Environmental risk factors in the development of adenocarcinoma of the oesophagus or gastric cardia: a cross-sectional study in a Dutch cohort

The demethylase ALKBH5 mediates ZKSCAN3 expression through the m6A modification to activate VEGFA transcription and thus participates in MNNG-induced gastric cancer progression

N-Nitroso compounds (NOCs) are recognized as important factors that promote gastric cancer development, but the specific effects and potential mechanisms by which NOC exposure promotes gastric cancer are still poorly understood. In this study, we explored the effects and potential molecular mechanisms of NOCs on the promotion of gastric cancer using methylnitronitrosoguanidine (MNNG), a classical direct carcinogen of NOC. The results of in vivo and in vitro experiments showed that chronic and low-concentration MNNG exposure significantly promoted the malignant progression of tumors, including cell migration, cell invasion, vasculogenic mimicry (VM) formation, cell spheroid formation, stem cell-like marker expression, and gastric cancer growth and metastasis. Mechanistically, we revealed that demethylase ALKBH5 regulated the level of the N6‑methyladenosine (m6A) modification in the 3'UTR and CDS region of the ZKSCAN3 mRNA to promote ZKSCAN3 expression, mediated the binding of ZKSCAN3 to the VEGFA promoter region to regulate VEGFA transcription, and participated in MNNG-induced gastric cancer cell migration, invasion, VM formation, cell spheroid formation, stem cell-like marker expression and ultimately gastric cancer progression. In addition, our study revealed that ALKBH5-ZKSCAN3-VEGFA signaling was significantly activated during MNNG-induced gastric carcinogenesis, and further studies in gastric cancer patients showed that ALKBH5, ZKSCAN3, and VEGFA expression were upregulated in cancers compared with paired gastric mucosal tissues, that ALKBH5, ZKSCAN3, and VEGFA could serve as important biomarkers for determining patient prognosis, and that the molecular combination showed greater prognostic value. These findings provide a theoretical basis for developing gastric cancer interventions for NOCs and for determining gastric cancer progression.

YTHDF1 mediates N-methyl-N-nitrosourea-induced gastric carcinogenesis by controlling HSPH1 translation

YT521-B homology (YTH) domain family (YTHDF) proteins serve as readers that directly recognise m6A modifications. In this study, we aim to probe the role of YTHDF1 in environmental carcinogen-induced malignant transformation of gastric cells and gastric cancer (GC) carcinogenesis. We established a long-term low-dose MNU-induced malignant transformation model in gastric epithelial cells. In vivo and in vitro experiments were conducted to validate the malignant phenotype and characterise the roles of YTHDF1 and its downstream genes in malignant transformation cells. Additionally, we explored downstream m6A modification targets of YTHDF1 using RNA-sequencing, RNA immunoprecipitation, and proteomics analyses, and conducted validation experiments in cell experiments and clinical samples. Long-term low-dose exposure of MNU converted normal Gges-1 cells into malignant cells. YTHDF1 mRNA and protein expression are increased in MNU-induced malignant cells (p<0.001). Meanwhile, YTHDF1 knockdown inhibits the malignant potential of MNU-treated cells (p<0.01). YTHDF1 knockdown specifically suppresses HSPH1 protein, but not RNA levels. RIP-qPCR validates HSPH1 is the target of YTHDF1 (p<0.01). HSPH1 knockdown impairs the malignant potential of MNU-induced transformed cells. The increased expression of the key regulatory factor YTHDF1 in MNU-induced gastric carcinogenesis affects malignant transformation and tumorigenesis by regulating the translation of downstream HSPH1. These findings provide new potential targets for preventing and treating environmental chemical-induced gastric carcinogenesis.

N-methyl-N-nitrosourea induces zebrafish anomalous angiogenesis through Wnt/β-catenin pathway

N-methyl-N-nitrosourea (MNU) is a prevalent environmental carcinogen, which leads to tumors in various organs in animal models, while the mechanisms involved were still not fully understood. It is well known that anomalous angiogenesis is a key step in tumorigenesis and progression. In this study, we found that MNU induced abnormal angiogenesis which was accompanied by upregulation of rspo1, p53 and vegfaa in zebrafish embryos. Moreover, it revealed that MNU-induced ectopic sprouting of blood vessels was significantly reduced in rspo1-knockdown but not p53-knockdown embryos, indicating that rspo1 was necessary for MNU-induced abnormal angiogenesis. Additionally, pharmaceutical activation or inhibition of Wnt/β-catenin signaling pathway using (2'Z,3'E)- 6-bromoindirubin-3'-oxime or CCT036477 significantly increased or inhibited the pro-angiogenic effect of MNU on developing zebrafish embryos, which was confirmed by the effect of proliferation and migration in MNU-treated bEnd.3 cells. These data together indicated that rspo1/Wnt/β-catenin/vegfaa axis is involved in the modulation of MNU-induced anomalous angiogenesis.

Lifestyle, WCRF/AICR Recommendations, and Esophageal Adenocarcinoma Risk: A Systematic Review of the Literature

One of the most notable changes in the epidemiology of esophageal cancer (EC) is the rising incidence and prevalence of esophageal adenocarcinoma (EAC) in developed countries. The aim of this systematic review was to collect and summarize all the available evidence regarding lifestyle, diet, and EAC risk. We searched the PubMed and Scopus databases in January 2021 for studies providing information about lifestyle, diet, WCRF/AICR recommendations, and EAC risk; published in English; without a time filter. The Newcastle-Ottawa Scale was used to assess risk of bias. The results are stratified by risk factor. A total of 106 publications were included. Half of the case-control studies were judged as high quality, whilst practically all cohort studies were judged as high quality. Body mass index and waist circumference were associated with increased EAC risk. Physical activity did not appear to have a significant direct role in EAC risk. A diet rich in fruit, vegetables, and whole grains appeared to be more protective than a Western diet. Alcohol does not seem to be related to EAC, whereas smokers, particularly heavy smokers, have an increased risk of EAC. Prevention remains the best option to avert EAC. Comprehensible and easy to follow recommendations should be provided to all subjects. Protocol ID number: CRD-42021228762, no funds received.

High-throughput sequencing reveals circular RNA hsa_circ_0000592 as a novel player in the carcinogenesis of gastric carcinoma

Background/Aim: Gastric cancer is one of the most common malignant tumors, and its complex pathogenesis has not been fully elucidated. Circular RNAs (circRNAs) are involved in various biological processes and human diseases. However, their exact functional roles and mechanisms of action remain largely unclear. We previously discovered the differential expression of non-coding RNAs (ncRNAs) during the malignant transformation of human gastric epithelial cells. In this study, we investigated the functional roles of a significantly up-regulated circRNA (hsa_circ_0000592) in gastric cancer. Methods: N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced malignant-transformed gastric epithelial cells (GES-1-T) and normal gastric epithelial cells (GES-1-N) were analyzed by high-throughput circRNA sequencing. The top 15 up-regulated circRNAs in high-throughput sequencing results were further confirmed by qRT-PCR in different gastric epithelial cell lines. The function of the most significant circRNA (hsa_circ_0000592) was investigated by using RNA interference (RNAi) assays, fluorescence in situ hybridization analysis (FISH), and bioinformatics prediction methods. Results: A total of 1509 genes were up-regulated and 3142 genes were down-regulated in GES-1-T cells when compared with GES-1-N cells. When compared with GES-1-N cells, hsa_circ_0000592 was obviously up-regulated in GES-1-T cells, as well as in other gastric cancer cell lines. The silencing of hsa_circ_0000592 mRNA led to a decrease in cell proliferation, cell cycle arrest at the G0/G1 phase, an increased rate of apoptosis, and a reduction in cell migration. Furthermore, FISH showed that hsa_circ_0000592 was mainly located in the cytoplasm, and a bioinformatics analysis suggested that hsa_circ_0000592 might function by sponging multiple miRNAs, and most notably four conserved miRNAs, including miR-139-3p, miR-200, miR-367-3p, and miR-33a-3p. Conclusion: This study is the first to identify hsa_circ_0000592 as a novel circRNA with a critical role in MNNG-induced gastric cancer. Due to the essential role of hsa_circ_0000592 in gastric carcinoma cells, it may be considered as a potential biomarker for use in diagnosing gastric carcinoma. Our findings provide a new insight into the function of circRNAs in environmental carcinogen-induced gastric cancer.

Physical Activity and Gastrointestinal Cancer Risk: A Review

Introduction: Western lifestyle characterized by increased consumption of red meat, fat, processed food, smoking, alcohol drinking, lower consumption of vegetables and physical inactivity has been associated with a higher gastrointestinal cancer risk. Digestive system cancers are diagnosed at late stages when they show poor response to treatment and are associated with a high mortality rate. Colorectal, gastric, esophageal and pancreatic cancers are among the most common cancers worldwide. Studies show that more than 50% of gastrointestinal cancers develop as a result of inappropriate lifestyle. An inverse association between physical activity and many chronic diseases has been proved so far. However, the association between physical activity and some gastrointestinal cancers is still controversial. This study was aimed to determine the association between physical activity and gastrointestinal cancers risk.

Methods: We conducted a comprehensive search of English and Persian databases from February 2007 till December 2017, for studies investigating the association of physical activity and risk of gastrointestinal cancers. Finally, after reading full text of articles, 123 studies were included.

Results: Physical activity can be helpful in reducing the risk of gastrointestinal cancer, especially colon and pancreatic cancers. The risk reduction is not similar for different types of gastrointestinal cancers and also among males and females.

Conclusion: Different types of physical activity are associated with a lower risk of gastrointestinal cancer. However, it is unknown which type and intensity of physical activity are associated with a protective effect against gastro-intestinal cancer.

N-methyl-N-nitro-N-nitrosoguanidine-mediated ING4 downregulation contributed to the angiogenesis of transformed human gastric epithelial cells

AIMS

Angiogenesis is associated with the progression and mortality of gastric cancer. Epidemiological evidences indicate that long-term N-nitroso compounds (NOCs) exposure predominantly contributes to the mortality of gastric cancer. Therefore, further reduced mortality of gastric cancer demands to explore the exact mechanisms of NOCs induced angiogenesis. As a tumor suppressor gene, inhibitor of growth protein 4 (ING4) plays an important role in pathological angiogenesis. In this study, we will investigate ING4 expression level in human gastric epithelial cells after the long-term low dose exposure of N-methyl-N-nitro-N-nitrosoguanidine (MNNG) and the pathological impact of MNNG-reduced ING4 on angiogenesis of transformed cells.

MAIN METHODS

The soft agar colony formation assay, Western blotting, immunofluorescence and wound healing assay were used to evaluate the characteristics of transformed cells. HUVEC growth and tube formation assays were performed to test the angiogenic abilities. EMSA, luciferase reporter gene assay, real-time PCR and Western blotting were used to explore the exact mechanism.

KEY FINDINGS

By establishing transformed human gastric epithelial cells via chronic low dose treatment, a gradually ING4 downregulation was observed in the later-stage of MNNG-induced cell transformation. Moreover, we demonstrated that MNNG exposure-reduced ING4 expression significantly resulted into aggravating angiogenesis through increasing the phosphorylation level of NF-κB p65 and subsequently DAN binding activity and regulating the expressions of NF-κB p65 downstream pro-angiogenic genes, MMP-2 and MMP-9.

SIGNIFICANCE

Our findings provided a significant mechanistic insight into angiogenesis of MNNG-transformed human gastric epithelial cell and supported the concept that ING4 may be a relevant therapeutic target for gastric cancer.

Clinicopathologic Characteristics of Elderly with Gastric Cancer, and the Risk Factors of Postoperative Complications

PURPOSE

In China, gastric cancer (GC), which is one of the most common malignant tumors, has an increasing incidence in elderly population due to aging process. Since a considerable number of elderly patients with GC accepting surgical treatments developed postoperative complications, it is necessary to evaluate risk factors for postoperative complications.

MATERIALS AND METHODS

In the present study, the clinicopathologic characteristics of 3,024 elderly patients (aged ≥65 years) with GC, who underwent surgery between 1996 and 2006, were examined and contributing factors for postoperative complications were analyzed. A total of 2,915 non-elderly patients (aged <65 years) with GC during the same period were enrolled as a control group. Clinicopathologic characteristics of non-elderly patients were investigated and compared with elderly group.

RESULTS

As to clinicopathologic characteristics, significant differences were detected in terms of location of primary lesions between elderly patients and non-elderly patients (p <.05), whereas no statistical difference was observed in other characteristics between two groups (p >.05). Surgical property and method in elderly patients were similar to that in non-elderly patients (p >.05). Regression analysis showed that diabetes, chronic pulmonary disease, preoperative anemia, preoperative hypoalbuminemia, combined organ excision, and blood transfusion were independent factors for complications in elderly patients (p <.05), with some differences from non-elderly group.

CONCLUSIONS

Elderly group with GC had distinctive clinicopathologic characteristics. Surgery remains principal treatment for elderly, and proper preoperative measures are required to decrease postoperative complications.

Ischemic heart disease, factor predisposing to Barrett's adenocarcinoma: A case control study

AIM

To define the significance of ischemic heart disease (IHD) (stable angina to infarction) co-existance in Barrett esophagus (BE) patients and patients with esophageal adenocarcinoma (AdE).

METHODS

All BE/AdE patients in Blackpool-Wyre-Fylde area and Trikala prefecture identified from medical records. Patient clinical details were obtained from hospital and General Practitioner records. Additional information was gathered from validated questionnaire.

RESULTS

Forty (33%) AdE and 83 (19%) BE patients had IHD (P = 0.002). Eighteen (15%) AdE and 34 (8%) BE patients had suffered a myocardial infarction (P = 0.03). Three (3%) AdE and 7 (2%) BE patients had severe heart failure (P = 0.82). Thirty-nine (47%) BE with IHD and 8 (20%) AdE patients with IHD consumed aspirin daily (P = 0.004). Seventh-seven (93%) BE patients with IHD and 36 (90%) AdE patients with IHD were on statins (P = 0.86). Logistic regression analysis: AdE was more frequent in the elderly, with long term reflux, long BE and concurrent IHD (odds ratio: 2.086, P = 0.001) not consuming statins. Eighteen (22%) BE patients with IHD [16 (84%) with myocardial infarction] vs 33 (10%) without IHD died from non-neoplastic causes within 24 mo from BE diagnosis (P = 0.005).

CONCLUSION

IHD is more prevalent in AdE than BE patients. Increased prevalence of AdE is related with the presence of myocardial infarction but not severe heart failure, possibly because patients with BE and severe IHD have low life expectancy.

Physical activity is associated with reduced risk of esophageal cancer, particularly esophageal adenocarcinoma: a systematic review and meta-analysis

Background

Physical activity has been inversely associated with risk of several cancers. We performed a systematic review and meta-analysis to evaluate the association between physical activity and risk of esophageal cancer (esophageal adenocarcinoma [EAC] and/or esophageal squamous cell carcinoma [ESCC]).

Methods

We conducted a comprehensive search of bibliographic databases and conference proceedings from inception through February 2013 for observational studies that examined associations between recreational and/or occupational physical activity and esophageal cancer risk. Summary adjusted odds ratio (OR) estimates with 95% confidence intervals (CI) were estimated using the random-effects model.

Results

The analysis included 9 studies (4 cohort, 5 case–control) reporting 1,871 cases of esophageal cancer among 1,381,844 patients. Meta-analysis demonstrated that the risk of esophageal cancer was 29% lower among the most physically active compared to the least physically active subjects (OR, 0.71; 95% CI, 0.57-0.89), with moderate heterogeneity (I² = 47%). On histology-specific analysis, physical activity was associated with a 32% decreased risk of EAC (4 studies, 503 cases of EAC; OR, 0.68; 95% CI, 0.55-0.85) with minimal heterogeneity (I² = 0%). There were only 3 studies reporting the association between physical activity and risk of ESCC with conflicting results, and the meta-analysis demonstrated a null association (OR, 1.10; 95% CI, 0.21-5.64). The results were consistent across study design, geographic location and study quality, with a non-significant trend towards a dose–response relationship.

Conclusions

Meta-analysis of published observational studies indicates that physical activity may be associated with reduced risk of esophageal adenocarcinoma. Lifestyle interventions focusing on increasing physical activity may decrease the global burden of EAC.

miR-21 regulates N-methyl-N-nitro-N'-nitrosoguanidine-induced gastric tumorigenesis by targeting FASLG and BTG2

MicroRNAs (miRNAs) are recently discovered regulators of gene expression and are important in the regulation of many cellular events. Evidence collected to date shows that miRNAs are altered after exposure to environmental toxicants. However, the role that miR-21 plays in the gastric tumorigenesis induced by environmental carcinogens remains largely unknown. The aim of this study was to characterize the regulatory role of miR-21 in the carcinogenic processes following exposure to the N-nitroso carcinogen N-methyl-N-nitro-N'-nitrosoguanidine (MNNG). We found a progressive dose- and time-dependent increase in miR-21 expression following treatment with MNNG. Dysregulated miR-21 affected both cell growth in GES-1 cells and the gastric tumorigenesis induced with MNNG. These data demonstrate the involvement of miR-21 in the malignant transformation and tumorigenesis activated by MNNG. We also established that the Fas ligand (FASLG) and B-cell translocation gene 2 (BTG2), regulated by miR-21, contribute to the transformation induced by MNNG in GES-1 cells. This is the first study to show that miR-21 is involved in chemical carcinogenesis in vivo and in vitro. The regulation by miR-21 of the gastric carcinogenesis induced by MNNG highlights the functional roles of miRNAs in chemical carcinogenesis, and offers a new explanation of the mechanisms underlying chemical carcinogenesis.

Physical activity and risks of esophageal and gastric cancers: a meta-analysis

BACKGROUND

The incidence of esophageal and gastric cancer has been increasing rapidly worldwide in recent years, although the reason for this increase is unclear. Here, a statistical synthesis of studies that evaluated the association between physical activity, a well-known protecting factor against death and other chronic diseases, and the risk of esophageal and gastric cancer was performed.

METHODS

Potentially suitable studies were identified using Medline and Embase. The reference lists of all included articles and those of several recent reviews were searched manually. Studies were included if they (1) were published as case-control or cohort studies evaluating the association between physical activity and risk of esophageal or gastric cancer; and (2) reported point estimates (i.e., risk ratios, odds ratios) and measures of variability (i.e., 95% confidence intervals [CIs]) for physical activity and risk of esophageal or gastric cancer.

RESULTS

Fifteen studies were identified (7 cohorts, 8 case-controls; 984 esophageal and 7,087 gastric cancers). Collectively, they indicated that the risk of gastric cancer was 13% lower among the most physically active people than among the least active people (RR = 0.87, 95% confidence interval [CI] = 0.78 to 0.97) and that of esophageal cancer was 27% lower (RR = 0.73, 95% CI = 0.56 to 0.97).

CONCLUSIONS

Pooled results from observational studies support a protective effect of physical activity against both esophageal and gastric cancer.

Dietary fiber and the risk of precancerous lesions and cancer of the esophagus: a systematic review and meta-analysis

Dietary fiber has several anticarcinogenic effects and is thought to be protective against esophageal cancer. The aim of this systematic review was to quantify the association between dietary fiber and the risk of esophageal cancer by investigating histological subtypes of esophageal cancer and the stage at which fiber may influence the carcinogenic pathway. Systematic search strategies were used to identify relevant studies, and adjusted odds ratios (ORs) were combined using random-effects meta-analyses to assess the risk of cancer when comparing extreme categories of fiber intake. Ten relevant case-control studies were identified within the timeframe searched. Pooled estimates from eight studies of esophageal adenocarcinoma revealed a significant inverse association with the highest fiber intakes (OR 0.66; 95% confidence interval [CI] 0.44-0.98). Two studies also identified protective effects of dietary fiber against Barrett's esophagus. Similar, though nonsignificant, associations were observed when results from five studies of fiber intake and risk of squamous cell carcinoma were combined (OR 0.61; 95%CI 0.31-1.20). Dietary fiber is associated with protective effects against esophageal carcinogenesis, most notably esophageal adenocarcinoma. Potential methods of action include modification of gastroesophageal reflux and/or weight control.

Role of aspirin in chemoprevention of esophageal adenocarcinoma: a meta-analysis

OBJECTIVE

To identify whether regular aspirin use protects against esophageal adenocarcinoma (EA) and if so, the effect of the duration and frequency of drug exposure.

METHODS

Studies were selected from five journal/trial databases based on defined inclusion and exclusion criteria; most notably, the provision of multivariate EA odds ratios (ORs) in those taking regular aspirin. A subgroup analysis was then performed by stratifying the results according to the frequency and duration of aspirin use. The reliability of these investigations was assessed by calculating study heterogeneity and observing any elements of publication bias.

RESULTS

Nine studies were selected for the main analysis, of which five were included in the frequency analysis and three assessed the duration of aspirin use. Data pooling revealed a statistically significant EA OR of 0.671 (95% CI 0.526-0.856, P = 0.001) among all aspirin users, suggesting a protective effect. The results for duration and frequency did not reach statistical significance but nonetheless suggested possible benefits of longer, more frequent drug regimens that may be statistically confirmed by studies of larger sample sizes. Funnel plots and statistical tests demonstrated a minimal impact of publication bias on our results.

CONCLUSION

Aspirin use confers a significant protective effect against EA with a suggestion that the degree of protection may be increased by the longer duration and higher frequency of usage.

Diverging trends in the incidence of reflux-related and Helicobacter pylori-related gastric cardia cancer

GOALS

To describe historical incidence trends of 2 subtypes of gastric cardia cancer.

BACKGROUND

The incidence of gastric cardia cancer has increased in western countries. Prior studies have treated cardia cancer as a single entity, but recent data suggest that there are 2 distinct subtypes: reflux-related and Helicobacter pylori-related.

STUDY

We conducted a population-based study using Connecticut Tumor Registry data from 1955 to 2007. Age-adjusted incidence rates (per 100,000 person-years) were calculated for gastric cancer, as a whole and by anatomic subsite, and for esophageal adenocarcinoma. Cardia and noncardia cancer incidence rates were further adjusted to account for cases with unspecified subsite. Mathematical formulas were derived to calculate incidence rates for reflux-related and H. pylori-related cardia cancer.

RESULTS

The adjusted incidence of cardia cancer was 4.0 per 100,000 in 1955 to 1959, decreased to 2.4 per 100,000 in 1965 to 1969 before increasing to 3.4 per 100,000 by 2003 to 2007. The incidence of H. pylori-related cardia cancer decreased from 3.7 to 1.0 per 100,000 over the study period, whereas reflux-related cardia cancer increased progressively from 0.3 to 2.4 per 100,000. The curves for reflux-related cardia cancer and esophageal adenocarcinoma closely mirrored each other, and their combined incidence increased from 0.5 per 100,000 in 1955 to 1959 to 5.6 per 100,000 in 2003 to 2007.

CONCLUSIONS

The incidence of reflux-related cardia cancer has steadily increased, whereas H. pylori-related cardia cancer has declined progressively since the mid-20th century. Trends in reflux-related cardia cancer and esophageal adenocarcinoma incidence are very similar, suggesting that these 2 cancers share a similar etiology and pathophysiological process.

Methodological issues when analysing the role of physical activity in gastric cancer prevention: a critical review

The beneficial effect of physical activity (PA) has been confirmed in several types of cancer (especially colon and breast tumours). However, the role of PA as a risk factor directly related to the incidence of gastric cancer is still open to doubt. This is in part due to the fact that most studies have not considered gastric sub-site or histology of oesophageal cancer, as well as the different approaches used in order to measure PA. Indeed, some studies have tried to link gastric cancer to PA intensity and timing, whereas others have focused on a specific PA type such as recreational, occupational or sporting activity. Furthermore, most of them do not use validated questionnaires, and others create a PA index and employ different unit measures (metabolic equivalents, hours/week, times per week, etc.), which makes it difficult to compare its findings. Under these circumstances, this brief critical review aims to explore and show all the methodological issues that need to be taken into account in order to objectify the link between PA and gastric cancer, as well as provide alternative solutions to these matters.

Update: modern approaches to the treatment of localized esophageal cancer

The optimal treatment strategy for esophageal cancer continues to be a topic of debate. Improvements in chemotherapy drugs, surgical techniques, and radiotherapy planning and delivery have led to the design of treatment approaches that are specific to both the stage of the tumor and the overall performance status of the patient. Surgery continues to be the standard treatment option for localized disease, but multimodality treatments that include radiation and chemotherapy with surgery are increasingly used. The next few years will continue to see improvements in radiation techniques, especially proton beam treatment; the development of additional minimally invasive surgical approaches to minimize postoperative side effects; and the discovery of molecular biomarkers to help specifically target treatment of esophageal cancer in individual patients.

Aspirin use and the risk of gastric cancer: a meta-analysis

PURPOSE

Studies investigating the association between aspirin use and gastric cancer risk have reported conflicting results. The objective of this study was to quantitatively summarize the evidence for such a relationship.

RESULTS

Two investigators independently searched the Medline, PubMed, Embase, and Academic Search Premier (EBSCO) databases. Fourteen studies with a total number of 5,640 gastric cancer cases were identified. Most of the study populations were Caucasian. The combined results based on all studies showed there was no statistically significant difference between aspirin use and gastric cancer risk (odds ratio (OR) = 0.80, 95% confidence intervals (CI) = 0.54-1.19). When stratifying by study designs and gender, results were similar except for cohort and randomized controlled trial (RCT) studies (OR = 0.72, 95% CI = 0.62-0.84). When stratifying by location and Helicobacter pylori (H. pylori) infection, we observed there were lower risks in noncardia gastric cancer (OR = 0.62, 95% CI = 0.55-0.69) and H. pylori-infected individuals (OR = 0.62, 95% CI = 0.42-0.90) for aspirin users. Among Caucasians, there were lower risks for noncardia gastric cancer (OR = 0.73, 95% CI = 0.62-0.87) and H. pylori-infected individuals (OR = 0.62, 95% CI = 0.42-0.90) also.

CONCLUSIONS

This meta-analysis indicated that regular use of aspirin may be associated with reduced risk of noncardia gastric cancer, especially among Caucasians; for H. pylori-infected subjects the result was similar.

Physical activity and esophageal and gastric carcinoma in a large prospective study

BACKGROUND

Few studies have investigated the relationship of physical activity to esophageal and gastric carcinoma according to histology and anatomic site.

METHODS

This study prospectively investigated the association between physical activity and esophageal and gastric carcinoma in a cohort of 487,732 U.S. men and women, followed from 1995-1996 to December 31, 2003. All analyses were performed in 2007-2008.

RESULTS

During 8 years of follow-up study, 523 cases of esophageal carcinoma (149 squamous cell and 374 adenocarcinoma) and 642 cases of gastric carcinoma (313 cardia and 329 noncardia) were documented. Physical activity was associated with reduced risk of esophageal and gastric adenocarcinomas but was unrelated to esophageal squamous cell carcinoma. The inverse association with physical activity was strongest for gastric noncardia adenocarcinoma (multivariate relative risk [RR] for highest versus lowest physical activity level=0.62, 95% CI=0.44, 0.87). Relationships were weaker but evident for gastric cardia adenocarcinoma (RR=0.83; 95% CI=0.58, 1.19) and esophageal adenocarcinoma (RR=0.75; 95% CI=0.53, 1.06). No significant relationship with physical activity was observed for esophageal squamous cell carcinoma (RR=1.05; 95% CI=0.64, 1.74). Exclusion of cases diagnosed during the first 2 follow-up years did not change those estimates, indicating that the findings are not due to decreased activity levels among participants with undiagnosed cancer at entry.

CONCLUSIONS

Physical activity may play a role in the prevention of upper gastrointestinal tract adenocarcinomas. No association was seen between physical activity and esophageal squamous cell carcinoma.

The incidence of esophageal cancer and high-grade dysplasia in Barrett's esophagus: a systematic review and meta-analysis

Barrett's esophagus is a well-recognized precursor of esophageal adenocarcinoma. Surveillance of Barrett's esophagus patients is recommended to detect high-grade dysplasia (HGD) or early cancer. Because of wide variation in the published cancer incidence in Barrett's esophagus, the authors undertook a systematic review and meta-analysis of cancer and HGD incidence in Barrett's esophagus. Ovid Medline (Ovid Technologies, Inc., New York, New York) and EMBASE (Elsevier, Amsterdam, the Netherlands) databases were searched for papers published between 1950 and 2006 that reported the cancer/HGD risk in Barrett's esophagus. Where possible, early incident cancers/HGD were excluded, as were patients with HGD at baseline. Forty-seven studies were included in the main analysis, and the pooled estimate for cancer incidence in Barrett's esophagus was 6.1/1,000 person-years, 5.3/1,000 person-years when early incident cancers were excluded, and 4.1/1,000 person-years when both early incident cancer and HGD at baseline were excluded. Corresponding figures for combined HGD/cancer incidence were 10.0 person-years, 9.3 person-years, and 9.1/1,000 person-years. Compared with women, men progressed to cancer at twice the rate. Cancer or HGD/cancer incidences were lower when only high-quality studies were analyzed (3.9/1,000 person-years and 7.7/1,000 person-years, respectively). The pooled estimates of cancer and HGD incidence were low, suggesting that the cost-effectiveness of surveillance is questionable unless it can be targeted to those with the highest cancer risk.