eQTL Set-Based Association Analysis Identifies Novel Susceptibility Loci for Barrett Esophagus and Esophageal Adenocarcinoma.

BACKGROUND: Over 20 susceptibility single-nucleotide polymorphisms (SNP) have been identified for esophageal adenocarcinoma (EAC) and its precursor, Barrett esophagus (BE), explaining a small portion of heritability. METHODS: Using genetic data from 4,323 BE and 4,116 EAC patients aggregated by international consortia including the Barrett's and Esophageal Adenocarcinoma Consortium (BEACON), we conducted a comprehensive transcriptome-wide association study (TWAS) for BE/EAC, leveraging Genotype Tissue Expression (GTEx) gene-expression data from six tissue types of plausible relevance to EAC etiology: mucosa and muscularis from the esophagus, gastroesophageal (GE) junction, stomach, whole blood, and visceral adipose. Two analytical approaches were taken: standard TWAS using the predicted gene expression from local expression quantitative trait loci (eQTL), and set-based SKAT association using selected eQTLs that predict the gene expression. RESULTS: Although the standard approach did not identify significant signals, the eQTL set-based approach identified eight novel associations, three of which were validated in independent external data (eQTL SNP sets for EXOC3, ZNF641, and HSP90AA1). CONCLUSIONS: This study identified novel genetic susceptibility loci for EAC and BE using an eQTL set-based genetic association approach. IMPACT: This study expanded the pool of genetic susceptibility loci for EAC and BE, suggesting the potential of the eQTL set-based genetic association approach as an alternative method for TWAS analysis.

Germline variation in the insulin-like growth factor pathway and risk of Barrett's esophagus and esophageal adenocarcinoma.

Genome-wide association studies (GWAS) of esophageal adenocarcinoma (EAC) and its precursor, Barrett's esophagus (BE), have uncovered significant genetic components of risk, but most heritability remains unexplained. Targeted assessment of genetic variation in biologically relevant pathways using novel analytical approaches may identify missed susceptibility signals. Central obesity, a key BE/EAC risk factor, is linked to systemic inflammation, altered hormonal signaling and insulin-like growth factor (IGF) axis dysfunction. Here, we assessed IGF-related genetic variation and risk of BE and EAC. Principal component analysis was employed to evaluate pathway-level and gene-level associations with BE/EAC, using genotypes for 270 single-nucleotide polymorphisms (SNPs) in or near 12 IGF-related genes, ascertained from 3295 BE cases, 2515 EAC cases and 3207 controls in the Barrett's and Esophageal Adenocarcinoma Consortium (BEACON) GWAS. Gene-level signals were assessed using Multi-marker Analysis of GenoMic Annotation (MAGMA) and SNP summary statistics from BEACON and an expanded GWAS meta-analysis (6167 BE cases, 4112 EAC cases, 17 159 controls). Global variation in the IGF pathway was associated with risk of BE (P = 0.0015). Gene-level associations with BE were observed for GHR (growth hormone receptor; P = 0.00046, false discovery rate q = 0.0056) and IGF1R (IGF1 receptor; P = 0.0090, q = 0.0542). These gene-level signals remained significant at q < 0.1 when assessed using data from the largest available BE/EAC GWAS meta-analysis. No significant associations were observed for EAC. This study represents the most comprehensive evaluation to date of inherited genetic variation in the IGF pathway and BE/EAC risk, providing novel evidence that variation in two genes encoding cell-surface receptors, GHR and IGF1R, may influence risk of BE.

Surgery versus radical endotherapies for early cancer and high-grade dysplasia in Barrett's oesophagus.

BACKGROUND: Barrett's oesophagus is one of the most common pre-malignant lesions in the world. Currently the mainstay of therapy is surgical management of advanced cancer but this has improved the five-year survival very little since the 1980s. As a consequence, improved survival relies on early detection through endoscopic surveillance programmes. Success of this strategy relies on the fact that late-stage pre-malignant lesions or very early cancers can be cured by intervention. Currently there is considerable controversy over which method is best: that is conventional open surgery or endotherapy (techniques involving endoscopy). OBJECTIVES: We used data from randomised controlled trials (RCTs) to examine the effectiveness of endotherapies compared with surgery in people with Barrett's oesophagus, those with early neoplasias (defined as high-grade dysplasia (HGD) and those with early cancer (defined as carcinoma in-situ, superficially invasive, early cancer or superficial cancer T-1m (T1-a) and T-1sm (T1-b)). SEARCH METHODS: We used the Cochrane highly sensitive search strategy to identify RCTs in MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), ISI Web of Science, EBMR, Controlled Trials mRCT and ISRCTN, and LILACS, in July and August 2008. The searches were updated in 2009 and again in April 2012. SELECTION CRITERIA: Types of studies: RCTs comparing endotherapies with surgery in the treatment of high-grade dysplasia or early cancer. All cellular types of cancer were included (i.e. adenocarcinomas, squamous cell carcinomas and more unusual types) but will be discussed separately. TYPES OF PARTICIPANTS: patients of any age and either gender with a histologically confirmed diagnosis of early neoplasia (HGD and early cancer) in Barrett's or squamous lined oesophagus. Types of interventions; endotherapies (the intervention) compared with surgery (the control), all with curative intent. DATA COLLECTION AND ANALYSIS: Reports of studies that meet the inclusion criteria for this review would have been analysed using the methods detailed in Appendix 9. MAIN RESULTS: We did not identify any studies that met the inclusion criteria. In total we excluded 13 studies that were not RCTs but that compared surgery and endotherapies. AUTHORS' CONCLUSIONS: This Cochrane review has indicated that there are no RCTs to compare management options in this vital area, therefore trials should be undertaken as a matter of urgency. The problems with such randomised methods are standardising surgery and endotherapies in all sites, standardising histopathology in all centres, assessing which patients are fit or unfit for surgery and making sure there are relevant outcomes for the study (i.e. long-term survival (over five or more years)) and no progression of HGD.

A feasibility trial of Acetic acid-targeted Biopsies versus nontargeted quadrantic biopsies during BArrett's surveillance: the ABBA trial.

BACKGROUND: The aims of this study were to compare neoplasia detection rates for nontargeted biopsies (Seattle protocol) versus acetic acid-targeted biopsies (Portsmouth protocol) during Barrett's surveillance and to explore feasibility, patient/clinician experience, acceptance, and barriers/enablers to study participation and implementation of the acetic acid technique. METHODS: This was a mixed-methods feasibility study including a pilot multicenter, randomized, crossover trial with qualitative interviews. Patients under Barrett's surveillance with no history of neoplasia were included. Patients underwent two endoscopies, one with each protocol, 8 weeks apart. Outcomes included recruitment and retention rates, neoplasia yield, and number of biopsies. RESULTS: 200 patients were recruited from 6 centers, and 174 (87.0 %) underwent both procedures. Neoplasia prevalence was 4.7 % (9/192). High grade dysplasia and cancer were detected with both protocols. Five low grade dysplasias were detected (two with acetic acid, four with nontargeted biopsies; one lesion was detected with both techniques). A total of 2139 biopsies were taken in the nontargeted arm and 226 in the acetic acid arm. Both patients and clinicians found the acetic acid technique acceptable. Based on these data, a noninferiority, tandem, crossover trial would require an estimated 2828 patients. CONCLUSIONS: We demonstrated the feasibility of performing a crossover endoscopy trial in Barrett's surveillance. Low neoplasia yield makes this design necessary and qualitative results demonstrated patient and clinician acceptance. The reduced numbers of biopsies suggest that the acetic acid technique could result in cost savings, providing the lack of missed pathology can be proven in a fully powered definitive trial.

Germline variation in inflammation-related pathways and risk of Barrett's oesophagus and oesophageal adenocarcinoma.

OBJECTIVE: Oesophageal adenocarcinoma (OA) incidence has risen sharply in Western countries over recent decades. Local and systemic inflammation is considered an important contributor to OA pathogenesis. Established risk factors for OA and its precursor, Barrett's oesophagus (BE), include symptomatic reflux, obesity and smoking. The role of inherited genetic susceptibility remains an area of active investigation. Here, we explore whether germline variation related to inflammatory processes influences susceptibility to BE/OA. DESIGN: We used data from a genomewide association study of 2515 OA cases, 3295 BE cases and 3207 controls. Our analysis included 7863 single-nucleotide polymorphisms (SNPs) in 449 genes assigned to five pathways: cyclooxygenase (COX), cytokine signalling, oxidative stress, human leucocyte antigen and nuclear factor-κB. A principal components-based analytic framework was employed to evaluate pathway-level and gene-level associations with disease risk. RESULTS: We identified a significant signal for the COX pathway in relation to BE risk (p=0.0059, false discovery rate q=0.03), and in gene-level analyses found an association with microsomal glutathione-S-transferase 1 (MGST1); (p=0.0005, q=0.005). Assessment of 36 MGST1 SNPs identified 14 variants associated with elevated BE risk (q<0.05). Four of these were subsequently confirmed (p<5.5×10-5) in a meta-analysis encompassing an independent set of 1851 BE cases and 3496 controls, and are known strong expression quantitative trait loci for MGST1. Three such variants were associated with similar elevations in OA risk. CONCLUSIONS: This study provides the most comprehensive evaluation of inflammation-related germline variation in relation to risk of BE/OA and suggests that variants in MGST1 influence disease susceptibility.

BOB CAT: A Large-Scale Review and Delphi Consensus for Management of Barrett's Esophagus With No Dysplasia, Indefinite for, or Low-Grade Dysplasia.

OBJECTIVES: Barrett's esophagus (BE) is a common premalignant lesion for which surveillance is recommended. This strategy is limited by considerable variations in clinical practice. We conducted an international, multidisciplinary, systematic search and evidence-based review of BE and provided consensus recommendations for clinical use in patients with nondysplastic, indefinite, and low-grade dysplasia (LGD). METHODS: We defined the scope, proposed statements, and searched electronic databases, yielding 20,558 publications that were screened, selected online, and formed the evidence base. We used a Delphi consensus process, with an 80% agreement threshold, using GRADE (Grading of Recommendations Assessment, Development and Evaluation) to categorize the quality of evidence and strength of recommendations. RESULTS: In total, 80% of respondents agreed with 55 of 127 statements in the final voting rounds. Population endoscopic screening is not recommended and screening should target only very high-risk cases of males aged over 60 years with chronic uncontrolled reflux. A new international definition of BE was agreed upon. For any degree of dysplasia, at least two specialist gastrointestinal (GI) pathologists are required. Risk factors for cancer include male gender, length of BE, and central obesity. Endoscopic resection should be used for visible, nodular areas. Surveillance is not recommended for <5 years of life expectancy. Management strategies for indefinite dysplasia (IND) and LGD were identified, including a de-escalation strategy for lower-risk patients and escalation to intervention with follow-up for higher-risk patients. CONCLUSIONS: In this uniquely large consensus process in gastroenterology, we made key clinical recommendations for the escalation/de-escalation of BE in clinical practice. We made strong recommendations for the prioritization of future research.

Polymorphisms near TBX5 and GDF7 are associated with increased risk for Barrett's esophagus.

BACKGROUND & AIMS: Barrett's esophagus (BE) increases the risk of esophageal adenocarcinoma (EAC). We found the risk to be BE has been associated with single nucleotide polymorphisms (SNPs) on chromosome 6p21 (within the HLA region) and on 16q23, where the closest protein-coding gene is FOXF1. Subsequently, the Barrett's and Esophageal Adenocarcinoma Consortium (BEACON) identified risk loci for BE and esophageal adenocarcinoma near CRTC1 and BARX1, and within 100 kb of FOXP1. We aimed to identify further SNPs that increased BE risk and to validate previously reported associations. METHODS: We performed a genome-wide association study (GWAS) to identify variants associated with BE and further analyzed promising variants identified by BEACON by genotyping 10,158 patients with BE and 21,062 controls. RESULTS: We identified 2 SNPs not previously associated with BE: rs3072 (2p24.1; odds ratio [OR] = 1.14; 95% CI: 1.09-1.18; P = 1.8 × 10(-11)) and rs2701108 (12q24.21; OR = 0.90; 95% CI: 0.86-0.93; P = 7.5 × 10(-9)). The closest protein-coding genes were respectively GDF7 (rs3072), which encodes a ligand in the bone morphogenetic protein pathway, and TBX5 (rs2701108), which encodes a transcription factor that regulates esophageal and cardiac development. Our data also supported in BE cases 3 risk SNPs identified by BEACON (rs2687201, rs11789015, and rs10423674). Meta-analysis of all data identified another SNP associated with BE and esophageal adenocarcinoma: rs3784262, within ALDH1A2 (OR = 0.90; 95% CI: 0.87-0.93; P = 3.72 × 10(-9)). CONCLUSIONS: We identified 2 loci associated with risk of BE and provided data to support a further locus. The genes we found to be associated with risk for BE encode transcription factors involved in thoracic, diaphragmatic, and esophageal development or proteins involved in the inflammatory response.

Surgery versus radical endotherapies for early cancer and high-grade dysplasia in Barrett's oesophagus.

BACKGROUND: Barrett's oesophagus is one of the most common pre-malignant lesions in the world. Currently the mainstay of therapy is surgical management of advanced cancer but this has improved the five-year survival very little since the 1980s. As a consequence, improved survival relies on early detection through endoscopic surveillance programmes. Success of this strategy relies on the fact that late-stage pre-malignant lesions or very early cancers can be cured by intervention. Currently there is considerable controversy over which method is best: that is conventional open surgery or endotherapy (techniques involving endoscopy). OBJECTIVES: We used data from randomised controlled trials (RCTs) to examine the effectiveness of endotherapies compared with surgery in people with Barrett's oesophagus, those with early neoplasias (defined as high-grade dysplasia (HGD) and those with early cancer (defined as carcinoma in-situ, superficially invasive, early cancer or superficial cancer T-1m (T1-a) and T-1sm (T1-b)). SEARCH METHODS: We used the Cochrane highly sensitive search strategy to identify RCTs in MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), ISI Web of Science, EBMR, Controlled Trials mRCT and ISRCTN, and LILACS, in July and August 2008. The searches were updated in 2009 and again in April 2012. SELECTION CRITERIA: Types of studies: RCTs comparing endotherapies with surgery in the treatment of or early cancer. All cellular types of cancer were included (i.e. adenocarcinomas, squamous cell carcinomas and more unusual types) but will be discussed separately. TYPES OF PARTICIPANTS: patients of any age and either gender with a histologically confirmed diagnosis of early neoplasia (HGD and early cancer) in Barrett's or squamous lined oesophagus.Types of interventions; endotherapies (the intervention) compared with surgery (the control), all with curative intent. DATA COLLECTION AND ANALYSIS: Reports of studies that meet the inclusion criteria for this review would have been analysed using the methods detailed in Appendix 9. MAIN RESULTS: We did not identify any studies that met the inclusion criteria. In total we excluded 13 studies that were not RCTs but that compared surgery and endotherapies. AUTHORS' CONCLUSIONS: This Cochrane review has indicated that there are no RCTs to compare management options in this vital area, therefore trials should be undertaken as a matter of urgency. The problems with such randomised methods are standardising surgery and endotherapies in all sites, standardising histopathology in all centres, assessing which patients are fit or unfit for surgery and making sure there are relevant outcomes for the study (i.e. long-term survival (over five or more years)) and no progression of HGD.

Endoscopic therapies for the prevention and treatment of early esophageal neoplasia.

Esophageal cancers have traditionally been diagnosed late and prognosis has been dire. For many years the only real treatment option was esophagectomy with substantial morbidity and mortality. This situation has now changed dramatically. Improvements have been achieved in surgical outcomes and there is an array of new effective treatment options now available, particularly for the increasing proportion diagnosed with early-stage disease. Minimally invasive endoscopic therapies can now prevent, cure or palliate esophageal cancers. This article aims to investigate the role and evidence base for these new therapeutic options.

Surgery versus radical endotherapies for early cancer and high grade dysplasia in Barrett's oesophagus.

BACKGROUND: Barrett's oesophagus is one of the most common premalignant lesions in the world. Currently the mainstay of therapy is surgical management of advanced cancer but this has improved the five-year survival very little in the last 30 years. As a consequence, improved survival relies on early detection through endoscopic surveillance programmes. Success of this strategy relies on the fact that late stage premalignant lesions or very early cancers can be cured by intervention. Currently there is considerable controversy over which method is best: i.e. conventional open surgery or endotherapy (techniques involving endoscopy). OBJECTIVES: We used data from randomised controlled trials to examine the effectiveness of endotherapies compared with surgery, in people with Barrett's Oesophagus; those with early neoplasias (defined as high grade dysplasia (HGD), and those with early cancer (defined as carcinoma in-situ, superficially invasive, early cancer or superficial cancer T-1m (T1-a) and T-1sm (T1-b)). SEARCH STRATEGY: We used the Cochrane highly sensitive search strategy to identify randomised trials in MEDLINE, EMBASE, CENTRAL, ISI Web of Science, EBMR, Controlled Trials mRCT and ISRCTN and LILACS, in July and August 2008. SELECTION CRITERIA: Types of studies: randomised controlled trials comparing endotherapies with surgery in the treatment of high grade dysplasia (HGD), or early cancer. All cellular types of cancer were included (i.e. adenocarcinomas, squamous cell carcinomas and more unusual types) but will be discussed separately. TYPES OF PARTICIPANTS: patients of any age and either gender with a histologically confirmed diagnosis of early neoplasia (HGD and early cancer) in Barrett's or squamous lined oesophagus.Types of interventions; endotherapies (the intervention) compared with surgery (the control), all with curative intent. DATA COLLECTION AND ANALYSIS: Reports of studies which meet the inclusion criteria for this review would have been analysed using the methods detailed in Appendix 9. MAIN RESULTS: We did not identify any studies which met the inclusion criteria. AUTHORS' CONCLUSIONS: This Cochrane review has indicated that there are no randomised control trials to compare management options in this vital area, therefore trials should be undertaken as a matter of urgency. The problems with such randomised methods are standardising surgery and endotherapies in all sites; standardising histopathology in all centres; assessing which patients are fit or unfit for surgery; and making sure there are relevant outcomes for the study i.e. long term survival (over five or more years) and no progression of high grade dysplasia.

Surgery versus radical endotherapies for early cancer and high grade dysplasia in Barrett's oesophagus.

BACKGROUND: Barrett's oesophagus is one of the most common premalignant lesions in the world. Currently the mainstay of therapy is surgical management of advanced cancer but this has improved the five-year survival very little in the last 30 years. As a consequence, improved survival relies on early detection through endoscopic surveillance programmes. Success of this strategy relies on the fact that late stage premalignant lesions or very early cancers can be cured by intervention. Currently there is considerable controversy over which method is best: i.e. conventional open surgery or endotherapy (techniques involving endoscopy). OBJECTIVES: We used data from randomised controlled trials to examine the effectiveness of endotherapies compared with surgery, in people with Barrett's Oesophagus; those with early neoplasias (defined as high grade dysplasia (HGD), and those with early cancer (defined as carcinoma in-situ, superficially invasive, early cancer or superficial cancer T-1m (T1-a) and T-1sm (T1-b)). SEARCH STRATEGY: We used the Cochrane highly sensitive search strategy to identify randomized trials in MEDLINE, EMBASE, CENTRAL, ISI Web of Science, EBMR, Controlled Trials mRCT and ISRCTN and LILACS, in July and August 2008. SELECTION CRITERIA: Types of studies: randomised controlled trials comparing endotherapies with surgery in the treatment of high grade dysplasia (HGD), or early cancer. All cellular types of cancer were included (i.e. adenocarcinomas, squamous cell carcinomas and more unusual types) but will be discussed separately. TYPES OF PARTICIPANTS: patients of any age and either gender with a histologically confirmed diagnosis of early neoplasia (HGD and early cancer) in Barrett's or squamous lined oesophagus.Types of interventions; endotherapies (the intervention) compared with surgery (the control), all with curative intent. DATA COLLECTION AND ANALYSIS: Reports of studies which meet the inclusion criteria for this review would have been analysed using the methods detailed in Appendix 9. MAIN RESULTS: We did not identify any studies which met the inclusion criteria. AUTHORS' CONCLUSIONS: This Cochrane review has indicated that there are no randomised control trials to compare management options in this vital area, therefore trials should be undertaken as a matter of urgency. The problems with such randomised methods are standardising surgery and endotherapies in all sites; standardising histopathology in all centres; assessing which patients are fit or unfit for surgery; and making sure there are relevant outcomes for the study i.e. no progression of high grade dysplasia or long term survival i.e. over five years.

Management of Barrett's esophagus in the UK: overtreated and underbiopsied but improved by the introduction of a national randomized trial.

OBJECTIVES: To assess the variation in practice of Barrett's esophagus (BE) management in comparison with accepted international guidelines before and after the introduction of a large BE randomized controlled trial (RCT) with protocols including those of tissue sampling. DESIGN: A validated anonymized questionnaire was sent to 401 senior attending gastroenterologists asking for details of their current management of BE, especially histological sampling. Of the 228 respondents, 57 individuals (each from a different center) were in the first group to enter the ASPirin Esomeprazole (BE) Chemoprevention Trial (AspECT), and we assessed change in practice in these centers. RESULTS: Ninety percent of specialists did not take adequate biopsies for histological diagnosis. Furthermore, 74% would consider aggressive surgical resection for prevalent cases of high-grade dysplasia in BE as their first-line choice despite the associated perioperative mortality. Ninety-two percent claim their lack of adherence to guidelines is because there is a need for stronger evidence for surveillance and medical interventions. Effect of the AspECT trial: Those clinicians in centers where the AspECT trial has started have improved adherence to ACG guidelines compared with their previous practice (P < 0.05). BE patients now get 18.8% more biopsies compared with previous practice, and 37.7% if the patient is entered into the AspECT trial (P < 0.01). CONCLUSIONS: This large study indicates both wide variation in practice and poor compliance with guidelines. Because optimal histology is arguably the most important facet of BE management, the improvement in practice in centers taking part in the AspECT trial indicates an additional value of large international RCTs.

An epidemiological study of achalasia among the South Asian population of Leicester, 1986-2005.

Achalasia is an uncommon esophageal motility disorder of unknown etiology that predominantly affects people over the age of 50. The overall incidence in this study was 0.89 cases/10(5)/year. There was no significant difference in the proportion of South Asian women with achalasia compared to the proportion of men affected in the whole population nor between the male-to-female ratio in the patient group compared to the healthy population. Throughout the twentieth century there have been sporadic attempts to find any etiological link but to date none have been confirmed. However, there is evidence that environmental factors may be important and these are reflected in geographical differences in the distribution of the disease. In this study we were also unable to identify any triggering factor responsible for the development of achalasia.