The difference in gastric cancer between Japan, USA and Europe: what are the facts? what are the suggestions?

Cluster classification of a Brazilian gastric cancer cohort reveals remarkable populational differences in normal p53 rate

BACKGROUND

Queiroz et al. showed that the application of cluster methodology for classifying gastric cancer is suitable and efficient within a Brazilian cohort, which is known for its population heterogeneity. The study highlighted the potential utilization of this method within public health services due to its low-cost, presenting a viable means to improve the diagnosis and prognosis of gastric cancer.

BACKGROUND

Our Brazilian cohort with gastric cancer has a distinct distribution between mutated and normal p53.

BACKGROUND

New genetic marker-based classifications improve gastric cancer diagnosis accuracy.

BACKGROUND

Machine learning integration enhances predictive value in gastric cancer diagnosis.

BACKGROUND

Molecular biomarkers complement clinical decisions, advancing personalized medicine.

OBJECTIVE

Gastric adenocarcinoma remains an aggressive disease with a poor prognosis, as evidenced by a 5-year survival rate of approximately 31%. The histological classifications already proposed do not accurately reflect the high biological heterogeneity of this neoplasm, particularly in diverse populations, and new classification systems using genetic markers have recently been proposed. Following these newly proposed models, we aimed to assess the cluster distribution in a Brazilian cohort. Furthermore, we evaluated whether the inclusion of other clinical and histological parameters could enhance the predictive value.

METHODS

We used a previously described four-immunohistochemistry/EBER-ISH marker to classify a cohort of 30 Brazilian patients with gastric adenocarcinoma into five different clusters and compared the distribution with other genetically diverse populations. Furthermore, we used artificial intelligence methods to evaluate whether other clinical and pathological parameters could improve the results of the methodology.

RESULTS

Disclosing the genetic variability between populations, we observed a more balanced distribution of the aberrant/normal p53 ratio (0.6) between patients negative for the other markers tested, unlike previous studies with Asian and North American populations. In addition, decision tree analysis reinforced the efficiency of these new classifications, as the stratification accuracy was not altered with or without additional data.

CONCLUSION

Our study underscores the importance of local research in characterizing diverse populations and highlights the complementary role of molecular biomarkers in personalized medicine for gastric adenocarcinoma, enhancing diagnostic accuracy and potentially improving survival rates.

Comparison of different treatment strategies for T3N1-3 stage gastric cancer based on the SEER database

Treatment options for T3N1 stage gastric cancer exhibit regional variation, with optimal approach remaining unclear. We derived our data from the SEER database, using Cox proportional risk regression models for univariate and multivariate analyses of 5-years overall survival (5yOS) and 5-years cancer-specific survival (5yCSS). The results showed that younger age, female, non-white race, highly differentiated histologic grade, non-Signet ring cell adenocarcinoma, low N stage, lesser curvature of the stomach, OP followed by adjuvant C/T with or without RT, partial gastrectomy, C/T and others, Radiation therapy, and Chemotherapy were significantly associated with better 5yOS and 5yCSS. For patients with stage T3N1-3 gastric cancer, multimodal treatment regimens demonstrate superior survival outcomes compared to surgery or radiotherapy alone. Among them, OP followed by adjuvant C/T with or without RT emerges as particularly efficacious, potentially offering enhanced benefits for non-Asian populations.

Comprehensive assessment of immune context and immunotherapy response via noninvasive imaging in gastric cancer

BACKGROUNDThe tumor immune microenvironment can provide prognostic and therapeutic information. We aimed to develop noninvasive imaging biomarkers from computed tomography (CT) for comprehensive evaluation of immune context and investigate their associations with prognosis and immunotherapy response in gastric cancer (GC).METHODSThis study involved 2,600 patients with GC from 9 independent cohorts. We developed and validated 2 CT imaging biomarkers (lymphoid radiomics score [LRS] and myeloid radiomics score [MRS]) for evaluating the IHC-derived lymphoid and myeloid immune context respectively, and integrated them into a combined imaging biomarker [LRS/MRS: low(-) or high(+)] with 4 radiomics immune subtypes: 1 (-/-), 2 (+/-), 3 (-/+), and 4 (+/+). We further evaluated the imaging biomarkers' predictive values on prognosis and immunotherapy response.RESULTSThe developed imaging biomarkers (LRS and MRS) had a high accuracy in predicting lymphoid (AUC range: 0.765-0.773) and myeloid (AUC range: 0.736-0.750) immune context. Further, similar to the IHC-derived immune context, 2 imaging biomarkers (HR range: 0.240-0.761 for LRS; 1.301-4.012 for MRS) and the combined biomarker were independent predictors for disease-free and overall survival in the training and all validation cohorts (all P < 0.05). Additionally, patients with high LRS or low MRS may benefit more from immunotherapy (P < 0.001). Further, a highly heterogeneous outcome on objective response ​rate was observed in 4 imaging subtypes: 1 (-/-) with 27.3%, 2 (+/-) with 53.3%, 3 (-/+) with 10.2%, and 4 (+/+) with 30.0% (P < 0.0001).CONCLUSIONThe noninvasive imaging biomarkers could accurately evaluate the immune context and provide information regarding prognosis and immunotherapy for GC.

Immunotherapy for advanced gastric cancer

Gastric cancer (GC) is believed to be the fifth most common cancer and the third most common cause of death worldwide. Treatment techniques include radiation, chemotherapy, gastrectomy, and targeted treatments are often employed. Some hopeful results from the development of GC immunotherapy have already changed treatment approaches. Along with previous combination medicines, new immunotherapies have been developed that target distinct molecules. Despite ongoing studies into the current therapeutic options and significant improvements in this field, the prognosis for the ailment is poor. Since there are few treatment options and a delay in detection, the illness actually advances, spreads, and metastasizes. The bulk of immunotherapies in use today rely on cytotoxic immune cells, monoclonal antibodies, and gene-transferred vaccines. Immune checkpoint inhibitors have become more popular. In this review, we sought to examine the viewpoint and development of several immunotherapy treatment modalities for advanced GC, as well as the clinical results thus far reported. Additionally, we outlined tumor immune escape and tumor immunosurveillance.

History and Future of HER2-Targeted Therapy for Advanced Gastric Cancer

Human epidermal growth factor receptor 2 (HER2) is a receptor tyrosine kinase that belongs to the human epidermal growth factor receptor family. It is overexpressed/amplified in approximately 20% of gastric or gastroesophageal junction cancers. HER2 is being developed as a therapeutic target in a variety of cancers, and several agents have been shown to be effective in breast cancer. The development of HER2-targeted therapy for gastric cancer successfully began with trastuzumab. However, while effective in breast cancer, the successive anti-HER2 agents lapatinib, T-DM1, and pertuzumab failed to demonstrate benefits regarding survival in gastric cancer compared with the existing standard therapies. Intrinsic differences lie between gastric and breast cancer in terms of HER2-positive tumor biology, which may make development difficult. Recently, a novel anti-HER2 agent, trastuzumab deruxtecan, was introduced, and the development of HER2-positive gastric cancer agents has been moving to the next stage. This review summarizes the current HER2-targeted therapy for gastric or gastroesophageal cancer in chronological order and describes the promising future of HER2-targeted therapy.

Immunohistochemical Analysis of Nicotinamide Phosphoribosyltransferase Expression in Gastric and Esophageal Adenocarcinoma (AEG)

Nicotinamide phosphoribosyltransferase (NAMPT) represents a major component in cellular energy metabolism, which is also crucial for cancer cells that have elevated aerobic glycolysis; moreover, targeting the NAD salvage pathway by inhibition of NAMPT was shown effective in a subgroup of gastric cancer cell lines. In order to study the expression levels of NAMPT in adenocarcinoma of the esophagogastric junction and stomach (AEG/S) we performed immunohistochemical analysis in a cohort of 296 tumor samples using tissue-microarrays (TMAs). In the present investigation, we saw a high expression of NAMPT in only a minority of our large AEG/S cohort. Although we did not find a correlation between NAMPT expression and survival, subgroup analysis showed that NAMPT expression was more frequent in older patients (>65 years, p = 0.049) and was associated with a numerical shorter survival that did not reach statistical significance within this age group. In conclusion, we did not find significance for any prognostic effect of NAMPT in our AEG/S cohort; however, the evaluation of other NAD metabolic enzymes is needed as molecular predictors of response to potential NAMPT inhibition in the treatment of patients with AEG/S.

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.

Retrieval of 30 Lymph Nodes Is Mandatory for Selected Stage II Gastric Cancer Patients

Background

According to the 8th edition AJCC staging manual, a least of 16 lymph nodes retrieval (LNRs) is the minimal requirement for lymph nodes (LNs) dissection of gastric cancer surgery. Previous studies have shown that increasing the number of LNRs (≥30) prolongs survival for selected patients. However, the necessity of retrieving 30 or more LN for stage II gastric cancer patients is still under debate.

Aim

This study aims to explore the impact of retrieving 30 or more lymph nodes on the survival of stage II cancer patients.

Methods

A total of 1,177 patients diagnosed with stage II gastric cancer were enrolled in this study. The clinicopathological parameters and the impact of different LNRs (<30 or ≥30) and positive lymph node ratio (NR) on overall survival (OS) were retrospectively analyzed.

Results

The mean number of LNRs was 34 ± 15. A total of 44% (518/1,177) of patients had an LNRs <30, while 56% (659/1,177) of patients had an LNRs ≥30. The 5-year survival rate was 81% for all patients, 76% for the LNRs <30 group, and 86% for LNRs ≥30 group, respectively (P = 0.003). The survival benefit of retrieving 30 lymph nodes was significant in certain subgroups: age >60 years/male/underwent total gastrectomy/stage IIB. For N+ patients, higher NR was significantly correlated with poor survival.

Conclusion

The survival benefit of retrieving 30 LNs varies in different subgroups. An LNRs of 30 is mandatory for selected stage II gastric cancer patients.

Involvement of APRIL in Helicobacter pylori-related gastric cancer

BACKGROUND/AIMS

A proliferation-inducing ligand (APRIL, also known as TNFSF13, CD256) is a member of the tumor necrosis factor (TNF) superfamily and involved in a diverse set of diseases. In this work, we explored the potential associations and underlying mechanism in patients suffered from gastric cancer between the expression of APRIL and H. pylori infection.

METHODS

We analyzed APRIL expression levels in 200 GC tissue samples by immunohistochemistry staining. H. pylori infection was detected by modified Giemsa staining. The biological effects of APRIL on human GC cells in vitro and in vivo were tested by CCK-8 assay, colony formation, flow cytometry detection, transwell migration assay, matrigel invasion assay, and tumor xenograft assay in animals.

RESULTS

APRIL reactivity was positively correlated with H. pylori infection in vitro and vivo. It turned out that the decrease of miR-145 expression was dose-dependent and time-dependent on H. pylori infection and in consistent with APRIL expression. MiR-145 significantly attenuated the effect of H. pylori infection on APRIL gene expression in SGC7901 and BGC823 cell lines. Furthermore, APRIL overexpression promoted the proliferation, migration, invasion, and transfer of GC cells and decreased apoptosis, while APRIL knockdown suppressed these effects. We confirmed that APRIL activated the canonical NF-κB pathway through phosphorylation of AKT.

CONCLUSION

The expression of APRIL, which promoted the proliferation, migration, invasion, viability, and metastasis of GC cells, was upregulated in human H. pylori-infected GC through miR-145. Besides, APRIL-induced gastric tumorigenicity via activating NF-κB pathway. These results may provide a framework for the deeper analysis of APRIL in GC risk and prognosis.

Multidisciplinary team consultation for resectable Gastric Cancer: A propensity score matching analysis

Purpose: Previous studies proposed that the multidisciplinary team (MDT) consultation could improve tumor staging accuracy and outcomes of patients with gastric malignancy. However, evidence-based reports remain limited. This study aimed to determine the effectiveness of MDT for tumor staging accuracy and outcomes of patients with resectable gastric cancer, and to explore the potential factors affecting its effectiveness. Methods: This retrospective study enrolled 719 gastric cancer patients who underwent gastrectomy in our hospital. After propensity score matching, 378 patients were selected, including 189 in the non-MDT group and 189 in the MDT group. Data regarding baseline characteristics, staging, treatments, and survival were analyzed. Results: The data showed that the staging accuracy in the MDT group and non-MDT group was comparable (53% vs 61% for T stage, 46.1% vs 35.3% for N stage, and 78.3% vs 78.7% for M stage). The MDT group had a higher proportion of preoperative chemotherapy (39.2% vs 28%, p=0.03) and laparoscopic surgery (82.5% vs 72%, p=0.02) than the non-MDT group. However, the achievement of R0 resection was similar in the two groups (93.7% vs 88.9%, p=0.73). There was no significant difference in the 1-year and 3-year overall survival rates between the two groups. Moreover, we observed poor patient compliance when the MDT recommended further examinations, radiotherapy, or chemotherapy before surgical interventions. Conclusion: MDT consultation has limited effects on improving the staging accuracy and treatment outcomes including survival of patients with resectable gastric cancer. Poor patient compliance may be a factor affecting the effectiveness of MDT consultation.

Quality of Life Associated with Ramucirumab Treatment in Patients with Advanced Gastric Cancer in Japan: Exploratory Analysis from the Phase III RAINBOW Trial

BACKGROUND AND OBJECTIVE

Gastric cancer has been associated with notable geographic heterogeneity in previous multi-regional studies. In particular, patients from Japan have better outcomes compared with patients from other regions. Here, we assess patient-focused outcomes for the subgroup of Japanese patients in the global RAINBOW study.

METHODS

Quality of life (QoL) was assessed using the European Organization for Research and Treatment of Cancer Quality-of-Life Questionnaire-Core 30 (QLQ-C30) at baseline and 6-week intervals. Investigators assessed performance status before each 4-week cycle. Time-to-deterioration in each QLQ-C30 scale was defined as randomization to first worsening of ≥ 10 points (on a 100-point scale). Time-to-deterioration in performance status was defined as first worsening to ≥ 2. Hazard ratios were estimated using Cox proportional hazards models.

RESULTS

The Japan subgroup contained 140 patients (ramucirumab plus paclitaxel, n = 68; placebo plus paclitaxel, n = 72); baseline QoL data were available for all patients. At baseline, QLQ-C30 scores were similar between study arms. Of the 15 QLQ-C30 scales, nine had a hazard ratio < 1, indicating similar or numerically longer time-to-deterioration in QoL for ramucirumab plus paclitaxel; all 95% confidence intervals included 1. Best mean change from baseline numerically favored ramucirumab plus paclitaxel in most QoL scales. The hazard ratios for time-to-deterioration of performance status to ≥ 2 were 0.64 in the Japan subgroup and 0.88 in the non-Asian subgroup. The Japan subgroup had better QoL at baseline compared with the non-Asian subgroup.

CONCLUSIONS

Treatment with ramucirumab plus paclitaxel maintained QoL and performance status over time compared with placebo plus paclitaxel in the Japan subgroup of the RAINBOW trial. These data suggest that the heterogeneity in gastric cancer between geographic regions includes multiple measures of QoL.

TRIAL REGISTRATION NUMBER

NCT01170663 (first submitted 21 July, 2010).

A Molecular Stratification of Chilean Gastric Cancer Patients with Potential Clinical Applicability

Gastric cancer (GC) is a complex and heterogeneous disease. In recent decades, The Cancer Genome Atlas (TCGA) and the Asian Cancer Research Group (ACRG) defined GC molecular subtypes. Unfortunately, these systems require high-cost and complex techniques and consequently their impact in the clinic has remained limited. Additionally, most of these studies are based on European, Asian, or North American GC cohorts. Herein, we report a molecular classification of Chilean GC patients into five subtypes, based on immunohistochemical (IHC) and in situ hybridization (ISH) methods. These were Epstein-Barr virus positive (EBV+), mismatch repair-deficient (MMR-D), epithelial to mesenchymal transition (EMT)-like, and accumulated (p53+) or undetected p53 (p53-). Given its lower costs this system has the potential for clinical applicability. Our results confirm relevant molecular alterations previously reported by TCGA and ACRG. We confirm EBV+ and MMR-D patients had the best prognosis and could be candidates for immunotherapy. Conversely, EMT-like displayed the poorest prognosis; our data suggest FGFR2 or KRAS could serve as potential actionable targets for these patients. Finally, we propose a low-cost step-by-step stratification system for GC patients. To the best of our knowledge, this is the first Latin American report on a molecular classification for GC. Pending further validation, this stratification system could be implemented into the routine clinic.

Clinical and pathological staging of gastric cancer: Current perspectives and implications

Accurate categorization of invasive depth and lymph node metastasis or optimization of TNM categories is fundamentally critical for prognostic assessment and decision making regarding subsequent therapies after surgery for gastric cancer. Improving the precision of the TNM staging is the ongoing goal. The evolution of the staging system indicates that there is no "ideal staging". Every update has criticized the lack of a standard approach for the stages to date. T staging depends on the accurate determination of the depth of infiltration based on pathological continuous sections. N staging is susceptible to the influence of lymph node detection, and insufficient lymph node detection can lead to N staging migration. M staging is required to improve the detection rate of peritoneal positive free cancer cells to determine the high risk factors of peritoneal metastasis. At present, the quality of standardized pathological diagnosis of gastric cancer requires improvement. Based on a review of the literature and experience from multiple gastric cancer centers, we present a new development in TNM staging and a way to improve clinical and pathological quality control of gastric cancer.

Multidisciplinary Approach in Improving Survival Outcome of Early-Stage Gastric Cancer

BACKGROUND

The necessity of extensive lymph node (LN) dissection/examination and adjuvant therapy for patients with early gastric cancer (EGC, Tis-T1, any N) remains controversial. We aim to refine treatment recommendations for patients with EGC through a reflective analysis for the survival gap between Eastern and Western countries.

METHODS

EGC patients diagnosed between 2004 and 2014 were identified from the National Cancer Database (NCDB) and a large medical center in China. Adequate LN yield was defined as ≥25 LNs examined.

RESULTS

In the US cohort, 14.4% of (1104/7641) patients with EGC had ≥25 LNs examined. The 5-y overall survival (OS) was significantly better than those with <25 LNs (78.9% versus 68.5%, P < 0.001). Examination of ≥25 LNs was an independent predictor of better OS after adjusting all known prognostic factors. Patients with ≥25 LNs examined had significantly higher chance of having LN-positive disease compared to patients with <25 LNs (14.9% versus 10.7%, P < 0.001). A similar stage migration phenomenon was observed in Chinese cohort (LN positive: 25.2% versus 18.4% in ≥25 LNs and <25 LNs examined group, respectively, P = 0.02). In the US cohort, adjuvant therapy was associated with a significant survival benefit for LN-positive patients (5-y OS: 71.0% versus 43.0% for with/without adjuvant therapy, respectively, P < 0.001) but not in LN-negative patients (5-y OS: 71.2% versus 71.5%, P = 0.90).

CONCLUSIONS

Adequate lymphadenectomy and LN examination are critical components of EGC management. Adjuvant therapy should be strongly encouraged for all EGC patients with LN-positive disease in the United States.

One Size Does Not Fit All: Marked Heterogeneity in Incidence of and Survival from Gastric Cancer among Asian American Subgroups

BACKGROUND

Asian Americans are at higher risk for noncardia gastric cancers (NCGC) relative to non-Hispanic Whites (NHW). Asian Americans are genetically, linguistically, and culturally heterogeneous, yet have mostly been treated as a single population in prior studies. This aggregation may obscure important subgroup-specific cancer patterns.

METHODS

We utilized data from 13 regional United States cancer registries from 1990 to 2014 to determine secular trends in incidence and survivorship from NCGC. Data were analyzed for NHWs and the six largest Asian American subgroups: Chinese, Japanese, Filipino, Korean, Vietnamese, and South Asian (Indian/Pakistani).

RESULTS

There exists substantial heterogeneity in NCGC incidence between Asian subgroups, with Koreans (48.6 per 100,000 person-years) having seven-fold higher age-adjusted incidence than South Asians (7.4 per 100,000 person-years). Asians had generally earlier stages of diagnosis and higher rates of surgical resection compared with NHWs. All Asian subgroups also demonstrated higher 5-year observed survival compared with NHWs, with Koreans (41.3%) and South Asians (42.8%) having survival double that of NHWs (20.1%, P < 0.001). In multivariable regression, differences in stage of diagnosis and rates of resection partially explained the difference in survivorship between Asian subgroups.

CONCLUSIONS

We find substantial differences in incidence, staging, histology, treatment, and survivorship from NCGC between Asian subgroups, data which challenge our traditional perceptions about gastric cancer in Asians. Both biological heterogeneity and cultural/environmental differences may underlie these findings.

IMPACT

These data are relevant to the national discourse regarding the appropriate role of gastric cancer screening, and identifies high-risk racial/ethnic subgroups who many benefit from customized risk attenuation programs.

Is the AJCC TNM staging system still appropriate for gastric cancer patients survival after 5 years?

PURPOSE

The aim of this study was to evaluate the prognostic value of the eighth AJCC TNM staging classification for patients with gastric cancer who had already survived for 5 years.

PATIENTS AND METHODS

Patients who underwent radical gastrectomy at a large eastern center were considered. The prognostic value of staging systems were assessed and compared. Additional external validation was performed using a dataset from the Surveillance, Epidemiology, and End Result (SEER) database.

RESULTS

The 5-year overall survival (OS) rate for patients in the training set was 59.4%. With the prolongation of the survival time after surgery, the 5-year OS improved significantly (P < 0.05). However, there were no significant differences in survival curves among patients who have survived 5 years after surgery. The AUC and χ2 of the eighth AJCC classification for predicting of 5-year OS decreased gradually after surgery and appeared stable after 5 years. For patients who survived 5 years after surgery, we constructed a new TNM staging system (nTNM) according to the survival curves of T stage and N stage. A 2-step multivariate analysis showed that nTNM, age and sex were independent prognostic factors. The nTNM demonstrated superior prognostic stratification, with higher c-statistic and likelihood ratio chi-square scores and lower AIC values than those of the AJCC classification. Similar results were observed in the external validation set.

CONCLUSION

The nTNM predicted an additional survival more accurately than did the AJCC classification for patients who have survived 5 years after surgery; this may guide decisions regarding surveillance.

Comparison of gastric cancer survival after R0 resection in the US and China

BACKGROUND AND OBJECTIVES

Gastric cancer (GC) outcomes differ between Asian and Western countries, even when controlling for contributing factors, but whether this difference holds true for China remains inadequately studied. We sought to compare the presentation, treatment, and outcomes of patients with GC undergoing curative intent (R0) resection between the US and China, and to ascertain whether geography/ institution is an independent predictor of disease-specific survival (DSS).

METHODS

Data were analyzed from patients with GC undergoing R0 resection at high-volume cancer centers in the US (Memorial Sloan Kettering Cancer Center [MSKCC], n = 1378) and China (Fujian Medical University Union Hospital [FMUUH], n = 4262) between 2000 and 2014. Factors associated with DSS were examined by multivariate analysis.

RESULTS

The 5-year DSS ( P < 0.001) for all patients was better at MSKCC than at FMUUH, even among patients not receiving preoperative chemotherapy ( P < 0.001), but stratification by substage eliminated this difference ( P > 0.05). Factors independently associated with DSS included age, histology, tumor size, T category, N category, gastrectomy type, and preoperative chemotherapy, but not institution.

CONCLUSIONS

Although the presentation of patients with GC between MSKCC and FMUUH differs, survival of patients with curatively resected GC, when matched for clinical stage, is comparable.

Gastric Cancer Etiology and Management in Asia and the West

Regional variation in treatment paradigms for gastric adenocarcinoma has attracted a great deal of interest. Between Asia and the West, major differences have been identified in tumor biology, implementation of screening programs, extent of surgical lymphadenectomy, and routine use of neoadjuvant versus adjuvant treatment strategies. Minimally invasive techniques, including both laparoscopic and robotic platforms, have been studied in both regions, with attention to safety, feasibility, and long-term oncologic outcomes. The purpose of this review is to discuss advances in the understanding of the etiology and underlying biology of gastric cancer, as well as the current state of management, focusing on the differences between Asia and the West.

The application of transgenic and gene knockout mice in the study of gastric precancerous lesions

Gastric intestinal metaplasia is a precursor for gastric dysplasia, which is in turn, a risk factor for gastric adenocarcinoma. Gastric metaplasia and dysplasia are known as gastric precancerous lesions (GPLs), which are essential stages in the progression from normal gastric mucosa to gastric cancer (GC) or gastric adenocarcinoma. Genetically-engineered mice have become essential tools in various aspects of GC research, including mechanistic studies and drug discovery. Studies in mouse models have contributed significantly to our understanding of the pathogenesis and molecular mechanisms underlying GPLs and GC. With the development and improvement of gene transfer technology, investigators have created a variety of transgenic and gene knockout mouse models for GPLs, such as H/K-ATPase transgenic and knockout mutant mice and gastrin gene knockout mice. Combined with Helicobacter infection, and treatment with chemical carcinogens, these mice develop GPLs or GC and thus provide models for studying the molecular biology of GC, which may lead to the discovery and development of novel drugs. In this review, we discuss recent progress in the use of genetically-engineered mouse models for GPL research, with particular emphasis on the importance of examining the gastric mucosa at the histological level to investigate morphological changes of GPL and GC and associated protein and gene expression.

[Metastatic stomach cancer: Clinical trials in Asia and in Occident]

Although cytotoxic chemotherapy is the main therapeutic option to treat gastric cancer in the metastatic setting, molecular targeted agents have recently been introduced in an effort to improve survival outcomes which in average do not exceed 1 year. Trastuzumab and ramucirumab, antibodies directed against HER2 and VEGFR2, respectively, may provide clinical benefit for some patients. Results of clinical studies show that Asian patients have increased survival compared to Caucasian patients. Differences between populations, and in particular the presence of polymorphisms capable of influencing the availability of fluorouracil, have been suggested as possible explanations. Other factors including histology, surgical procedures, administration of neoadjuvant chemotherapy in Western countries and screening programs in Asia have also been suggested. However, none of these elements can fully explain this phenomenon. The aim of this article is to present the main protocols used in clinical practice, the perspectives of metastatic gastric cancer treatment and the particularities observed in Asian and Caucasian patients.

Which staging system better predicts 10-year survival for gastric cancer? A study using an international multicenter database

PURPOSE

Our aim was to evaluate the prognostic performance of the 8th edition AJCC staging system for gastric cancer survival after 10 years or more.

PATIENTS AND METHODS

An international multicenter database was constructed (total n = 4537) by combining gastric cancer cases from the SEER database (n = 3066) and the database (n = 1471) of the Department of Gastric Surgery, Fujian Medical University Union Hospital. The relative discriminatory abilities were assessed using the likelihood ratio chi-square test, Akaike's Information Criterion (AIC) and Harrell's concordance index (c-statistic).

RESULTS

The 10-year overall survival rate for all the patients was 32.2%. A 2-step multivariate analysis showed that the 8th edition staging system was an independent factor for long-term overall survival. It also had higher likelihood ratio chi-square score, c-statistic and smaller AIC values compared with the 7th edition. However, stages IB and IIA of the TNM staging system showed a similar prognosis (both P > 0.05). Based on the survival data, we revised the 8th edition by merging stages IB and IIA into 1 category in the training set. The modified staging system demonstrated superior prognostic stratification with a higher c-statistic, likelihood ratio chi-square score and smaller AIC values compared to the 8th edition. Similar results were observed in the external validation set.

CONCLUSION

The 8th edition AJCC TNM classification predicts the 10-year survival of gastric cancer patients more accurately than the 7th edition. However, by merging stages IB and IIA into 1 category, we propose a revised TNM stage system that provides an optimal prognosis.

Global patterns and trends in stomach cancer incidence: Age, period and birth cohort analysis

The cases of stomach cancer (SC) incidence are increasing per year and the SC burden has remained very high in some countries. We aimed to evaluate the global geographical variation in SC incidence and temporal trends from 1978 to 2007, with an emphasis on the effect of birth cohort. Joinpoint regression and age-period-cohort model were applied. From 2003 to 2007, male rate were 1.5- to 3-fold higher than female in all countries. Rates were highest in Eastern Asian and South American countries. Except for Uganda, all countries showed favorable trends. Pronounced cohort-specific increases in risk for recent birth cohorts were seen in Brazil, Colombia, Iceland, New Zealand, Norway, Uganda and US white people for males and in Australia, Brazil, Colombia, Costa Rica, Czech Republic, Ecuador, Iceland, India, Malta, New Zealand, Norway, Switzerland, United Kingdom, Uganda, US black and white people for females. The cohort-specific ratio for male significantly decreased in Japan, Malta and Spain for cohorts born since 1950 and in Austria, China, Croatia, Ecuador, Russia, Switzerland and Thailand for cohorts born since 1960 and for female in Japan for cohorts born since 1950 and in Canada, China, Croatia, Latvia, Russia and Thailand for cohorts born since 1960. Disparities in incidence and carcinogenic risk persist worldwide. The favorable trends may be due to changes in environmental exposure and lifestyle, including decreased Helicobacter pylori prevalence, increased intake of fresh fruits and vegetables, the availability of refrigeration and decreased intake of salted and preserved food and smoking prevalence.

Profiling cancer-associated genetic alterations and molecular classification of cancer in Korean gastric cancer patients

Recently, the Cancer Genome Atlas (TCGA) Research Network and Asian Cancer Research Group provided a new classification of gastric cancer (GC) to aid the development of biomarkers for targeted therapy and predict prognosis. We studied associations between genetically aberrant profiles of cancer-related genes, environmental factors, and histopathological features in 107 paired gastric tumor-non-tumor tissue GC samples. 6.5% of our GC cases were classified as the EBV subtype, 17.8% as the MSI subtype, 43.0% as the CIN subtype, and 32.7% as the GS subtype. The distribution of four GC subgroups based on the TCGA and our dataset were similar. The MSI subtype showed a hyper-mutated status and the best prognosis among molecular subtype. However, molecular classification based on the four GC subtypes showed no significant survival differences in terms of overall survival (p= 0.548) or relapse-free survival (RFS, p=0.518). The P619fs*43 in ZBTB20 was limited to MSI group (n= 5/19, 26.3%), showing similar trends observed in TCGA dataset.

Genetic alterations of the RTK/RAS/MAPK and PI3K/AKT/mTOR pathways were detected in 34.6% of GC cases (37 individual cases). We also found two cases with likely pathogenic variants (NM_004360.4: c. 2494 G>A, p.V832M) in the CDH1 gene.

Here, we classified molecular subtypes of GC according to the TCGA system and provide a critical starting point for the design of more appropriate clinical trials based on a comprehensive analysis of genetic alterations in Korean GC patients.

High-throughput Protein and mRNA Expression-based Classification of Gastric Cancers Can Identify Clinically Distinct Subtypes, Concordant With Recent Molecular Classifications

Gastric cancers have recently been classified into several types on the basis of molecular characterization, and the new taxonomy has shown to have clinical relevance. However, the technology required for thorough molecular classification is complicated and expensive, currently preventing widespread use. We aimed to reproduce the results of molecular classification using only simple techniques, that is, immunohistochemical analysis and in situ hybridization. We classified a cohort of 349 successive gastric adenocarcinomas into 5 subtypes, on the basis of protein or mRNA expression of MLH1, E-cadherin, p53, and Epstein-Barr virus. We observed that the subtypes presented distinct clinicopathologic characteristics and corresponded to the molecular classifications previously reported. Epstein-Barr virus -positive tumors were more common in male individuals and in the body of the stomach. Microsatellite-unstable (MSI) tumors, which showed aberrant MLH1 expression, were correlated with increased age and intestinal histology. Both types showed better overall survival than the other types. Gastric cancers with reduced expression of E-cadherin, corresponding to the epithelial to mesenchymal transition or genome stable subtypes, showed the poorest overall survival, with a high prevalence of poorly cohesive carcinoma (ie, diffuse type, of the Lauren classification system). In conclusion, we were able to reproduce a previously reported molecular classification of gastric cancers using immunohistochemical analysis and in situ hybridization. We verified the effectiveness and applicability of this method, which shows promise for use in a clinical setting in the foreseeable future.

Examining the gastric cancer survival gap between Asians and whites in the United States

BACKGROUND

Globally, Asian countries bear a disproportionate gastric cancer burden. Asian Americans, the fastest growing minority population in the US, have higher gastric cancer survival than non-Hispanic whites (NHWs) despite higher incidence. Benefitting from uniform cancer registry standards within the US, we examine for the first time the heterogeneity in the Asian American population, which may elucidate the causes of these disparities.

METHODS

SEER gastric cancer data from 2000 to 2012 were used to calculate 5-year survival estimates for NHWs and the six largest Asian ethnicities. Multivariate analyses were performed to identify critical prognostic factors and survival disparities between Asian groups and NHWs.

RESULTS

We analyzed 33,313 NHW and 8473 Asian gastric cancer cases. All Asian groups had significantly higher 5-year survival than NHWs, at 29.8%. Among Asians, Koreans and Vietnamese had the highest and lowest survival, at 45.4% and 35.7%, respectively. The Korean survival advantage was largely attributable to relatively high proportions of localized stage and low proportions of cardia tumors. After adjusting for major prognostic factors, the survival disadvantage of NHWs, while attenuated, remained significant in comparison to all Asian groups (HR: 1.33, 95% CI: 1.24-1.43; reference: Korean). The survival disparities within the Asian groups vanished with adjustment.

CONCLUSIONS

This study characterizes distinctive gastric cancer survival patterns among the six major Asian groups and NHWs in the US. The favorable survival for Koreans is largely attributable to specific clinical factors, particularly stage at diagnosis. The causes of the survival disadvantage for NHWs remain elusive.

Potential diagnostic and prognostic significance of plasma prolidase activity in gastric cancer

Aim: Plasma prolidase activities (PPAs) in cases of gastric cancer. Methodology/results: This study was based on a prospective design. 60 patients with gastric cancer (operable cases: 48; inoperable: 12) and 60 healthy controls were included in the study. Prolidase activity was analyzed. The mean PPA levels in the operable, inoperable and control groups were 45.60 ± 4.20, 54.35 ± 4. 9 and 10.92 ± 0.79 U/l, respectively (p < 0.001). PPA decreased significantly after tumor resection. PPA level was significant in differentiating operable cases from inoperable (sensitivity: 91.7%; specificity: 85.2%). Discussion/conclusion: PPA was significantly higher in patients with inoperable gastric cancer than in operable cases and the control group. A strong correlation was found between tumor volume and PPA.

Racial and Ethnic Variability in the Prevalence and Incidence of Comorbidities Associated with Gastric Cancer in the United States

PURPOSE

Comorbidities are known to impact quality of life, treatment choices, and survival. Our objectives were to characterize comorbid conditions in a cohort of elderly gastric cancer patients and to determine if there is variability in the prevalence or incidence of the comorbid conditions across racial/ethnic groups.

METHODS

A total of 12,612 individuals, ≥66 years of age, diagnosed with gastric cancer between 2000 and 2007, and an equal number of gender- and region-matched cancer-free individuals, were identified using the National Cancer Institute's Surveillance, Epidemiology, and End Results registry linked to Medicare claims in the United States. The prevalence (%) in the year before diagnosis and the 12-month incidence rates after diagnosis were estimated for 32 chronic and ten acute comorbid conditions for the entire cohort and by race/ethnicity (Asian, Black, Hispanic, White, and other) and Asian subgroups (e.g., Chinese, Filipino, Japanese, Pacific Islander).

RESULTS

White and Black cases exhibited the highest prevalence of most comorbid conditions. Asian and Pacific Islander cases exhibited the lowest. There was substantial variability in the 12-month incidence of the comorbidities across the racial/ethnic groups. Electrolyte disorder was the most common incident condition among Whites and Blacks. With the exception of Whites, anemia was the most common incident condition in all racial and ethnic groups 180 days following chemotherapy.

CONCLUSIONS

There is variability in the prevalence and incidence in comorbidities across racial/ethnic groups.

Proposal of a new stage grouping of gastric cancer for TNM classification: International Gastric Cancer Association staging project

BACKGROUND

The current AJCC staging system for gastric cancer (AJCC7) incorporated several major revisions to the previous edition. The T and N categories and the stage groups were newly defined, and adenocarcinoma of the esophagogastric junction (EGJ) was reclassified and staged according to the esophageal system. Studies to validate these changes showed inconsistent results. The International Gastric Cancer Association (IGCA) launched a project to support evidence-based revisions to the next edition of the AJCC staging system.

METHODS

Clinical and pathological data on patients who underwent curative gastrectomy at 59 institutions in 15 countries between 2000 and 2004 were retrospectively collected. Patients lost to follow-up within 5 years of surgery were excluded. Patients treated with neoadjuvant therapy were excluded. The data were analyzed in total, and separately by region of treatment.

RESULTS

Of 25,411 eligible cases, 84.8 % were submitted from 24 institutions of Japan and Korea, 6.4 % from other Asian countries, and 8.8 % from 29 Western institutions. The T and N categories of AJCC7 clearly stratified the patient survival. Patients with pN3a and pN3b showed distinct prognosis in all regions, and by introducing pN3a and pN3b into a cluster analysis, we established a new stage grouping with better stratification than AJCC7, especially among stage III subgroups. Survival of Siewert type 2 and 3 EGJ tumors was better stratified by this IGCA stage grouping than by either esophageal or gastric scheme of AJCC7.

CONCLUSIONS

For the next revision of AJCC classification, we propose a new stage grouping based on a large, worldwide data collection.

N staging: the role of the pathologist

Gastric cancer is the second cause of cancer-related mortality worldwide. Metastases, including lymph nodes ones, heavily influence the prognosis of this disease. The pathological detection of positive lymph nodes is pivotal for an optimal prognostication and clinical management of affected individuals. Several factors influence the pathological investigation of surgical specimens, ultimately affecting the number of retrieved lymph nodes and, with it, the reliability of N staging. The pathologist plays a central role in optimizing this process. Factors influencing lymph node retrieval and analysis will be herein reviewed, together with the procedures adopted for an optimal pathological analysis of lymph nodes in gastric cancer.

Gastric tumour-derived ANGPT2 regulation by DARPP-32 promotes angiogenesis

OBJECTIVE

Overexpression of dopamine and cAMP-regulated phosphoprotein, Mr 32000 (DARPP-32), and its truncated isoform (t-DARPP) are associated with gastric tumorigenesis. Herein, we investigated the role of DARPP-32 proteins in regulating angiopoietin 2 (ANGPT2) and promoting tumour angiogenesis.

DESIGN

Quantitative real-time RT-PCR, immunoblotting, luciferase reporter, immunofluorescence, immunohistochemistry and angiogenesis assays were applied to investigate the regulation of angiogenesis by DARPP-32 proteins.

RESULTS

Overexpression of DARPP-32 significantly increased the mRNA and protein levels of ANGPT2 in gastric cancer cells. The overexpression of DARPP-32 T34A mutant or the N-terminal truncated isoform, t-DARPP, led to similar effects ruling out the T34-dependent regulation of protein phosphatase 1 activity in regulating ANGPT2. DARPP-32 proteins induced a secreted form of ANGPT2, which was detectable in the media, functionally active, and able to induce angiogenesis, measured by the human umbilical vein endothelial cells tube formation assay. Antibody blocking of the secreted ANGPT2 abrogated its function. To identify the mechanism by which DARPP-32 regulates ANGPT2, we examined the activities of NF-κB and signal transducer and activator of transcription 3 (STAT3), known regulators of angiogenesis. The results ruled out NF-κB and showed induction of STAT3 phosphorylation, activation and nuclear localisation. Inhibition or knockdown of STAT3 significantly attenuated the induction of ANGPT2 by DARPP-32 proteins. In vivo xenograft models demonstrated that overexpression of DARPP-32 promotes angiogenesis and tumour growth. Analyses of human gastric cancer tissues showed a strong correlation between DARPP-32 and ANGPT2.

CONCLUSIONS

Our novel findings establish the role of DARPP-32-STAT3 axis in regulating ANGPT2 in cancer cells to promote angiogenesis and tumorigenesis.

Lymph node retrieval and examination during the implementation of extended lymph node dissection for gastric cancer in a non-specialized western institution

The optimal degree of lymph node dissection for gastric cancer is still matter of debate. Particularly, there are serious doubts about the reproducibility of extended lymph node dissection in western surgical units, and no studies to date have investigated factors influencing lymph node retrieval and examination during the learning curve. Univariate and multivariate retrospective analysis of 21 variables were carried out on a prospective series of 313 consecutive resections for gastric cancer performed by ten different surgeons, with lymph node retrieval and analysis performed by ten different pathologists. Endpoints were number of examined lymph nodes per patient, number of cases with inadequate nodal staging (<15 examined lymph nodes) and lymph node ratio (calculated as the absolute ratio between the number of metastatic and the number of examined lymph nodes). The number of examined lymph nodes per patient (mean ± SD 28.3 ± 14.1, median 26, range 2-78) was independently influenced by age, pN status, the type of gastric resection, the degree of lymph node dissection and single pathologist. There were 47 cases (15.0%) with incomplete nodal staging that was independently determined by the degree of lymph node dissection and by the pathologist. Lymph node ratio was independently influenced by the number of metastatic lymph nodes, the disease stage and by the histological subtype of the tumor. The role of an experienced or dedicated pathologist should not be underevaluated in western series when dealing with lymph node retrieval and examination. Lymph node ratio appeared not to be significantly influenced by the number of examined lymph nodes, being independently influenced only by the number of metastatic lymph nodes, the disease stage and by the histological subtype of the tumor. It could be therefore tested as a prognostic factor limiting the stage-migration phenomenon induced by extended lymph node dissection.

The survival difference between gastric cancer patients from the UK and Japan remains after weighted propensity score analysis considering all background factors

BACKGROUND

Previous studies comparing survival between gastric cancer (GC) patients from the West and the East were based on the assumption that background factors and prognostic factors were identical. The aim of the current study was to compare the survival of GC patients from the UK and Japan using weighted propensity score analysis after identifying all different background factors.

METHODS

Data from 464 patients from the Leeds Teaching Hospital NHS Trust, Leeds, UK (LTHT), and 465 patients from the Kanagawa Cancer Center Hospital, Yokohama, Japan (KCCH), who had surgery for GC were analyzed. Prognostic factors for overall survival (OS) and cancer-specific survival (CSS) were identified by univariate and multivariate analyses. Survival was compared by propensity score weighting after adjusting for all significantly different background factors.

RESULTS

Most background factors were different between LTHT and KCCH patients. Unadjusted stage-specific OS and CSS were significantly better in KCCH. Independent prognostic factors for unadjusted OS and CSS were pT and pN in KCCH and in addition tumor location, pancreatectomy, resection margin status and number of examined lymph nodes in LTHT. Even after adjusting for all background characteristics, survival remained better in KCCH.

CONCLUSIONS

These results suggest that differences in background factors are unable to fully explain the survival difference of GC patients between UK and Japan. Comprehensive studies into the biology of GC and/or host factors are needed to fully understand the survival difference.

Molecular classification of gastric cancer

Gastric cancer (GC), a heterogeneous disease characterized by epidemiologic and histopathologic differences across countries, is a leading cause of cancer-related death. Treatment of GC patients is currently suboptimal due to patients being commonly treated in a uniform fashion irrespective of disease subtype. With the advent of next-generation sequencing and other genomic technologies, GCs are now being investigated in great detail at the molecular level. High-throughput technologies now allow a comprehensive study of genomic and epigenomic alterations associated with GC. Gene mutations, chromosomal aberrations, differential gene expression and epigenetic alterations are some of the genetic/epigenetic influences on GC pathogenesis. In addition, integrative analyses of molecular profiling data have led to the identification of key dysregulated pathways and importantly, the establishment of GC molecular classifiers. Recently, The Cancer Genome Atlas (TCGA) network proposed a four subtype classification scheme for GC based on the underlying tumor molecular biology of each subtype. This landmark study, together with other studies, has expanded our understanding on the characteristics of GC at the molecular level. Such knowledge may improve the medical management of GC in the future.

Differences in gastric cancer survival between the U.S. and China

BACKGROUND

Previous comparisons of gastric cancer between the West and the East have focused predominantly on Japan and Korea, where early gastric cancer is prevalent, and have not included the Chinese experience, which accounts for approximately half the world's gastric cancer.

METHODS

Patient characteristics, surgical procedures, pathologic information, and survival were compared among gastric cancer patients who underwent curative intent gastrectomy at two large volume cancer centers in China and the US between 1995 and 2005.

RESULTS

Median age and body mass index were significantly higher in US patients. The proportion of proximal gastric cancer was comparable. Gastric cancer patients in China had larger tumors and a later stage at presentation. The median number of positive lymph nodes was higher (5 vs 4, P < 0.02) despite a lower lymph node retrieval (16 vs 22, P < 0.001) in Chinese patients. The probability of death due to gastric cancer in Chinese patients was 1.7 fold of that in the US (P < 0.0001) after adjusting for important prognostic factors.

CONCLUSIONS

Even after adjusting for important prognostic factors Chinese gastric cancer patients have a worse outcome than US gastric cancer patients. The differences between Chinese and US gastric cancer are a potential resource for understanding the disease.

Prognostic Role of Diffusion-weighted MR Imaging for Resectable Gastric Cancer

PURPOSE

To prospectively investigate the role of apparent diffusion coefficient (ADC) calculated from diffusion-weighted magnetic resonance (MR) imaging as a potential prognostic biomarker in the evaluation of the aggressiveness of gastric cancer.

MATERIALS AND METHODS

This prospective study had institutional review board approval. Informed consent was obtained from all patients. Between October 2009 and December 2013, a total of 99 patients (65 men, 34 women; mean age, 62.02 years; age range, 32.33-85.15 years) with biopsy-proved cancer (28 esophagogastric junction and 71 gastric cancers) were examined with a 1.5-T MR imaging system, including T1-, T2-, and diffusion-weighted sequences. ADC measurements were obtained. Seventy-one patients were directly treated with surgery, while 28 underwent neoadjuvant chemotherapy beforehand. Pathologic ADC, pathologic T and N stages, tumor location, surgical approach, and histologic subtype were investigated with univariate and multivariate analyses by using the Cox regression model.

RESULTS

At a total median follow-up period of 21 months, 31 patients had died. The median follow-up was 25 months for the surgery-only group (19 of 31 events [61%]) and 28 months for the chemotherapy group (12 of 31 events [39%]). In the multivariate analysis, ADC values of 1.5 × 10(-3) mm(2)/sec or lower were associated with a negative prognosis, both in the total population (log-relative risk, 1.73; standard error, 0.56; P = .002) and in the surgery-only (log-relative risk, 1.97; standard error, 0.66; P = .003) and chemotherapy (log-relative risk, 2.93; standard error, 1.41; P = .03) groups, along with other significant prognostic factors (in particular, pathologic T and N stages).

CONCLUSION

Pathologic ADC represents a strong independent prognostic factor in the evaluation of the aggressiveness of gastric cancer, in addition to clinical and surgical variables.

Surgical management of gastric cancer: the East vs. West perspective

Gastric cancer is a unique malignancy, with definite geographic differences in incidence, pathology, treatment and outcome. While the incidence has been declining in the Western hemisphere, steady rates have been reported in Eastern countries, particularly South Korea and Japan. One of the most profound differences between the East and West centers around treatment strategies, with Western clinicians routinely adopting a neoadjuvant approach, prior to surgical resection. Eastern clinicians, however, favor primary surgical therapy and have pioneered many of the techniques currently used worldwide. From endoscopic therapies to minimally-invasive surgery, including laparoscopic and robotic techniques, the Eastern surgeons have studied their techniques with high-volumes of patients. Western surgeons, practicing in systems where gastric cancer care is not centralized, typically have performed less aggressive surgical resections, although generally see more advanced diseases. In the era where global care is becoming more standardized, however, the differences in surgical practice have lessened. This review compares the surgical techniques and outcomes for gastric cancer practiced in the East with those standard in the West.

Comparison of gastric cancer survival between Caucasian and Asian patients treated in the United States: results from the Surveillance Epidemiology and End Results (SEER) database

BACKGROUND

The prognosis for gastric cancer is better for Asian than for Caucasian patients. The primary driver of this difference is unknown. This study determined whether the survival advantage of Asian ethnicity continued to hold after control was used for other well-known prognostic factors.

METHODS

In this study, 12,773 patients who underwent gastrectomy for treatment of adenocarcinoma of the stomach were identified from the Surveillance, Epidemiology, and End Results cancer registry. Patients with cardia tumor were excluded from the study. The independent prognostic effect of ethnicity was evaluated by adjusting for other known factors.

RESULTS

The Asian patients tended to have a diagnosis at an earlier age (66.8 vs. 68.5 years), more lymph nodes examined (16 vs. 13), and more positive lymph nodes (5.1 vs. 4.8). Survival was better for the Asian patients than for the Caucasian patients, with a 12 % 5-year survival difference. Among the patients with IB, IIA, and IIB disease, the Asian patients had 37, 72, and 13 months longer median survival time than the corresponding Caucasian patients. The multivariate Cox model showed persistence of this result after adjustment for imbalances of age, gender, tumor grade, and number of examined and positive lymph nodes. The largest risk reduction was observed for the stage IA patients (31 %) and the smallest for the stage IIIC patients (9 %).

CONCLUSION

After excluding proximal gastric cancers, controlling for the imbalance of known prognostic factors, and decreasing in the influence of D2 lymphadenectomy, stage migration, and chemo/radiation therapy by including only patients treated in the United States, this study found that the survival advantage of Asian ethnicity continued to be present.

Hereditary diffuse gastric cancer - pathophysiology and clinical management

Hereditary Diffuse Gastric Cancer is an autosomal dominant inherited gastric cancer syndrome caused by germline alterations in CDH1 (E-cadherin) and CTNNA1 (alpha-E-catenin) genes. Germline CDH1 alterations encompass small frameshifts, splice-site, nonsense, and missense mutations, as well as large rearrangements. Most CDH1 truncating mutations are pathogenic, and several missense CDH1 mutations have a deleterious effect on E-cadherin function. CDH1 testing should be performed in probands. Screening of at-risk individuals is indicated from the age of consent following counselling with a multidisciplinary team. In mutation-positive individuals prophylactic gastrectomy is recommended. Endoscopic surveillance is an option for those refusing/postponing gastrectomy, those with mutations of undetermined significance, and in CDH1-negative families. Ongoing research focus on the search of genetic causes other than CDH1 or CTNNA1 germline defects; assessment of the pathogenicity and penetrance of CDH1 missense mutations and identification of somatic mechanisms behind the progression from early (indolent) lesions to invasive (lethal) carcinomas.

How prognostic and predictive biomarkers are transforming our understanding and management of advanced gastric cancer

BACKGROUND

Gastric cancer (GC) is the second leading cause of cancer death worldwide. GC is a heterogeneous disease in terms of histology, anatomy, and epidemiology. There is also wide variability in how GC is treated in both the resectable and unresectable settings. Identification of prognostic and predictive biomarkers is critical to help direct and tailor therapy for this deadly disease.

METHODS

A literature search was done using Medline and MeSH terms for GC and predictive biomarkers and prognostic biomarkers. The search was limited to human subjects and the English language. There was no limit on dates. Published data and unpublished abstracts with clinical relevance were included.

RESULTS

Many potential prognostic and predictive biomarkers have been assessed for GC, some of which are becoming practice changing. This review is focused on clinically relevant biomarkers, including EGFR, HER2, various markers of angiogenesis, proto-oncogene MET, and the mammalian target of rapamycin.

CONCLUSION

GC is a deadly and heterogeneous disease for which biomarkers are beginning to change our understanding of prognosis and management. The recognition of predictive biomarkers, such as HER2 and vascular endothelial growth factor, has been an exciting development in the management of GC, validating the use of targeted drugs trastuzumab and ramucirumab. MET is another potential predictive marker that may be targeted in GC with drugs such as rilotumumab, foretinib, and crizotinib. Further identification and validation of prognostic and predictive biomarkers has the potential transform how this deadly disease is managed.

Treatment of patients with advanced gastric cancer: experience from an Indian tertiary cancer center

Majority of patients in developing countries diagnosed with gastric cancer have an advanced stage at presentation with overall poor performance status. The aim of the study was to assess outcomes of first- and second-line chemotherapy and determine prognostic factors among patients with advanced gastric cancer (AGC). Using a prospectively maintained database, we identified 144 patients with AGC treated at Tata Memorial Centre between January 2012 and September 2013. Sixteen patients received best supportive care, and 128 patients received palliative chemotherapy. Cox regression was used for multivariate analysis of survival. Of 128 patients, 42(33%) received Cape-Ox, 22(17.1%) EOX and 47(36.7%) DOX while rest received other regimens. PS was 2 in 36 (28%) patients at presentation, and 97% of patients had ≥3 sites of metastasis. Forty-eight patients (37.5%) had signet ring histology. Median follow-up was 9 months. Median progression-free survival/overall survival (OS) was 6/8 months, respectively. Of 93 patients who progressed 39 (41.9%) patients received second-line chemotherapy. Multivariate analysis for OS showed that PS and use of taxane in first-line setting were significant prognostic factors. Patients who received second-line therapy had longer survival than those who did not (12 vs. 6 months; P=0.002). The overall outcome of our patients is comparable to the Western reported data despite an advanced disease at presentation.

Endoscopic submucosal dissection in the colorectum: Feasibility in the Canadian setting

Endoscopic submucosal dissection is a minimally invasive endoscopic technique for the removal of gastrointestinal tumours that is increasingly being used for colonic neoplasms to spare resection of colon in selected patients. Colonic endoscopic submucosal dissection is technically challenging and was initially pioneered in Japan but increasingly used in selected western centres. Its use in Canada is currently limited, and the authors review the challenges and opportunities, in addition to the unique training infrastructure required to practice the procedure under supervision. Specific tools are required to perform endoscopic submucosal dissection and meticulous attention to detail is essential. The authors provide a combined Japanese and Canadian perspective to this technique, and discuss training and performance of endoscopic submucosal dissection as well as potential indications.

Genetic mutation analysis of human gastric adenocarcinomas using ion torrent sequencing platform

Gastric cancer is the one of the major causes of cancer-related death, especially in Asia. Gastric adenocarcinoma, the most common type of gastric cancer, is heterogeneous and its incidence and cause varies widely with geographical regions, gender, ethnicity, and diet. Since unique mutations have been observed in individual human cancer samples, identification and characterization of the molecular alterations underlying individual gastric adenocarcinomas is a critical step for developing more effective, personalized therapies. Until recently, identifying genetic mutations on an individual basis by DNA sequencing remained a daunting task. Recent advances in new next-generation DNA sequencing technologies, such as the semiconductor-based Ion Torrent sequencing platform, makes DNA sequencing cheaper, faster, and more reliable. In this study, we aim to identify genetic mutations in the genes which are targeted by drugs in clinical use or are under development in individual human gastric adenocarcinoma samples using Ion Torrent sequencing. We sequenced 737 loci from 45 cancer-related genes in 238 human gastric adenocarcinoma samples using the Ion Torrent Ampliseq Cancer Panel. The sequencing analysis revealed a high occurrence of mutations along the TP53 locus (9.7%) in our sample set. Thus, this study indicates the utility of a cost and time efficient tool such as Ion Torrent sequencing to screen cancer mutations for the development of personalized cancer therapy.

Is concomitant splenectomy beneficial for the long-term survival of patients with gastric cancer undergoing curative gastrectomy? A single-institution study

BACKGROUND

Curative resection is the treatment of choice for gastric cancer, but it is unclear whether gastrectomy should also include splenectomy. We retrospectively analyzed long-term survival in patients in our hospital who underwent gastrectomy plus splenectomy (G+S) or gastrectomy alone (G-A) for gastric cancer.

METHODS

We identified 214 patients who underwent surgery with curative intent between 1980 and 2003. Of these, 100 underwent G+S, and 114 underwent G-A. The primary endpoint was 5-year overall survival (OS).

RESULTS

Median follow-up was 18 months in patients who underwent G+S, and 26.5 months in patients who underwent G-A. The 5-year OS rate was significantly higher in patients who underwent G-A (33.8%; 95% CI 24.2 to 43.4%) than in those who underwent G+S (28.8%; 95% CI 19.6 to 38.0%) (log-rank test, P=0.013).

CONCLUSIONS

Splenectomy does not benefit patients undergoing gastrectomy for gastric cancer. Routine splenectomy should be abandoned in patients undergoing radical resections for gastric cancer.

Does D2 plus para-aortic nodal dissection surgery offer a better survival outcome compared to D2 surgery only for gastric cancer consistently? A definite result based on a hospital population of nearly two decades

BACKGROUND AND AIMS

Curative resection is the treatment of choice for gastric cancer. Although it has been concluded that D2 lymphadenectomy plus para-aortic nodal dissection does not improve survival rate in curable gastric cancer, it is unclear whether D2 plus para-aortic nodal dissection has a benefit in some groups of patients. We conducted a retrospective study in our hospital, in which we compared D2 with D2 plus para-aortic nodal dissection lymphadenectomy for gastric cancer in subgroups of each clinical characteristic in terms of long-term survival after surgery.

MATERIAL AND METHODS

We selected 1792 patients who had undergone the treatment with curative intent between 1990 and 2007, 1344 in the D2 group and 448 in the D2 plus para-aortic nodal dissection group. Each procedure was verified by pathological analyses. The primary end points were 5-year overall survival.

RESULTS AND CONCLUSIONS

Median follow-up periods were 50 months for patients assigned to D2 group and 54 months for patients assigned to D2 plus para-aortic nodal dissection group. Overall 5-year survival was not significantly higher in patients assigned to D2 plus para-aortic nodal dissection surgery compared to those assigned to D2 surgery (31.2% (95% confidence interval: 19.8%-42.6%) vs 26.6% (95% confidence interval: 20.3%-32.9%); log-rank p = 0.433). D2 plus para-aortic nodal dissection surgery should only be used for curable gastric cancer of T3-4 and N2 stage and should not be used for T1 disease and total gastrectomy.

Race and correlations between lymph node number and survival for patients with gastric cancer

BACKGROUND

There is ongoing debate whether extended lymphadenectomy improves survival in gastric cancer patients who undergo surgical resection. We previously observed that Korean-American patients had the highest overall survival in Los Angeles County. Our objective was to assess lymph node (LN) number and its impact on survival for Korean-American gastric cancer patients.

METHODS

We utilized the National Cancer Institute's Surveillance, Epidemiology, and End Results registry to identify Korean-Americans with gastric adenocarcinoma treated with curative-intent gastrectomy between 1988 and 2008. We grouped patients according to examined LN number (1-15 and 16+) and compared characteristics. We performed similar analysis for white patients.

RESULTS

Out of 982 Korean-American patients with gastric adenocarcinoma, most patients had 1-15 examined LNs (60 %). When we compared LN groups, we observed higher overall survival in the 1-15 group than the 16+ group (5-year survival, 59 % vs 52 %, respectively; p = 0.04). However, LN number was not prognostic of overall survival on stepwise Cox proportional hazards analysis. In contrast, LN number was prognostic for white patients.

CONCLUSIONS

Although examined LN number may impact survival for white patients, outcomes of Korean-American gastric cancer patients were independent of LN number. Our data suggest that survival of Korean-American gastric cancer patients are comparable with outcomes from East Asian hospitals and may be independent of surgical technique.

Quality of life, immunomodulation and safety of adjuvant mistletoe treatment in patients with gastric carcinoma - a randomized, controlled pilot study

Background

Mistletoe (Viscum album L.) extracts are widely used in complementary cancer therapy. Aim of this study was to evaluate safety and efficacy of a standardized mistletoe extract (abnobaVISCUM® Quercus, aVQ) in patients with gastric cancer.

Patients and Methods

32 operated gastric cancer patients (stage Ib or II) who were waiting for oral chemotherapy with the 5-FU prodrug doxifluridine were randomized 1:1 to receive additional therapy with aVQ or no additional therapy. aVQ was injected subcutaneously three times per week from postoperative day 7 to week 24 in increasing doses. EORTC QLQ-C30 and -STO22 Quality of Life questionnaire, differential blood count, liver function tests, various cytokine levels (tumor necrosis factor (TNF)-alpha, interleukin (IL)-2), CD 16⁺/CD56⁺ and CD 19⁺ lymphocytes were analyzed at baseline and 8, 16 and 24 weeks later.

Results

Global health status (p <0.01), leukocyte- and eosinophil counts (p ≤0.01) increased significantly in the treatment group compared to the control group. Diarrhea was less frequently reported (7% vs. 50%, p=0.014) in the intervention group. There was no significant treatment effect on levels of TNF-alpha, IL-2, CD16⁺/CD56⁺ and CD 19⁺ lymphocytes and liver function tests measured by ANOVA.

Conclusion

Additional treatment with aVQ is safe and was associated with improved QoL of gastric cancer patients. ClinicalTrials.Gov Registration number NCT01401075.

A systematic review of surgery for non-curative gastric cancer

BACKGROUND

Most gastric cancer patients present with advanced stage disease precluding curative surgical treatment. These patients may be considered for palliative resection or bypass in the presence of major symptoms; however, the utility of surgery for non-curative, asymptomatic advanced disease is debated and the appropriate treatment strategy unclear.

PURPOSE

To evaluate the non-curative surgical literature to better understand the limitations and benefits of non-curative surgery for advanced gastric cancer.

METHODS

A literature search for non-curative surgical interventions in gastric cancer was conducted using MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials databases from 1 January 1985 to 1 December 2009. All abstracts were independently rated for relevance by a minimum of two reviewers. Outcomes of interest were procedure-related morbidity, mortality, and survival.

RESULTS

Fifty-nine articles were included; the majority were retrospective, single institution case series. Definitions describing the treatment intent for gastrectomy were incomplete in most studies. Only five were truly performed with relief of symptoms as the primary indication for surgery, while the majority were considered non-curative or not otherwise specified. High rates of procedure-related morbidity and mortality were demonstrated for all surgeries across the majority of studies and treatment-intent categories. Median and 1-year survival were poor, and values ranged widely within surgical approaches and across studies.

CONCLUSIONS

A lack of transparent documentation of disease burden and symptoms limits the surgical literature in non-curative gastric cancer. Improved survival is not evident for all patients receiving non-curative gastrectomy. Further prospective research is required to determine the optimal intervention for palliative gastric cancer patients.

Morbidity and mortality after non-curative gastrectomy for gastric cancer in elderly patients

BACKGROUND AND OBJECTIVES

This study examined the surgical outcome of non-curative resection in elderly patients with gastric cancer.

METHODS

The study reviewed 278 patients who underwent non-curative resection for advanced gastric cancer. The clinicopathological features of elderly patients (≥ 75 years, n = 257) and younger patients (<75 years, n = 21) were compared.

RESULTS

Although no difference was observed in terms of preoperative performance, there were distinct differences in terms of albumin level, presence of symptoms, and the rate of comorbidities between the two groups. The postoperative morbidity and mortality rate did not differ between the two groups. Age, preoperative performance status, preoperative transfusion, and presence of comorbidity were not independent predictors of postoperative complications. However, the extent of gastric resection and combined resection were closely related to postoperative complications in patients with non-curative gastrectomy.

CONCLUSIONS

In a setting of non-curative resection for gastric cancer, age was not a limiting factor. Rather, the risk of postoperative morbidity should be considered carefully in total gastrectomy and combined resection.

[The Comparison between 6th and 7th International Union Against Cancer/American Joint Committee on Cancer Classification for Survival Prognosis of Gastric Cancer]

BACKGROUND/AIMS

The tumor-node-metastasis (TNM) staging is an useful system to assess the prognosis of any solid cancer. As new TNM staging classification of 7th stomach cancer was revised in 2009, we evaluated the prognostic predictability of the 7th International Union Against Cancer/American Joint Committee on Cancer (UICC/AJCC) TNM classification compared to 6th UICC/AJCC TNM classification in gastric cancer.

METHODS

From January 2000 to December 2009, 5-year survival rates of 266 patients with gastric cancer were calculated by the 6th and 7th UICC/AJCC TNM classification.

RESULTS

Using the 7th UICC/AJCC TNM classification, there was no significant difference in the 5-year cumulative survival rates (5 YSR) between stage IIA and IIB, IIB and IIIA, and IIIA and IIIB (70% vs. 71%, p=0.530; 71% vs. 80%, p=0.703; 80% vs. 75%, p=0.576, respectively) though significant differences of the survival rates were observed among stages of 6th edition. Using T stage of 7th edition, 5 YSR was not different between T2 and T3 (86% vs. 82%, p=0.655). Using N stage of 7th edition, 5 YSR were not different between N1 and N2, N3a and N3b (79% vs. 81%, p=0.506; 41% vs. 17%, p=0.895, respectively).

CONCLUSIONS

The 7th UICC/AJCC TNM classification had poor prognostic predictability in gastric cancer compared to the 6th edition.