACKGROUND

Quality of Life (QoL) plays an important role in patients with peritoneal metastasis and is deteriorating continuously until death. Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC) is an innovative palliative treatment of peritoneal metastasis. We present the first QoL results under PIPAC therapy.

METHODS

Retrospective analysis of QLQ30 questionnaire results during repeated courses of PIPAC applications in palliative patients with pretreated peritoneal metastasis.

RESULTS

91 patients (M:F = 40:51, median age 64 (34-77) years) with 158 PIPAC applications were analyzed. 86% patients had previously received systemic chemotherapy. Peritoneal metastasis was advanced (Peritoneal Carcinomatosis Index I = 16 ± 10). At admission, only moderate impairment of functioning (62-83%) and symptom scores (17-47%) was observed. 48 patients received at least 2 PIPAC every 6 weeks. After PIPAC # 1, the global physical score deteriorated slightly (from 82% to 75%), but improved after PIPAC # 2 (up to 89%). Gastrointestinal symptoms (nausea/vomiting, constipation, diarrhoea, anorexia) remained stable under PIPAC therapy.

CONCLUSIONS

Quality of life was relatively high in this group of patients with advanced, pretreated peritoneal metastasis, explaining their wish for further therapy. Functioning scores and disease-related symptoms were not altered for at least 3 months in the patients able to receive repeated PIPAC. Except for a transient moderate increase of pain scores, PIPAC did not cause therapy-related QoL deterioration, especially no gastrointestinal symptoms.

Pressurized intraperitoneal aerosol chemotherapy (PIPAC): occupational health and safety aspects

Background

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a novel approach for treating peritoneal carcinomatosis. First encouraging results have been obtained in human patients. However, delivering chemotherapy as an aerosol might result in an increased risk of exposure to health care workers, as compared with other administration routes.

Methods

PIPAC was applied in two human patients using chemotherapeutic drugs (doxorubicin and cisplatin), and air contamination levels were measured under real clinical conditions. Air was collected on a cellulose nitrate filter with a flow of 22.5 m³/h. To exclude any risk for health care workers, both procedures were remote controlled. Toxicological research of cisplatin was performed according to NIOSH 7300 protocol. Sampling and analysis were performed by an independent certification organization.

Results

The following safety measures were implemented: closed abdomen, laminar airflow, controlled aerosol waste, and protection curtain. No cisplatin was detected in the air (detection limit < 0.000009 mg/m³) at the working positions of the surgeon and the anesthesiologist under real PIPAC conditions.

Conclusions

For the drugs tested, PIPAC is in compliance with European Community working safety law and regulations. Workplace contamination remains below the tolerance margin. The safety measures and conditions as defined above are sufficient. Further protecting devices, such as particulate (air purifying) masks, are not necessary. PIPAC can be used safely in the clinical setting if the conditions specified above are met. However, a toxicological workplace analysis must be performed to confirm that the procedure as implemented complies with local regulations.

Efficacy and safety of pressurized intraperitoneal aerosol chemotherapy (PIPAC) in women with recurrent gynaecological cancer and peritoneal carcinomatosis

e16523

Background: Peritoneal carcinomatosis (PC) is common in ovarian (OC) and other gynaecological cancers. We have developed an innovative therapy, Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC), which improves local tumor drug uptake and can be combined with systemic chemotherapy. PIPAC achieves outstanding local biodisponibility with low systemic exposure. Liver and renal toxicity are minimal. The procedure is safe for health workers. We present first results obtained in end-stage PC from gynaecological origin. Methods: Since 1.12.2011 we have performed 18 PIPAC applications in 9 end-stage PC patients with OC (n = 4), papillary (n = 3), tuba (n = 1) and cervix (n = 1) cancer. Mean age was 64.6 ± 16 years. In 4 instances, PIPAC was combined with cytoreductive surgery. Patients were followed-up until Dec, 2012 or until death. Tumor response was assessed by macroscopy (PCI) and microscopy. Results: No intraoperative complication was noted. Mean operating time (PIPAC alone) was 97 ± 20 min. PIPAC could be repeated at 6-weeks intervals (4x: n = 1; 3x: n = 3: 1x: n = 5). In one case, adhesions prevented iterative PIPAC. No adverse event > 2 CTCAE was noted after PIPAC alone. Six patients are alive. Median survival has not been reached after a mean follow-up of 8 months, actuarial survival after one year is 58,3%. Four patients were eligible for response assessment after repeated PIPAC. One showed complete remission (CR), three partial remission (PR). Performance index (Karnofsky) increased from 62 ± 17 % to 82 ± 5 % after therapy. Conclusions: These first results are promising. PIPAC can induce a regression of PC in advanced, therapy-resistant gynaecological cancers. PIPAC is well tolerated and can improve patient’s performance. First survival data are encouraging. PIPAC will now be evaluated in a phase-II clinical trial with cisplatin and doxorubicine (EudraCT 2012-004397-26) in therapy-resistant, recurrent OC.

Renal and hepatic toxicities after pressurized intraperitoneal aerosol chemotherapy (PIPAC)

Background

Both in animal models and in human patients, pressurized intraperitoneal aerosol chemotherapy (PIPAC) has been shown to improve local bioavailability of chemotherapy in peritoneal nodules, as compared with conventional peritoneal lavage. Pharmacokinetic studies show a low drug concentration in peripheral venous blood. However, hepatic and renal toxicities induced by delivering chemotherapeutic drugs into the abdomen as a pressurized aerosol have not yet been investigated.

Methods

Liver and renal function as well as toxicity parameters were monitored after eight PIPAC applications with doxorubicin (1.5 mg/m² body surface) and cisplatin (7.5 mg/m² body surface) in three end-stage patients suffering therapy-resistant peritoneal carcinomatosis. PIPAC was repeated at 4-week intervals (three times in two patients, twice in one patient). Peripheral venous blood was collected preoperatively and then daily until the 5th postoperative day, and sent to the hospital’s clinical chemistry laboratory. Statistical analysis was performed by analysis of variance (ANOVA).

Results

Gamma-glutamyltransferase was significantly elevated (p < 0.05) in the early postoperative phase. Glutamic oxaloacetic transaminase [aspartate aminotransferase], glutamic pyruvic transaminase [alanine aminotransferase], and bilirubin levels were not influenced by the procedure. Quick-test remained normal. Serum creatinine levels were not altered.

Conclusions

Under the above conditions, PIPAC did not induce clinically relevant liver cytotoxicity. Liver metabolism and function were not altered. Renal function remained within the normal range. No cumulative toxicity was observed after repeated PIPAC. PIPAC appears to be associated with very limited hepatic and renal toxicity, which might be a significant advantage over other administration routes.

Description of a novel approach for intraperitoneal drug delivery and the related device

BACKGROUND

Two significant limitations of intraperitoneal drug therapy are limited drug distribution and poor penetration into peritoneal nodules. A possible solution is the application of the so-called "therapeutic pneumoperitoneum," taking advantage of the gaseous nature and the pressure of capnoperitoneum during laparoscopy. Our objective was to develop a device able to apply such therapeutic pneumoperitoneum.

METHODS

The technology presented here is a spraying device and can be introduced through a trocar. It is driven by mechanical pressure and consists of an injector, a line, and a nozzle. An in vivo experimental study was performed in five pigs. A transvaginal cholecystectomy was performed. At the end of the procedure, a standard dose of methylene blue was sprayed/infused into the abdominal cavity for 30 min (4 test animals w/therapeutic pneumoperitoneum (12 mmHg CO(2)) and 1 control animal w/conventional lavage (2 l intra-abdominal volume with extracorporeal circulation)). At the end of the procedure, all animals were autopsied and the peritoneum was analyzed. Outcome criteria were: (1) drug distribution (as assessed by the stained peritoneal surface at autopsy), and (2) diffusion into the peritoneum (presence or not of macroscopic staining of the outer aspect of the peritoneum immediately after surgery).

RESULTS

Stained peritoneal surface was larger after aerosol application compared with peritoneal lavage, and staining more intense. Hidden peritoneal surfaces and the anterior abdominal wall were stained only in the aerosol group. In contrast to peritoneal lavage, the outer aspect of peritoneal membrane was immediately stained after pressurized spraying.

CONCLUSIONS

This device and the related approach significantly improve both distribution and penetration of a test substance into the peritoneal cavity in a large animal model. This might be a significant progress in treating intraperitoneal disease, in particular peritoneal carcinomatosis.

[Value of surgery in the palliative therapy for rectal cancer]

The treatment of advanced rectal cancer is a complicated task that can only poorly be reduced to the simple question "to operate or not to operate?" Instead the following factors must be taken into consideration: symptomatic versus non-symptomatic patients, emergency surgery versus elective surgery, proximal versus distal rectal cancer, local advanced versus metastatic disease, primary tumour versus recurrence, unresectable versus potentially resectable metastases, resection versus diversionary surgical procedures, etc. Also within the conservative group one must decide between interventional therapy (combined chemotherapy, stent placement, radiotherapy, etc.) and purely palliative therapy. Results from studies are not sufficient for the formulation of general recommendations. However, there are only few arguments against a surgical procedure in a symptomatic situation when the primary tumour dominates. In cases of metastasizing colorectal cancer modern chemotherapeutic procedures and new antibody therapies can markedly prolong survival. These results cannot be achieved by surgery alone. In this situation, it should be considered whether the longer life expectancy will be accompanied by the later occurrence of symptoms, which again justifies a surgical indication within the framework of multimodality therapy. The widely differing starting situations lead to different therapeutic approaches so that an individual indication can be made in the course of a tumour board discussion.

Influence of subclinical tumor spreading on survival after curative surgery for colorectal cancer

OBJECTIVE

To determine epithelial cell dissemination in patients with localized colorectal cancer.

DESIGN

Prospective observational study.

SETTING

Academic hospital.

PARTICIPANTS

Two hundred twenty-two patients operated on for colorectal cancer.

MAIN OUTCOME MEASURES

Epithelial cell dissemination was determined using immunohistochemistry or cytology in histologically negative lymph nodes, the peritoneal cavity, and bone marrow. Prognostic significance was determined in relation to 140 clinicopathological variables. Median follow-up was 61 months.

RESULTS

Of 140 patients who underwent curative surgery; 25 (17.9%) died of cancer-related causes; 10 (7.1%), of other causes; and 11 (7.8%) developed local recurrence. Tumor cells were present in the peritoneal cavity of 22% of patients, but this finding had only borderline influence on disease-free survival (P = .07). Lymph node micrometastases correlated with T category but not with survival. The presence of epithelial cells in the bone marrow was detected in 64% of patients but was not associated with tumor stage or survival. Multivariate analysis failed to identify occult tumor cell dissemination into any body compartment as an independent prognostic factor of disease-free survival.

CONCLUSIONS

Tumor cells disseminate into various body compartments in early stages of disease. In about two-thirds of patients, tumor cells are left in the body after so-called curative surgery. However, the presence of minimal residual disease has no independent prognostic significance in relation to established risk factors for tumor progression. Thus, other factors, such as the presence of a cellular metastatic phenotype and/or ineffective immunological response, must play an important role.

Emphysema and secondary pneumothorax in young adults smoking cannabis

BACKGROUND

We observed a remarkable increase in the number of young patients who presented with lung emphysema and secondary spontaneous pneumothorax (SSP) at our institution for over a period of 30 months; most of them have a common history of marijuana abuse.

STUDY DESIGN

Retrospective case series.

METHODS

Seventeen young patients presented with spontaneous pneumothorax with bullous lung emphysema were systematically evaluated over a period of 30 months. All were regular marijuana smokers. Clinical history, chest X-ray, CT-scan, lung function test, and laboratory and histological examinations were assessed. We compared the findings of this group (group I) with the findings of non-marijuana smoking patients (group II) in the same period. The findings of this series were also compared with the findings of 75 patients presented with pneumothorax in a previous period from January 2000 till March 2002 (group III).

RESULTS

In group I, there were 17 patients: the median age of the patients was 27 years (range 19-43 years), 16 males and 1 female. All were living in Switzerland. All but one smoked marijuana daily for a mean of 8.8 years and tobacco for 11.8 years. CT-scan showed multiple bullae at the apex or significant bullous emphysema with predominance in the upper lobes only in two patients. Only two patients had reduced forced first second expiratory volume (FEV1) and one reduced vital capacity (VC) below the predicted 50%. This correlated with the subjectively asymptomatic condition of the patients. All but two patients were treated by video-assisted thoracoscopic surgery (VATS) for prevention of relapsing pneumothorax. Histology showed severe lung emphysema, inflammation, and heavily pigmented macrophages. In group II, there were 85 patients: there were 78 males, the median age was 24 years (range 17-40 years), 74 patients smoked tobacco for 13.4 years but no marijuana. CT-scan in 72 patients showed only small bullae at the apex but no significant emphysema; other clinical, laboratory, and histopathological findings showed no significant difference in group I. In group III, there were 75 patients: there were 71 males and 4 females. Mean age was 25 years (range 16-46 years). Six smoked marijuana daily for a mean of 3.2 years, and 62 smoked tobacco for 14 years. CT-scan done in 59 patients showed few small bullae at the apex but no significant lung emphysema. The presence of lung emphysema on CT-scan in group I was significantly different than in groups II and III (p=0.14). No significant difference was found among all groups in the form of clinical, laboratory, and histopathological findings.

CONCLUSIONS

In case of emphysema in young individuals, marijuana abuse has to be considered in the differential diagnosis. The period of marijuana smoking seems to play an important role in the development of lung emphysema. This obviously quite frequent condition in young and so far asymptomatic patients will have medical, financial, and ethical impact, as some of these patients may be severely handicapped or even become lung transplant candidates in the future.

Proteomics in cancer

Proteomic studies have generated numerous datasets of potential diagnostic, prognostic, and therapeutic significance in human cancer. Two key technologies underpinning these studies in cancer tissue are two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and mass spectrometry (MS). Although surface-enhanced laser desorption/ionization time-of-flight (SELDI-TOF)-MS is the mainstay for serum or plasma analysis, other methods including isotope-coded affinity tag technology, reverse-phase protein arrays, and antibody microarrays are emerging as alternative proteomic technologies. Because there is little overlap between studies conducted with these approaches, confirmation of these advanced technologies remains an elusive goal. This problem is further exacerbated by lack of uniform patient inclusion and exclusion criteria, low patient numbers, poor supporting clinical data, absence of standardized sample preparation, and limited analytical reproducibility (in particular of 2D-PAGE). Despite these problems, there is little doubt that the proteomic approach has the potential to identify novel diagnostic biomarkers in cancer. In therapeutic proteomics, the challenge is significant due to the complexity systems under investigation (i.e., cells generate over 10(5) different polypeptides). However, the most significant contribution of therapeutic proteomics research is expected to derive not from single experiments, but from the synthesis and comparison of large datasets obtained under different conditions (e.g., normal, inflammation, cancer) and in different tissues and organs. Thus, standardized processes for storing and retrieving data obtained with different technologies by different research groups will have to be developed. Shifting the emphasis of cancer proteomics from technology development and data generation to careful study design, data organization, formatting, and mining is crucial to answer clinical questions in cancer research.