Peritoneal metastases from extra-abdominal cancer – A population-based study

EDI3 knockdown in ER-HER2+ breast cancer cells reduces tumor burden and improves survival in two mouse models of experimental metastasis

BACKGROUND

Despite progress understanding the mechanisms underlying tumor spread, metastasis remains a clinical challenge. We identified the choline-producing glycerophosphodiesterase, EDI3 and reported its association with metastasis-free survival in endometrial cancer. We also observed that silencing EDI3 slowed cell migration and other cancer-relevant phenotypes in vitro. Recent work demonstrated high EDI3 expression in ER-HER2+ breast cancer compared to the other molecular subtypes. Silencing EDI3 in ER-HER2+ cells significantly reduced cell survival in vitro and decreased tumor growth in vivo. However, a role for EDI3 in tumor metastasis in this breast cancer subtype was not explored. Therefore, in the present work we investigate whether silencing EDI3 in ER-HER2+ breast cancer cell lines alters phenotypes linked to metastasis in vitro, and metastasis formation in vivo using mouse models of experimental metastasis.

METHODS

To inducibly silence EDI3, luciferase-expressing HCC1954 cells were transduced with lentiviral particles containing shRNA oligos targeting EDI3 under the control of doxycycline. The effect on cell migration, adhesion, colony formation and anoikis was determined in vitro, and significant findings were confirmed in a second ER-HER2+ cell line, SUM190PT. Doxycycline-induced HCC1954-luc shEDI3 cells were injected into the tail vein or peritoneum of immunodeficient mice to generate lung and peritoneal metastases, respectively and monitored using non-invasive bioluminescence imaging. Metabolite levels in cells and tumor tissue were analyzed using targeted mass spectrometry and MALDI mass spectrometry imaging (MALDI-MSI), respectively.

RESULTS

Inducibly silencing EDI3 reduced cell adhesion and colony formation, as well as increased susceptibility to anoikis in HCC1954-luc cells, which was confirmed in SUM190PT cells. No influence on cell migration was observed. Reduced luminescence was seen in lungs and peritoneum of mice injected with cells expressing less EDI3 after tail vein and intraperitoneal injection, respectively, indicative of reduced metastasis. Importantly, mice injected with EDI3-silenced cells survived longer. Closer analysis of the peritoneal organs revealed that silencing EDI3 had no effect on metastatic organotropism but instead reduced metastatic burden. Finally, metabolic analyses revealed significant changes in choline and glycerophospholipid metabolites in cells and in pancreatic metastases in vivo.

CONCLUSIONS

Reduced metastasis upon silencing supports EDI3's potential as a treatment target in metastasizing ER-HER2+ breast cancer.

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.

Unravelling Peritoneal Carcinomatosis Using Cross-Sectional Imaging Modalities

Peritoneal carcinomatosis (PC) refers to malignant epithelial cells that spread to the peritoneum, principally from abdominal malignancies. Until recently, PC prognosis has been considered ill-fated, with palliative therapies serving as the only treatment option. New locoregional treatments are changing the outcome of PC, and imaging modalities have a critical role in early diagnosis and disease staging, determining treatment decision making strategies. The aim of this review is to provide a practical approach for detecting and characterizing peritoneal deposits in cross-sectional imaging modalities, taking into account their appearances, including the secondary complications, the anatomical characteristics of the peritoneal cavity, together with the differential diagnosis with other benign and malignant peritoneal conditions. Among the cross-sectional imaging modalities, computed tomography (CT) is widely available and fast; however, magnetic resonance (MR) performs better in terms of sensitivity (92% vs. 68%), due to its higher contrast resolution. The appearance of peritoneal deposits on CT and MR mainly depends on the primary tumour histology; in case of unknown primary tumour (3-5% of cases), their behaviour at imaging may provide insights into the tumour origin. The timepoint of tumour evolution, previous or ongoing treatments, and the peritoneal spaces in which they occur also play an important role in determining the appearance of peritoneal deposits. Thus, knowledge of peritoneal anatomy and fluid circulation is essential in the detection and characterisation of peritoneal deposits. Several benign and malignant conditions show similar imaging features that overlap those of PC, making differential diagnosis challenging. Knowledge of peritoneal anatomy and primary tumour histology is crucial, but one must also consider clinical history, laboratory findings, and previous imaging examinations to achieve a correct diagnosis. In conclusion, to correctly diagnose PC in cross-sectional imaging modalities, knowledge of peritoneal anatomy and peritoneal fluid flow characteristics are mandatory. Peritoneal deposit features reflect the primary tumour characteristics, and this specificity may be helpful in its identification when it is unknown. Moreover, several benign and malignant peritoneal conditions may mimic PC, which need to be considered even in oncologic patients.

Primary and secondary tumors of the peritoneum: key imaging features and differential diagnosis with surgical and pathological correlation

Peritoneal malignancies represent a diagnostic challenge for abdominal radiologists, oncologists, surgeons and pathologists in multidisciplinary teams, who must address their differential diagnosis, staging and treatment. In this article, we explain the pathophysiology of these processes and lay out the role of different imaging techniques in their evaluation. Then, we review the clinical and epidemiological aspects, the main radiological features and the therapeutic approaches for each primary and secondary peritoneal neoplasm, with surgical and pathological correlation. We further describe other rare peritoneal tumors of uncertain origin and a variety of entities that may mimic peritoneal malignancy. Finally, we summarize the key imaging findings of each peritoneal neoplasm to facilitate an accurate differential diagnosis that may impact patient management.Clinical relevance statementImaging plays an essential role in the evaluation of peritoneal malignancies, assessing their extension, detecting unfavorable sites of involvement and facilitating an accurate differential diagnosis, helping to choose the best therapeutic approach.

Histopathological Evaluation and Molecular Diagnostic Tests for Peritoneal Metastases with Unknown Primary Site-a Review

Cancer of unknown primary (CUP) is a well-studied entity with guidelines available for the management of patients with CUP. The peritoneum represents one of the metastatic sites in CUP, and peritoneal metastases (PM) could present as CUP. PM of unknown origin remains a poorly studied clinical entity. There is only one series of 15 cases, one population-based study, and few other case reports on this subject. Studies on CUP, in general, cover some common tumour histological types like adenocarcinomas and squamous carcinomas. Some of these tumours may have a good prognosis though majority have high-grade disease with a poor long-term outcome. Some of the histological tumour types commonly seen in the clinical scenario of PM like mucinous carcinoma have not been studied. In this review, we divide PM into five histological types-adenocarcinomas, serous carcinomas, mucinous carcinomas, sarcomas and other rare varieties. We provide algorithms to identify the primary tumour site using immunohistochemistry when imaging, and endoscopy fails to establish the primary tumour site. The role of molecular diagnostic tests for PM or unknown origin is also discussed. Current literature on site-specific systemic therapy based on gene expression profiling does not show a clear benefit of this approach over empirical systemic therapies.

Peritoneal Metastases from Extraperitoneal Primary Tumors: Incidence, Treatment, and Survival from a Nationwide Database

The objective of this study was to assess the incidence, treatment, and survival of patients with synchronous peritoneal metastases (PM) from extraperitoneal primary tumors. A cohort was selected from the Netherlands Cancer Registry (NCR), in which all patients diagnosed with PM in 2017 and 2018 were screened for eligibility. The five most common primary extraperitoneal origins of PM were included for further analyses: lung, breast, urinary tract, and kidney cancer and malignant melanoma. Survival was investigated using log-rank test between different primary tumor locations. In total, 480 patients were diagnosed with synchronous PM from extraperitoneal origins. The proportion of patients with PM per extraperitoneal origin ranged between 0.1 and 1.1%, with the highest proportion in lung cancer patients. Of all patients, 234 (49%) received tumor-directed treatment and 246 (51%) received no tumor-directed treatment. Survival in patients with PM from lung, breast, urinary tract, and kidney cancer and malignant melanoma was 1.6 months, 15.7 months, 5.4 months, 3.4 months, and 2.1 months, respectively (p < 0.001). In this study, a small, although significant number of patients with extraperitoneal cancer developed PM. The reported survival in patients with PM ranged between 1.6 and 15.7 months. Only half of the patients with PM received tumor-directed treatment and survival in patients without tumor-directed treatment was only 1.2 months. These findings are stressing the need to explore new diagnostic tools that may enable earlier diagnosis of PM and may potentially lead to a more effective treatment.

Research progress of Astragalus membranaceus in treating peritoneal metastatic cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Peritoneal metastasis is a manifestation of advanced cancer often associated with a poor prognosis and poor response to treatment. Astragalus membranaceus (Fisch.) Bunge is a commonly used medicinal material in traditional Chinese medicine with various biological activities. In patients with cancer, Astragalus membranaceus has demonstrated anti-tumor effects, immune regulation, postoperative recurrence and metastasis prevention, and survival prolongation.

AIM OF THE STUDY

Peritoneal metastasis results from tumor cell and peritoneal microenvironment co-evolution. We aimed to introduce and discuss the specific mechanism of action of Astragalus membranaceus in peritoneal metastasis treatment to provide a new perspective for treatment and further research.

MATERIALS AND METHODS

We consulted reports on the anti-peritoneal metastases effects of Astragalus membranaceus from PubMed, Web of Science, China National Knowledge Infrastructure, and Wanfang databases, as well as Google Scholar. Meanwhile, we also obtained data from published medical works and doctoral and master's theses. Then, we focused on the research progress of Astragalus membranaceus in peritoneal metastatic cancer treatment. Plant names are provided in accordance with "The Plant List" (www.theplantlist.org).

RESULTS

To date, more than 200 compounds have been isolated from Astragalus membranaceus. Among them, Astragalus polysaccharides, saponins, and flavonoids are the main bioactive components, and their effects on cancer have been extensively studied. In this review, we systematically summarize the effects of Astragalus membranaceus on the peritoneal metastasis microenvironment and related mechanisms, including maintaining the integrity of peritoneal mesothelial cells, restoring the peritoneal immune microenvironment, and inhibiting the formation of tumor blood vessels, matrix metalloproteinase, and dense tumor spheroids.

CONCLUSIONS

Our analysis demonstrates that Astragalus membranaceus could be a potential therapeutic for preventing the occurrence of peritoneal metastasis. However, it might be too early to recommend its use owing to the paucity of reliable in vivo experiment, clinical data, and evidence of clinical efficacy. In addition, previous studies of Astragalus membranaceus report inconsistent and contradictory findings. Therefore, detailed in vitro, in vivo, and clinical studies on the mechanism of Astragalus membranaceus in peritoneal metastatic cancer treatment are warranted.

Challenges and Considerations in Identifying the Origin of Peritoneal Carcinomatosis: A Case Report

Invasive lobular cancer (ILC) of the breast is the second most common type of invasive breast cancer. Clinical determination of the growth pattern of ILC of the breast is difficult. Furthermore, the ILC of the breast has a unique metastatic pattern that involves gastrointestinal and peritoneal sites. Our patient was initially misdiagnosed with left ovarian cancer based on the findings of positron emission tomography and computed tomography. Herein, we report a case of ILC of the breast presenting as peritoneal carcinomatosis. The ESMO Clinical Practice Guidelines for cancers of unknown primary sites were used in the diagnosis of the carcinoma of unknown primary origin. Image-guided biopsy and immunohistochemical staining are also useful in the diagnosis of these cancer types.

The molecular biology of peritoneal metastatic disease

Peritoneal metastases are a common form of tumor cell dissemination in gastrointestinal malignancies. Peritoneal metastatic disease (PMD) is associated with severe morbidity and resistance to currently employed therapies. Given the distinct route of dissemination compared with distant organ metastases, and the unique microenvironment of the peritoneal cavity, specific tumor cell characteristics are needed for the development of PMD. In this review, we provide an overview of the known histopathological, genomic, and transcriptomic features of PMD. We find that cancers representing the mesenchymal subtype are strongly associated with PMD in various malignancies. Furthermore, we discuss the peritoneal niche in which the metastatic cancer cells reside, including the critical role of the peritoneal immune system. Altogether, we show that PMD should be regarded as a distinct disease entity, that requires tailored treatment strategies.

Peritoneal Carcinomatosis From Malignant Melanoma After Wide Local Excision of a T1a Lesion: A Case Report

Cutaneous melanoma is an aggressive skin cancer with a high propensity for distant metastasis. Peritoneal metastasis from cutaneous malignant melanoma is extremely rare and associated with a low five-year overall survival rate. This report reviews a case of a 78-year-old man with peritoneal carcinomatosis after a wide local excision of a T1a invasive malignant melanoma of the scalp 10 months prior. Although rare, patients with a recent history of melanoma who present with obscure or odd symptoms should be worked up for metastatic disease by their surgeon or medical oncologist. Carcinomatosis can develop, and early treatment with immunotherapy has been shown to improve five-year overall survival and progression-free survival in patients with advanced melanoma.

Therapeutic Strategies and Oncological Outcome of Peritoneal Metastases from Lung Cancer: A Systematic Review and Pooled Analysis

The peritoneum is an unusual site of metastases from lung cancer, and optimal management at the moment remains unclear and mostly based on palliative strategies. Therefore, the aim of the study was to investigate demographic characteristics, management and overall survival of patients with peritoneal metastases from lung cancer (PCLC). A PRISMA-compliant systematic review and pooled analysis was performed searching all English studies published until December 2022. PROSPERO, CRD42022349362. Inclusion criteria were original articles including patients with peritoneal carcinomatosis from lung cancer, specifying at least one outcome of interest. Exclusion criteria were being unable to retrieve patient data from articles, and the same patient series included in different studies. Among 1746 studies imported for screening, twenty-one were included (2783 patients). Mean overall survival was between 0.5 and 5 months after peritoneal carcinomatosis diagnosis and 9 and 21 months from lung cancer diagnosis. In total, 27% of patients underwent first-line or palliative chemotherapy and 7% of them surgery. Management differs significantly among published studies. The literature on PCLC is scarce. Its incidence is low but appears to be substantially rising and is likely to be an underestimation. Prognosis is very poor and therapeutic strategies have been limited and used in a minority of patients. Subcategories of PCLC patients may have an improved prognosis and may benefit from an aggressive oncological approach, including cytoreductive surgery. Further investigation would be needed in this regard.

Activated Leukocyte Cell Adhesion Molecule (ALCAM), a Potential 'Seed' and 'Soil' Receptor in the Peritoneal Metastasis of Gastrointestinal Cancers

Activated Leukocyte Cell Adhesion Molecule (ALCAM/CD166) is a cell-cell adhesion protein conferring heterotypic and homotypic interactions between cells of the same type and different types. It is aberrantly expressed in various cancer types and has been shown to be a regulator of cancer metastasis. In the present study, we investigated potential roles of ALCAM in the peritoneal transcoelomic metastasis in gastrointestinal cancers, a metastatic type commonly occurred in gastro-intestinal and gynaecological malignancies and resulting in poor clinical outcomes. Specifically, we studied whether ALCAM acts as both a 'seed' receptor in these tumour cells and a 'soil' receptor in peritoneal mesothelial cells during cancer metastasis. Gastric cancer and pancreatic cancer tissues with or without peritoneal metastasis were compared for their levels of ALCAM expression. The impact of ALCAM expression in these tumours was also correlated to the patients' clinical outcomes, namely peritoneal metastasis-free survival. In addition, cancer cells of gastric and pancreatic origins were used to create cell models with decreased or increased levels of ALCAM expression by genetic knocking down or overexpression, respectively. Human peritoneal mesothelial cells were also genetically transfected to generate cell models with different profiles of ALCAM expression. These cell models were used in the tumour-mesothelial interaction assay to assess if and how the interaction was influenced by ALCAM. Both gastric and pancreatic tumour tissues from patients who developed peritoneal metastases had higher levels of ALCAM transcript than those without. Patients who had tumours with high levels of ALCAM had a much shorter peritoneal metastasis free survival compared with those who had low ALCAM expression (p = 0.006). ALCAM knockdown of the mesothelial cell line MET5A rendered the cells with reduced interaction with both gastric cancer cells and pancreatic cancer cells. Likewise, levels of ALCAM in both human gastric and pancreatic cancer cells were also a determining factor for their adhesiveness to mesothelial cells, a process that was likely to be triggered the phosphorylation of the SRC kinase. A soluble ALCAM (sALCAM) was found to be able to inhibit the adhesiveness between cancer cells and mesothelial cells, mechanistically behaving like a SRC kinase inhibitor. ALCAM is an indicator of peritoneal metastasis in both gastric and pancreatic cancer patients. It acts as not only a potential peritoneal 'soil' receptor of tumour seeding but also a 'soil' receptor in peritoneal mesothelial cells during cancer metastasis. These findings have an important therapeutic implication for treating peritoneal transcoelomic metastases.

Large Ascites in a Cirrhotic Patient Reveal an Isolated and Late Metastasis of Ductal Breast Cancer: A Case Study

Breast cancer is the most prevalent cancer in women worldwide, and its prevalence has increased since the introduction of screening programs. Most cases are discovered at an early stage; however, despite effective treatment, some cases progress to metastasis. The most common breast cancer metastatic locations are the bone, liver, and lungs. Ascites malignant due to peritoneal involvement is a rare manifestation of metastatic breast cancer. After 8 years of well-controlled breast cancer, we report a 54-year-old woman who presents with malignant ascites and is known to have cirrhosis of the liver.

Peritoneal carcinomatosis secondary to metastatic lung cancer complicated with acute suppurative appendicitis: A case report and literature review

RATIONALE

Lung cancer (LC) is a malignant tumor with the highest morbidity and mortality in the world. The most common metastatic sites of LC are the brain (47%), bone (36%), liver (22%), adrenal glands (15%), thoracic cavity (11%) and distant lymph nodes (10%). Peritoneal carcinomatosis (PC) is a rare clinical event in LC patients. Considering the rarity and nonspecific clinical symptoms of peritoneal metastasis among LC patients, a case of peritoneal metastasis secondary to LC incidentally observed by laparoscopic appendectomy is unusual.

PATIENT CONCERNS

Here, we present a 53-year-old never-smoker woman who presented to the emergency department with a 2-day history of pain in the right abdominal quadrant. Later, laparoscopy revealed acute suppurative appendicitis accompanied by a peritoneal metastatic mass.

DIAGNOSIS

The patient was diagnosed with PC secondary to metastatic LC complicated with acute suppurative appendicitis by immunohistochemistry. Positron emission tomography computed tomography (PET CT) findings further strengthen the evidence of PC from LC.

OUTCOMES

Based on the results of genomic analysis, the patient received targeted therapy with osimertinib 80 mg/d.

LESSONS

Due to the discovery of new targets, the use of molecular therapies improved progression-free survival (PFS) and overall survival (OS), which increases the chance of identifying peritoneal metastasis of LC. For LC patients with abdominal symptoms, clinicians should be aware of the possibility of peritoneal metastasis from LC, especially for patients diagnosed with lung adenocarcinoma or with pleural effusion.

EZH2-H3K27me3 mediated KRT14 upregulation promotes TNBC peritoneal metastasis

Triple-Negative Breast Cancer (TNBC) has a poor prognosis and adverse clinical outcomes among all breast cancer subtypes as there is no available targeted therapy. Overexpression of Enhancer of zeste homolog 2 (EZH2) has been shown to correlate with TNBC's poor prognosis, but the contribution of EZH2 catalytic (H3K27me3) versus non-catalytic EZH2 (NC-EZH2) function in TNBC progression remains elusive. We reveal that selective hyper-activation of functional EZH2 (H3K27me3) over NC-EZH2 alters TNBC metastatic landscape and fosters its peritoneal metastasis, particularly splenic. Instead of H3K27me3-mediated repression of gene expression; here, it promotes KRT14 transcription by attenuating binding of repressor SP1 to its promoter. Further, KRT14 loss significantly reduces TNBC migration, invasion, and peritoneal metastasis. Consistently, human TNBC metastasis displays positive correlation between H3K27me3 and KRT14 levels. Finally, EZH2 knockdown or H3K27me3 inhibition by EPZ6438 reduces TNBC peritoneal metastasis. Altogether, our preclinical findings suggest a rationale for targeting TNBC with EZH2 inhibitors.

The different faces of metastatic melanoma in the gastrointestinal tract

Melanoma is the most aggressive form of skin cancer, with tendency to spread to any organ of the human body, including the gastrointestinal tract (GIT). The diagnosis of metastases to the GIT can be difficult, as they may be clinically silent for somewhile and may occur years after the initial melanoma diagnosis. CT imaging remains the standard modality for staging and surveillance of melanoma patients, and in most cases, it will be the first imaging modality to identify GIT lesions. However, interpretation of CT studies in patients with melanoma can be challenging as lesions may be subtle and random in distribution, as well as sometimes mimicking other conditions. Even so, early diagnosis of GIT metastases is critical to avoid emergency hospitalisations, whilst surgical intervention can be curative in some cases. In this review, we illustrate the various imaging presentations of melanoma metastases within the GIT, discuss the clinical aspects and offer advice on investigation and management. We offer tips intended to aid radiologists in their diagnostic skills and interpretation of melanoma imaging scans.

Intra-Abdominal Malignant Melanoma: Challenging Aspects of Epidemiology, Clinical and Paraclinical Diagnosis and Optimal Treatment—A Literature Review

According to European consensus-based interdisciplinary guidelines for melanoma, cutaneous melanoma (CM) is the most deadly form of dermatological malignancy, accounting for 90% of the deaths of skin cancer patients. In addition to cutaneous melanoma, mucosal melanoma occurs in four major anatomical sites, including the upper respiratory tract, the conjunctiva, the anorectal region, and the urogenital area. As this cancer type metastasizes, a classification used in the current medical literature is the distinction between secondary lesions and primary malignant melanoma of the abdominal cavity. Given that malignant melanoma is the most common cancer that spreads to the gastrointestinal tract, different imaging modalities compete to diagnose the phenomenon correctly and to measure its extension. Treatment is primarily surgery-based, supported by immunotherapy, and prolongs survival, even when performed at stage IV illness. In the end, special forms of malignant melanoma are discussed, such as melanoma of the genito-urinary tract and amelanotic/achromic melanoma. The importance of this present literature review relies on yielding and grouping consistent and relevant, updated information on the many aspects and challenges that a clinician might encounter during the diagnosis and treatment of a patient with intra-abdominal melanoma.

Selected Patients With Peritoneal Metastases From Breast Cancer May Benefit From Cytoreductive Surgery: The Results of a Multicenter Survey

Background

Even though breast cancer is the most frequent extra-abdominal tumor causing peritoneal metastases, clear clinical guidelines are lacking. Our aim is to establish whether cytoreductive surgery (CRS) could be considered in selected patients with peritoneal metastases from breast cancer (PMBC) to manage abdominal spread and allow patients to resume or complete other medical treatments.

Methods

We considered patients with PMBC treated in 10 referral centers from January 2002 to May 2019. Clinical data included primary cancer characteristics (age, histology, and TNM) and data on metastatic disease (interval between primary BC and PM, molecular subtype, other metastases, and peritoneal spread). Overall survival (OS) was estimated using the Kaplan–Meier method. Univariate and multivariable data for OS were analyzed using the Cox proportional hazards model.

Results

Of the 49 women with PMBC, 20 were treated with curative aim (CRS with or without HIPEC) and 29 were treated with non-curative procedures. The 10-year OS rate was 27%. Patients treated with curative intent had a better OS than patients treated with non-curative procedures (89.2% vs. 6% at 36 months, p < 0.001). Risk factors significantly influencing survival were age at primary BC, interval between BC and PM diagnosis, extra-peritoneal metastases, and molecular subtype.

Conclusions

The improved outcome in selected cases after a multidisciplinary approach including surgery should lead researchers to regard PMBC patients with greater attention despite their scarce epidemiological impact. Our collective efforts give new information, suggest room for improvement, and point to further research for a hitherto poorly studied aspect of metastatic BC.

Current Trends in Cytoreductive Surgery (CRS) and Hyperthermic Intraperitoneal Chemotherapy (HIPEC) for Peritoneal Disease from Appendiceal and Colorectal Malignancies

Peritoneal carcinomatosis (PC) is a poor prognostic factor for all malignancies. This extent of metastatic disease progression remains difficult to treat with systemic therapies due to poor peritoneal vascularization resulting in limited drug delivery and penetration into tissues. Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) are surgical interventions that directly target peritoneal tumors and have improved outcomes for PC resulting from appendiceal and colorectal cancer (CRC). Despite these radical therapies, long-term survival remains infrequent, and recurrence is common. The reasons for these outcomes are multifactorial and signal the need for the continued development of novel therapeutics, techniques, and approaches to improve outcomes for these patients. Here, we review landmark historical studies that serve as the foundation for current recommendations, recent discoveries, clinical trials, active research, and areas of future interest in CRS/HIPEC to treat PC originating from appendiceal and colorectal malignancies.

Palliative Gastrointestinal Surgery in Patients With Advanced Peritoneal Carcinomatosis: Clinical Experience and Development of a Predictive Model for Surgical Outcomes

Background

Palliative gastrointestinal (GI) surgery potentially relieves distressing symptoms arising from intestinal obstruction (IO) in patients with advanced peritoneal carcinomatosis (PC). As surgery is associated with significant morbidity risks in advanced cancer patients, it is important for surgeons to select patients who can benefit the most from this approach. Hence, we aim to determine predictors of morbidity and mortality after palliative surgery in patients with PC. In addition, we evaluate the utility of the UC Davis Cancer Care nomogram (UCDCCn) and develop a simplified model to predict short-term surgical mortality in these patients.

Methods

A retrospective review of patients with IO secondary to PC undergoing palliative GI surgery was performed. Logistic regression was used to determine independent predictors of 30-day morbidity and mortality after surgery. UCDCCn was evaluated using the area under the curve (AUC) for discriminatory power and the Hosmer-Lemeshow test for calibration. Our simplified model was developed using logistic regression and evaluated using cross-validation.

Results

A total of 254 palliative GI surgeries were performed over a 10-year duration. The 30-day morbidity and mortality were 43% (n = 110) and 21% (n = 53), respectively. Preoperative albumin, age, and emergency nature of surgery were significant independent predictors for 30-day morbidity. A simplified model using preoperative Eastern Cooperative Oncology Group (ECOG) status and albumin (AUC = 0.71) achieved better predictive power than UCDCCn (AUC = 0.66) for 30-day mortality.

Conclusion

Good ECOG status and high preoperative albumin levels were independently associated with good short-term outcomes after palliative GI surgery. Our simplified model may be used to conveniently and efficiently select patients who stand to benefit the most from surgery.

Primary and metastatic peritoneal surface malignancies

Peritoneal surface malignancies comprise a heterogeneous group of primary tumours, including peritoneal mesothelioma, and peritoneal metastases of other tumours, including ovarian, gastric, colorectal, appendicular or pancreatic cancers. The pathophysiology of peritoneal malignancy is complex and not fully understood. The two main hypotheses are the transformation of mesothelial cells (peritoneal primary tumour) and shedding of cells from a primary tumour with implantation of cells in the peritoneal cavity (peritoneal metastasis). Diagnosis is challenging and often requires modern imaging and interventional techniques, including surgical exploration. In the past decade, new treatments and multimodal strategies helped to improve patient survival and quality of life and the premise that peritoneal malignancies are fatal diseases has been dismissed as management strategies, including complete cytoreductive surgery embedded in perioperative systemic chemotherapy, can provide cure in selected patients. Furthermore, intraperitoneal chemotherapy has become an important part of combination treatments. Improving locoregional treatment delivery to enhance penetration to tumour nodules and reduce systemic uptake is one of the most active research areas. The current main challenges involve not only offering the best treatment option and developing intraperitoneal therapies that are equivalent to current systemic therapies but also defining the optimal treatment sequence according to primary tumour, disease extent and patient preferences. New imaging modalities, less invasive surgery, nanomedicines and targeted therapies are the basis for a new era of intraperitoneal therapy and are beginning to show encouraging outcomes.

CD122-targeted interleukin-2 and αPD-L1 treat bladder cancer and melanoma via distinct mechanisms, including CD122-driven natural killer cell maturation

Bladder cancer (BC) and melanoma are amenable to immune checkpoint blockade (ICB) therapy, yet most patients with advanced/metastatic disease do not respond. CD122-targeted interleukin (IL)-2 can improve ICB efficacy, but mechanisms are unclear. We tested αPD-L1 and CD122-directed immunotherapy with IL-2/αIL-2 complexes (IL-2c) in primary and metastatic bladder and melanoma tumors. IL-2c treatment of orthotopic MB49 and MBT-2 BC generated NK cell antitumor immunity through enhanced activation, reduced exhaustion, and promotion of a mature, effector NK cell phenotype. By comparison, subcutaneous B16-F10 melanoma, which is IL-2c sensitive, requires CD8⁺ T and not NK cells, yet we found αPD-L1 efficacy requires both CD8⁺ T and NK cells. We then explored αPD-L1 and IL-2c mechanisms at distinct metastatic sites and found intraperitoneal B16-F10 metastases were sensitive to αPD-L1 and IL-2c, with IL-2c but not αPD-L1, increasing CD122⁺ mature NK cell function, confirming conserved IL-2c effects in distinct cancer types and anatomic compartments. αPD-L1 failed to control tumor growth and prolong survival in B16-F10 lung metastases, yet IL-2c treated B16-F10 lung metastases effectively even in T cell and adaptive immunity deficient mice, which was abrogated by NK cell depletion in wild-type mice. Flow cytometric analyses of NK cells in B16-F10 lung metastases suggest that IL-2c directly boosts NK cell activation and effector function. Thus, αPD-L1 and IL-2c mediate nonredundant, immune microenvironment-specific treatment mechanisms involving CD8⁺ T and NK cells in primary and metastatic BC and melanoma. Mechanistic differences suggest effective treatment combinations including in other tumors or sites, warranting further studies.

Endoscopic ultrasound guided fine needle biopsy (EUS-FNB) from peritoneal lesions: a prospective cohort pilot study

Background

Diagnostic laparoscopy is often a necessary, albeit invasive, procedure to help resolve undiagnosed peritoneal diseases. Previous retrospective studies reported that EUS-FNA is feasible on peritoneal and omental lesions, however, EUS-FNA provided a limited amount of tissue for immunohistochemistry stain (IHC).

Aim

This pilot study aims to prospectively determine the effectiveness of EUS-FNB regarding adequacy of tissue for IHC staining, diagnostic rate and the avoidance rate of diagnostic laparoscopy or percutaneous biopsy in patients with these lesions.

Methods

From March 2017 to June 2018, patients with peritoneal or omental lesions identified by CT or MRI at the King Chulalongkorn Memorial Hospital, Bangkok, Thailand were prospectively enrolled in the study. All Patients underwent EUS-FNB. For those with negative pathological results of EUS-FNB, percutaneous biopsy or diagnostic laparoscopy was planned. Analysis uses percentages only due to small sample sizes.

Results

A total of 30 EUS-FNB passes were completed, with a median of 3 passes (range 2–3 passes) per case. For EUS-FNB, the sensitivity, specificity, PPV, NPV and accuracy of EUS-FNB from peritoneal lesions were 63.6%, 100%, 100%, 20% and 66.7% respectively. Adequate tissue for IHC stain was found in 25/30 passes (80%). The tissues from EUS results were found malignant in 7/12 patients (58.3%). IHC could be done in 10/12 patients (83.3%). Among the five patients with negative EUS results, two underwent either liver biopsy of mass or abdominal paracentesis, showing gallbladder cancer and adenocarcinoma. Two patients refused laparoscopy due to advanced pancreatic cancer and worsening ovarian cancer. The fifth patient had post-surgical inflammation only with spontaneous resolution. The avoidance rate of laparoscopic diagnosis was 58.3%. No major adverse event was observed.

Conclusions

EUS-FNB from peritoneal lesions provided sufficient core tissue for diagnosis and IHC. Diagnostic laparoscopy can often be avoided in patients with peritoneal lesions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-01953-9.

The Stress-Inducible BCL2A1 Is Required for Ovarian Cancer Metastatic Progression in the Peritoneal Microenvironment

Emerging evidence indicates that hypoxia plays a critical role in governing the transcoelomic metastasis of ovarian cancer. Hence, targeting hypoxia may be a promising approach to prevent the metastasis of ovarian cancer. Here, we report that BCL2A1, a BCL2 family member, acts as a hypoxia-inducible gene for promoting tumor progression in ovarian cancer peritoneal metastases. We demonstrated that BCL2A1 was induced not only by hypoxia but also other physiological stresses through NF-κB signaling and then was gradually reduced by the ubiquitin-proteasome pathway in ascites-derived ovarian cancer cells. The upregulated BCL2A1 was frequently found in advanced metastatic ovarian cancer cells, suggesting its clinical relevance in ovarian cancer metastatic progression. Functionally, BCL2A1 enhanced the foci formation ability of ovarian cancer cells in a stress-conditioned medium, colony formation in an ex vivo omental tumor model, and tumor dissemination in vivo. Under stress conditions, BCL2A1 accumulated and colocalized with mitochondria to suppress intrinsic cell apoptosis by interacting with the BH3-only subfamily BCL2 members HRK/BAD/BID in ovarian cancer cells. These findings indicate that BCL2A1 is an early response factor that maintains the survival of ovarian cancer cells in the harsh tumor microenvironment.

Hyperthermic Intraperitoneal Chemotherapy: A Critical Review

Simple Summary

Patients with cancer of the digestive system or ovarian cancer are at risk of developing peritoneal metastases (PM). In some patients with PM, surgery followed by intraperitoneal (IP) chemotherapy has emerged as a valid treatment option. The addition of hyperthermia is thought to further enhance the efficacy of IP chemotherapy. However, the results of recent clinical trials in large bowel cancer have put into question the use of hyperthermic intraperitoneal chemotherapy (HIPEC). Here, we review the rationale and current results of HIPEC for PM and propose a roadmap to further progress.

Abstract

With increasing awareness amongst physicians and improved radiological imaging techniques, the peritoneal cavity is increasingly recognized as an important metastatic site in various malignancies. Prognosis of these patients is usually poor as traditional treatment including surgical resection or systemic treatment is relatively ineffective. Intraperitoneal delivery of chemotherapeutic agents is thought to be an attractive alternative as this results in high tumor tissue concentrations with limited systemic exposure. The addition of hyperthermia aims to potentiate the anti-tumor effects of chemotherapy, resulting in the concept of heated intraperitoneal chemotherapy (HIPEC) for the treatment of peritoneal metastases as it was developed about 3 decades ago. With increasing experience, HIPEC has become a safe and accepted treatment offered in many centers around the world. However, standardization of the technique has been poor and results from clinical trials have been equivocal. As a result, the true value of HIPEC in the treatment of peritoneal metastases remains a matter of debate. The current review aims to provide a critical overview of the theoretical concept and preclinical and clinical study results, to outline areas of persisting uncertainty, and to propose a framework to better define the role of HIPEC in the treatment of peritoneal malignancies.

Synchronous peritoneal metastases from lung cancer: incidence, associated factors, treatment and survival: a Dutch population-based study

Peritoneal metastases (PM) from lung cancer are rare and it is unknown how they affect the prognosis of patients with lung cancer. This population-based study aimed to assess the incidence, associated factors, treatment and prognosis of PM from lung cancer. Data from the Netherlands Cancer Registry were used. All patients diagnosed with lung cancer between 2008 and 2018 were included. Logistic regression analysis was performed to identify factors associated with the presence of PM. Cox regression analysis was performed to identify factors associated with the overall survival (OS) of patients with PM. Between 2008 and 2018, 129,651 patients were diagnosed with lung cancer, of whom 2533 (2.0%) patients were diagnosed with PM. The European Standardized Rate of PM increased significantly from 0.6 in 2008 to 1.4 in 2018 (p < 0.001). Age between 50 and 74 years, T3-4 tumour stage, N2-3 nodal stage, tumour morphology of a small cell lung cancer or adenocarcinoma, and the presence of systemic metastases were associated with the presence of PM. The median OS of patients with PM was 2.5 months. Older age, male sex, T3-4 tumour stage, N2-3 nodal stage, not receiving systemic treatment, and the presence of systemic metastases were associated with a worse OS. Synchronous PM were diagnosed in 2.0% of patients with lung cancer and resulted in a very poor survival.

Failed Apoptosis Enhances Melanoma Cancer Cell Aggressiveness

Triggering apoptosis remains an efficient strategy to treat cancer. However, apoptosis is no longer a final destination since cancer cells can undergo partial apoptosis without dying. Recent evidence shows that partial mitochondrial permeabilization and non-lethal caspase activation occur under certain circumstances, although it remains unclear how failed apoptosis affects cancer cells. Using a cancer cell model to trigger non-lethal caspase activation, we find that melanoma cancer cells undergoing failed apoptosis have a particular transcriptomic signature associated with focal adhesions, transendothelial migration, and modifications of the actin cytoskeleton. In line with this, cancer cells surviving apoptosis gain migration and invasion properties in vitro and in vivo. We further demonstrate that failed apoptosis-associated gain in invasiveness is regulated by the c-Jun N-terminal kinase (JNK) pathway, whereas its RNA sequencing signature is found in metastatic melanoma. These findings advance our understanding of how cell death can both cure and promote cancer.

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for peritoneal metastasis from breast cancer: a preliminary report of 4 cases

Background

Breast cancer (BC) has the highest morbidity and the fifth-highest mortality rate among women in China. Peritoneal metastases from BC are rare, and presently, there are no guidelines or international consensus on its treatment. Patients with a prognosis of peritoneal carcinomatosis (PC) have poorer survival rates than patients with other regional metastases from BC.

Methods

Four BC PC patients, who had undergone cytoreductive surgery (CRS) + hyperthermic intraperitoneal chemotherapy (HIPEC), participated in this study. Clinicopathologic characteristics and overall survival (OS) data were collected and analyzed.

Results

Patients' average age when they underwent CRS + HIPEC was 59.8 years. The average time of CRS + HIPEC was 8.8 h. The median number of resected organ areas was 7. Following CRS + HIPEC, each of the 4 patients survived for 31, 28, 16 and 52 months, respectively. There were no serious adverse events during the perioperative period.

Conclusions

The study examined the detailed process of CRS + HIPEC and found that patients with BC PC may benefit from this treatment. The 4 cases provided evidence that the integrated therapy of CRS + HIPEC is a promising strategy that could improve outcomes for BC PC patients. Further, no serious adverse events (SAEs) occurred during the CRS + HIPEC perioperative period.

A Four-Inflow Construction to Ensure Thermal Stability and Uniformity during Hyperthermic Intraperitoneal Chemotherapy (HIPEC) in Rats

BACKGROUND

Hyperthermic intraperitoneal chemotherapy (HIPEC) after cytoreductive surgery (CRS) is used for treating peritoneal metastases of various origins. Present HIPEC protocols have rarely been validated for relevant parameters such as optimal agent, duration and perfusate temperature. In vitro experiments are not completely representative of clinical circumstances. Therefore, a good preclinical in vivo HIPEC model is needed in which temperature distributions can be well-controlled and are stable throughout treatments.

METHODS

We designed a setup able to generate and maintain a homogeneous flow during a 90-min HIPEC procedure using our in-house developed treatment planning tools and computer aided design (CAD) techniques. Twelve rats were treated with heated phosphate-buffered saline (PBS) using two catheter setups (one vs. four- inflows) and extensive thermometry. Simulated and measured thermal distribution and core temperatures were evaluated for the different setups.

RESULTS

Overall, the four-inflow resulted in more stable and more homogeneous thermal distributions than the one-inflow, with lower standard deviations (0.79 °C vs. 1.41 °C at the outflow, respectively) and less thermal losses. The average thermal loss was 0.4 °C lower for rats treated with the four-inflow setup. Rat core temperatures were kept stable using occasional tail cooling, and rarely exceeded 39 °C.

CONCLUSION

Increasing the number of inflow catheters from one to four resulted in increased flow and temperature homogeneity and stability. Tail cooling is an adequate technique to prevent rats from overheating during 90-min treatments. This validated design can improve accuracy in future in vivo experiments investigating the impact of relevant parameters on the efficacy of different HIPEC protocols.

68Ga-FAPI Outperforms 18F-FDG PET/CT in Identifying Bone Metastasis and Peritoneal Carcinomatosis in a Patient With Metastatic Breast Cancer

A 60-year-old woman, previously treated for breast cancer, was referred to gastroenterologists due to persistent abdominal distension. F-FDG PET/CT revealed multiple abnormal foci at the skeleton including the bilateral ilium, peritoneum, and omentum. Ga-FAPI PET/CT was performed for further detecting the primary lesion, which showed a greater number of bone metastases and higher uptake in peritoneal carcinomatoses than F-FDG. Biopsy at the left ilium and omentum indicated metastases from breast cancer. This case highlighted that Ga-FAPI may outperforms F-FDG PET/CT in identifying bone metastasis and peritoneal carcinomatosis.

Non-Small Cell Lung Cancer With Synchronous Peritoneal Adenocarcinoma: A Rare Independent Combination

Lung cancer is one of the most common malignancies worldwide, and metastasis occurs in more than one-third of cases. Common sites of metastatic disease are the brain, spine, nerve, adrenal glands, bone, liver, and pleura. Peritoneal involvement, however, is rare, and peritoneal involvement found in lung cancer is presumed to be metastatic until proven otherwise. This is due to the fact that primary peritoneal adenocarcinoma is uncommon and difficult to distinguish from the metastatic spread.  Here, we report on a case of a 73-year-old woman who presented with ascites. Evaluation of ascitic fluid was consistent with adenocarcinoma. Subsequent CT of the chest revealed a 4.3-cm mass in the lower lobe of the left lung, which was determined to be poorly differentiated squamous cell carcinoma on histopathology. This is a rare case of two synchronous primary cancers: adenocarcinoma and poorly differentiated squamous cell carcinoma.  To conclude, physicians should be familiar with an independent presentation of squamous cell carcinoma of the lung and peritoneal carcinomatosis in the same patient, as the outcome of independent tumors is poor in most cases.

A Case of Diffuse Metastatic Melanoma With Massive Spontaneous Hemoperitoneum

The incidence rate for melanoma continues to rise in the USA. The majority of melanoma cases are detected at an early stage and are amenable to surgical excision. Advanced melanoma with diffuse intraabdominal metastasis is rare. We present a case of a 50-year-old female with no known primary or history of melanoma who presented with massive intraabdominal bleeding secondary to diffuse metastatic melanoma with peritoneal implants. Diagnosing metastatic melanoma could be challenging. Clinicians should be aware of hemoperitoneum or peritoneal carcinomatosis as potential manifestations of malignant melanoma to expedite appropriate management.

Clinical efficacy of osimertinib for a patient with ileus due to peritoneal carcinomatosis

We report a patient of stage IV lung adenocarcinoma who developed ileus due to peritoneal carcinomatosis. We placed an ileus tube and started an oral intake of osimertinib. Within one month, the tumor had shrunk, and the ileus was controlled.

Unusual Pattern of Invasive Lobular Carcinoma Metastasis: A Case Report

Patient: Female, 58

Final Diagnosis: Metastasis of breast cancer to the sigmoid colon, appendix, and ovaries

Symptoms: Abdominal pain

Medication: —

Clinical Procedure: Abdominal laparotomy

Specialty: Surgery

Synchronous peritoneal carcinomatosis from a buccal squamous cell carcinoma: a case report focusing on possible metastatic mechanisms and novel therapeutic modalities

A 53-year-old male patient was diagnosed with squamous cell carcinoma of buccal mucosa with synchronous diffuse peritoneal carcinomatosis, a very rare presentation for oral cancer. His disease was highly resistant to intensive systemic chemotherapy and progressed rapidly. So far as we know, there were only five cases with peritoneal involvement by metastatic head and neck cancer reported prior to this patient in the English literature. Immunohistochemistry study revealed that tumour specimens from both oral cavity and peritoneum were negative for tumour necrosis factor alpha and CD24 but positive for CD44 and CD36. These four molecules have been disclosed to be involved in the process of peritoneal metastasis from ovarian cancer. Their roles in the metastatic pathway and possible therapeutic policy targeting at them will be thoroughly discussed.

Surgical treatment of intraperitoneal metastases from lung cancer: two case reports and a review of the literature

BACKGROUND

Peritoneal metastases are often reported in several abdominal tumors. Peritoneal diffusion from extra-abdominal tumors is thought to be rare. Lung cancer is one of the most common cancers in the world with early metastases and it is associated with poor prognosis in advanced stages. Peritoneal metastases from lung cancer are uncommon and the real mechanism of its diffusion to the peritoneum is unknown. However, its clinical behavior is similar to any other peritoneal metastasis from abdominal tumors.

CASE PRESENTATION

We present two Caucasian patients (a 44-year-old man and a 59-year-old man) with bowel obstruction from peritoneal metastases from non-small cell lung cancer who successfully underwent emergency cytoreductive surgery and had a good prognosis and survival.

CONCLUSIONS

In our patients with isolated peritoneal metastases from lung cancer, cytoreduction showed good prognosis with acceptable morbidity. This treatment option might be considered in highly selected cases to improve survival. Strict follow-up is mandatory to allow early diagnosis of peritoneal diffusion.

Peritoneal Metastases from Breast Cancer: A Scoping Review

Breast cancer is the leading cause of cancer deaths amongst American women aged 20 to 59. While the incidence of breast cancer has been increasing, its mortality rates have significantly declined from 1989 to 2016. As a result, the number of survivors considerably increased. This impacts the detection and management of recurrences. Peritoneal metastases from breast cancer is a rare and challenging clinical presentation. There is a lack of knowledge syntheses and specific recommendations for the management of breast cancer peritoneal metastases. This review aims to determine the pattern of spread, prognosis, diagnosis, and role of surgery in this subset of patients.

Relevant studies were searched in PubMed and Web of Science between April and June 2019. Included studies were written in English and reported data on breast cancer peritoneal or gastrointestinal metastases. Articles published before 1990, case reports, editorials, and articles with no full text available were excluded. Data abstraction was performed for citation information, population, sample, methods, relevant results, mentioned limitations, and study design.

The search identified 505 unique reports. A total of 21 articles were included in the synthesis. Sixteen articles were observational studies, four were experimental, and one article was a proof-of-concept study. Amongst all observational studies, the diagnostic methods and criteria for breast cancer carcinomatosis were particularly heterogeneous, including ascites cytology, biopsy, surgical exploration, and various computed tomography (CT) findings. The majority of pathology and imaging reports demonstrated that breast cancer peritoneal metastases are mainly associated with invasive lobular carcinoma (ILC) and the following intrinsic subtypes: HER2-enriched, luminal B and basal-like. Experimental studies demonstrated that peritoneal metastases can be studied using breast cancer xenograft models. Somatic loss of both p53 and E-cadherin was associated with ILC peritoneal spread. Studies on prognosis and treatment highlighted that peritoneal metastases were associated with a poorer prognosis than other metastatic sites. In terms of surgical management, there is a paucity of data on the outcomes of hyperthermic intraperitoneal chemotherapy (HIPEC) in these patients. However, included studies suggested a role for cytoreductive surgery in selected patients when there is no residual disease after the procedure.

This review summarizes data on the development, diagnosis, prognosis, and treatment of breast cancer peritoneal and gastrointestinal metastases. Patients’ survival is significantly reduced in comparison with other distant metastatic sites. A deeper understanding of the invasion mechanisms and the role of surgery will be important.

Comparison of implantation sites for the development of peritoneal metastasis in a colorectal cancer mouse model using non-invasive bioluminescence imaging

The development of cancer mouse models is still needed for the identification and preclinical validation of novel therapeutic targets in colorectal cancer, which is the third leading cause of cancer-related deaths in Europe. The purpose of this study was to determine the most accurate tumour cell injection method to obtain suitable peritoneal metastasis (PM) for subsequent therapeutic treatments. Here, we grafted murine colon carcinoma CT-26 cells expressing luciferase into immunocompetent BALB-c mice by intravenous injection (IV group), subcutaneous injection (SC group), intraperitoneal injection after peritoneal scratching (A group) or intraperitoneal injection alone (IP group). Tumour growth was monitored by bioluminescence during the first 15 days post-grafting. The peritoneal carcinomatosis index was evaluated macroscopically, histology, immunohistochemistry and multiphoton microscopy were performed in peritoneal tumour tissue. Upon implantation, no tumour growth was observed in the IV group, similar to the non-injected group. Both the IP and SC groups showed intermediate growth rates, but the SC group produced only a single subcutaneous nodule. The A group exhibited the highest tumour growth at 15 days post-surgery. Anatomic and histologic analyses corroborated the existence of various tumour nodules, and multiphoton microscopy was used to evaluate tumour fibrosis-infiltrating cells in a non-pathologic peritoneum. In conclusion, limited PM was obtained by IP injection, whereas IP injection after peritoneal scratching led to an extensive PM murine model for evaluating new therapeutics.