A systematic review of the accuracy and utility of peritoneal cytology in patients with gastric cancer

The clinical implications of staging laparoscopy in the diagnostic workup of gastric cancer patients: A population based study

BACKGROUND

Since 2016, staging laparoscopy has been implemented in the diagnostic workup of patients with gastric cancer. Staging laparoscopy aims to detect incurable disease (peritoneal metastases and irresectable tumors) and to prevent futile laparotomies.

METHODS

In this population-based nationwide study, we sought patient- and tumor characteristics associated with undergoing a staging laparoscopy. Additionally, we analyzed the prevalence of synchronous peritoneal metastases, the outcome of the staging laparoscopy and its clinical impact on treatment decisions. All patients diagnosed with non-cardia gastric cancer from the Netherlands Cancer Registry between 2016 and 2021 were included.

RESULTS

Alongside tumor characteristics, patient characteristics such as younger age, absence of comorbidities and lower WHO performance status were associated with performing a staging laparoscopy. In the study period, an increase in the proportion of patients who underwent a staging laparoscopy was observed, from 19.6% in 2016 to 32.3% in 2021 (p-value<0.001). In the same period, the prevalence of synchronous peritoneal metastases increased from 25% to 31%. In 37.6% of the patients who had the outcome of their staging laparoscopy reported, had incurable disease diagnosed during staging laparoscopy. Significantly less of these patients were treated with triplet regimens as compared to patients with a negative staging laparoscopy (18.5 vs. 76.3%; p-value<0.001).

CONCLUSION

The implementation of staging laparoscopy in gastric cancer patients paralleled the increase in diagnosis of incurable disease and a decrease in the application of triplet systemic therapies in these patients.

Impact of Minimally Invasive Surgery on Early and Late Outcomes of Patients With Gastric Cancer Treated Using Neoadjuvant Chemotherapy

BACKGROUND

Gastric cancer is the fifth most common neoplasm and the third leading cause of cancer-related death worldwide. Neoadjuvant chemotherapy is recommended for Stages II-III resectable tumors, but the comparative effectiveness of minimally invasive surgery (MIS) versus open gastrectomy (OG) post-neoadjuvant therapy has not been adequately investigated.

METHODS

A retrospective cohort analysis was performed on patients with clinical Stage II and III gastric adenocarcinoma who underwent neoadjuvant chemotherapy followed by either MIS or OG between 2007 and 2020. Propensity score matching was utilized to compare the clinical and surgical outcomes, morbidity, and mortality, and the influence of MIS on 3-year survival rates was evaluated.

RESULTS

After matching, no statistical differences in clinical aspects were noted between the two groups. MIS was associated with increased D2 lymphadenectomy, curative intent, and complete neoadjuvant therapy. Furthermore, this therapeutic approach resulted in reduced transfusion rates and shorter hospital stays. Nonetheless, no significant differences were observed in global, clinical, or surgical complications or mortality between the two groups. Weight loss emerged as a significant risk factor for complications, but MIS did not independently affect survival rates. Extended resection and higher American Society of Anesthesiology scores were independent predictors of reduced survival.

CONCLUSION

MIS after neoadjuvant chemotherapy for gastric cancer appears to be a viable option, with oncological outcomes comparable to those of OG, less blood loss, and shorter hospital stays. Although MIS did not independently affect long-term survival, it offered potential benefits in terms of postoperative recovery and morbidity. Further studies are needed to validate these findings, especially across diverse populations.

Comparison of Peritoneal Cytology Results Before and After Resection in Gastric Cancer Patients

OBJECTIVE

Peritoneal cytology is used to detect the peritoneal spread of gastric cancer and to assess survival rate. The aim of this study was to compare the risk factors, recurrence, and survival of gastric cancer patients with positive and negative peritoneal cytology before and after resection.

MATERIALS AND METHODS

Patients with gastric cancer who underwent elective surgery were retrospectively analysed. The study covered a period between September 2018 and September 2020. After applying the exclusion criteria, 57 patients were included in the study. For the purpose of this study, peritoneal cytology was taken from the same three intra-abdominal regions before and after resection from patients with operable gastric cancer.

RESULTS

Of the 57 patients included in the study, 36 (63.2%) were male patients and 21 (36.8%) were female patients. Preoperative or postoperative malignant cytology was detected in 12 patients (21.1%). Tumour diameter was larger in patients with preoperatively detected malignant cytology than in the patients with postoperatively positive malignant cytology (66.67 mm vs. 44.44 mm) (p = 0.006). The recurrence rate was higher in patients with preoperative and postoperative positive cytology than in those with negative cytology (p = 0.019). The survival of patients with preoperative malignant cytology was worse than the survival of patients with preoperative benign cytology (p = 0.011). A significant correlation was found between lymphovascular invasion (+), perineural invasion (+), T4, Stage 3 disease, number of malignant lymph nodes, and preoperative cytology positivity (p <0.05).

CONCLUSION

In our study, we found that the preoperative cytology positivity is associated with lymphovascular invasion positivity, perineural invasion positivity, T4 tumour, Stage 3 disease, and the number of malignant lymph nodes. Postoperative positive cytology was not associated with the same variables. Because of the significant associations in preoperative positivity, fluid samples should be obtained immediately after the abdomen is open and before the tumour is manipulated. If possible, fluid samples should be taken from different quadrants, but if the sample is to be taken from a single quadrant, it should be taken from the pelvis.

Peritoneal Tumor DNA as a Prognostic Biomarker in Gastric Cancer: A Systematic Review and Meta-Analysis

PURPOSE

Gastric cancers commonly spread to the peritoneum. Its presence significantly alters patient prognosis and treatment-intent; however, current methods of peritoneal staging are inaccurate. Peritoneal tumor DNA (ptDNA) is tumor-derived DNA detectable in peritoneal lavage fluid. ptDNA positivity may indicate peritoneal micrometastasis and may be more sensitive than cytology in staging the peritoneum. In this meta-analysis, we evaluated the prognostic potential of ptDNA in gastric cancer.

METHODS

PubMed, Embase, Scopus, and Web of Science databases were searched using PRISMA guidelines. Studies published between January 1, 1990, and April 30, 2023, containing quantitative data relating to ptDNA in gastric cancer were meta-analyzed.

RESULTS

Six studies were analyzed. Of the total 757 patients with gastric adenocarcinoma, 318 (42.0%) were stage I, 311 (41.0%) were stage II/III, 116 (15.3%) were stage IV, and 22 (2.9%) were undetermined. Overall, ptDNA detected cytology-positive cases with a sensitivity and specificity of 85.2% (95% CI, 66.5 to 100.0) and 91.5% (95% CI, 86.5 to 96.6), respectively. Additionally, ptDNA was detected in 54 (8.5%) of 634 cytology-negative patients. The presence of ptDNA negatively correlated with pathological stage I (relative risk [RR], 0.29 [95% CI, 0.13 to 0.66]) and positively correlated with pathological stage IV (RR, 8.61 [95% CI, 1.86 to 39.89]) disease. Importantly, ptDNA positivity predicted an increased risk of peritoneal-specific metastasis (RR, 13.81 [95% CI, 8.11 to 23.53]) and reduced 3-year progression-free (RR, 5.37 [95% CI, 1.39 to 20.74]) and overall (hazard ratio, 4.13 [95% CI, 1.51 to 11.32]) survival.

CONCLUSION

ptDNA carries valuable prognostic information and can detect peritoneal micrometastases in patients with gastric cancer. Its clinical utility in peritoneal staging for gastric cancer deserves further investigation.

The prognostic impact of peritoneal tumour DNA in gastrointestinal and gynaecological malignancies: a systematic review

Peritoneal metastases from various abdominal cancer types are common and carry poor prognosis. The presence of peritoneal disease upstages cancer diagnosis and alters disease trajectory and treatment pathway in many cancer types. Therefore, accurate and timely detection of peritoneal disease is crucial. The current practice of diagnostic laparoscopy and peritoneal lavage cytology (PLC) in detecting peritoneal disease has variable sensitivity. The significant proportion of peritoneal recurrence seen during follow-up in patients where initial PLC was negative indicates the ongoing need for a better diagnostic tool for detecting clinically occult peritoneal disease, especially peritoneal micro-metastases. Advancement in liquid biopsy has allowed the development and use of peritoneal tumour DNA (ptDNA) as a cancer-specific biomarker within the peritoneum, and the presence of ptDNA may be a surrogate marker for early peritoneal metastases. A growing body of literature on ptDNA in different cancer types portends promising results. Here, we conduct a systematic review to evaluate the prognostic impact of ptDNA in various cancer types and discuss its potential future clinical applications, with a focus on gastrointestinal and gynaecological malignancies.

Idiopathic Chronic Pancreatitis Presenting as Hemorrhagic Ascites: A Case Report

This report presents a perplexing case involving a 16-year-old adolescent presenting with persistent upper abdominal pain and distention. The patient had no history of substance abuse or animal-related encounters. Clinical examination revealed abdominal tension, distention, and localized tenderness. Laboratory analysis indicated elevated white blood cell count, mildly reduced hemoglobin and platelet levels, and notably heightened amylase and lipase levels. Serum albumin displayed a minor decrease. Despite repeated consultations and ultrasound evaluations, the underlying cause remained elusive. Advanced imaging unveiled substantial abdominopelvic ascites, a shrunken pancreas with an expanded main duct, and thickening at the ileocecal junction. Ascitic fluid analysis unveiled hemorrhagic fluid with elevated cell and neutrophil counts. Notably, the fluid accumulation extended into the omental apron covering the intestines. Biopsy results ruled out malignancy and chronic infections. We diagnosed him as a case of idiopathic chronic pancreatitis presenting as hemorrhagic ascites. This case underscores the intricacies of diagnosing complex abdominal disorders. A comprehensive approach, involving multidisciplinary collaboration, rigorous diagnostic assessments, and meticulous patient evaluation, is essential for elucidating such challenging clinical scenarios.

The Role of Staging Laparoscopy for Gastric Cancer Patients: Current Evidence and Future Perspectives

A significant proportion of patients diagnosed with gastric cancer is discovered with peritoneal metastases at laparotomy. Despite the continuous improvement in the performance of radiological imaging, the preoperative recognition of such an advanced disease is still challenging during the diagnostic work-up, since the sensitivity of CT scans to peritoneal carcinomatosis is not always adequate. Staging laparoscopy offers the chance to significantly increase the rate of promptly diagnosed peritoneal metastases, thus reducing the number of unnecessary laparotomies and modifying the initial treatment strategy of gastric cancer. The aim of this review was to provide a comprehensive summary of the current literature regarding the role of staging laparoscopy in the management of gastric cancer. Indications, techniques, accuracy, advantages, and limitations of staging laparoscopy and peritoneal cytology were discussed. Furthermore, a focus on current evidence regarding the application of artificial intelligence and image-guided surgery in staging laparoscopy was included in order to provide a picture of the future perspectives of this technique and its integration with modern tools in the preoperative management of gastric cancer.

The role of cytology in patients undergoing pressurized intraperitoneal aerosol chemotherapy (PIPAC) treatment for peritoneal carcinomatosis

Objectives

Cytology of ascites or peritoneal washing is a routine part of staging of peritoneal metastases (PM). We aim to determine value of cytology in patients undergoing pressurized intraperitoneal aerosol chemotherapy (PIPAC).

Methods

Single-center retrospective cohort study included consecutive patients having PIPAC for PM of different primary between January 2015 and January 2020.

Results

A total of 75 patients (median 63 years (IQR 51-70), 67 % female) underwent a total of 144 PIPAC. At PIPAC 1 59 % patients had positive and 41 % patients had negative cytology. Patients with negative and positive cytology only differed in terms of symptoms of ascites (16% vs. 39 % respectively, p=0.04), median ascites volume (100 vs. 0 mL, p=0.01) and median PCI (9 vs. 19, p<0.01). Among 20 patients who completed 3 PIPACs (per protocol), cytology changed in one from positive to negative, and in two from negative to positive. Median overall survival was 30.9 months in the per protocol group and 12.9 months in patients having <3 PIPACs (=0.519).

Conclusions

Positive cytology under PIPAC treatment is more frequently encountered in patients with higher PCI and symptomatic ascites. Cytoversion was rarely observed and cytology status had no impact on treatment decisions in this cohort.

Exosomes as a Source of Biomarkers for Gastrointestinal Cancers

Exosomes are small, lipid-bilayer bound extracellular vesicles of 40-160 nanometers in size that carry important information for intercellular communication. Exosomes are produced more by tumor cells than normal cells and carry tumor-specific content, such as DNA, RNA, and proteins, which have been implicated in tumorigenesis, tumor progression, and treatment response. Due to the critical role of exosomes in cancer development and progression, they can be exploited to develop specific biomarkers and therapeutic targets. Since exosomes are present in various biofluids, such as blood, saliva, urine, and peritoneal fluid, they are ideally suited to be developed as liquid biopsy tools for early diagnosis, molecular profiling, disease surveillance, and treatment response monitoring. In the past decade, numerous studies have been published about the functional significance of exosomes in a wide variety of cancers, with a particular focus on exosome-derived RNAs and proteins as biomarkers. In this review, utilizing human studies on exosomes, we highlight their potential as diagnostic, prognostic, and predictive biomarkers in gastrointestinal cancers.

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.

Risk Assessment and Preventive Treatment for Peritoneal Recurrence Following Radical Resection for Gastric Cancer

As the most common recurrence pattern after radical gastric cancer resection, peritoneal recurrence is a major cause of mortality, which affects the prognosis of patients to a very large extent. Peritoneal status and risk of peritoneal recurrence can be evaluated by peritoneal lavage cytology, photodynamic diagnosis, imaging examination, and pathologic analysis. Presently, there is no standard approach for preventing peritoneal recurrence after radical surgery; furthermore, controversies exist regarding the effects of some preventive methods. Among the preventive methods, there are high expectations about the potential of preoperative therapy, surgical skill improvement, hyperthermic intraperitoneal chemotherapy, and postoperative treatment to reduce the incidence of peritoneal recurrence after radical gastrectomy. This study aimed to analyze the results of previous studies on the risk assessment and preventive methods of peritoneal recurrence after radical gastrectomy in recent years. We hope to provide references for better approach to clinical diagnosis and treatment strategies for peritoneal recurrence after radical gastrectomy.

The Chinese Society of Clinical Oncology (CSCO): Clinical guidelines for the diagnosis and treatment of gastric cancer, 2021

There exist differences in the epidemiological characteristics, clinicopathological features, tumor biological characteristics, treatment patterns, and drug selections between gastric cancer patients from the Eastern and Western countries. The Chinese Society of Clinical Oncology (CSCO) has organized a panel of senior experts specializing in all sub-specialties of gastric cancer to compile a clinical guideline for the diagnosis and treatment of gastric cancer since 2016 and renews it annually. Taking into account regional differences, giving full consideration to the accessibility of diagnosis and treatment resources, these experts have conducted expert consensus judgment on relevant evidence and made various grades of recommendations for the clinical diagnosis and treatment of gastric cancer to reflect the value of cancer treatment and meeting health economic indexes in China. The 2021 CSCO Clinical Practice Guidelines for Gastric Cancer covers the diagnosis, treatment, follow-up, and screening of gastric cancer. Based on the 2020 version of the CSCO Chinese Gastric Cancer guidelines, this updated guideline integrates the results of major clinical studies from China and overseas for the past year, focused on the inclusion of research data from the Chinese population for more personalized and clinically relevant recommendations. For the comprehensive treatment of non-metastatic gastric cancer, attentions were paid to neoadjuvant treatment. The value of perioperative chemotherapy is gradually becoming clearer and its recommendation level has been updated. For the comprehensive treatment of metastatic gastric cancer, recommendations for immunotherapy were included, and immune checkpoint inhibitors from third-line to the first-line of treatment for different patient groups with detailed notes are provided.

Surgical Treatment for Gastric Cancer

Surgery is an essential component of curative-intent treatment strategies for gastric cancer. However, the care of each patient with gastric cancer must be individualized based on patient and tumor characteristics. It is important that all physicians who will be caring for patient with gastric cancer understand the current best practices of surgical management to provide patients with the highest quality of care. This article aims to provide this information while acknowledging areas of surgical management that are still controversial.

The benefits of surgery plus extensive intraoperative peritoneal lavage (EIPL) for patients with gastric cancer compared with surgery alone: a systematic review and meta-analysis

This study aims to synthesize the benefits of surgery plus extensive intraoperative peritoneal lavage (EIPL) for patients with gastric cancer compared with surgery alone. We searched Pubmed, Embase, Web of Science, Cochrane library, ClinicalTrials.gov and World Health Organization International Clinical Trials Registry Platform (ICTRP) for randomized controlled trials from 2000 to 2021 according to the inclusion and exclusion criteria. The reference lists of studies meeting the criteria were also screened for additional studies. The quality of these studies was assessed by the Cochrane Collaboration Risk of Bias Tool. An inverse-variance random-effects model of DerSimonian and Laird was used to synthesize the HRs and corresponding 95% CIs of short-term outcomes: hospital mortality and postoperative complications. For long-term outcomes (peritoneal recurrence and 3-year or 5-year overall survival rate), narrative synthesis was used. 4 of 43 studies were included for quantitative analysis. For short-term outcomes, the pooled HRs of hospital mortality and postoperative complications are 0.422 (95%CI: 0.037, 4.790) and 0.774 (95%CI: 0.376, 1.592). For long-term outcomes, despite the inconsistent results, patients receiving EPIL did not have reduced peritoneal recurrence and 3-year or 5-year overall survival rate. Compared with surgery alone, surgery plus EIPL does not have more benefits for patients with gastric cancer.

Clinical Significance of Peritoneal Fluid Examination for Free Cancer Cells in Patients Qualified for Surgery for Gastric Cancer

Background: Peritoneal lavage cytology in patients with gastric cancer may correlate with an unfavorable prognosis. This study evaluated the presence of free cancer cells in the peritoneal lavage of a population of patients with gastric cancer and its correlation with the outcome of surgical treatment.

Methods: One hundred patients diagnosed with gastric or gastrointestinal junction adenocarcinoma underwent surgery. In all patients, a cytological and immunohistochemical analysis of peritoneal lavage was performed. Based on the presence of free cancer cells (fcc) at the cytological and immunohistochemical examination of peritoneal lavage, patients undergoing surgery for gastric cancer were divided into two groups: fcc (+) and fcc (–).

Results: A total of 100 patients, 37 women, and 63 men with a median age of 65 years were included in the study. In the entire study group, 16 (16%) patients were positive for the presence of free cancer cells (fcc +) at peritoneal lavage examination. However, in the group of patients who underwent gastrectomy, fcc (+) was found in 10 out of 77 (13%) patients. The presence of cancer cells in peritoneal lavage was a strong predictive factor in an unfavorable outcome after surgery, and 1-year and 2-year patient survival was 34 and 0% in fcc (+) patients and 79 and 59% in fcc (–), respectively. Moreover, the presence of free cancer cells was associated with a five-fold increased risk of death within 2 years after surgery. When analyzing the group of patients undergoing R0/R1 surgery, this difference was even more significant (p < 0.0001).

Conclusions: The presence of free cancer cells in peritoneal lavage may significantly affect the outcome of patients with gastric cancer. Radical surgery in patients with free cancer cells in the peritoneal lavage did not result in a survival advantage. Identification of free cancer cells could help for a better stratification of gastric cancer patients, identifying those patients who could better benefit from a radical surgical treatment, finally improving long-term survival.

Extended intraoperative peritoneal lavage as prophylactic peritoneal recurrence for locally advanced gastric cancer: a prospective randomized trial

BACKGROUND

To demonstrate whether extensive intraoperative peritoneal lavage (EIPL) could yield better results in overall survival and less recurrence, regardless of peritoneal cytology, compared to standard peritoneal lavage (SPL).

METHODS

A prospective randomised multicenter study including 94 patients (47 per arm) to detect a 20% difference in 3-year overall survival in patients with locally advanced tumours without peritoneal carcinomatosis. Three samples of peritoneal fluid were obtained (at the beginning, the end of procedure and after the assigned peritoneal lavage). Clinicopathological and surgical data were analysed by group. Postoperative complications, location of recurrence and surgical approach were evaluated. Overall survival was calculated by the Kaplan-Meier method and the uni/multivariate analysis for prognostic factors was carried out using Cox regression analysis.

RESULTS

A total of 86 patients were analysed (4 excluded per group). No statistical differences were observed in clinicopathological or surgical data between groups, considering both groups well-balanced for analysis. Overall survival at 3 years was 64.3% for SPL vs. 62.3% for EIPL (p 0.421). Only three patients had at least one positive peritoneal cytology (1:2). There were no differences regarding postoperative complications (SPL: 37.2% vs. EIPL: 32.5%, p 0.65) or between location of recurrence and number of recurrences. The number of recurrences did not differ between surgical approaches, but locoregional and peritoneal recurrences were fewer with the laparoscopic approach (p 0.048).

CONCLUSIONS

The regular use of extensive peritoneal lavage in patients with locally advanced gastric cancer, regardless of peritoneal cytology, has not been effective as prophylaxis of peritoneal recurrence or better survival.

A narrative review of intraperitoneal chemotherapy and cytoreductive surgery (CRS) for peritoneal metastases in gastric cancer

Peritoneal carcinomatosis of gastric origin is an aggressive tumor entity. Historically it has been considered a terminal disease with no long-term survival, due to limited therapeutic options. However, as a better understanding of tumor biology has evolved in recent years, novel multimodal treatment strategies incorporating intraperitoneal (IP) chemotherapy-hyperthermic intraperitoneal chemotherapy (HIPEC), early postoperative intraperitoneal chemotherapy (EPIC), neoadjuvant intraperitoneal-systemic chemotherapy protocol (NIPS)-and cytoreductive surgery (CRS) have demonstrated promising oncologic outcomes and even long-term survival in selected patients. Most of the studies published to date are retrospective in nature. These studies involve heterogenous patient populations, a wide variety of chemotherapeutic drugs, and show wide variation in outcomes between institutions. Thus, it is difficult to evaluate the results. This review summarizes our current knowledge regarding IP chemotherapy and CRS for peritoneal metastases (PM) in gastric cancer (GC). We describe our institutional treatment regimens. We also provide a brief overview of new, targeted therapies that may show promise in the future.

[Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in gastric cancer]

BACKGROUND

Gastric cancer with peritoneal metastases is associated with an extremely poor prognosis. Developed multimodal treatment concepts, which include a combination of perioperative systemic treatment and cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC), show promising results with respect to improvement of the long-term survival.

METHODS

This article contains a review of the literature of published studies on the topic of gastric cancer and peritoneal metastasis.

RESULTS

The prognosis of patients with gastric cancer peritoneal carcinomatosis shows an extremely limited median survival of 7 months under palliative second-line systemic treatment. The median survival time increased to 12 months with cytoreductive surgery and in combination with HIPEC showed a positive effect on survival in individual studies.

EXPERT OPINION

Treatment recommendations for patients with peritoneal metastases of gastric cancer should be carried out by experts in surgical reference centers.

Flow cytometry-based analysis of tumor-leukocyte ratios in peritoneal fluid from patients with advanced gastric cancer

Background

The frequency of tumor cell dissemination in the peritoneal cavity is critically related to the progression of peritoneal metastases (PM). Recently, flow cytometry (FCM) has been successfully used to detect tumor cells in malignant effusions.

Methods

A total of 143 single cell suspensions derived from ascites or peritoneal lavages from patients with advanced gastric cancer (GC) were stained with monoclonal antibodies to CD45 and to CD326 as well as 4,6‐diamidino‐2‐phenylindole (DAPI) and FVS780. Using FCM, tumor‐leukocyte ratio (TLR) were calculated from CD45(−)CD326(+) tumor cell counts/ CD45(+)CD326(+) leukocyte counts in DAPI (+) FVS780(−) gated area. In 54 patients, the ratios of CD11b(+), CD4(+) and CD8(+) cells in CD45(+) leukocytes were evaluated in parallel.

Results

TLR of 69 patients with PM were significantly higher than those of 74 without PM (p < .001) and log(TLR) showed strong correlation with peritoneal cancer index scores in 51 PM (+) patients (r = 0.439). TLR in PM (+) patients also correlated with the ratio of CD11b (+) myeloid cells (r = 0.547), and correlated inversely with those of CD4(+) (r = −0.490) and CD8(+) T cells (r = −0.648). In PM (−) patients who underwent gastrectomy, TLR never exceeded 0.1% in patients with primary GC without serosal involvement (<T4). However, TLR in patients with T4 GC were significantly higher (p < .05) and peritoneal recurrence occurred in 6/8 patients whose TLR exceeded 0.1%.

Conclusion

TLR in peritoneal fluid reflects tumor burden and the immune environment in peritoneal cavity. Multicolor FCM may provide additional information which can be used for the treatment of the patients with PM.

Gastric Cancer with Radiographically Occult Metastatic Disease: Biology, Challenges, and Diagnostic Approaches

Gastric adenocarcinoma is an aggressive cancer that demonstrates heterogeneous biology depending on patient ethnicity, tumor location, tumor type, and genetic profile. It remains the third leading cause of cancer deaths worldwide and was estimated to result in 782,000 deaths in 2018. Challenges exist in accurately assessing the disease burden, as available radiological staging often underestimates metastatic disease. This diagnostic handicap, along with the poor understanding of the heterogeneous biology of gastric cancer, has hindered the development of effective therapeutic solutions and thus halted improvement in patient outcomes over the last few decades. The management of occult peritoneal disease is complicated, as most patients are understaged by standard imaging studies and therefore thought to have local diseases. In this article, we systematically review recent literature on the limitations that are associated with standard radiographic staging, discuss recent molecular biology advances to better identify and diagnose occult peritoneal disease, and propose possible management strategies to approach this complicated clinical problem.

Indication and Prognostic Significance of Conversion Surgery in Patients with Liver Metastasis from Gastric Cancer

OBJECTIVE

Chemotherapy is generally recommended as the first-line standard treatment in patients with liver metastasis from gastric cancer. However, the clinical impact of surgical treatment remains unclear in responders after chemotherapy. The present study aimed to investigate the tumor response and prognosis after chemotherapy and to assess the clinical indication of conversion surgery in responders.

METHODS

The study retrospectively reviewed the clinical data of 44 patients with liver metastasis from gastric cancer who were treated with chemotherapy between February 2002 and January 2019. These patients were classified into progressive disease (PD) and non-PD groups according to tumor response.

RESULTS

Among the 44 patients, 7 and 26 had peritoneal dissemination and ≥5 had metastatic liver nodules. Additionally, 15 and 29 patients had PD and non-PD, respectively. Surgical treatment was significantly correlated with tumor response (p < 0.0321). Prognostic differences between the PD and non-PD groups were significant (p < 0.0001). Moreover, gastrectomy and hepatectomy were significantly correlated with the number of liver metastases (≥5 vs. <5, respectively) in the non-PD group (p = 0.0025 and p = 0.0169, respectively). The 3-year survival rates among patients with non-PD undergoing both gastrectomy and hepatectomy (n = 6), gastrectomy alone (n = 7), and nonsurgical treatments (n = 16) were 100, 66.7, and 0%, respectively (p = 0.0026). Multivariate analysis identified peritoneal dissemination as an independent prognostic factor (p = 0.0225).

CONCLUSION

Our preliminary results suggest that conversion surgery for gastric cancer with liver metastasis might be clinically indicated in chemotherapy responders with <5 metastatic liver nodules and without peritoneal dissemination.

Intraperitoneal cancer-immune microenvironment promotes peritoneal dissemination of gastric cancer

A solid tumor consists of cancer and stromal cells, which comprise the tumor microenvironment (TME). Tumor-associated macrophages (TAMs) are usually abundant in the TME, contributing to tumor progression. In cases of peritoneal dissemination of gastric cancer (GC), the contribution of intraperitoneal TAMs remains unclear. Macrophages from peritoneal washings of GC patients were analyzed, and the link between intraperitoneal TAMs and GC cells was investigated to clarify the interaction between them in peritoneal dissemination. Macrophages were predominant among leukocytes constituting the microenvironment of the peritoneal cavity. The proportion of CD163-positive TAMs was significantly higher in stage IV than in stage I GC. Co-culture with TAMs potentiated migration and invasion of GC. IL-6 was the most increased in the medium of in vitro co-culture of macrophages and GC, and IL-6 elevation was also observed in the peritoneal washes with peritoneal dissemination. An elevated concentration of intraperitoneal IL-6 was correlated with a poor prognosis in clinical cases. In conclusion, intraperitoneal TAMs are involved in promoting peritoneal dissemination of GC via secreted IL-6. TAM-derived IL-6 could be a potential therapeutic target for peritoneal dissemination of GC.

The use of intraperitoneal chemotherapy for gastric malignancies

Introduction: Gastric cancer is the fourth/fifth most common malignancy worldwide, with only a quarter of patients achieving a 5-year survival rate. It has been estimated that 15-50% or more of patients have peritoneal disease upon surgical exploration. Until the early 1990s, peritoneal metastasis was considered as terminal stage of the disease; in the late 1990s, selected patients with peritoneal metastasis were recategorized as local disease. Over the past two decades, the treatment of peritoneal involvement has transformed, and cytoreductive surgery plus intraperitoneal therapy have drastically altered the natural course of several malignancies. Areas covered: We performed a review of studies available on PubMed from 1 January 2014 to 31 July 2019 and the analysis of their reference citations. We describe the most current intraperitoneal chemotherapy opportunities in the treatment of gastric cancer: hyperthermic intraoperative intraperitoneal chemotherapy (HIPEC), laparoscopic hyperthermic intraperitoneal chemotherapy (LHIPEC), neoadjuvant intraperitoneal and systemic chemotherapy (NIPS), LHIPEC + NIPS, extensive intraoperative peritoneal lavage (EIPL), early postoperative intraperitoneal chemotherapy (EPIC), and pressurized intraperitoneal aerosol chemotherapy (PIPAC). Expert opinion: Comprehensive treatment consisting of CRS combined with perioperative intraperitoneal/systemic chemotherapy can, today, be considered an effective strategy to improve the long-term survival of gastric cancer patients with peritoneal metastasis.

Calculation of a clinical predictive factors identifying peritoneal disease on a staging laparoscopy in gastric cancers

Introduction:

Staging laparoscopy (SL) is the current standard staging workup for loco-advanced gastric cancers (GCs). Materials and Methods: We analyzed the data of all patients with loco-regionally advanced, nonmetastatic GCs, who underwent SL for the evaluation of peritoneal carcinomatosis (PC).

Materials and Methods:

We analyzed the data of all patients with loco-regionally advanced, nonmetastatic GCs, who underwent SL for the evaluation of peritoneal carcinomatosis (PC).

Results:

Between December 2013 and October 2016, 363 patients underwent SL, of which 75 (20.7%) were found to have PC on SL. Age ≤40 years, CA 19-9 > upper limit of normal, and low serum albumin levels (≤3.5 g/dl) correlated significantly with the presence of PC on SL. There was a statistically significant difference in the median overall survival between patients with radiologically detected PC and SL detected PC (8.67 months vs. 15.3 months;P < 0.0001).

Conclusion:

SL upstaged disease status in 20.7% of patients. Clinical factors, identified in this study, need further validation in larger prospective cohorts before being used in clinical practice. Patients with radiologically detected PC have lower survival as compared to those with PC on SL.

Utilidad de la laparoscopia de estadificación frente a la tomografía axial computarizada para detectar metástasis peritoneales en el adenocarcinoma gástrico avanzado

  Introducción. El adenocarcinoma gástrico es una de las neoplasias más frecuentes. La tomografía computarizada abdominal con contraste es el método estándar para la estadificación; tiene una sensibilidad del 30 al 73 % y una especificidad del 83 al 100 %. La laparoscopia detecta hasta el 30 % de los casos de enfermedad metastásica que no se haya observado en los estudios de imágenes. En la Clínica Universitaria Colombia se realiza estadificación rutinaria con tomografía y laparoscopia más lavado peritoneal. Objetivos. Determinar la utilidad de la laparoscopia para detectar la carcinomatosis peritoneal en los pacientes con adenocarcinoma gástrico avanzado en un centro de referencia. Materiales y métodos. Se llevó a cabo un estudio descriptivo y retrospectivo, en el cual se analizaron todas las historias clínicas de los pacientes con cáncer gástrico atendidos en la Clínica Universitaria Colombia entre el 2013 y el 2016. Se confrontó el hallazgo de la laparoscopia con el de la tomografía abdominal, buscando falsos negativos para la enfermedad peritoneal. Resultados. Se incluyeron 94 pacientes con adenocarcinoma gástrico. La localización en el cuerpo gástrico fue la más frecuente (47,9 %). La tomografía reportó estadio T3 en el 56,4 %, N0 en el 55,3 % y M0 en el 97,9 % de los casos. La laparoscopia reportó estadio T3 en el 43,6 %, ganglios comprometidos en el 56,4 % y carcinomatosis peritoneal (M1) en el 11,7 %. Discusión. Un radiólogo experimentado detecta una gran proporción de las enfermedades peritoneales, pero la laparoscopia detecta hasta 11 % de aquellas que no son evidentes en los exámenes de imágenes. El lavado peritoneal no prolonga el tiempo quirúrgico ni incrementa la morbilidad, lo cual favorece su realización rutinaria. Se puede recomendar la laparoscopia en aquellos pacientes con resultados tomográficos negativos, evitando la cirugía cuando la neoplasia es irresecable. La laparoscopia tiene un impacto positivo en el manejo integral del cáncer gástrico, acorde con la literatura mundial.

The Morphological Analysis of Cells in the Peritoneal Washing Fluids of Patients with Gastric Cancer

The cytology of peritoneal washing fluids for gastric cancer is the most basic method for judging peritoneal micrometastasis. However, the clinical value of this method is not clear at present. A retrospective analysis was performed on 277 patients with pathologically proven and surgically treated gastric cancer. The peritoneal washing fluids were collected after opening the abdomen and before the operation, and were sent to the cytology laboratory for screening of occult cancer cells in the collected washing fluids. The number of cases diagnosed as cancer cells, reactive mesothelial cells, serosal balls, and traumatic mesothelial cells were 42, 18, 27, and 190, respectively. Typical adenocarcinoma cell nests were found in eight of 10 T4b samples, whereas 34 cases of cancer cells in T3 and T4a showed that these cell nests usually contained mesothelial cells, and the three-dimensional stereoscopic sense of the nests was not obvious. In the specific subcellular morphological changes of both reactive mesothelial cells and serosal balls, the changes of both the contour of nuclear membrane and the polarity of cell alignment were present only in stage T3 and T4a. The presence or absence of mesothelial cells in the nests of cancer cells and the changes of the contour of nuclear membrane and of the polarity of cell alignment in reactive mesothelial cells or serosal balls may help us to predict the depth of invasion of cancer cells.

Use of the term atypical cells in the reporting of ascitic fluid cytology: A caveat

Background

Abdominal paracentesis is a routine diagnostic procedure for assessment of patients with recent onset or worsening of ascites.

Objectives

The objective of the study is to (1) review clinically confirmed cases of malignancy with negative, atypical, and suspicious cytology reports and provide reasoning for discrepancies and (2) recalculate sensitivity, specificity, and predictive values after review.

Materials and Methods

Papanicolaou smears of ascitic fluid paracentesis samples received over one calendar year were reviewed retrospectively by an expert in cytopathology blinded to the final clinical and/or histopathological diagnoses. Cases with discrepancies after review were noted. Sensitivity, specificity, and predictive values were calculated before and after review of slides. Data were analyzed using SPSS version 16.

Results

Malignant etiology was identified in 49/115 cases (42.6%) with female genital tract being the most common site of malignancy (22, 44.8%). The remaining 66 (57.4%) had a benign etiology with hepatic cirrhosis in 42 cases (63.6%). A review revealed discrepancies in five cases, three of which were earlier called negative for malignant cells (one case each of ovarian adenocarcinoma, cecal adenocarcinoma, and cholangiocarcinoma). Two cases of ovarian adenocarcinoma that were reported as atypical/reactive mesothelial hyperplasia showed malignant cells upon review. Sensitivity and specificity after review were 69.4% and 100%, respectively, with 100% positive predictive value.

Conclusion

Being a minimally invasive procedure, abdominal paracentesis continues to be an important diagnostic tool in guiding patient management. A proper morphological assessment with adequate clinical information and correlation with other investigations can be used to arrive at a definitive diagnosis in most cases. The term "atypical" can be misleading and is often used for want of clinical information and is best avoided.

Detection of free intraperitoneal tumour cells in peritoneal lavage fluid from patients with peritoneal metastasis before and after treatment with pressurised intraperitoneal aerosol chemotherapy (PIPAC)

AIMS

In this study, we investigated whether free intraperitoneal tumour cells (FITC) were detectable in ascites or peritoneal lavage fluid (PLF) from patients with peritoneal metastasis (PM) before and after treatment with pressurised intraperitoneal aerosol chemotherapy (PIPAC).

METHODS

Ascites or PLF retrieved at the first and third PIPAC procedures was analysed by conventional cytology, carcinoembryonic antigen (CEA) and total protein concentration, and quantitative reverse transcriptase PCR (qRT-PCR) for mRNA expression of CEA, epithelial cell adhesion molecule (EpCAM) and cancer antigen 125 (CA-125). Conventional cytology and qRT-PCR were also performed in a negative control group (benign PLF specimens and inflammatory ascites). The treatment response was compared with the histological response based on repeated peritoneal biopsies evaluated by the Peritoneal Regression Grading Score (PRGS).

RESULTS

Thirty-five patients with PM of various origins were included from 2015 to 2016. At the first PIPAC procedure, FITC were detected by conventional cytology (sensitivity 0.58, specificity 1.00), CEA protein (cut-off 0.4 µg/L, sensitivity 0.71), CEA mRNA (sensitivity 0.75, specificity 1.00), EpCAM mRNA (sensitivity 0.71, specificity 1.00) and CA-125 mRNA (sensitivity 0.43, specificity 1.00). The combination of CEA/EpCAM mRNA had a sensitivity of 0.88 and a specificity of 1.00. The evaluation of ascites or PLF retrieved at the third PIPAC procedure failed to detect treatment response, when compared with the histological PRGS.

CONCLUSIONS

The evaluation of CEA and EpCAM mRNA detects FITC with a high sensitivity and an excellent specificity, but is not useful for response evaluation in patients treated with PIPAC.

TRIAL REGISTRATION NUMBER

NCT02320448.

Review and Update on the Role of Peritoneal Cytology in the Treatment of Gastric Cancer

BACKGROUND

Positive peritoneal cytology (Cyt+) even in the absence of macroscopic disease is associated with poor prognosis in patients with gastric cancer and deemed as M1 disease. Recent years have seen advancements in the evaluation strategies for peritoneal washings and management of patients with Cyt+. The aim of this review was to describe the newest paradigms in the management of patients with gastric cancer who have Cyt+ without macroscopic peritoneal metastases.

METHODS

A comprehensive literature review was performed to identify studies on the management of gastric cancer and thereby to summarize relevant information on the accuracy of various diagnostic tests and controversies involved in the treatment of patients with Cyt+.

RESULTS

Although conventional cytology remains the standard technique for assessment of peritoneal washings, it is limited by low sensitivity. The role of immunohistochemistry and molecular techniques for the assessment of peritoneal washings is evolving. Although systemic chemotherapy remains the standard of care for patients with Cyt+ disease, the role of gastrectomy, intraperitoneal chemotherapy, extensive intraperitoneal saline lavage, and hyperthermic intraperitoneal chemotherapy is being evaluated.

CONCLUSIONS

Clinical decision-making in patients with Cyt+ remains controversial given the seemingly technical resectable albeit biologically unresectable or aggressive disease that portends an overall poor prognosis. Current management strategies are evolving, and further studies are needed to develop an optimal treatment strategy for these patients.

Optimizing outcomes for patients with gastric cancer peritoneal carcinomatosis

Peritoneal carcinomatosis (PC) from gastric cancer has traditionally been considered a terminal progression of the disease and is associated with poor survival outcomes. Positive peritoneal cytology similarly worsens the survival of patients with gastric cancer and treatment options for these patients have been limited. Recent advances in multimodality treatment regimens have led to innovative ways to care for and treat patients with this disease burden. One of these advances has been to use neoadjuvant therapy to try and convert patients with positive cytology or low-volume PC to negative cytology with no evidence of active peritoneal disease. These strategies include the use of neoadjuvant systemic chemotherapy alone, using neoadjuvant laparoscopic heated intraperitoneal chemotherapy (NLHIPEC) after systemic chemotherapy, or using neoadjuvant intraperitoneal and systemic chemotherapy (NIPS) in a bidirectional manner. For patients with higher volume PC, cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) have been mainstays of treatment. When used together, CRS and HIPEC can improve overall outcomes in properly selected patients, but overall survival outcomes remain unacceptably low. The extent of peritoneal disease, commonly measured by the peritoneal carcinomatosis index (PCI), and the completeness of cytoreduction, has been shown to greatly impact outcomes in patients undergoing CRS and HIPEC. The uses of NLHIPEC and NLHIPEC plus NIPS have both been shown to decrease the PCI and thus increase the opportunity for complete cytoreduction. Newer therapies like pressurized intraperitoneal aerosol chemotherapy and immunotherapy, such as catumaxomab, along with improved systemic chemotherapeutic regimens, are being explored with great interest. There is exciting progress being made in the management of PC from gastric cancer and its' treatment is no longer futile.

Integrated fluorescent cytology with nano-biologics in peritoneally disseminated gastric cancer

Gastric cancer patients positive for peritoneal cytology are at increased risk of tumor recurrence, but although a certain proportion of cytology‐positive patients relapse rapidly with aggressive progression, others survive longer with conventional chemotherapies. This heterogeneity makes it difficult to stratify patients for more intensive therapy and poses a substantial challenge for the implementation of precision medicine. We developed a new approach to identify biologically malignant subpopulations in cytology‐positive gastric cancer patients, using a green fluorescent protein (GFP)‐expressing attenuated adenovirus in which the telomerase promoter regulates viral replication (TelomeScan, OBP‐401). The fluorescence emitted from TelomeScan‐positive cells was successfully quantified using a multi‐mode microplate reader. We then analyzed clinical peritoneal washes obtained from 68 gastric cancer patients and found that patients positive for TelomeScan had a significantly worse prognosis. In 21 cytology‐positive patients, the median survival time of those who were TelomeScan positive (235 days) was significantly shorter than that for those who were TelomeScan negative (671 days; P = 0.0062). This fluorescent virus‐guided cytology detects biologically malignant cancer cells from the peritoneal washes of gastric cancer patients and may thus be useful for both therapy stratification and precision medicine approaches based on genetic profiling of disseminated cells.

Surgery with curative intent for stage IV gastric cancer: Is it a reality of illusion?

Gastric cancer with metastases outside of the regional lymph nodes is deemed oncologically unresectable. Nevertheless, some metastatic lesions are technically resectable by applying established surgical techniques such as para-aortic lymphadenectomy and hepatectomy. At the time of compilation of the Japanese gastric cancer treatment guidelines version 4, systematic reviews were conducted to see whether it is feasible to make any recommendation to dissect both the primary and metastatic lesions with intent to cure, possibly as part of multimodality treatment. Long-term survivors were found among carefully selected groups of patients both in prospective and retrospective studies. In addition, there is a growing list of publications reporting encouraging outcomes of gastrectomy conducted after exceptionally good response to chemotherapy, usually among patients who underwent R0 resection. This type of surgery is often referred to as conversion surgery. It is sometimes difficult to define a clear borderline between curative surgery scheduled after neoadjuvant chemotherapy and the conversion surgery. This review summarizes what we knew after the literature reviews conducted at the time of compiling the Japanese guidelines and in addition reflects some new findings obtained thereafter through clinical trials and retrospective studies. Metastases were divided into three categories based on the major metastatic pathways: lymphatic, hematogenous, and peritoneal. In each of these categories, there were findings that could provide hope for patients with metastatic disease. These findings implied that the surgical technique that we already use could become more useful upon further developments in antineoplastic agents and drug delivery.

Adjuvant Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC) in resected high-risk colon cancer patients - study protocol for the PIPAC-OPC3 Trial. A prospective, controlled phase 2 Study

BACKGROUND

Peritoneal metastasis (PM) is the second most common site of recurrence in colon cancer (CC) patients and accounts for approximately one-third of all recurrences. Patients with T4 or intraperitoneal perforated colon cancers have an increased risk of developing PM, and since manifest PM is difficult to treat, high-risk patients should be offered prophylactic treatment. Here, we propose a study of adjuvant oxaliplatin administered as pressurized intraperitoneal aerosol chemotherapy (PIPAC OX) in patients with high-risk colon cancer (T4, perforated tumors, ovarian metastasis).

METHODS

PIPAC-OPC3 CC is a non-randomized, non-blinded phase 2 cohort study designed to treat high-risk colon cancer patients with adjuvant PIPAC-directed therapy. Based on an expected 90 % peritoneal recurrence-free survival with adjuvant PIPAC against the estimated 75 % without, 60 patients are needed (α: 0.05, power: 0.8). Eligible patients will receive two PIPAC treatments with oxaliplatin (92 mg/m2) at 4-6 week intervals. During laparoscopy, the peritoneum is biopsied at two locations, and peritoneal lavage with 500 mL of saline and laparoscopic ultrasound is performed. The patients are screened for adverse medical events and surgery-related complications after each PIPAC procedure. After the second PIPAC procedure, the patients will be examined in the outpatient clinic and followed with CT scans 12, 24 and 36 months after resection. The primary outcome of the PIPAC-OPC3 CC trial is to evaluate if PIPAC-directed adjuvant therapy can reduce the risk of PM. Secondary outcomes include the number of conversions from positive to negative peritoneal lavage cytology after one PIPAC procedure, completion rate of two adjuvant PIPAC treatments, toxicity and complication rate and recurrence-free and overall survival rates after 1, 3 and 5 years.

RESULTS

It is expected that PIPAC-directed adjuvant therapy can provide an absolute risk reduction of 15 % regarding the development of PM in high-risk colon cancer patients, and that this may result in increased survival rates. We expect that free intraperitoneal tumor cells (FITC) may be detected by peritoneal lavage performed just prior to the administration of PIPAC-directed therapy, and that this treatment may convert FITC-positive patients to a FITC-negative status.

CONCLUSIONS

This study may provide important knowledge to be used in designing additional studies on PIPAC in the adjuvant setting of other primary cancers.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT03280511 (2017-09-12). European Clinical Trials Database (EudraCT) 2017-002637-37.

Tumor exosome-mediated promotion of adhesion to mesothelial cells in gastric cancer cells

Background

Peritoneal metastasis consists of a highly complex series of steps, and the details of the underlying molecular mechanism remain largely unclear. In this study, the effects of tumor-derived exosomes (TEX) on the progression of gastric cancers were investigated in peritoneal metastasis.

Results

TEX were internalized in both mesothelial and gastric cancer cells in a cellular origin non-specific manner. Internalization of TEX into mesothelial cells promoted significant adhesion between mesothelial and gastric cancer cells, and TEX internalization into gastric cancer cells significantly promoted migratory ability, while internalization of mesothelial cell-derived exosomes did not. Expression of adhesion-related molecules, such as fibronectin 1 (FN1) and laminin gamma 1 (LAMC1), were increased in mesothelial cells after internalization of TEX from gastric cancer cell line and malignant pleural effusion.

Methods

TEX were extracted from cell-conditioned medium by ultracentrifugation. The effects of TEX on the malignant potential of gastric cancer were investigated in adhesion, invasion, and proliferation assays. PCR array as well as western blotting were performed to determine the underlying molecular mechanisms. The molecular changes in mesothelial cell after internalization of TEX derived from malignant pleural effusion were also confirmed.

Conclusions

TEX may play a critical role in the development of peritoneal metastasis of gastric cancer, which may be partially due to inducing increased expression of adhesion molecules in mesothelial cells.

Microscopic peritoneal carcinomatosis in gastric cancer: Prevalence, prognosis and predictive factors

Peritoneal carcinomatosis (PC) is typically identified in advanced stage gastric cancer and is frequently considered to be an incurable disease. Along with macroscopic PC, microscopic PC may be diagnosed through pathological examination of tissue specimens and is not detectable during surgical intervention. The present study aimed to analyse the prevalence, prognostic value and predictive factors for microscopic PC. In the present retrospective study, data from patients with epithelial gastric cancer that were treated with curative intent surgery were examined. Patients with macroscopic PC were excluded. Additionally, the study population was divided into two groups based on the presence or absence of microscopic PC. The prevalence of microscopic PC was 5.5%. Microscopic PC exhibited a significant negative effect on overall survival. In addition, multivariate analyses revealed that the significant predictive factors for the presence of microscopic PC were adenocarcinoma of a diffuse type, lymphatic and vascular invasion, cancer location at the site of previous gastric surgery and a tumour extent >T2. In particular, the presence of lymphatic and vascular invasion was the most significant predictive factor. These results indicate that ≥5.5% of patients with gastric cancer who undergo surgery with a curative intent may benefit from more aggressive loco-regional treatment against microscopic PC at the time of surgery.

Prognostic significance, diagnosis and treatment in patients with gastric cancer and positive peritoneal washings. A review of the literature

Peritoneal dissemination is a common consequence of a relapse following a radical surgical treatment of gastric cancer. The development of the disease in the peritoneum depends not only on its stage, but also on free cancer cells exfoliated from the tumor mass or from involved lymph nodes, and which are capable of being implanted in the peritoneum. According to the latest TNM (7 edition; 2010) classification, patients with free cancer cells in the peritoneal washings qualify for stage IV of the disease. Patients in whom free cancer cells were found during the operation - have a recurrence of gastric cancer - mainly in the peritoneum, and the majority of them die within two years of the diagnosis. To properly assess the prognosis, it is vital to determine the stage of cancer by additionally assessing the washings for the presence of free cancer cells before taking a therapeutic decision. This also allows identifying those patients who require different medical procedures to obtain the best treatment results possible. Medical literature describes various methods of examining peritoneal washings aimed at detecting free cancer cells. The methods apply different cancer cell detection rates, sensitivity and specificity in prediction of a peritoneal relapse. Oncological Departments performing the evaluation of the washings employ non-standard methods of treatment in this group of patients and the results presented are promising.

Phase II Trial of Laparoscopic Hyperthermic Intraperitoneal Chemoperfusion for Peritoneal Carcinomatosis or Positive Peritoneal Cytology in Patients with Gastric Adenocarcinoma

PURPOSE

The aim of this phase II study was to perform neoadjuvant hyperthermic intraperitoneal chemoperfusion (HIPEC) via a minimally invasive approach without cytoreduction for patients with gastric cancer and positive peritoneal cytology or low-volume peritoneal carcinomatosis.

METHODS

Patients with gastric or gastroesophageal adenocarcinoma and positive peritoneal cytology or radiologically occult peritoneal carcinomatosis after systemic chemotherapy received laparoscopic HIPEC with mitomycin C 30 mg and cisplatin 200 mg. Patients whose peritoneal disease resolved were offered gastrectomy. The primary endpoint was overall survival (OS), with secondary endpoints of HIPEC complications and gastrectomy rate.

RESULTS

We enrolled 19 patients (6 with positive peritoneal cytology only and 13 with peritoneal carcinomatosis) and treated them with 38 laparoscopic HIPEC procedures. Patients had received a median of 8 cycles (range 3-12) of systemic chemotherapy prior to enrollment. Fourteen patients were also treated with chemoradiotherapy before or between cycles of HIPEC. The complication rate for HIPEC was 11% (4 of 38 procedures), the 30-day mortality rate was 0%, and the median length of hospital stay after HIPEC was 3 days (range 2-6). Five patients went on to receive gastrectomy. The median follow-up was 18.9 months, the median OS from the date of diagnosis of metastatic disease was 30.2 months, and the median OS from the first laparoscopic HIPEC was 20.3 months.

CONCLUSIONS

Laparoscopic HIPEC was well tolerated, and an encouraging number of patients demonstrated an absence of peritoneal disease after HIPEC and were able to undergo gastrectomy. Comparative studies will be required to clarify survival benefits.

Greater Omental Milky Spot Examination for Diagnosis of Peritoneal Metastasis in Gastric Cancer Patients

OBJECTIVE

To evaluate the diagnostic value of cytological greater omental milky spot examination for the diagnosis of peritoneal metastasis in gastric cancer patients.

METHODS

A total of 136 patients diagnosed with gastric cancer and without distant metastasis were enrolled in our study. All patients underwent laparoscopy and CH40 suspension liquid dye of peritoneal lymph nodes preoperatively as well as ascites or peritoneal lavage fluid collections and excisions of marked greater omental milky spot tissues perioperatively.

RESULTS

According to the laparoscopic results, the patients were divided into T1-T2 stage (n = 56) without and into T3-T4 stage (n = 80) with tumor invasion into the serosal layer. Among the T1-T2-stage patients, tumor cells could be detected in peritoneal lavage fluids in 2 cases, whereas with greater omental milky spot examination, peritoneal metastasis was detected in 8 cases. Among the 80 cases in the T3-T4 stage, tumor cells could be detected in 28 cases via peritoneal lavage cytology and in 43 cases by greater omental milky spot examinations, and 4 cases had cancer cell infiltration also in nonmilky spot omental areas. The statistical analysis showed that the staging accuracy rate of exfoliative cytology examination was superior to that of the laparoscopic exploration (P < .05), but its sensitivity was significantly lower than that obtained with cytological greater omental milky spot examinations (P < .05).

CONCLUSIONS

The laparoscopic exploration could make a preliminary diagnosis of peritoneal metastasis via serosal layer invasion detection. For further analyses, cytological examinations of greater omental milky spots were more sensitive than exfoliative cytology.

Regional but fatal: Intraperitoneal metastasis in gastric cancer

Peritoneal carcinomatosis appears to be the most common pattern of metastasis or recurrence and is associated with poor prognosis in gastric cancer patients. Many efforts have been made to improve the survival in patients with peritoneal metastasis. Hyperthermic intraperitoneal chemotherapy remains a widely accepted strategy in the treatment of peritoneal dissemination. Several phase II-III studies confirmed that the combined cytoreducitve surgery and hyperthermic intraperitoneal chemotherapy resulted in longer survival in patients with peritoneal carcinomatosis. In addition, proper selection and effective regional treatment in patients with high risk of peritoneal recurrence after resection will further improve prognosis in local advanced gastric cancer patients.

Recent insights in the therapeutic management of patients with gastric cancer

Gastric cancer remains frequent and one of the most lethal malignancies worldwide. In this article, we aimed to comprehensively review recent insights in the therapeutic management of gastric cancer, with focus on the surgical and perioperative management of resectable forms, and the latest advances regarding advanced diseases. Surgical improvements comprise the use of laparoscopic surgery including staging laparoscopy, a better definition of nodal dissection, and the development of hyperthermic intraperitoneal chemotherapy. The best individualized perioperative management should be assessed before curative-intent surgery for all patients and can consists in perioperative chemotherapy, adjuvant chemo-radiation therapy or adjuvant chemotherapy alone. The optimal timing and sequence of chemotherapy and radiation therapy with respect to surgery should be further explored. Patients with advanced gastric cancer have a poor prognosis. Nevertheless, they can benefit from doublet or triplet chemotherapy combination, including trastuzumab in HER2-positive patients. Upon progression, second-line therapy can be considered in patients with good performance status. Although anti-HER2 (trastuzumab) and anti-VEGFR (ramucirumab) may yield survival benefit, anti-EGFR and anti-HGFR therapies have failed to improve outcomes. Nevertheless, combination regimens containing cytotoxic drugs and targeted therapies should be further evaluated; keeping in mind that gastric cancer biology is different between Asia and the Western countries.

Effect of intraperitoneal chemotherapy and peritoneal lavage in positive peritoneal cytology in gastric cancer. Systematic review and meta-analysis

INTRODUCTION

The most common cause of tumour progression in advanced gastric cancer is peritoneal carcinosis (PC). The necessity to increase the survival in advanced diseases suggested to deliver the chemotherapy directly in the peritoneal cavity also in Cy+/PC- and to experiment the effect of massive peritoneal lavage to wash out the tumour cells. The aim of this study is to investigate the gain in term of survival and peritoneal recurrence rate of the intraperitoneal chemotherapy and/or peritoneal lavage in patients with Cy+/PC-.

MATERIAL AND METHODS

A systematic review with meta-analysis of trials about the effect of intraperitoneal chemotherapy (IPC) and/or peritoneal lavage (PL) on positive cytology in gastric cancer without carcinosis.

RESULTS

Three trials have been included (164 patients: 76 received surgery alone, 51 surgery + IPC and 37 surgery + IPC + PL). Two- and five-years survival is increased by IPC (RR = 1.62, RR = 3.10). 2 and 5 years survival is further increased by IPC + PL (RR = 2.33, RR = 6.19). Peritoneal recurrence is reduced by IPC (OR = 0.45) and by IPC + PL (OR = 0.13).

CONCLUSIONS

Two- and five-years overall survival in patients with free cancer cells without carcinosis is incremented by intraperitoneal chemotherapy. Peritoneal lavage further increases these survival rates and also it further decreases the peritoneal recurrence rate.

Prognostic role of gastrectomy in patients with gastric cancer with positive peritoneal cytology

This retrospective study identified the optimal treatment strategy for patients with gastric cancer with positive peritoneal cytology. We analyzed clinicopathologic and survival data for 54 patients who had undergone gastrectomy and/or chemotherapy for treatment of gastric cancer with positive peritoneal cytology with (n = 40) or without (n = 14) metastatic disease. The median overall survival did not differ significantly between patients with gastric cancer with positive peritoneal cytology with and without metastatic disease (19 versus 13 months, respectively). Among 14 clinicopathologic variables, the lack of gastrectomy was the only significant independent unfavorable factor for survival (odds ratio, 1.64; 95% confidence interval, 1.04-2.57; P = 0.03). The median overall survival significantly differed among patients who had undergone gastrectomy plus chemotherapy, chemotherapy alone, and gastrectomy alone (25, 10, and 17 months, respectively; P < 0.01). Gastrectomy may be optimal for patients with (gastric cancer with positive peritoneal cytology), considering its favorable prognostic effect with respect to perioperative chemotherapy.