Peritoneal-plasma barrier

The prognostic value of peritoneal metastases in patients with gastric cancer: a nationwide population-based study

Background

The peritoneum is a common metastatic site in gastric cancer. The prognosis of synchronous peritoneal metastases compared to other metastatic sites in gastric cancer remains understudied. This study aims to evaluate the impact of peritoneal metastases on survival in patients with metastatic gastric cancer.

Methods

Patients with gastric cancer and synchronous metastases between 2015 and 2020 were identified from the nationwide Netherlands Cancer Registry. Patients were categorized based on the site of metastases. Median overall survival (OS) was calculated for each metastatic site group. Multivariable Cox regression analyses were performed to evaluate the association between patient, tumour, and treatment characteristics, including the impact of systemic therapy, on OS.

Findings

A total of 4072 patients were included, of whom 1835 (45.1%) had peritoneal metastases. Of these, 58.1% had isolated peritoneal metastases. For patients with metastatic gastric cancer treated with systemic therapy, the median OS was 9.0 months (95% confidence interval (CI): 8.6-9.5), compared to 1.7 months (95% CI: 1.7-1.9) for treatment-naïve patients, who received only palliative care. The survival for patients with isolated peritoneal metastases (4.4 months, 95% CI: 4.0-4.8 months) was similar to those with isolated non-peritoneal metastases (4.6 months, 95% CI: 4.2-5.1 months, adjusted HR: 0.94, 95% CI: 0.86-1.03, p = 0.185). Systemic therapy was associated with comparable survival in patients with peritoneal metastases and those with metastases at other sites.

Interpretation

This study demonstrates that there is no statistically significant difference in survival between patients with isolated peritoneal metastases and those with isolated non-peritoneal metastases in gastric cancer. Our findings emphasize the unique prognostic landscape for peritoneal metastases in gastric cancer, underscoring the need for disease-specific evaluations, rather than relying on assumptions derived from other cancer types.

Funding

None.

[Is cytoreductive surgery with HIPEC adequately funded?]

BACKGROUND

Cytoreductive surgery followed by hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) is a treatment concept for highly selected patients with peritoneal metastases and primary tumors (PMT). A challenge from the perspective of hospitals is the cost intensity of this promising multimodal treatment option.

RESEARCH QUESTION

Which factors influence the cost and revenue structure of CRS/HIPEC treatment in the current diagnosis-related group (DRG) system according to § 17b of the German Hospital Financing Act (KHG)?

MATERIAL AND METHODS

The database for this analysis was constituted by all patients treated with combined CRS/HIPEC at a certified tumor center between 2017 and 2021. The statistical analysis performed was descriptive, using two-sample and multisample comparisons (ANOVA) as well as linear correlation and regression analyses.

RESULTS

The total length of hospitalization for 173 patients was on average 16.1 days and the average length of stay in the intensive care unit was 2.2 days. Postoperative complications occurred in 110 (63.6%) patients. The average DRG revenue obtained was € 21,658.48. The total costs for the combined CRS/HIPC treatment amounted to an average of € 23,764.77 and were therefore on average € 2106.29 (8.86%) higher than the DRG revenue granted for the treatment. The length of stay in the intensive care unit and the total length of hospitalization correlated positively with the treatment costs and DRG revenue.

DISCUSSION

This study presents key factors influencing the cost and revenue structure of CRS/HIPEC and illustrates that this promising surgical treatment approach is relevantly underfunded by the German DRG system. A reform of the current DRG system with special consideration of highly complex oncological treatment concepts is therefore recommended.

Management of Peritoneal Metastasis in Patients with Pancreatic Ductal Adenocarcinoma

The peritoneum is the second most common site of metastasis in patients with pancreatic ductal adenocarcinoma (PDAC). Up to half of all patients that undergo curative-intent resection eventually develop peritoneal metastasis (PM), which accounts for significant morbidity and drives mortality. Despite recent advances in management, PM is associated with very poor prognosis, which is often measured in weeks to months. Clinical manifestations including bowel obstruction, ascites, and urinary obstruction have profound impact on quality of life. Even with relatively advanced disease, PM often remains occult on imaging and thus tend to be underdiagnosed and understudied. Many patients with peritoneal-only PM are excluded from clinical trials because response cannot be measured by standard radiographic criteria. Furthermore, as patients with PM are not eligible for surgical resection and low-volume peritoneal disease is often not amenable to percutaneous biopsy, tissue samples for peritoneal-specific translational studies are limited. Intraperitoneal therapeutics have been proposed as an attractive option for PM, as better penetration of tumor tissue can be achieved with less systemic toxicity compared with intravenous chemotherapy. Heated intraperitoneal chemotherapy (HIPEC), typically combined with cytoreductive surgery (CRS), is an option for select patients with PM from gynecologic or gastrointestinal primary, and for patients with primary peritoneal mesothelioma. However, the incorporation of locoregional therapy for PM in patients with PDAC has been poorly studied given the aggressive nature of pancreatic cancer and overall poor prognosis. With recent advances in existing treatment options, there may be a subset of patients who may derive benefits from locoregional control with cytoreduction and/or intraperitoneal chemotherapy. Critically, additional work is needed to determine PM-favorable clinical and tumoral predictive biomarkers to identify patients who may benefit from a more aggressive approach. We describe the current state of management of patients with peritoneal metastasis from PDAC and review the available data exploring peritoneal-directed therapy with cytoreductive surgery and/or intraperitoneal chemotherapy.

Treatment of Gastric Cancer Carcinomatosis

Patients with gastric cancer peritoneal metastases (GCPM) have Stage IV disease. Systemic therapy is a crucial aspect of their care. Patients with GCPM should have their tumors tested for HER2 and PD-L1 expression and microsatellite instability for potential targeted therapies. If patients with synchronous GCPM have stable disease following neoadjuvant therapy, surgical intervention can be considered. Patients with positive cytology or low-volume peritoneal disease (peritoneal carcinomatosis index [PCI] < 7) may "convert" to negative cytology or resolution of peritoneal metastases following intraperitoneal therapy and may be candidates for subsequent gastrectomy.

Iterative Intraperitoneal Chemotherapy in Gastric Cancer Peritoneal Carcinomatosis

Background/objectives: Despite the incremental improvement of survival with systemic therapy in metastatic gastric cancer (GC), the outcomes of patients with peritoneal carcinomatosis (PC) remain poor. The limited effectiveness of systemic therapy is attributed to the blood-peritoneal barrier and anarchic intra-tumoral circulation, which reduce the penetration of systemic therapy. Approaches that incorporate intraperitoneal (IP) chemotherapy, in addition to systemic therapies, may be a viable alternate strategy. Therefore, we provide a review of biology of gastric cancer peritoneal metastasis and evidence for bidirectional iterative IP chemotherapy in GCPC. Methods: A comprehensive search in PubMed, Scopus, Embase, Web of Science, Google Scholar, and ClinicalTrials.gov was performed to find the relevant articles and ongoing phase II/III clinical trials in iterative IP chemotherapy in GCPC. Results: Intraperitoneal (IP) chemotherapy leverages the blood-peritoneal barrier to allow for the administration of high concentrations of chemotherapy directly to the peritoneal metastases, with a significant reduction in the systemic toxicity and enhanced drug efficacy against peritoneal metastasis. This pharmacokinetic advantage of IP chemotherapy can be further enhanced by additional measures such as heat or aerosolization. There are three IP chemotherapy approaches, namely, heated intraperitoneal chemotherapy (HIPEC), pressurized intraperitoneal aerosolized chemotherapy (PIPAC), and normothermic intraperitoneal chemotherapy (NIPEC). Recent evidence suggests that iterative IP chemotherapy combined with systemic therapy may offer significant survival benefits for patients with peritoneal metastasis. Furthermore, bidirectional treatment approaches may also increase the chances of surgical resection and survival. Conclusions: IP chemotherapy plays a pivotal role in the management of gastric carcinomatosis, particularly in combination with cytoreduction in highly selected patients. The combination of systemic and regional control may increase the chances of surgical resection and may ultimately lead to significant survival benefits.

Advances in microsphere-based therapies for peritoneal carcinomatosis: challenges, innovations, and future prospects

INTRODUCTION

Clinical outcomes for the treatment of peritoneal carcinomatosis (PC) have remained suboptimal. Microsphere-based intraperitoneal chemotherapy has shown considerable potential in preclinical studies. However, due to the complications associated with peritoneal adhesions, there has been a lack of comprehensive reviews focusing on the progress of microsphere applications in the treatment of PC.

AREAS COVERED

We provide an overview of the current clinical treatment strategies for PC and analyze the potential advantages of microspheres in this context. Regarding the issue of peritoneal adhesions induced by microspheres, we investigate the underlying mechanisms and propose possible solutions. Furthermore, we outline the future directions for the development of microsphere-based therapies in the treatment of PC.

EXPERT OPINION

Microspheres formulated with highly biocompatible materials to the peritoneum, such as sodium alginate, gelatin, or genipin, or with an optimal particle size (4 ~ 30 μm) and lower molecular weights (10 ~ 57 kDa), can prevent peritoneal adhesions and improve drug distribution. To further enhance the antitumor efficacy, enhancing the tumor penetration capability and specificity of microspheres, optimizing intraperitoneal distribution, and addressing tumor resistance have demonstrated significant potential in preclinical studies, offering new therapeutic prospects for the treatment of PC.

Emerging Treatment Modalities for Gastric Cancer With Macroscopic Peritoneal Metastases: A Systematic Review

Gastric cancer with macroscopic peritoneal metastases represents a major therapeutic challenge and is associated with a poor prognosis. This review aims to evaluate the efficacy and safety of new treatment modalities. A systematic search of PubMed was conducted to identify studies published between January 2014 and April 2024. Inclusion criteria were trials investigating novel therapies for gastric cancer with peritoneal metastases. Data on treatment efficacy, survival outcomes, and side effects were extracted.

The journey of nanoparticles in the abdominal cavity: Exploring their in vivo fate and impact factors

Peritoneal carcinomatosis (PC) is caused by metastasis of primary tumor cells from intra-abdominal organs to the peritoneal surface. Intraperitoneal (IP) chemotherapy allows close contact of high concentrations of therapeutic agents with cancer cells in the peritoneal cavity to prolong patient survival. However, conventional IP chemotherapy is prone to rapid elimination from the peritoneal cavity and lacks specificity towards cancer cells. To address these challenges, there is an imperative demand for exploiting novel drug delivery systems to enhance drug retention in the peritoneal cavity and target PC cells. Therefore, in this review, we first recapitulate the physiological structures and barriers associated with IP drug delivery, highlighting the in vivo fate of nanoparticles (NPs) after IP administration. Furthermore, the influence of physicochemical properties (particle size, charge, surface modification, and carrier composition) on the in vivo fate of NPs is discussed. Perspectives on the rational design of NPs for IP therapy and recent clinical progress are also provided.

Intraperitoneal administration of adeno-associated virus encoding microRNA-29b for the treatment of peritoneal metastasis

This study explores a novel therapeutic approach for peritoneal metastasis (PM) using AAV-mediated delivery of tumor suppressor microRNA-29b (miR-29b) to peritoneal mesothelial cells (PMC). AAV serotypes 2 and DJ demonstrate high transduction efficiency for human and murine PMC, respectively. In vitro analysis indicates that AAV vectors encoding miR-29b precursor successfully elevate miR-29b expression in PMC and their secreted small extracellular vesicle (sEV), thereby inhibiting mesothelial mesenchymal transition and reducing subsequent attachment of tumor cells. A single intraperitoneal (IP) administration of AAV-DJ-miR-29b demonstrates robust and sustained transgene expression, suppressing peritoneal fibrosis and inhibiting the development of PM from gastric and pancreatic cancers. Additionally, AAV-DJ-miR-29b enhances the efficacy of IP chemotherapy using paclitaxel, restraining the growth of established PM. While conventional gene therapy for cancer encounters challenges targeting tumor cells directly but delivering miRNA to the tumor stroma offers a straightforward and efficient means of altering the microenvironment, leading to substantial inhibition of tumor growth. AAV-mediated miR-29b delivery to peritoneum via IP route presents a simple, minimally invasive, and promising therapeutic strategy for refractory PM.

Patient-reported outcomes during first-line palliative systemic therapy alternated with pressurized intraperitoneal aerosol chemotherapy for unresectable colorectal peritoneal metastases: a single-arm phase II trial (CRC-PIPAC-II)

BACKGROUND

The CRC-PIPAC-II study prospectively assessed bidirectional therapy (BT) consisting of first-line palliative systemic therapy and electrostatic precipitation oxaliplatin-based pressurized intraperitoneal aerosol chemotherapy (ePIPAC-OX) in patients with unresectable colorectal peritoneal metastases (CPM). This study describes the exploration of patient-reported outcomes (PROs).

METHODS

In this phase II trial, 20 patients with isolated CPM were treated with up to three cycles of BT, each cycle consisting of two to three courses of systemic therapy, followed by ePIPAC-OX (92 mg/m2). Patients were asked to complete the EuroQoL EQ-5D-5L, EORTC QLQ-C30, and EORTC QLQ-CR29 questionnaires at baseline, during the first cycle of BT, and one and four weeks after each consecutive BT cycle. PRO scores were calculated and compared between baseline and each subsequent time point using linear-mixed modeling (LMM). PROs were categorized into symptom scales and function scales. Symptom scales ranged from 0 to 100, with 100 representing the maximum symptom load. Function scales ranged from 0 to 100, with 100 representing optimal functioning.

RESULTS

Twenty patients underwent a total of 52 cycles of bidirectional therapy. Most PROs (29 of 37, 78%) were not significantly affected during trial treatment. In total, only eight PROs (22%) were significantly affected during trial treatment: Six PROs (index value, global health status, emotional functioning, C30, appetite, and insomnia) showed transient improvement at different time points. Two PROs transiently deteriorated: pain initially improved during the first BT cycle [- 16, p < 0.001] yet worsened temporarily one week after the first two BT cycles (+ 20, p < 0.001; + 17, p = 0.004; respectively). Abdominal pain worsened temporarily one week after the first BT cycle (+ 16, p = 0.004), before improving again four weeks after treatment ended (- 10, p = 0.004). All significant effects on Pros were clinically significant and all deteriorations in PROs were of temporary nature.

DISCUSSION

Patients undergoing BT for unresectable CPM had significant, but reversible alterations in several PROs. Most affected PROs concerned improvements and only two PROs showed deteriorations. Both deteriorated PROs returned to baseline after trial treatment and were of a temporary nature. These outcomes help to design future studies on the role of ePIPAC in the palliative setting.

Innovative theranostic hydrogels for targeted gastrointestinal cancer treatment

Gastrointestinal tumors are the main causes of death among the patients. These tumors are mainly diagnosed in the advanced stages and their response to therapy is unfavorable. In spite of the development of conventional therapeutics including surgery, chemotherapy, radiotherapy and immunotherapy, the treatment of these tumors is still challenging. As a result, the new therapeutics based on (nano)biotechnology have been introduced. Hydrogels are polymeric 3D networks capable of absorbing water to swell with favorable biocompatibility. In spite of application of hydrogels in the treatment of different human diseases, their wide application in cancer therapy has been improved because of their potential in drug and gene delivery, boosting chemotherapy and immunotherapy as well as development of vaccines. The current review focuses on the role of hydrogels in the treatment of gastrointestinal tumors. Hydrogels provide delivery of drugs (both natural or synthetic compounds and their co-delivery) along with gene delivery. Along with delivery, hydrogels stimulate phototherapy (photothermal and photodynamic therapy) in the suppression of these tumors. Besides, the ability of hydrogels for the induction of immune-related cells such as dendritic cells can boost cancer immunotherapy. For more specific cancer therapy, the stimuli-responsive types of hydrogels including thermo- and pH-sensitive hydrogels along with their self-healing ability have improved the site specific drug delivery. Moreover, hydrogels are promising for diagnosis, circulating tumor cell isolation and detection of biomarkers in the gastrointestinal tumors, highlighting their importance in clinic. Hence, hydrogels are diagnostic and therapeutic tools for the gastrointestimal tumors.

Combined Nabpaclitaxel pressurized intraPeritoneal aerosol chemotherapy with systemic Nabpaclitaxel-Gemcitabine chemotherapy for pancreatic cancer peritoneal metastases: protocol of single-arm, open-label, phase II trial (Nab-PIPAC trial)

Objectives

Current therapies show limited efficacy against peritoneal metastases (PM) from pancreatic cancer. Pressurized intra-peritoneal aerosol chemotherapy (PIPAC) has emerged as a novel intraperitoneal drug delivery method. Recently, a dose-escalation study identified the safe dose of Nabpaclitaxel for PIPAC administration, an ideal intraperitoneal chemotherapy agent against pancreatic cancer. Combining systemic NabPaclitaxel-Gemcitabine with NabPaclitaxel-PIPAC may enhance disease control in pancreatic cancer patients with PM.

Methods

The Nab-PIPAC trial is a single-center, prospective, open-label, phase II study (ClinicalTrials.gov identifier: NCT05371223). Its primary goal is to evaluate the antitumor activity of the combined treatment based on Disease Control Rate (DCR) using RECISTv.1.1 criteria. Secondary objectives include feasibility, safety, pathological response, progression-free and overall survival, nutritional status, quality of life, pharmacokinetics of NabPaclitaxel-PIPAC, and PM molecular evolution via translational research. The treatment protocol consists of three courses, each with two cycles of intravenous NabPaclitaxel-Gemcitabine and one cycle of NabPaclitaxel-PIPAC, with standard metastatic pancreatic cancer doses for the former and 112.5 mg/m2 for the latter. Sample size follows Simon's two-stage design: 12 patients in stage one and 26 in stage two (80 % power, 0.1 alpha).

Results

Partial results will be available after first stage enrollment.

Conclusions

This trial aims to determine the antitumor efficacy and safety of combining NabPaclitaxel-PIPAC with systemic NabPaclitaxel-Gemcitabine in pancreatic cancer patients with PM.

Cytoreductive Surgery with Hyperthermic Intraperitoneal Chemotherapy for the Treatment of Peritoneal Sarcomatosis

(1) Background: Cytoreductive surgery (CRS) with HIPEC is considered the standard of care for selected patients with peritoneal carcinomatosis, but evidence-based treatment recommendations for the therapy of peritoneal sarcomatosis are scarce. (2) Methods: We retrospectively analyzed all adult patients treated with CRS and HIPEC for peritoneal sarcomatosis between 2017 and 2024. (3) Results: Ten patients with a median age of 46.1 years (range: 23-77 years) with metachronous (40%) or synchronous (60%) peritoneal sarcomatosis from six different tumor entities were treated according to tumor board recommendation using CRS and HIPEC with cisplatin and doxorubicin over 60 min at 42.0 °C. The length of stay in the intensive care unit and hospital was 1.24 (0.6-1.9 days) and 11.1 days (6-17 days), respectively. Complete cytoreduction was achieved in 90% of the patients, with a median PSI of 11.5. Postoperative complications occurred in five cases, but no surgical revisions were necessary, and no acute kidney damage was recorded. (4) Conclusions: CRS with HIPEC in the presence of peritoneal sarcomatosis could be safely performed in our collective. Whether this resulted in an oncological treatment benefit cannot be concluded in view of the heterogeneous and small collective. Therefore, larger and prospective studies are warranted.

Optimizing Timing of Intraperitoneal Chemotherapy to Enhance Intravenous Carboplatin Concentration

Despite advances in systemic chemotherapy, patients with gastric cancer (GC) and peritoneal metastases (PMs) continue to have poor prognoses. Intraperitoneal (IP) administration of Paclitaxel (PTX) combined with systemic chemotherapy shows promise in treating PMs from GC. However, methods of drug administration need to be optimized to maximize efficacy. In this study, we utilized a mouse model with PMs derived from a human GC cell line, administering PTX either IP or intravenously (IV), and Carboplatin (CBDCA) IV 0, 1, and 4 days after PTX administration. The PMs were resected 30 min later, and concentrations of PTX and CBDCA in resected tumors were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Results indicated that PTX concentrations were higher with IP administration than with IV administration, with significant differences observed on days 0 and 1. CBDCA concentrations 4 days post-IP PTX administration were higher than with simultaneous IV PTX administration. These findings suggest that IP PTX administration enhances CBDCA concentration in peritoneal tumors. Therefore, sequential IV administration of anti-cancer drugs appears more effective than simultaneous administration with IP PTX, a strategy that may improve prognoses for patients with PMs.

Systemic Treatment Strategies and Outcomes of Patients With Synchronous Peritoneal Metastases of Gastric Origin: A Nationwide Population-Based Study

BACKGROUND

Palliative systemic treatment is currently standard of care for metastatic gastric cancer. However, patients with peritoneal metastases of gastric origin are often underrepresented in clinical studies due to unmeasurable radiologic disease. This study describes the systemic treatment strategies and outcomes in patients with peritoneal metastases in a nationwide real-world setting.

METHODS

Patients with gastric adenocarcinoma and synchronous peritoneal metastases (with or without other metastases) diagnosed in the Netherlands between 2015 and 2020 were identified from the nationwide Netherlands Cancer Registry. Median overall survival (OS) and time-to-treatment failure were determined and multivariable Cox regression analyses were used to compare treatment groups, corrected for relevant tumor and patient characteristics.

RESULTS

In total, 1,972 patients were included, of whom 842 (43%) were treated with palliative systemic therapy. The majority received capecitabine + oxaliplatin (CAPOX; 44%), followed by fluorouracil/leucovorin/oxaliplatin (FOLFOX; 19%), and epirubicin + capecitabine + oxaliplatin (EOX; 8%). Of the 99 (45%) patients who received second-line systemic treatment, ramucirumab + paclitaxel were administered most frequently (63%). After adjustment for sex, age, comorbidities, performance status, tumor location, Lauren classification, and the presence of metastases outside of the peritoneum, patients treated with a triplet containing docetaxel and those treated with a regimen containing trastuzumab had a significantly longer OS compared with patients treated with a doublet containing a fluoropyrimidine derivate + oxaliplatin (hazard ratio [HR], 0.69; 95% CI, 0.52-0.91, and HR, 0.68; 95% CI, 0.51-0.91, respectively). Monotherapy was associated with a shorter OS (HR, 2.08, 95% CI, 1.53-2.83).

CONCLUSIONS

There is substantial heterogeneity in systemic treatment choices in patients with gastric cancer and peritoneal metastases in the Netherlands. In this study, patients treated with triplets containing docetaxel and with trastuzumab-containing regimens survived longer than patients who received doublet therapy. Despite this, median OS for all treatment groups remained below one year.

The Role of Hyperthermic Intrathoracic Chemotherapy (HITHOC) in Thoracic Tumors

Pleural mesothelioma (PM) is a rare but aggressive thoracic tumor with a poor prognosis. Multimodal treatment-including induction chemotherapy, aggressive surgical resection, radiotherapy and immunotherapy in selected cases-currently represents the best therapeutic option. Single-center studies advocate hyperthermic intrathoracic chemotherapy (HITHOC) during surgical resection as an additional therapeutic option, although its impact on post-operative morbidity and survival has not yet been evaluated on a larger scale. HITHOC can be applied not only in the case of mesothelioma, but also in the case of thymoma with pleural involvement or-in very selected cases-in patients with secondary pleural metastases. Despite favorable outcomes and reduced clinical risks, there is no uniform approach to HITHOC, and a wide variety of indications and technical applications are still reported. Based on available data, HITHOC seems to offer a clear benefit in regard to overall survival of all mesothelioma patients; however, multicenter randomized controlled trials are required to validate and standardize this approach. The aim of this review is to focus on the present role of HITHOC in thoracic tumors with pleural involvement as well as on future challenges, particularly in the light of possible combined therapy of thoracic tumors still presenting poor prognoses.

Improving diagnostic accuracy of identifying gastric cancer patients with peritoneal metastases: tumor-guided cell-free DNA analysis of peritoneal fluid

Detection of peritoneal dissemination (PD) in gastric cancer (GC) patients remains challenging. The feasibility of tumor-guided cell-free DNA (cfDNA) detection in prospectively collected peritoneal fluid (ascites and peritoneal lavage) was investigated and compared to conventional cytology in 28 patients. Besides conventional cytology, next generation sequencing was performed on primary tumor DNA and cell-free DNA from peritoneal fluid. Patients were retrospectively grouped into: a positive group (with PD) and a negative group (without PD). Detectable mutations were found in the primary tumor of 68% (n = 19). Sensitivity of PD detection by tumor-guided cfDNA analysis was 91%, compared to 64% by conventional cytology. Within the positive group (n = 11), tumor-guided cfDNA was detected in all patients with ascites samples (4/4, 100%) and in 86% (6/7) of the lavage samples, opposed to 4/4 (100%) patients with ascites and 43% (3/7) with lavage by conventional cytology. Within the negative group (n = 8), conventional cytology was negative for all samples. In two patients, tumor-guided cfDNA was detected in peritoneal lavage fluid. Interestingly, these 2 patients developed PD within 6 months, suggesting a prognostic value of tumor-guided cfDNA detection. This study showed that tumor-guided cfDNA detection in peritoneal fluids of GC patients is feasible and superior to conventional cytology in detecting PD.

Regional Therapy Approaches for Gastric Cancer with Limited Peritoneal Disease

PURPOSE

Despite advances in systemic therapy, outcomes of patients with gastric cancer (GC) peritoneal carcinomatosis (PC) remain poor, in part because of poor penetrance of systemic therapy into peritoneal metastasis due to the plasma-peritoneal barrier and anarchic intra-tumoral circulation. Hence, regional treatment approach with administration of chemotherapy directly into the peritoneal cavity (intraperitoneal, IP) under various conditions, combined with or without cytoreductive surgery (CRS) has remained an area of significant research interest. The purpose of this review is to provide high-level evidence for regional treatment approaches in the management of GCPC with limited peritoneal disease.

METHODS

A review of the current literature and ongoing clinical trials for regional IP therapies for GCPC was performed. Studies included in this review comprise of phase III randomized controlled trials, non-randomized phase II studies, high-impact retrospective studies, and active ongoing clinical trials for each available IP modality.

RESULTS

The three common IP approaches are heated intraperitoneal chemotherapy (HIPEC), normothermic intraperitoneal chemotherapy (NIPEC) and more recently introduced, pressurized intraperitoneal aerosolized chemotherapy (PIPAC). These IP approaches have been combined with systemic therapy and/or CRS with varying degrees of promising results, demonstrating evidence of improvements in survival rates and peritoneal disease control. Patient selection, optimization of systemic therapy, and completeness of cytoreduction have emerged as major factors influencing the design of contemporary and ongoing trials.

CONCLUSION

IP chemotherapy has a clear role in the management of patients with GCPC, and when combined with CRS in appropriately selected patients has the potential to significantly improve survival. Ongoing and upcoming IP therapy clinical trials hold great promise to shape the treatment paradigm for GCPC.

Exosomal miR-493 suppresses MAD2L1 and induces chemoresistance to intraperitoneal paclitaxel therapy in gastric cancer patients with peritoneal metastasis

Intraperitoneal (IP) chemotherapy with paclitaxel (PTX) for gastric cancer (GC) with peritoneal metastasis (PM) is considered a promising treatment approach, however, there are no useful biomarkers to predict the efficacy of IP therapy. We examined the association between intra-peritoneal exosomes, particularly exosomal micro-RNAs (exo-miRNAs), and IP-chemo sensitivity. MKN45 cells that were cultured with intra-peritoneal exosomes from patients who did not respond to IP therapy with PTX (IPnon-respond group) exhibited resistance to PTX compared with exosomes from responding patients (IPrespond group) (p = 0.002). A comprehensive search for exo-miRNAs indicated that miR-493 was significantly up-regulated in exosomes from the IPnon-respond group compared with those collected from the IPrespond group. The expression of miR-493 in PTX-resistant MKN45 cells (MKN45PTX-res) was higher compared with that in MKN45. In addition, MKN45PTX-res cells exhibited lower MAD2L1 gene and protein expression compared with MKN45. Finally, miR-493 enhancement by transfection of miR-493 mimics significantly down-regulated MAD2L1 expression in MKN45 cells and reduced PTX sensitivity. Our results suggest that intra-peritoneal exo-miR-493 is involved in chemoresistance to PTX by downregulating MAD2L1 in GC with PM. Exo-miR-493 may be a biomarker for chemoresistance and prognosis of GC patients with PM and may also be a promising therapeutic target.

Fluorescence-Guided Laparoscopy after Oral Hypericin Administration for Staging of Locally Advanced Gastric Cancer-A Pilot Study

(1) Background: Laparoscopic staging is essential in gastric cancer (GC) to rule out peritoneal metastasis (PM). Hypericin, a plant-derived fluorescent compound, has been suggested to improve laparoscopic visualization of PM from GC. This prospective, single-arm, open-label clinical trial aimed to assess the feasibility and safety of oral hypericin administration as well as the suitability of fluorescence-guided laparoscopy (FGL) for improving the sensitivity and specificity of staging in GC patients (EudraCT-Number: 2015-005277-21; clinicaltrials.gov identifier: NCT-02840331). (2) Methods: GC patients received Laif® 900, an approved hypericin-containing phytopharmaceutical, once orally two to four hours before white light and ultraviolet light laparoscopy. The peritoneal cancer index was evaluated, biopsies taken and hypericin concentrations in serum and peritoneal tissue were determined by mass spectrometry. (3) Results: Between 2017 and 2021, out of 63 patients screened for eligibility, 50 patients were enrolled and treated per protocol. The study intervention was shown to be feasible and safe in all patients. Standard laparoscopy revealed suspicious lesions in 27 patients (54%), among whom 16 (59%) were diagnosed with PM. FGL identified suspicious areas in 25 patients (50%), among whom PM was confirmed in 13 cases (52%). Although hypericin concentrations in serum reached up to 5.64 ng/mL, no hypericin was detectable in peritoneal tissue biopsies. (4) Conclusions: FGL in patients with GC was shown to be feasible but futile in this study. Sufficient levels of hypericin should be ensured in target tissue prior to reassessing FGL with hypericin.

Progress in Biological Research and Treatment of Pseudomyxoma Peritonei

Pseudomyxoma peritonei (PMP) is a rare disease characterized by extensive peritoneal implantation and mass secretion of mucus after primary mucinous tumors of the appendix or other organ ruptures. Cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) is currently the preferred treatment, with excellent efficacy and safety, and is associated with breakthrough progress in long-term disease control and prolonged survival. However, the high recurrence rate of PMP is the key challenge in its treatment, which limits the clinical application of multiple rounds of CRS-HIPEC and does not benefit from conventional systemic chemotherapy. Therefore, the development of alternative therapies for patients with refractory or relapsing PMP is critical. The literature related to PMP research progress and treatment was searched in the Web of Science, PubMed, and Google Scholar databases, and a literature review was conducted. The overview of the biological research, treatment status, potential therapeutic strategies, current research limitations, and future directions associated with PMP are presented, focuses on CRS-HIPEC therapy and alternative or combination therapy strategies, and emphasizes the clinical transformation prospects of potential therapeutic strategies such as mucolytic agents and targeted therapy. It provides a theoretical reference for the treatment of PMP and the main directions for future research.

A case of metachronous oligo-hepatic and peritoneal metastases of pancreatic cancer with a favorable outcome after conversion surgery combined with perioperative sequential chemotherapy

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies, and the prognosis for its recurrence after surgery is very poor. Here, we report a case of metachronous oligo-hepatic and peritoneal metastases in a patient who survived without recurrence for 3 years after conversion surgery combined with perioperative sequential chemotherapy using gemcitabine plus nab-paclitaxel (GnP) and modified FOLFIRINOX (mFOLFIRINOX). The patient was a 70-year-old man with pancreatic ductal carcinoma, classified as cT3N0M0, cStage IIA, who underwent a distal pancreatosplenectomy. At 1 year and 4 months later, two liver metastases and one peritoneal metastasis were detected. A systemic 9-month course of chemotherapy was administered with GnP and mFOLFIRINOX as the first- and second-line chemotherapeutic agents, respectively. The two liver metastases were judged as showing a partial response, but one dissemination was considered stable disease. After receiving informed consent from the patient, we performed resection of the disseminated tumor and lateral segmentectomy of the liver. Adjuvant chemotherapy using mFOLFIRINOX and GnP was administered for 10 months. The patient has now been alive for 5 years and 6 months after the initial pancreatosplenectomy, and 3 years and 3 months after the conversion surgery, without subsequent tumor recurrence. Thus, a multidisciplinary treatment approach including surgery and perioperative sequential chemotherapy using GnP and mFOLFIRINOX may be beneficial for treating metachronous oligo-hepatic and peritoneal metastases, depending on the patient's condition.

Emerging therapeutic approaches for peritoneal metastases from gastrointestinal cancers

Peritoneal metastases from gastrointestinal malignancies present difficult management decisions, with options consisting primarily of systemic chemotherapy or major surgery with or without hyperthermic intraperitoneal chemotherapy. Current research is investigating expanding therapeutic modalities, and the aim of this review is to provide an overview of the existing and emerging therapies for the peritoneal metastases from gastrointestinal cancers, primarily through the recent literature (2015 and newer). These include the current data with systemic therapy and cytoreduction with hyperthermic intraperitoneal or pressurized intraperitoneal aerosol chemotherapy, as well as novel promising modalities under investigation, including dominating oncolytic viral therapy and adoptive cellular, biologic, and bacteria therapy, or nanotechnology. The novel diverse strategies, although preliminary and preclinical in murine models, individually and collectively contribute to the treatment of peritoneal metastases, offering hope for improved outcomes and quality of life. We foresee that these evolving treatment approaches will facilitate the transfer of knowledge and data among studies and advance discovery of new drugs and optimized treatments for patients with peritoneal metastases.

Role of Circulating Tumor DNA Among Patients with Colorectal Peritoneal Metastases

PURPOSE

This was a review of circulating tumor DNA (ctDNA) in patients with peritoneal metastases from colorectal cancer.

METHODS

We searched the PubMed database for studies reporting detection of ctDNA in patients with colorectal cancer (CRC) and with peritoneal metastases (PM) from colorectal cancer (CRPM). We extracted data on the population included, number of subjects, study design, type of ctDNA assay used and schedule, and the major findings from these publications.

RESULTS

We identified 13 studies for review investigating ctDNA, using a variety of ctDNA assays, among 1787 patients with CRC without PM, as well as four eligible published and one unpublished (in press) studies, which included 255 patients with PM from any primary site and 61 patients with CRPM. Among the 13 studies investigating ctDNA among CRC without PM, posttreatment surveillance ctDNA was associated with recurrence and was generally more sensitive than imaging or tumor markers. Among the five studies including patients with PM, ctDNA was not universally able to detect the presence of PM, but when present, ctDNA predicted worse outcomes.

CONCLUSION

Circulating-tumor DNA is a potentially useful surveillance tool for patients with CRC. However, the sensitivity of ctDNA to detect CRPM is variable and warrants further inquiry.

Phase II Study of Intraperitoneal Administration of Paclitaxel Combined with S-1 and Cisplatin for Gastric Cancer with Peritoneal Metastasis

BACKGROUND

Intraperitoneal chemotherapy is promising for gastric cancer with peritoneal metastasis. Although a phase III study failed to show a statistically significant superiority of intraperitoneal paclitaxel combined with S-1 and intravenous paclitaxel, the sensitivity analysis suggested clinical efficacy. Thus, attempts to combine intraperitoneal paclitaxel with other systemic therapies with higher efficacy have been warranted. We sought to explore the efficacy of intraperitoneal paclitaxel with S-1 and cisplatin.

PATIENTS AND METHODS

Gastric cancer patients with peritoneal metastasis were enrolled in the phase II trial. In addition to the established S-1 and cisplatin regimen every 5 weeks, intraperitoneal paclitaxel was administered on days 1, 8, and 22 at a dose of 20 mg/m2. The primary endpoint was overall survival rate at 1 year after treatment initiation. Secondary endpoints were progression-free survival and toxicity.

RESULTS

Fifty-three patients were enrolled and fully evaluated for efficacy and toxicity. The 1-year overall survival rate was 73.6% (95% confidence interval 59.5-83.4%), and the primary endpoint was met. The median survival time was 19.4 months (95% confidence interval, 16.1-24.6 months). The 1-year progression-free survival rate was 49.6% (95% confidence interval, 34.6-62.9%). The incidences of grade 3/4 hematological and non-hematological toxicities were 43% and 47%, respectively. The frequent grade 3/4 toxicities included neutropenia (25%), anemia (30%), diarrhea (13%), and anorexia (17%). Intraperitoneal catheter and implanted port-related complications were observed in four patients. There was one treatment-related death.

CONCLUSIONS

Intraperitoneal paclitaxel combined with S-1 and cisplatin is well tolerated and active in gastric cancer patients with peritoneal metastasis.

Intraperitoneal irinotecan with concomitant FOLFOX and bevacizumab for patients with unresectable colorectal peritoneal metastases: protocol of the multicentre, open-label, phase II, INTERACT-II trial

INTRODUCTION

The peritoneum is the second most affected organ for the dissemination of colorectal cancer (CRC). Patients with colorectal peritoneal metastases (CPM) face a poor prognosis, despite the majority of patients being treated with palliative systemic therapy. The efficacy of palliative systemic therapy is limited due to the plasma-peritoneum barrier. The poor prognosis of unresectable CPM patients has resulted in the development of new treatment strategies where systemic therapy is combined with local, intraperitoneal chemotherapy. In the recently published phase I study, the maximum tolerated dose and thus the recommended phase II dose of intraperitoneal irinotecan was investigated and determined to be 75 mg. In the present study, the overall survival after treatment with 75 mg irinotecan with concomitant mFOLFOX4 and bevacizumab will be investigated.

MATERIALS AND METHODS

In this single-arm phase II study in two Dutch tertiary referral centres, 85 patients are enrolled. Eligibility criteria are an adequate performance status and organ function, histologically confirmed microsatellite stable and unresectable CPM, no previous palliative therapy for CRC, no systemic therapy<6 months for CRC prior to enrolment and no previous cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS and HIPEC). Patients will undergo a diagnostic laparoscopy as standard work-up for CPM and if the peritoneal disease is considered unresectable (eg, Peritoneal Cancer Index (PCI)>20, too extensive small bowel involvement), a peritoneal access port and a port-a-cath are placed for administration of intraperitoneal and intravenous chemotherapy, respectively. Patients may undergo up to 12 cycles of study treatment. Each cycle consists of intravenous mFOLFOX4 with bevacizumab and concomitant intraperitoneal irinotecan (75 mg), which is repeated every 2 weeks, with a maximum of 12 cycles. Modified FOLFOX-4 regimen consists of 85 mg/m2 oxaliplatin plus 200 mg/m2 LV and 5-FU 400 mg/m2 bolus on day 1 followed by 1600 mg/m2 5-FU as a 46 hours infusion. Study treatment ends after the 12th cycle, or earlier in case of disease progression or unacceptable toxicity. The primary outcome is overall survival and key secondary outcomes are progression-free survival, safety (measured by the amount of grade ≥3 adverse events (Common Terminology Criteria for Adverse Events V.5.0)), patient-reported outcomes and pharmacokinetics of irinotecan. It is hypothesised that the trial treatment will lead to a 4 month increase in overall survival; from a median of 12.2 to 16.2 months.

ETHICS AND DISSEMINATION

This study is approved by the Dutch Authority (CCMO, the Hague, the Netherlands), by a central medical ethics committee (MEC-U, Nieuwegein, the Netherlands) and by the institutional research boards of both research centres. Results will be submitted for publication in peer-reviewed medical journals and presented to patients and healthcare professionals.

TRIAL REGISTRATION NUMBER

NCT06003998.

Chimeric Antigen Receptor-T Cell and Oncolytic Viral Therapies for Gastric Cancer and Peritoneal Carcinomatosis of Gastric Origin: Path to Improving Combination Strategies

Precision immune oncology capitalizes on identifying and targeting tumor-specific antigens to enhance anti-tumor immunity and improve the treatment outcomes of solid tumors. Gastric cancer (GC) is a molecularly heterogeneous disease where monoclonal antibodies against human epidermal growth factor receptor 2 (HER2), vascular endothelial growth factor (VEGF), and programmed cell death 1 (PD-1) combined with systemic chemotherapy have improved survival in patients with unresectable or metastatic GC. However, intratumoral molecular heterogeneity, variable molecular target expression, and loss of target expression have limited antibody use and the durability of response. Often immunogenically "cold" and diffusely spread throughout the peritoneum, GC peritoneal carcinomatosis (PC) is a particularly challenging, treatment-refractory entity for current systemic strategies. More adaptable immunotherapeutic approaches, such as oncolytic viruses (OVs) and chimeric antigen receptor (CAR) T cells, have emerged as promising GC and GCPC treatments that circumvent these challenges. In this study, we provide an up-to-date review of the pre-clinical and clinical efficacy of CAR T cell therapy for key primary antigen targets and provide a translational overview of the types, modifications, and mechanisms for OVs used against GC and GCPC. Finally, we present a novel, summary-based discussion on the potential synergistic interplay between OVs and CAR T cells to treat GCPC.

Peritoneal Metastasis: A Dilemma and Challenge in the Treatment of Metastatic Colorectal Cancer

Peritoneal metastasis (PM) is a common mode of distant metastasis in colorectal cancer (CRC) and has a poorer prognosis compared to other metastatic sites. The formation of PM foci depends on the synergistic effect of multiple molecules and the modulation of various components of the tumor microenvironment. The current treatment of CRC-PM is based on systemic chemotherapy. However, recent developments in local therapeutic modalities, such as cytoreductive surgery (CRS) and intraperitoneal chemotherapy (IPC), have improved the survival of these patients. This article reviews the research progress on the mechanism, characteristics, diagnosis, and treatment strategies of CRC-PM, and discusses the current challenges, so as to deepen the understanding of CRC-PM among clinicians.

Progress in the Treatment of Peritoneal Metastatic Cancer and the Application of Therapeutic Nanoagents

Peritoneal metastatic cancer is a cancer caused by the direct growth of cancer cells from the primary site through the bloodstream, lymph, or peritoneum, which is a difficult part of current clinical treatment. In the abdominal cavity of patients with metastatic peritoneal cancer, there are usually nodules of various sizes and malignant ascites. Among them, nodules of different sizes can obstruct intestinal movement and form intestinal obstruction, while malignant ascites can cause abdominal distension and discomfort, and even cause patients to have difficulty in breathing. The pathology and physiology of peritoneal metastatic cancer are complex and not fully understood. The main hypothesis is "seed" and "soil"; i.e., cells from the primary tumor are shed and implanted in the peritoneal cavity (peritoneal metastasis). In the last two decades, the main treatment modalities used clinically are cytoreductive surgery (CRS), systemic chemotherapy, intraperitoneal chemotherapy, and combined treatment, all of which help to improve patient survival and quality of life (QOL). However, the small-molecule chemotherapeutic drugs used clinically still have problems such as rapid drug metabolism and systemic toxicity. With the rapid development of nanotechnology in recent years, therapeutic nanoagents for the treatment of peritoneal metastatic cancer have been gradually developed, which has improved the therapeutic effect and reduced the systemic toxicity of small-molecule chemotherapeutic drugs to a certain extent. In addition, nanomaterials have been developed not only as therapeutic agents but also as imaging agents to guide peritoneal tumor CRS. In this review, we describe the etiology and pathological features of peritoneal metastatic cancer, discuss in detail the clinical treatments that have been used for peritoneal metastatic cancer, and analyze the advantages and disadvantages of the different clinical treatments and the QOL of the treated patients, followed by a discussion focusing on the progress, obstacles, and challenges in the use of therapeutic nanoagents in peritoneal metastatic cancer. Finally, therapeutic nanoagents and therapeutic tools that may be used in the future for the treatment of peritoneal metastatic cancer are prospected.

2022 PSOGI Consensus on HIPEC Regimens for Peritoneal Malignancies: Diffuse Malignant Peritoneal Mesothelioma

BACKGROUND

Diffuse malignant peritoneal mesothelioma (DMPM) is a rare and aggressive primary peritoneal disease, with recommended treatment, in eligible patients, of a combination of complete cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). As treatment is multimodal, there is a wide heterogeneity of HIPEC protocols precluding clear comparisons. Standardization at an international level is required.

METHODS

The Peritoneal Surface Oncology Group International (PSOGI) designated a steering committee to produce consensus recommendations for HIPEC regimens, adapted to each etiology. The Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) methodology was used, based on a systematic review focused on main outcomes related to HIPEC regimens in DMPM patients and on the patient, intervention, comparator, and outcome (PICO) method to elaborate main questions. An opinion survey was added. Furthermore, a Delphi process was performed with voting from a panel of international experts.

RESULTS

Eleven questions were elaborated, including two for future research requirements and three to assess the HIPEC regimen preference of the panel. The level of evidence underlying questions was globally low. Overall, 75 (86%) and 67 (77%) of the 87 invited experts completed the vote at the first and second round, respectively. HIPEC following complete CRS was strongly supported by 88% of voters with no need to plan comparative studies with CRS alone for 61.2% of voters. Bi-drug regimens appeared to be preferred to mono-drug ones and cisplatin was globally favored. The opinion survey confirmed the combination of cisplatin and doxorubicin as the recommended regimen.

CONCLUSION

International consensus confirmed the indication of HIPEC following complete CRS in DMPM patients and recommended cisplatin-doxorubicin as the first-line HIPEC regimen.

Study protocol of a phase II clinical trial evaluating the efficacy of neoadjuvant intraperitoneal and systemic albumin-bound paclitaxel combined with camrelizumab and S-1 in the treatment of patients with exfoliative cell-positive gastric cancer

Background

Currently, gastric cancer with positive lavage cytology without gross peritoneal dissemination (GC-CY1) is a special type of metastatic form with poor prognosis. Consensus guidelines on treatment strategies for patients with GC-CY1 have not been established. This study involves a single-arm, prospective, phase II clinical trial to examine the efficacy and safety of neoadjuvant intraperitoneal and systemic (NIPS) albumin-bound paclitaxel combined with Camrelizumab and S-1 in the treatment of GC-CY1 patients.

Methods/design

This is a prospective single-center exploratory study, and the primary endpoints of the trial are R0 resection rate and conversion rate of abdominal free cancer cells (FCCs), with secondary endpoints of 3-year progression-free survival (PFS); 3-year overall survival (OS); objective remission rate (ORR); disease control rate (DCR); safety and TRG classification.

Discussion

This study is the first to apply NIPS albumin-bound paclitaxel combined with Camrelizumab and S-1 to the conversion therapy of GC-CY1 patients. It is speculated that this combination of regimens will increase the negative conversion rate of FCCs by 20%, which will provide innovative insights into conversion treatment ideas for GC-CY1 patients to be managed in a more comprehensive and optimized manner.

Clinical trial registration

http://clinicaltrials.gov/, identifier NCT05410847.

Hyperthermic Intraperitoneal Chemotherapy in Gastric Cancer: A Clinical Case Involving Long-Term Survival

Peritoneal metastasis is the most common pattern of synchronous and metachronous dissemination in gastric cancer (GC) and is associated with a poor prognosis. Even though systemic chemotherapy is the standard of care, the optimal therapeutic approach to peritoneal disease in this setting is yet to be defined. We present a case of a 26-year-old female diagnosed with locally advanced GC who developed peritoneal carcinomatosis (PC). The patient underwent cytoreductive surgery (CRS) along with hyperthermic intraperitoneal chemotherapy (HIPEC) with complete remission. She remained disease-free after six years, presenting with peritoneal recurrence 70 months after the procedure. This report describes a rare case of long-term survival following a controversial therapeutic approach.

Effects of Hyperthermia and Hyperthermic Intraperitoneal Chemoperfusion on the Peritoneal and Tumor Immune Contexture

Hyperthermia combined with intraperitoneal (IP) drug delivery is increasingly used in the treatment of peritoneal metastases (PM). Hyperthermia enhances tumor perfusion and increases drug penetration after IP delivery. The peritoneum is increasingly recognized as an immune-privileged organ with its own distinct immune microenvironment. Here, we review the immune landscape of the healthy peritoneal cavity and immune contexture of peritoneal metastases. Next, we review the potential benefits and unwanted tumor-promoting effects of hyperthermia and the associated heat shock response on the tumor immune microenvironment. We highlight the potential modulating effect of hyperthermia on the biomechanical properties of tumor tissue and the consequences for immune cell infiltration. Data from translational and clinical studies are reviewed. We conclude that (mild) hyperthermia and HIPEC have the potential to enhance antitumor immunity, but detailed further studies are required to distinguish beneficial from tumor-promoting effects.

Neoadjuvant Chemotherapy plus Interval Cytoreductive Surgery with or without Hyperthermic Intraperitoneal Chemotherapy (NIHIPEC) in the Treatment of Advanced Ovarian Cancer: A Multicentric Propensity Score Study

INTRODUCTION

Epithelial ovarian cancer (EOC) is primarily confined to the peritoneal cavity. When primary complete surgery is not possible, neoadjuvant chemotherapy (NACT) is provided; however, the peritoneum-plasma barrier hinders the drug effect. The intraperitoneal administration of chemotherapy could eliminate residual microscopic peritoneal tumor cells and increase this effect by hyperthermia. Intraperitoneal hyperthermic chemotherapy (HIPEC) after interval cytoreductive surgery could improve outcomes in terms of disease-free survival (DFS) and overall survival (OS).

MATERIALS AND METHODS

A multicenter, retrospective observational study of advanced EOC patients who underwent interval cytoreductive surgery alone (CRSnoH) or interval cytoreductive surgery plus HIPEC (CRSH) was carried out in Spain between 07/2012 and 12/2021. A total of 515 patients were selected. Progression-free survival (PFS) and OS analyses were performed. The series of patients who underwent CRSH or CRSnoH was balanced regarding the risk factors using a statistical analysis technique called propensity score matching.

RESULTS

A total of 170 patients were included in each subgroup. The complete surgery rate was similar in both groups (79.4% vs. 84.7%). The median PFS times were 16 and 13 months in the CRSH and CRSnoH groups, respectively (Hazard ratio (HR) 0.74; 95% CI, 0.58-0.94; p = 0.031). The median OS times were 56 and 50 months in the CRSH and CRSnoH groups, respectively (HR, 0.88; 95% CI, 0.64-1.20; p = 0.44). There was no increase in complications in the CRSH group.

CONCLUSION

The addition of HIPEC after interval cytoreductive surgery is safe and increases DFS in advanced EOC patients.

Peritoneal Surface Malignancies Originating From Urachal Carcinoma: Case Reports and Review of the Literature

Urachal carcinoma (UC) is a rare and aggressive tumor arising from the urachal remnants, with the potential for peritoneal dissemination. Patients diagnosed with UC often have a poor prognosis. To date, there is no standardized treatment. Our objective is to present two cases of patients with peritoneal carcinomatosis (PC) secondary to an UC, who were treated with cytoreductive surgery (CRS) and hyperthermic peroperative intraperitoneal chemotherapy (HIPEC). A review of the literature on CRS and HIPEC in UC suggests CRS and HIPEC to be a safe and viable treatment option. Two patients with PC of UC underwent CRS and HIPEC in our institution. All available data were gathered and reported on. A literary search was carried out to find all available cases of patients with PC secondary to UC treated with CRS and HIPEC. Both patients underwent CRS and HIPEC and are currently free of recurrence. Literature research revealed nine other publications adding up to a total of 68 additional cases. CRS and HIPEC can provide satisfactory long-term oncological outcome with acceptable morbidity and mortality rates in patients with PC of urachal origin. It should be considered as a safe and feasible treatment option with curative potential.

Peritoneal Mesothelioma: Systematic Review of Hyperthermic Intraperitoneal Chemotherapy (HIPEC) Protocol Outcomes

Diffuse malignant peritoneal mesothelioma (DMPM) prognosis was improved by the locoregional treatment combining cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). HIPEC is a multiparametric treatment with multiple protocols proposed and reviewed in this work. A systematic review of medical literature was performed according to PRISMA guidelines. The search strategy used "malignant peritoneal mesothelioma" and "HIPEC" as keywords in three databases. Studies were included if reporting precisely the HIPEC regimen and the related outcomes, if comparing regimen, or if reporting national/international guidelines. The GRADE methodology was used to rate the level of evidence. Twenty-eight studies were included in this review: 1 was a meta-analysis, 18 reported cohort outcomes, 4 retrospectively compared HIPEC regimens, and 5 were guidelines. Six HIPEC regimens were found, 4 with one drug (cisplatin, mitomycine-C, carboplatin, oxaliplatin), 2 using two drugs (cisplatin-doxorubicin or cisplatin-mitomycine-C). Cisplatin, up to 250 mg/m2 over 90 min, appeared as the key HIPEC drug with a toxicity profile well controlled by the concomitant intravenous perfusion of sodium thiosulfate. Comparative studies tended to show that a bi-drug regimen led to better long-term oncologic outcomes, with cisplatin 50 mg/m2 plus doxorubicin 15 mg/m2 being safe and more efficient. This late protocol was the most widely used and recommended in 3 out of 4 international guidelines. Cisplatin was the preferred drug for HIPEC in DMPM patients. Most of the time, it was combined with doxorubicin for 90 min. A harmonization of protocols and further comparative studies are needed to optimize HIPEC regimen choice.

Phase II clinical trial of sequential treatment with systemic chemotherapy and intraperitoneal paclitaxel for gastric and gastroesophageal junction peritoneal carcinomatosis - STOPGAP trial

BACKGROUND

Studies from Asia indicate that normothermic intraperitoneal chemotherapy (NIPEC) may confer survival benefit in patients with gastric peritoneal carcinomatosis (PC). However, data regarding this approach is lacking in western population. The current STOPGAP trial is intended to assess 1-year progression-free survival benefit of sequential systemic chemotherapy and paclitaxel NIPEC in patients with gastric/ gastroesophageal junction (GEJ) adenocarcinoma PC.

METHODS

This is a prospective, single center, single arm, phase II investigator-initiated clinical trial. Patients with histologically proven gastric/GEJ (Siewert 3) adenocarcinoma with positive peritoneal cytology or PC will be eligible to participate after three months of standard of care systemic chemotherapy and with no evidence of visceral metastasis on restaging scans. The primary treatment is iterative paclitaxel NIPEC with systemic paclitaxel and 5-fluorouracil, which will be administered on days1 and 8 and repeated every three weeks for 4 cycles. Patients will undergo diagnostic laparoscopy both before and after NIPEC to assess peritoneal cancer index (PCI). Patients with PCI less than or equal to 10 in whom complete cytoreduction (CRS) is feasible may opt to undergo CRS with heated intraperitoneal chemotherapy (HIPEC). The primary endpoint is 1-year progression free survival and secondary endpoints are overall survival and patient reported quality of life outcomes measured by EuroQol- 5 dimensions-5 level (EuroQol-5D-5L) questionnaire.

DISCUSSION

If the sequential approach of systemic chemotherapy followed by paclitaxel NIPEC proves beneficial, then this approach could be used in larger, muti-institutional randomized clinical trial of gastric PC.

TRIAL REGISTRATION

The trial was registered on 21/02/2021, under clinical trials.gov; Identifier: NCT04762953.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Intraperitoneal Chemotherapy for Unresectable Peritoneal Surface Malignancies

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

Effectiveness of Hyperthermic Intraperitoneal Chemotherapy Associated with Cytoreductive Surgery in the Treatment of Advanced Ovarian Cancer: Systematic Review and Meta-Analysis

OBJECTIVE

The use of hyperthermic intraperitoneal chemotherapy (HIPEC) as a treatment for epithelial ovarian cancer remains controversial. Our study aims to analyze the overall survival and disease-free survival for the use of HIPEC as a treatment for advanced epithelial ovarian cancer after neoadjuvant chemotherapy.

METHODS

A systematic review and meta-analysis was carried out using PubMed, Cochrane, Web of Science, and ClinicalTrials.gov. A total of six studies were used, comprising a total of 674 patients.

RESULTS

The results of our meta-analysis of all studies analyzed together (observational and randomized controlled trials (RCT)) did not achieve significant results. Contrary to the OS (HR = 0.56, 95% IC = 0.33-0.95, p = 0.03) and DFS (HR = 0.61, 95% IC = 0.43-0.86, p < 0.01) of the RCT analyzed separately, a clear impact on survival was suggested. The subgroup analysis showed that studies making use of higher temperatures (≥42 °C) for a shorter period of time (≤60 min) achieved better results for both OS and DFS, as well as the use of cisplatin as the form of chemotherapy in HIPEC. Moreover, the use of HIPEC did not increase high-grade complications.

CONCLUSIONS

The addition of HIPEC to cytoreductive surgery demonstrates an improvement in OS and DFS for patients with epithelial ovarian cancer in advanced stages, without an increase in the number of complications. The use of cisplatin as chemotherapy in HIPEC obtained better results.

Circulating Tumor DNA is Unreliable to Detect Somatic Gene Alterations in Gastrointestinal Peritoneal Carcinomatosis

INTRODUCTION

Tumor agnostic circulating tumor DNA (ctDNA) is routinely used to guide treatment decisions in gastrointestinal (GI) cancers, especially metastatic cancers. The amount of ctDNA detected in plasma is affected by stage, tumor burden, and tumor vascularization. We hypothesized that peritoneal carcinomatosis (PC) is associated with lower ctDNA levels than other metastatic sites in GI cancers due to the plasma-peritoneal barrier.

METHODS

We conducted a retrospective analysis of patients with stage II-IV GI cancers treated at our institution between 2015 and 2020 with available panel-based ctDNA results (Guardant 360^TM). ctDNA analysis was performed on early and pretreatment samples. We compared the reported maximum variant allele frequency (mVAF) of somatic mutations across metastatic sites.

RESULTS

Of the 279 patients with GI cancers (colorectal, upper GI, pancreaticobiliary), 212 had stage IV disease (PC: n = 61; visceral metastases: n = 138; other metastases: n = 13). Mean mVAF increased with increasing stages of disease (stage II: 3.6 ± 7; stage III: 6.4 ± 10; stage IV: 28.0 ± 51; p < 0.01). Among patients with stage IV disease, PC was associated with lower ctDNA levels independent of primary tumor site (PC only: 12.1%; PC+ visceral metastases: 26.8%; and visceral metastases only: 35.0%; p < 0.01). In a subset of patients (n = 27, matched pair analysis of genomic alterations (GAs) showed fewer GAs were detected in plasma compared with tissue.

CONCLUSIONS

PC of GI origin is associated with significantly lower ctDNA levels compared with visceral metastasis. Caution is warranted when interpreting ctDNA results from patients with PC due to lower sensitivity for detecting actionable mutations.

The Implementation of a PIPAC (Pressurized Intraperitoneal Aerosol Chemotherapy) Program in Portugal

N/a.

A phase II study of perioperative treatment in gastric cancer with No.16a2/b1 lymph node metastasis: DRAGON-06 trial

Although gastric cancer with para-aortic lymph node (PAN) metastasis is commonly regarded as unresectable, surgeons have explored the optimal treatment for patients with PAN metastases limited to No.16a2/b1 in the past few decades. Preoperative systemic therapy combined with D2 gastrectomy plus PAN dissection may improve the prognosis of these patients. In this multicenter phase II trial, 29 gastric cancer patients with PAN metastasis limited to No.16a2/b1 will receive preoperative treatment with nab-paclitaxel, oxaliplatin, S-1 (nab-POS: nab-paclitaxel, oxaliplatin, S-1) and sintilimab followed by D2 gastrectomy plus PAN dissection; and postoperative treatment with oral S-1, intravenous sintilimab and intraperitoneal paclitaxel. The end points for the study are 3-year overall survival, 3-year disease-free survival, pathological response rate, incidence of postoperative complications and adverse events.

[Peritoneal carcinomatosis of gastric cancer : Treatment options for peritoneal carcinomatosis of gastric cancer]

BACKGROUND

Gastric cancer is one of the most aggressive malignant diseases of the gastrointestinal tract with a high rate of metastasis. Peritoneal metastasis occurs in up to 60% of all patients and synchronously in up to 30% in locally advanced gastric cancer. Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) have been an established treatment option in selected patients for several years, as the HIPEC serves as an alternative administration route.

OBJECTIVE

This article presents a schematic display of the various treatment options depending on the extent of peritoneal carcinomatosis in a gastric cancer.

METHODS

A literature search and analysis of the current literature on the treatment of gastric cancer with peritoneal metastases were carried out. A differentiation was made between limited and extensive peritoneal carcinomatosis together with the appropriate treatment strategy.

RESULTS

Principally, individual systemic chemotherapy is the backbone of treatment of gastric cancer with peritoneal metastases. In selected patients and in cases of limited peritoneal carcinomatosis, CRS and HIPEC can be conducted and survival is improved; however, CRS is still contraindicated in cases of extensive peritoneal carcinomatosis and in exceptional cases pressurized intraperitoneal aerosol chemotherapy (PIPAC) can be carried out.

CONCLUSION

In selected patients CRS and HIPEC can lead to an improvement with respect to overall and disease-free survival. In cases of extensive peritoneal carcinomatosis, individualized chemotherapy remains the major treatment option.

Delivery of aPD-L1 antibody to i.p. tumors via direct penetration by i.p. route: Beyond EPR effect

Chemotherapy for peritoneal dissemination is poorly effective owing to limited drug transfer from the blood to the intraperitoneal (i.p.) compartment after intravenous (i.v.) administration. i.p. chemotherapy has been investigated to improve drug delivery to tumors; however, the efficacy continues to be debated. As anticancer drugs have low molecular weight and are rapidly excreted through the peritoneal blood vessels, maintaining the i.p. concentration as high as expected is a challenge. In this study, we examined whether i.p. administration is an efficient route of administration of high-molecular-weight immune checkpoint inhibitors (ICIs) for the treatment of peritoneal dissemination using a model of peritoneal disseminated carcinoma. After i.p. administration, the amount of anti-PD-L1 antibody transferred into i.p. tumors increased by approximately eight folds compared to that after i.v. administration. Intratumoral distribution analysis revealed that anti-PD-L1 antibodies were delivered directly from the i.p. space to the surface of tumor tissue, and that they deeply penetrated the tumor tissues after i.p. administration; in contrast, after i.v. administration, anti-PD-L1 antibodies were only distributed around blood vessels in tumor tissues via the enhanced permeability and retention (EPR) effect. Owing to the enhanced delivery, the therapeutic efficacy of anti-PD-L1 antibody in the peritoneal dissemination models was also improved after i.p. administration compared to that after i.v. administration. This is the first study to clearly demonstrate an EPR-independent delivery of ICIs to i.p. tumors by which ICIs were delivered in a massive amount to the tumor tissue via direct penetration after i.p. administration.

[Current status of surgical treatment of peritoneal metastases from colorectal cancer]

Cytoreductive surgery, often in combination with hyperthermic intraperitoneal chemotherapy (HIPEC), has been instrumental in improving the survival of patients with peritoneal metastases from colorectal cancer. Recent studies have highlighted the benefits of complete cytoreduction, while the role of the HIPEC treatment remains unclear. An oxaliplatin-based HIPEC over 30 min could not achieve any clear benefits in studies on colorectal cancer, neither in the therapeutic nor in the prophylactic setting, but caused relevant side effects and increased the morbidity. The negative results of these studies with respect to oxaliplatin-based HIPEC require critical appraisal; however, they should by no means be regarded as a general setback for surgical treatment of peritoneal metastases and be misunderstood as a general failure of this treatment. While HIPEC after complete surgical cytoreduction of peritoneal metastases from colorectal cancer requires further research, cytoreductive surgery should still be regarded as a highly effective treatment for suitable patients with limited abdominal tumor dissemination.

Hyperthermic intraperitoneal chemotherapy and colorectal cancer: From physiology to surgery

The pursuit of this paper is to collect principal reviews and systematic reviews about hyperthermic intraperitoneal chemotherapy (HIPEC) and cytoreductive surgery (CRS) used in colorectal cancer (CRC). We focus on principal biological aspects of CRC, hyperthermia effects, and surgical procedures. We searched PubMed/MEDLINE for the principal reviews and systematic reviews published from 2010 to 2021 regarding the bimodal treatment (CRS + HIPEC) against local and advanced CRC. In the literature, from several studies, it seems that the efficacy of bimodal treatment with an accurate CRS can extend overall survival. Despite these studies, there are not still any straight guidelines more detailed and scheduled about the use of combined treatment in patients with CRC. Even if the concept is still not very clear and shared, after a careful evaluation of the published data, and after some technical and pathophysiological descriptions, we concluded that it is possible to improve the overall survival and quality of life and to reduce the tumor relapse in patients affected by locally advanced (pT4) CRC with peritoneal metastases.

Integration of Genomic Biology Into Therapeutic Strategies of Gastric Cancer Peritoneal Metastasis

The peritoneum is a common site of metastasis in advanced gastric cancer (GC). Diagnostic laparoscopy is now routinely performed as part of disease staging, leading to an earlier diagnosis of synchronous peritoneal metastasis (PM). The biology of GCPM is unique and aggressive, leading to a dismal prognosis. These tumors tend to be resistant to traditional systemic therapy, and yet, this remains the current standard-of-care recommended by most international clinical guidelines. As this is an area of unmet clinical need, several translational studies and clinical trials have focused on addressing this specific disease state. Advances in genomic sequencing and molecular profiling have revealed several promising therapeutic targets and elucidated novel biology, particularly on the role of the surrounding tumor microenvironment in GCPM. Peritoneal-specific clinical trials are being designed with a combination of locoregional therapeutic strategies with systemic therapy. In this review, we summarize the new knowledge of cancer biology, advances in surgical techniques, and emergence of novel therapies as an integrated strategy emerges to address GCPM as a distinct clinical entity.

Impact of Cytoreductive Surgery with Hyperthermic Intraperitoneal Chemotherapy in the Treatment of Gastric Cancer with Peritoneal Carcinomatosis: A Systematic Review and Meta-analysis

BACKGROUND

Despite promising results, the effectiveness of cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) in patients with gastric cancer with peritoneal carcinomatosis (GCPC) has not been systematically evaluated. The aim of this systematic review is to compare the survival, complications and risk of recurrence between CRS + HIPEC versus CRS alone in GCPC.

PATIENTS AND METHODS

A systematic review was performed in MEDLINE and Web of Science according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Primary studies with patients with GCPC older than 18 years were included. Methodological Index for Non-randomized Studies (MINORS) criteria were used to assess the quality of the studies. We performed random-effects meta-analysis of risk ratios (RR). We assessed heterogeneity using the I² statistic.

RESULTS

Five studies were included in the qualitative and four in the quantitative analysis. The overall survival (OS) rate after 1 year was 3.65 times higher for CRS + HIPEC than CRS alone [RR = 3.65, 95% confidence interval (95% CI) = 1.01-13.26, I² = 73%]. The OS rate after 5 years was more than three times higher for CRS + HIPEC than for CRS alone (RR = 3.25, 95% CI = 1.28-8.26, I² = 8%). No significant differences between CRS + HIPEC and CRS alone related to complications were found (RR = 1.05, 95% CI = 0.83-1.33, I² = 0%). The risk of peritoneal recurrence was significantly lower for CRS + HIPEC than for CRS alone (RR = 0.23, 95% CI = 0.11-0.48, I² = 40%). The results may be associated with some information or indication bias.

CONCLUSIONS

Results should be analysed cautiously given the detected heterogeneity and limitations of included studies. However, treatment with CRS + HIPEC seems to increase the survival of patients with GCPC, more than treatment with CRS alone, decrease the risk of peritoneal recurrence and not be associated with more complications.