Single Patient Classifier Assay, Microsatellite Instability, and Epstein-Barr Virus Status Predict Clinical Outcomes in Stage II/III Gastric Cancer: Results from CLASSIC Trial

Investigating the relationship between Epstein-Barr virus infection and gastric cancer: A systematic review and meta-analysis

Background and Aims

Gastric cancer (GC) is a common cancer type worldwide, and various factors can be involved in its occurrence. One of these factors is Epstein-Barr virus (EBV) infection. In this regard, a systematic review and meta-analysis was conducted to achieve a better understanding of the EBV prevalence in GC samples.

Methods

English databases were searched and studies that reported the prevalence and etiological factors of EBV related to GC from July 2007 to November 2022 were retrieved. The reported data were selected based on the inclusion and exclusion criteria. The pooled prevalence of EBV infection with 95% confidence intervals was calculated. Quality assessment, heterogeneity testing, and publication bias assessment were also performed. The literature search showed 953 studies, of which 87 studies met our inclusion criteria and were used for meta-analysis.

Results

The pooled prevalence of EBV infection related to GC was estimated to be 9.5% (95% confidence interval [CI]: 8.2%-11%) in the general population. The prevalence of EBV infection related to GC by gender was 13.5% (95% CI: 11.1%-16.3%) in males and 7.6% (95% CI: 5.4%-10.6%) in females. No significant differences were observed in terms of geographical region. Out of the 87 studies included in the meta-analysis, the most common diagnostic test was in situ hybridization (58 cases).

Conclusions

Altogether, the results indicated that EBV infection is one of the important factors in the development of GC. However, this does not necessarily mean that EBV infection directly causes GC since other factors may also be involved in the development of GC. Therefore, it is recommended to conduct extensive epidemiological studies on various aspects of the relationship between this virus and GC, which can provide valuable information for understanding the relationship between EBV and GC.

Clinical outcomes of Epstein-Barr virus (EBV)-associated metastatic and locally advanced unresectable gastric cancers (GCs) in patients receiving first-line fluoropyrimidine and platinum (FP) doublet chemotherapy

BACKGROUND

Epstein-Barr virus-associated gastric cancer (EBVaGC) is a distinct molecular subgroup showing excellent outcomes after surgery for localized disease. Prominent immune cell infiltration in EBVaGC reflects the immunogenicity of Epstein-Barr virus (EBV) and, as suggested by some investigators, responsiveness to immune checkpoint inhibitors in the palliative setting. However, few data are available on the prevalence, clinical characteristics, and prognosis of EBVaGC patients receiving palliative cytotoxic chemotherapy.

METHODS

In this retrospective study, we identified 1061 patients with metastatic, recurrent, or locally advanced unresectable gastric cancer (GC) who started first-line fluoropyrimidine/platinum (FP) doublet chemotherapy with or without trastuzumab from January 2015 to August 2018. For 766 patients with available tumor tissue, the presence of EBV in cancer cells was evaluated by EBV-encoded RNA in situ hybridization and correlated with clinical characteristics and treatment outcomes.

RESULTS

Among the patients evaluated (n = 766), 40 (5.0%) were EBV-positive. EBVaGC was associated with male sex (p = 0.009) and lower neutrophil-lymphocyte ratio (NLR < 2.46, p = 0.03). Efficacy of first-line FP chemotherapy, in terms of response rate ad progression-free survival (PFS), did not differ between EBVaGC and EBV-negative GC (overall response rate: 53.8% vs. 51.8%, p = 0.99; median PFS: 6.4 vs. 6.7 months, p = 0.90). However, overall survival tended to be better with EBVaGC than EBV-negative GC (16.4 vs. 14.0 months, p = 0.07).

CONCLUSIONS

EBVaGC accounted for 5% of metastatic/unresectable GCs. While EBVaGC was not associated with better response to or PFS following first-line cytotoxic chemotherapy, it showed a trend toward better overall survival.

Molecular profile of gastric adenocarcinoma, relevant epidemiological factors - Systematic review and meta-analysis relating sex with Epstein-Barr virus and unstable microsatellites subtypes

INTRODUCTION

Gastric epithelial tumors exhibit morphological heterogeneity, diverse biological behaviors, and different oncopathological pathways. The Cancer Genome Atlas (TCGA) proposed a molecular classification of gastric adenocarcinomas based on genetic and molecular findings, which shows particular characteristics of diagnosis, prognosis, and indirectly, therapeutic alternatives. Within this classification, Epstein-Barr virus-positive (EBV+) and high microsatellite instability (MSI-H) subtypes stand out as subtypes that present a less aggressive biological behavior and a highly mutilated phenotype. This study conducted a systematic review with an emphasis on epidemiological and prognostic factors based on the molecular classification proposed by TCGA.

METHODS

A broad, comprehensive, and reproducible search with methodological rigor was conducted for study selection using the ROBINS-I and GRADEpro protocols and appropriate combinations of keywords.

RESULTS

A total of 25 studies were selected: six with a complete classification similar to TCGA and 19 with a distinction between MSI-H and EBV+. The application of meta-analysis calculations reinforces the prevalence of positive Epstein-Barr adenocarcinomas in males and high microsatellite instability in females, with a high level of certainty of evidence and low risk of bias in the analyzed studies due to the rigorous methods used.

CONCLUSION

The molecular classification proposed by TCGA shows limited dissemination, with MSI-H and EBV+ subtypes being the most researched, probably due to the benefit of the association with immunotherapies. However, the subclassification cannot be restricted to less than a quarter of the cases, and improvements in this aspect are urgent for the construction of knowledge on this important topic of global health.

Plasma EBV DNA as a prognostic factor in EBV associated gastric cancer: a multicenter, prospective study (EBV PRESAGE study)

Purpose

The Cancer Genome Atlas Research Network identified Epstein-Barr-Virus (EBV)-positive gastric cancer as a distinct molecular subtype. The prevalence is 8-9% and the histological examination shows pronounced lymphocytic infiltration, elevated levels of IFN-γ and consequently overexpression of PD-L1. The role of plasma EBV DNA load as a prognostic factor in patients with this cancer subtype is still to be defined.

Methods and analysis

The present multicenter prospective observational study "EBV PRESAGE", involving German and Italian cancer centers, aims to evaluate the prognostic role of plasma EBV DNA in EBV-related gastric cancer (GC). The objective is to study the association between plasma EBV DNA load at different consecutive time points and the patient's prognosis. Every patient with a new diagnosis of gastric cancer (including gastroesophageal junction adenocarcinoma) will be screened for Epstein-Barr encoded small Region (EBER) on tissue biopsies using in situ hybridization (ISH). If EBER ISH is positive, blood analysis for plasma EBV DNA will be conducted. The plasma EBV quantitative analysis will be centralized, and extraction, detection, and quantification of EBV DNA in plasma samples will be performed using real-time PCR.

Discussion

We hypothesized that plasma EBV DNA represents a non-invasive tool for monitoring EBV-related GC and might be valuable as a prognostic marker.

BMI trajectories, associations with outcomes and predictors in elderly gastric cancer patients undergoing radical gastrectomy: a prospective longitudinal observation study

OBJECTIVES

Elderly gastric cancer patients undergoing radical gastrectomy are prone to experience unexpected weight loss. Preoperative weight risk prediction may be a promising way to prevent weight loss and improve prognosis. The objectives of this study were to explore the BMI trajectory of elderly gastric cancer patients one year after surgery, evaluate theirs the association with outcomes, and explore their related predictors, so as to provide evidence for weight management and prognosis improvement.

METHODS

412 gastric cancer patients were included and recorded BMI at 6 time points. The trajectories of BMI were analyzed by growth mixture modeling, and the associations of BMI trajectories with outcomes as well as their predictors were investigated by regression models.

RESULTS

We identified 3 classes of BMI trajectories: the "slow-decreasing BMI", "rapid-decreasing BMI" and "maintaining BMI". Compared with class1, patients in class 2 were more likely to have a higher frequency of readmission within 1-year(β = 0.59, 95%CI: 0.29, 0.89, P < 0.001) and a higher rate of mortality within 1-year(β = 24.74, 95%CI: 9.60, 63.74, P < 0.001) ; patients in class 3 were more likely to have a higher quality of life (β=-10.46, 95%CI: -17.70, -3.22, P = 0.005) and fewer readmission times within one year (β=-0.43, 95%CI: -0.77, -0.09, P = 0.015). Predictors of decreasing BMI trajectories were TNM stage, comorbidity, anxiety, family cohesion and social support(P < 0.05).

CONCLUSIONS

Our findings can provide a basis for screening high-risk elderly gastric cancer patients with poor prognosis, implementing risk stratification, formulating accurate weight management programs and improving prognosis.

IMPLICATIONS FOR CANCER SURVIVORS

The results of our study can provide gastric cancer survivors with preoperative risk screening based on predictive factors so that nutritional support and weight management can be implemented in a timely manner to improve prognosis.

EBV and MSI Status in Gastric Cancer: Does It Matter?

We investigated the impactof microsatellite instability (MSI) and Epstein-Barr virus (EBV) status in gastric cancer (GC), regarding response to perioperative chemotherapy (POPChT), overall survival (OS), and progression-free survival (PFS). We included 137 cases of operated GC, 51 of which were submitted to POPChT. MSI status was determined by multiplex PCR and EBV status by EBV-encoded RNA in situ hybridization. Thirty-seven (27%) cases presented as MSI-high, and seven (5.1%) were EBV+. Concerning tumor regression after POPChT, no differences were observed between the molecular subtypes, but females were more likely to respond (p = 0.062). No significant differences were found in OS or PFS between different subtypes. In multivariate analysis, age (HR 1.02, IC 95% 1.002-1.056, p = 0.033) and positive lymph nodes (HR 1.82, IC 95% 1.034-3.211, p = 0.038) were the only prognostic factors for OS. However, females with MSI-high tumors treated with POPChT demonstrated a significantly increased OS compared to females with MSS tumors (p = 0.031). In conclusion, we found a high proportion of MSI-high cases. MSI and EBV status did not influence OS or PFS either in patients submitted to POPChT or surgery alone. However, superior survival of females with MSI-high tumors suggests that sex disparities and molecular classification may influence treatment options in GC.

Clinicopathologic and genomic characteristics of mucinous gastric adenocarcinoma

BACKGROUND

Mucinous gastric adenocarcinoma (MGC) is a rare but distinctive histologic subtype of gastric cancer (GC). The clinico-pathologic and genomic characteristics of MGC have not been well evaluated.

METHODS

We collected individual data from five cohorts targeting the microsatellite instability (MSI) of GC (n = 5089) to evaluate the clinico-pathologic characteristics of MGC. In addition, public genomic databases were used for genomic analysis. The characteristics of MGC were compared with those of non-mucinous GC (NMGC).

RESULTS

MGC (n = 158, 3.1%) showed distinctive characteristics in terms of age, sex, and TNM stage compared to NMGC (n = 4931). MGC was frequently associated with MSI-high (OR: 2.24, 95% confidence interval [CI] 1.44-3.40, p < 0.001), while mutually exclusive to the Epstein-Barr virus type. The prognosis of MGC was better than that of NMGC (adj.HR: 0.731, 95% CI 0.556-0.962, p = 0.025). There was no clear benefit from postoperative chemotherapy in MGC. TP53 was the main driver mutation in the MGC without recurrent variants. MGC was related to high expression of GPR120 and B3GNT6 and moderate regulation of epithelial-mesenchymal transition (EMT)-up signature with a high EMT-down signature, and those characteristics was related to favorable prognosis of GC (log-rank p = 0.044, p < 0.001, p < 0.001, respectively). MSI-H of MGC was associated with low cancer-associate fibroblasts but high CD274 (PD-L1) expression compared to microsatellite stable MGC, suggesting that immune checkpoint inhibitors may be useful for the MSI-H of MGC.

CONCLUSION

MGC could be a surrogate for performing MSI but not the EBV test in GC. Further, its genetic characteristics lead to a favorable prognosis for MGC.

Novel Biomarkers of Gastric Adenocarcinoma: Current Research and Future Perspectives

Simple Summary

Gastric cancer is characterized by poor survival rates despite surgery and chemotherapy. Current research focuses on biomarkers to improve diagnosis and prognosis, and to enable targeted treatment strategies. The aim of our review was to give an overview over the wide range of novel biomarkers in gastric cancer. These biomarkers are targets of a specific treatment, such as antibodies against human epidermal growth factor receptor 2. Other promising biomarkers for targeted therapies that have shown relevance in clinical trials are vascular endothelial growth factor, programmed cell death protein 1, and Claudin 18.2. There is a vast number of biomarkers based on DNA, RNA, and protein expression, as well as detection of circulating tumor cells and the immune tumor microenvironment.

Abstract

Overall survival of gastric cancer remains low, as patients are often diagnosed with advanced stage disease. In this review, we give an overview of current research on biomarkers in gastric cancer and their implementation in treatment strategies. The HER2-targeting trastuzumab is the first molecular targeted agent approved for gastric cancer treatment. Other promising biomarkers for targeted therapies that have shown relevance in clinical trials are VEGF and Claudin 18.2. Expression of MET has been shown to be a negative prognostic factor in gastric cancer. Targeting the PD-1/PD-L1 pathway with immune checkpoint inhibitors has proven efficacy in advanced gastric cancer. Recent technology advances allow the detection of circulating tumor cells that may be used as diagnostic and prognostic indicators and for therapy monitoring in gastric cancer patients. Prognostic molecular subtypes of gastric cancer have been identified using genomic data. In addition, transcriptome profiling has allowed a comprehensive characterization of the immune and stromal microenvironment in gastric cancer and development of novel risk scores. These prognostic and predictive markers highlight the rapidly evolving field of research in gastric cancer, promising improved treatment stratification and identification of molecular targets for individualized treatment in gastric cancer.

Single patient classifier as a prognostic biomarker in pT1N1 gastric cancer: Results from two large Korean cohorts

Objective

Benefits of adjuvant treatment in pT1N1 gastric cancer (GC) remain controversial. Additionally, an effective biomarker for early GC is the need of the hour. The prognostic and predictive roles of single patient classifier (SPC) were validated in stage II/III GC. In this study, we aimed to elucidate the role of SPC as a biomarker for pT1N1 GC.

Methods

The present retrospective biomarker study (NCT03485105) enrolled patients treated for pT1N1 GC between 1996 and 2012 from two large hospitals (the Y cohort and S cohort). For SPC, mRNA expression of four classifier genes (GZMB, WARS, SFRP4 and CDX1) were evaluated by real-time reverse transcription-polymerase chain reaction assay. The SPC was revised targeting pT1 stages and the prognosis was stratified as high- and low-risk group by the expression of SFRP4, a representative epithelial-mesenchymal transition marker.

Results

SPC was evaluated in 875 patients (n=391 and 484 in the Y and S cohorts, respectively). Among 864 patients whose SPC result was available, 41 (4.7%) patients experience GC recurrence. According to revised SPC, 254 (29.4%) patients were classified as high risk [123 (31.5%) and 131 (27.1%) in the Y and S cohorts, respectively]. The high risk was related to frequent recurrence in both Y and S cohort (log-rank P=0.023, P<0.001, respectively), while there was no difference byGZMB and WARS expression. Multivariable analyses of the overall-cohort confirmed the high risk of revised SPC as a significant prognostic factor [hazard ratio (HR): 4.402 (2.293−8.449), P<0.001] of GC. A significant difference was not detected by SPC in the prognosis of patients in the presence and absence of adjuvant treatment (log-rank P=0.670).

Conclusions

The present study revealed the revised SPC as a prognostic biomarker of pT1N1 GC and suggested the use of the revised SPC for early-stage GC as like stage II/III.

Development and validation of deep learning classifiers to detect Epstein-Barr virus and microsatellite instability status in gastric cancer: a retrospective multicentre cohort study

BACKGROUND

Response to immunotherapy in gastric cancer is associated with microsatellite instability (or mismatch repair deficiency) and Epstein-Barr virus (EBV) positivity. We therefore aimed to develop and validate deep learning-based classifiers to detect microsatellite instability and EBV status from routine histology slides.

METHODS

In this retrospective, multicentre study, we collected tissue samples from ten cohorts of patients with gastric cancer from seven countries (South Korea, Switzerland, Japan, Italy, Germany, the UK and the USA). We trained a deep learning-based classifier to detect microsatellite instability and EBV positivity from digitised, haematoxylin and eosin stained resection slides without annotating tumour containing regions. The performance of the classifier was assessed by within-cohort cross-validation in all ten cohorts and by external validation, for which we split the cohorts into a five-cohort training dataset and a five-cohort test dataset. We measured the area under the receiver operating curve (AUROC) for detection of microsatellite instability and EBV status. Microsatellite instability and EBV status were determined to be detectable if the lower bound of the 95% CI for the AUROC was above 0·5.

FINDINGS

Across the ten cohorts, our analysis included 2823 patients with known microsatellite instability status and 2685 patients with known EBV status. In the within-cohort cross-validation, the deep learning-based classifier could detect microsatellite instability status in nine of ten cohorts, with AUROCs ranging from 0·597 (95% CI 0·522-0·737) to 0·836 (0·795-0·880) and EBV status in five of eight cohorts, with AUROCs ranging from 0·819 (0·752-0·841) to 0·897 (0·513-0·966). Training a classifier on the pooled training dataset and testing it on the five remaining cohorts resulted in high classification performance with AUROCs ranging from 0·723 (95% CI 0·676-0·794) to 0·863 (0·747-0·969) for detection of microsatellite instability and from 0·672 (0·403-0·989) to 0·859 (0·823-0·919) for detection of EBV status.

INTERPRETATION

Classifiers became increasingly robust when trained on pooled cohorts. After prospective validation, this deep learning-based tissue classification system could be used as an inexpensive predictive biomarker for immunotherapy in gastric cancer.

FUNDING

German Cancer Aid and German Federal Ministry of Health.

Microsatellite Instability and Effectiveness of Adjuvant Treatment in pT1N1 Gastric Cancer: A Multicohort Study

BACKGROUND

Microsatellite status is a prognostic biomarker in advanced gastric cancer. This retrospective study aimed to investigate the usefulness of microsatellite status in predicting prognosis and response to adjuvant treatment in pT1N1 gastric cancer.

PATIENTS AND METHODS

Among 875 patients who underwent radical gastrectomy for pT1N1 gastric cancer at two tertiary hospitals, 838 with available microsatellite instability (MSI) data were included and classified into two groups according to microsatellite status: microsatellite stable (MSS) and MSI-high (MSI-H). Recurrence-free survival rate and risk factors for tumor recurrence were analyzed.

RESULTS

Of 838 gastric cancer patients, 100 (11.9%) were MSI-H and 307 (36.6%) received adjuvant treatment. During median follow-up of 70 months, 42 (5.0%) patients experienced gastric cancer recurrence; hematogenous recurrences were the most common (45.2%). Recurrence-free survival was similar in the MSS and MSI-H groups (p = 0.27), and adjuvant treatment did not show an oncological benefit over surgery alone for pT1N1 gastric cancer (p = 0.53). On univariate analysis, age, operation period, and Lauren classification were significantly associated with tumor recurrence, while adjuvant treatment and MSI status were not associated with tumor recurrence. On multivariate analysis, MSI status was not associated with tumor recurrence, and adjuvant treatment worsened the tumor recurrence risk [hazard ratio (HR) 2.373, 95% confidence interval (CI) 1.125-5.006, p = 0.023).

CONCLUSION

MSI status may not be a prognostic factor for tumor recurrence or a predictor of response to adjuvant treatment in pT1N1 gastric cancer patients. Considering that the effect of adjuvant treatment to decrease the risk of tumor recurrence is not clear, it may not be indicated in pT1N1 patients.

Clinical Significance of Tumor and Immune Cell PD-L1 Expression in Gastric Adenocarcinoma

BACKGROUND/AIM

The prognostic relevance of programmed cell death ligand-1 (PD-L1) protein expression in gastric cancer (GC) remains controversial. The aims of the present study were to determine the correlations between tumor cell (TC) and immune cell (IC) PD-L1 protein levels with prognosis, and to determine the correlation between PD-L1 expression and different molecular GC subtypes.

MATERIALS AND METHODS

TC and IC PD-L1 protein levels were measured in 286 GC patients. The patients were classified according to the Cancer Genome Atlas and Asian Cancer Research Group guidelines using immunohistochemistry and in situ hybridization.

RESULTS

TC and IC PD-L1 protein levels were positively correlated with patient survival. TC PD-L1 expression was negatively correlated with tumor grade. TC and IC PD-L1 expression was associated with improved prognosis in Epstein-Barr virus negative (EBV^-), microsatellite instability (MSI) rather than microsatellite stability (MSS) subgroup GC patients.

CONCLUSION

PD-L1 protein expression in TCs and ICs can be used as a prognostic indicator for GC patients, particularly in the EBV^-, MSI, and MSS subgroups.

Characterization and clinical evaluation of microsatellite instability and loss of heterozygosity in tumor-related genes in gastric cancer

Microsatellite instability (MSI) detection is widely used in the diagnosis and prognosis evaluation of colorectal cancer. However, for gastric cancer (GC), there is no standard panel of microsatellites (MSs) used in clinical guidance. The present study aimed to identify useful predictors of the clinical features and for the prognosis of GC, based on an investigation of MSI and loss of heterozygosity (LOH) in tumor-related genes. First, from 20 tumor-related genes which were proven to be important to the development of GC, 91 MSs were identified, and PCR amplification, short tandem repeat scanning analysis and TA clone sequencing were used to analyze MSI and LOH in the first set of 90 GC samples. Subsequently, the same method was used to detect the MSI/LOH of the optimized loci in the second set of 136 GC samples. MSI/LOH in the mismatch repair genes was highly consistent with that in oncogenes and tumor suppressor genes, respectively. The length of the core sequence was a main factor for the MSI/LOH rate. The MSI of 12 single loci was significantly associated with lymph node metastasis. The MSI in TP53-1 and the LOH in MGMT-10 were significantly associated with early stages of tumor infiltration depth. The LOH in MGMT-10, PTN-2 and MCC-17 was significantly associated with TNM stage. The LOH in TP53-1 and ERBB2-12 was associated with adenocarcinoma. The MSI/LOH in 6 single loci of 5 tumor-related genes was associated with poor prognosis of GC. The present study demonstrated that the MSI/LOH of loci in tumor-associated genes was associated with 4 clinicopathological characteristics and outcomes of GC. These results may provide potential specific biomarkers for the clinical prediction and treatment of GC.

Neoadjuvant and adjuvant multimodality therapies in resectable esophagogastric adenocarcinoma

Introduction: Gastric and esophageal adenocarcinoma is a leading cause of cancer-related death globally. Surgery is the cornerstone modality for cure where feasible. Clinical studies over the past two decades have provided evidence for the use of perioperative chemotherapy and chemoradiotherapy to improve patient outcomes. However, there remains no global consensus in the optimal use of these therapies.Areas covered: In this review, the authors summarize the latest evidence for perioperative multimodality therapy in resectable esophagogastric adenocarcinoma including the use of combination chemotherapy and targeted therapy containing regimens. In addition, the authors discuss some of the clinical and molecular biomarkers, such as PET imaging and microsatellite instability which can inform future practice and further clinical investigation.Expert opinion: A multimodal approach has been proven to improve survival outcomes over surgery alone. Whilst there is no global standard of care for multi-modality therapies in resectable OG cancer, clinical trials are refining the use of chemotherapy and radiotherapy in the neoadjuvant and adjuvant settings. Further investigation is on-going to further optimize therapy and the integration of molecular targeted agents.

Prognostic impact of microsatellite instability in gastric cancer

Gastric cancer is a common and deadly cancer. Several factors are associated with its prognosis; however, controversy exists about the role of microsatellite instability (MSI). We aimed to determine the 5-year overall survival (OS) of MSI in gastric adenocarcinoma. A cross-sectional study was carried out on gastric adenocarcinoma in clinical stages I to III treated with D2 gastrectomy between 2010-2013. MSI was demonstrated by immunohistochemistry. We performed a survival analysis comparing cases with and without MSI. From 102 cases, 9.8% showed MSI. The median age was 63 years (range 33-91 years), and 57.8% were men. The more prevalent site of occurrence was the antrum (46.1%), 78.5% of the cases presented in stage III, 47.1% were of the diffuse type, 45.1% were of an intestinal type, and 7.8% were mixed. MSI cases were associated with lower clinical stages (stages I-II) and with better 5-year OS (100 vs. 47 months, p = 0.017). In a multivariate analysis, MSI was independently associated with better survival (HR = 0.209, 95% CI: 0.046-0.945, p = 0.042). MSI gastric cancers presented in early clinical stages and had favourable prognosis compared with non-MSI cancers.

EBV-Positive Gastric Cancer: Current Knowledge and Future Perspectives

Gastric cancer is the fifth most common malignant tumor and second leading cause of cancer-related deaths worldwide. With the improved understanding of gastric cancer, a subset of gastric cancer patients infected with Epstein–Barr virus (EBV) has been identified. EBV-positive gastric cancer is a type of tumor with unique genomic aberrations, significant clinicopathological features, and a good prognosis. After EBV infects the human body, it first enters an incubation period in which the virus integrates its DNA into the host and expresses the latent protein and then affects DNA methylation through miRNA under the action of the latent protein, which leads to the occurrence of EBV-positive gastric cancer. With recent developments in immunotherapy, better treatment of EBV-positive gastric cancer patients appears achievable. Moreover, studies show that treatment with immunotherapy has a high effective rate in patients with EBV-positive gastric cancer. This review summarizes the research status of EBV-positive gastric cancer in recent years and indicates areas for improvement of clinical practice.

Clinical Behavior and Treatment Response of Epstein-Barr Virus-Positive Metastatic Gastric Cancer: Implications for the Development of Future Trials

BACKGROUND

Epstein-Barr virus (EBV)-positive gastric cancers (GCs) have been recently identified as a molecular subgroup showing excellent outcomes after surgery for early-stage disease and responsiveness to immune checkpoint inhibitors (ICIs) for metastatic stage. No data are available on the prevalence, clinical characteristics, and prognosis of this subgroup of GCs in the metastatic setting.

MATERIALS AND METHODS

In this cohort study, we assessed the impact of EBV status in patients with metastatic GC treated with chemotherapy at two Italian institutions.

RESULTS

Among the 175 cases analyzed, only 7 (4%) were EBV positive and all showed long-lasting and even complete responses to first-line chemotherapy with fluorouracil and platinum and a significantly better survival compared with EBV-negative patients (3-year overall survival: 80% vs. 20.1%; hazard ratio: 0.12).

CONCLUSION

If confirmed in larger data sets, our results may give a strong rationale for investigating the addition of ICIs to chemotherapy, in order to maximize the chance of achieving durable and complete responses in this uncommon subtype of GC.

IMPLICATIONS FOR PRACTICE

To date, no data are available on the prevalence and clinical characteristics of patients with Epstein-Barr virus (EBV)-positive metastatic gastric cancer (GC), a specific subtype of GC showing excellent outcomes after radical surgery in early-stage disease and responsiveness to immune checkpoint inhibitors (ICIs). This cohort study showed that patients with EBV-positive GC who did not receive ICIs had exceptional, long-lasting, and even complete responses to first-line chemotherapy with fluorouracil and platinum and a significantly better survival compared with EBV-negative patients. If confirmed in larger series, these results may give a strong rationale for investigating the combination of chemotherapy and ICIs to achieve durable and potentially complete response in this uncommon subtype of GC.

Clinicopathological Significance of EBV-Infected Gastric Carcinomas: A Meta-Analysis

Background and objectives: The present study aims to elucidate the clinicopathologic significance of Epstein-Barr virus (EBV) infection in gastric carcinomas (GCs) through a meta-analysis. Materials and Methods: Sixty-one eligible studies were included in the present meta-analysis. The included patients, with and without EBV infection, were 2063 and 17,684, respectively. We investigated the clinicopathologic characteristics and various biomarkers, including programmed death-ligand 1 (PD-L1) expression and tumor-infiltrating lymphocytes (TILs). Results: The estimated EBV-infected rate of GCs was 0.113 (95% confidence interval (CI): 0.088-0.143). The EBV infection rates in GC cells were 0.138 (95% CI: 0.096-0.194), 0.103 (95% CI: 0.077-0.137), 0.080 (95% CI: 0.061-0.106), and 0.042 (95% CI: 0.016-0.106) in the population of Asia, America, Europe, and Africa, respectively. There was a significant difference between EBV-infected and noninfected GCs in the male: female ratio, but not other clinicopathological characteristics. EBV infection rates were higher in GC with lymphoid stroma (0.573, 95% CI: 0.428-0.706) than other histologic types of GCs. There were significant differences in high AT-rich interactive domain-containing protein 1A (ARID1A) and PD-L1 expressions, and high CD8+ TILs between EBV-infected and noninfected GCs. Conclusions: Our results showed that EBV infection of GCs was frequently found in male patients and GCs with lymphoid stroma. EBV infection was significantly correlated with ARID1A and PD-L1 expressions and CD8+ TILs in GCs.

A Multi-cohort Study of the Prognostic Significance of Microsatellite Instability or Mismatch Repair Status after Recurrence of Resectable Gastric Cancer

PURPOSE

High microsatellite instability (MSI) is related to good prognosis in gastric cancer. We aimed to identify the prognostic factors of patients with recurrent gastric cancer and investigate the role of MSI as a prognostic and predictive biomarker of survival after tumor recurrence.

Materials and Methods

This retrospective cohort study enrolled patients treated for stage II/III gastric cancer who developed tumor recurrence and in whom the MSI status or mismatch repair (MMR) status of the tumor was known. MSI status and the expression of MMR proteins were evaluated using polymerase chain reaction and immunohistochemical analysis, respectively.

RESULTS

Of the 790 patients included, 64 (8.1%) had high MSI status or MMR deficiency. The tumor-node-metastasis stage, type of recurrence, Lauren classification, chemotherapy after recurrence, and interval to recurrence were independently associated with survival after tumor recurrence. The MSI/MMR status and receiving adjuvant chemotherapy were not associated with survival after recurrence. In a subgroup analysis of patients with high MSI or MMR-deficient gastric cancer, those who did not receive adjuvant chemotherapy had better treatment response to chemotherapy after recurrence than those who received adjuvant chemotherapy.

CONCLUSION

Patients with high MSI/MMR-deficient gastric cancer should be spared from adjuvant chemotherapy after surgery, but aggressive chemotherapy after recurrence should be considered. Higher tumor-node-metastasis stage, Lauren classification, interval to recurrence, and type of recurrence are associated with survival after tumor recurrence and should thus be considered when establishing a treatment plan and designing clinical trials targeting recurrent gastric cancer.

Global updates in the treatment of gastric cancer: a systematic review. Part 1: staging, classification and surgical treatment

Gastric cancer (GC) is the fifth malignancy and the third cause of cancer death worldwide, according to the global cancer statistics presented in 2018. Its definition and staging have been revised in the eight edition of the AJCC/TNM classification, which took effect in 2018. Novel molecular classifications for GC have been recently established and the process of translating these classifications into clinical practice is ongoing. The cornerstone of GC treatment is surgical, in a context of multimodal therapy. Surgical treatment is being standardized, and is evolving according to new anatomical concepts and to the recent technological developments. This is leading to a massive improvement in the use of mini-invasive techniques. Mini-invasive techniques aim to be equivalent to open surgery from an oncologic point of view, with better short-term outcomes. The persecution of better short-term outcomes also includes the optimization of the perioperative management, which is being implemented on large scale according to the enhanced recovery after surgery principles. In the era of precision medicine, multimodal treatment is also evolving. The long-time-awaited results of many trials investigating the role for preoperative and postoperative management have been published, changing the clinical practice. Novel investigations focused both on traditional chemotherapeutic regimens and targeted therapies are currently ongoing. Modern platforms increase the possibility for further standardization of the different treatments, promote the use of big data, and open new possibilities for surgical learning. This systematic review in two parts assesses all the current updates in GC treatment.

Clinical Implications of Microsatellite Instability in Early Gastric Cancer

Purpose

We aimed to evaluate the clinical characteristics of microsatellite instability in early gastric cancer.

Materials and Methods

The microsatellite instability status of resected early gastric tumors was evaluated using two mononucleotide repeat markers (BAT25 and BAT26) and three dinucleotide repeat markers (D5S346, D2S123, and D17S250). Tumors with instability in two or more markers were defined as microsatellite instability-high (MSI-H) and others were classified as microsatellite stable (MSS).

Results

Overall, 1,156 tumors were included in the analysis, with 85 (7.4%) classified as MSI-H compared with MSS tumors. For MSI-H tumors, there was a significant correlation with the female sex, older age, tumor location in the lower gastric body, intestinal histology, lymphovascular invasion (LVI), and submucosal invasion (P<0.05). There was also a trend toward an association with lymph node (LN) metastasis (P=0.056). In mucosal gastric cancer, there was no significant difference in MSI status in tumors with LN metastasis or tumors with LVI. In submucosal gastric cancer, LVI was more frequently observed in MSI-H than in MSS tumors (38.9% vs. 25.0%, P=0.027), but there was no difference in the presence of LN metastases. The prognosis of MSI-H tumors was similar to that of MSS tumors (log-rank test, P=0.797, the hazard ratio for MSI-H was adjusted by age, sex, pT stage, and the number of metastatic LNs, 0.932; 95% confidence interval, 0.423–2.054; P=0.861).

Conclusions

MSI status was not useful in predicting prognosis in early gastric cancer. However, the frequent presence of LVI in early MSI-H gastric cancer may help guide the appropriate treatment for patients, such as endoscopic treatment or limited LN surgical dissection.

Prognostic significance of body mass index and prognostic nutritional index in stage II/III gastric cancer

INTRODUCTION

Preoperative body weight and nutritional status are related to prognosis in patients with gastric cancer; however, the prognostic impact of postoperative in these variables is unclear. We aimed to investigate the association of preoperative/postoperative body mass index (BMI) and prognostic nutritional index (PNI) with prognosis in patients with gastric cancer.

MATERIALS AND METHODS

We retrospectively 1868 patients with stage II/III gastric cancer treated with gastrectomy between January 2006 and December 2010. We divided the populations into 3 groups according to BMI; underweight, normal, and overweight. Patients were divided into 3 groups according to BMI (underweight, normal-weight, overweight). PNI was classified into low and high (cutoff value; 49.7). The association of preoperative BMI/PNI and their changes (6 months postoperatively) with clinicopathologic characteristics were evaluated.

RESULTS

Preoperative underweight and low PNI were related to poor prognosis (log-rank p < 0.001 for both). There was a positive correlation between preoperative BMI and PNI (mean preoperative PNI: 51.13 [underweight], 53.37 [normal-weight], and 55.16 [overweight]; p < 0.001). Preoperative BMI and PNI were independent prognostic factors for disease-free survival along with age and TNM stage (p < 0.001 for both). BMI changes from normal-weight to underweight and from overweight to normal/underweight were related to poor prognosis (log-rank p = 0.021 and p = 0.013, respectively). PNI changes were related to prognosis in both the preoperative low and high PNI groups (p < 0.001 and p = 0.019, respectively).

CONCLUSION

Preoperative BMI and PNI and their postoperative changes are related to prognosis in patients with stage II/III gastric cancer. Careful nutritional intervention after gastrectomy can improve prognosis.

Clinical and molecular prognostic markers of survival after surgery for gastric cancer: tumor-node-metastasis staging system and beyond

For accurately predicting prognosis and for effectively describing cancer states at a certain point during treatment to other care providers and patients, various staging systems have been utilized in gastric cancer. Among these, the UICC/AJCC tumor-node-metastasis (TNM) staging system is most widely used. However, even within the same substage, gastric cancers can vary substantially in regards to prognosis after treatment. For more accurate and individualized prognostication, staging systems have been found to benefit from including molecular markers and genomic subtypes, in addition to clinicopathological parameters, such as age, sex, tumor size, tumor location, Lauren classification, number of lymph nodes resected, extent of surgical resection, lymphovascular invasion, and adjuvant chemotherapy. In this review article, we review and summarize relevant biomarkers for gastric cancer that can be incorporated into the current anatomy-based TNM staging system, as well as results from validation studies thereof.

Prognostic and Predictive Factors for the Curative Treatment of Esophageal and Gastric Cancer in Randomized Controlled Trials: A Systematic Review and Meta-Analysis

BACKGROUND

An overview of promising prognostic variables and predictive subgroups concerning the curative treatment of esophageal and gastric cancer from randomized controlled trials (RCTs) is lacking. Therefore, we conducted a systematic review and meta-analysis.

METHODS

PubMed, EMBASE, CENTRAL, and ASCO/ESMO conferences were searched up to March 2019 for RCTs on the curative treatment of esophageal or gastric cancer with data on prognostic and/or predictive factors for overall survival. Prognostic factors were deemed potentially clinically relevant according to the following criteria; (1) statistically significant (p < 0.05) in a multivariate analysis, (2) reported in at least 250 patients, and (3) p < 0.05, in ≥ 33% of the total number of patients in RCTs reporting this factor. Predictive factors were potentially clinically-relevant if (1) the p-value for interaction between subgroups was <0.20 and (2) the hazard ratio in one of the subgroups was significant (p < 0.05).

RESULTS

For gastric cancer, 39 RCTs were identified (n = 13,530 patients) and, for esophageal cancer, 33 RCTs were identified (n = 8618 patients). In total, we identified 23 potentially clinically relevant prognostic factors for gastric cancer and 16 for esophageal cancer. There were 15 potentially clinically relevant predictive factors for gastric cancer and 10 for esophageal cancer.

CONCLUSION

The identified prognostic and predictive factors can be included and analyzed in future RCTs and be of guidance for nomograms. Further validation should be performed in large patient cohorts.

Ten Thousand Consecutive Gastrectomies for Gastric Cancer: Perspectives of a Master Surgeon

As radical gastrectomy with lymph node dissection is currently the best strategy to cure gastric cancer, the role of the surgeon remains quite important in conquering it. Dr. Sung Hoon Noh, a surgeon and surgical oncologist specializing in gastric cancer, has treated gastric cancer for 30 years and has conducted over 10000 cases of gastrectomy for gastric cancer. He first adapted an electrocautery device into gastric cancer surgery and has led standardization of surgical procedures, including spleen preserving gastrectomy. His procedures based on patient-oriented insights have become the basis of the concept of enhanced recovery after surgery. He has also contributed to improving patient's survival through adoption of a multidisciplinary approach: he proved the benefit of adjuvant chemotherapy after radical D2 gastrectomy for stage II/III gastric cancer in clinical trials, updating treatment guidelines throughout the world. Dr. Noh also opened the era of precision medicine for treating gastric cancer, as he developed and validated a mRNA expression based algorithm to predict prognosis and response to chemotherapy. This article reviews his contribution and long history of service in the field of gastric cancer. The perspectives of this master surgeon, based on his profound experience and insights, will outline directions for integrative multidisciplinary health care and how can surgeons prepare for the future.