Non-biopsy detection of intestinal metaplasia and dysplasia in Barrett's esophagus: a prospective multicenter study

Towards screening Barrett's oesophagus: current guidelines, imaging modalities and future developments

Barrett's oesophagus is the only known precursor to oesophageal adenocarcinoma (OAC). Although guidelines on the screening and surveillance exist in Barrett's oesophagus, the current strategies are inadequate. Oesophagogastroduodenoscopy (OGD) is the gold standard method in screening for Barrett's oesophagus. This invasive method is expensive with associated risks negating its use as a current screening tool for Barrett's oesophagus. This review explores current definitions, epidemiology, biomarkers, surveillance, and screening in Barrett's oesophagus. Imaging modalities applicable to this condition are discussed, in addition to future developments. There is an urgent need for an alternative non-invasive method of screening and/or surveillance which could be highly beneficial towards reducing waiting times, alleviating patient fears and reducing future costs in current healthcare services. Vibrational spectroscopy has been shown to be promising in categorising Barrett's oesophagus through to high-grade dysplasia (HGD) and OAC. These techniques need further validation through multicentre trials.

Barrett's esophagus: best practices for treatment and post-treatment surveillance

Barrett's esophagus (BE) is a premalignant condition that increases the risk of esophageal adenocarcinoma (EAC). Significantly more common in the Western world, risk factors include increased age, male sex, white race, gastro-esophageal reflux disease (GERD), central obesity, and cigarette smoking. The rates of progression to cancer depend on the grade of Barrett's dysplasia. Screening for BE is recommended in patients with GERD and additional risk factors. Endoscopic surveillance of patients with BE likely improves overall outcomes. Advanced endoscopic imaging can help increase the efficiency of current endoscopic surveillance. Endoscopic therapy is safe and effective for the treatment of dysplastic BE and intramucosal EAC, but ongoing surveillance following treatment is necessary. This review will cover screening, surveillance, advanced imaging, chemoprevention, endoscopic treatment, and post-treatment surveillance of BE.

Role of endoscopy in early oesophageal cancer

Incidence of oesophageal adenocarcinoma has increased exponentially in the West over the past few decades. Following detection of advanced cancers, 5-year survival rates remain bleak, making identification of early neoplasia, which has a better outcome, important. Detection of subtle oesophageal lesions during endoscopy can be challenging, and advanced imaging techniques might improve their detection. High-definition endoscopy has become a standard in most endoscopy centres, and this technology probably provides better delineation of mucosal features than standard-definition endoscopy. Various image enhancement techniques are now available with the development of new electronics and software systems. Image enhancement with chromoendoscopy using dyes has been a cost-effective option for many years, yet these techniques have been replaced in some contexts by electronic chromoendoscopy, which can be used with the press of a button. However, Lugol's chromoendoscopy remains the gold standard to identify squamous dysplasia. Identification and characterization of subtle neoplastic lesions could help to target biopsies and perform endoscopic resection for better local staging and definitive therapy. In vivo histology with techniques such as confocal endomicroscopy could make endotherapy feasible within a shorter timescale than when relying on histology on tissue samples. Once early neoplasia is identified, treatments include endoscopic resection, endoscopic submucosal dissection or various ablative techniques. Endotherapy has the advantage of being a less invasive technique than oesophagectomy, and is associated with lower mortality and morbidity. Endoscopic ablation therapies have evolved over the past few years, with radiofrequency ablation showing the best results in terms of success rates and complications in Barrett dysplasia.

High Mobility Group A proteins in esophageal carcinomas

We have recently shown that HMGA2 is overexpressed in esophageal squamous cell carcinoma (ESCC) and its detection allows to discriminate between cancer and normal surrounding tissue proposing HMGA2 as a novel diagnostic marker. Interestingly, esophageal adenocarcinoma shows an opposite behavior with the overexpression of HMGA1 but not HMGA2. Moreover, we show that the suppression of HMGA2 in 2 ESCC cell lines reduces the malignant phenotype. Then, this paper highlights a differential induction of the HMGA proteins, depending on the cancer histological type, and reinforces the perspective of an innovative esophageal cancer therapy based on the suppression of the HMGA protein function and/or expression.

ASGE Technology Committee systematic review and meta-analysis assessing the ASGE Preservation and Incorporation of Valuable Endoscopic Innovations thresholds for adopting real-time imaging-assisted endoscopic targeted biopsy during endoscopic surveillance of Barrett's esophagus

BACKGROUND AND AIMS

Endoscopic real-time imaging of Barrett's esophagus (BE) with advanced imaging technologies enables targeted biopsies and may eliminate the need for random biopsies to detect dysplasia during endoscopic surveillance of BE. This systematic review and meta-analysis was performed by the American Society for Gastrointestinal Endoscopy (ASGE) Technology Committee to specifically assess whether acceptable performance thresholds outlined by the ASGE Preservation and Incorporation of Valuable Endoscopic Innovations (PIVI) document for clinical adoption of these technologies have been met.

METHODS

We conducted meta-analyses calculating the pooled sensitivity, negative predictive value (NPV), and specificity for chromoendoscopy by using acetic acid and methylene blue, electronic chromoendoscopy by using narrow-band imaging, and confocal laser endomicroscopy (CLE) for the detection of dysplasia. Random effects meta-analysis models were used. Statistical heterogeneity was evaluated by means of I(2) statistics.

RESULTS

The pooled sensitivity, NPV, and specificity for acetic acid chromoendoscopy were 96.6% (95% confidence interval [CI], 95-98), 98.3% (95% CI, 94.8-99.4), and 84.6% (95% CI, 68.5-93.2), respectively. The pooled sensitivity, NPV, and specificity for electronic chromoendoscopy by using narrow-band imaging were 94.2% (95% CI, 82.6-98.2), 97.5% (95% CI, 95.1-98.7), and 94.4% (95% CI, 80.5-98.6), respectively. The pooled sensitivity, NPV, and specificity for endoscope-based CLE were 90.4% (95% CI, 71.9-97.2), 98.3% (95% CI, 94.2-99.5), and 92.7% (95% CI, 87-96), respectively.

CONCLUSIONS

Our meta-analysis indicates that targeted biopsies with acetic acid chromoendoscopy, electronic chromoendoscopy by using narrow-band imaging, and endoscope-based CLE meet the thresholds set by the ASGE PIVI, at least when performed by endoscopists with expertise in advanced imaging techniques. The ASGE Technology Committee therefore endorses using these advanced imaging modalities to guide targeted biopsies for the detection of dysplasia during surveillance of patients with previously nondysplastic BE, thereby replacing the currently used random biopsy protocols.

Advances in the management of Barrett's esophagus and early esophageal adenocarcinoma

The incidence of esophageal adenocarcinoma (EAC) has markedly increased in the United States over the last few decades. Barrett’s esophagus (BE) is the most significant known risk factor for this malignancy. Theoretically, screening and treating early BE should help prevent EAC but the exact incidence of BE and its progression to EAC is not entirely known and cost-effectiveness studies for Barrett’s screening are lacking. Over the last few years, there have been major advances in our understanding of the epidemiology, pathogenesis and endoscopic management of BE. These developments focus on early recognition of advanced histology and endoscopic treatment of high-grade dysplasia. Advanced resection techniques now enable us to endoscopically treat early esophageal cancer. In this review, we will discuss these recent advances in diagnosis and treatment of Barrett’s esophagus and early esophageal adenocarcinoma.

Advanced Imaging in Barrett's Esophagus

Barrett's esophagus (BE) is present in up to 5.6% of the US population and is the precursor lesion for esophageal adenocarcinoma. Surveillance endoscopy is the primary management approach for BE. However, standard protocol biopsies have been associated with significant miss rates of dysplastic lesions in patients with BE. Thus, a variety of methods to optimize the imaging of BE have been developed to improve the efficiency and diagnostic yield of surveillance endoscopy in detecting early neoplasia. These techniques use changes that occur at macroscopic, microscopic, and subcellular levels in early neoplasia and are the focus of this article.

I-SCAN targeted versus random biopsies in Barrett's oesophagus

BACKGROUND

The accuracy and effectiveness of targeted oesophageal biopsies in Barrett's oesophagus to detect dysplasia using new magnification techniques are unknown. Aim of this study was to investigate whether the combined use of acetic acid, magnification and electronic filters allows the same accuracy as the four-quadrant random biopsies pattern; pathologist interobserver agreement both in low grade and high grade dysplasia was also assessed.

METHODS

Fifty-four consecutive patients newly diagnosed with Barrett's oesophagus were enrolled in a prospective study from a single endoscopy unit. Biopsies were evaluated by the local pathologist and by an expert pathologist from another pathology unit.

MAIN OUTCOME MEASUREMENT

Dysplasia detection rate and interobserver agreement for the histologic diagnosis of dysplasia.

RESULTS

The use of acetic acid, magnification and electronic filters showed an unacceptably low dysplasia detection rate by the two pathologists (9.2% and 5.5% for targeted biopsies, respectively). The interobserver agreement for low grade dysplasia between pathologists was low (Cohen's K weighted=0.45).

CONCLUSIONS

In an average setting, the standard four-quadrant method should still be preferred, along with the implementation of a routine second evaluation by an expert pathologist.

British Society of Gastroenterology guidelines on the diagnosis and management of Barrett's oesophagus

These guidelines provide a practical and evidence-based resource for the management of patients with Barrett's oesophagus and related early neoplasia. The Appraisal of Guidelines for Research and Evaluation (AGREE II) instrument was followed to provide a methodological strategy for the guideline development. A systematic review of the literature was performed for English language articles published up until December 2012 in order to address controversial issues in Barrett's oesophagus including definition, screening and diagnosis, surveillance, pathological grading for dysplasia, management of dysplasia, and early cancer including training requirements. The rigour and quality of the studies was evaluated using the SIGN checklist system. Recommendations on each topic were scored by each author using a five-tier system (A+, strong agreement, to D+, strongly disagree). Statements that failed to reach substantial agreement among authors, defined as >80% agreement (A or A+), were revisited and modified until substantial agreement (>80%) was reached. In formulating these guidelines, we took into consideration benefits and risks for the population and national health system, as well as patient perspectives. For the first time, we have suggested stratification of patients according to their estimated cancer risk based on clinical and histopathological criteria. In order to improve communication between clinicians, we recommend the use of minimum datasets for reporting endoscopic and pathological findings. We advocate endoscopic therapy for high-grade dysplasia and early cancer, which should be performed in high-volume centres. We hope that these guidelines will standardise and improve management for patients with Barrett's oesophagus and related neoplasia.

Confocal laser endomicroscopy for in vivo diagnosis of Barrett's oesophagus and associated neoplasia: a pilot study conducted in a single Italian centre

BACKGROUND

Diagnosis and management of Barrett's oesophagus are controversial. Technical improvements in real-time recognition of intestinal metaplasia and neoplastic foci provide the chance for more effective target biopsies. Confocal laser endomicroscopy allows to analyze living cells during endoscopy.

AIMS

To assess the diagnostic accuracy, inter- and intra-observer variability of endomicroscopy for detecting in vivo neoplasia (dysplasia and/or early neoplasia) in Barrett's oesophagus.

METHODS

Prospective pilot study. Patients referred for known Barrett's oesophagus were screened. Endomicroscopy was carried out in a circular fashion, every 1-2 cm, on the whole columnar-lined distal oesophagus. Visible lesions, when present, were analyzed first. Targeted biopsies were taken. Confocal images were classified according to confocal Barrett classification. Endomicroscopic and histological findings were compared.

RESULTS

Forty-eight out of 50 screened patients underwent endomicroscopy. Visible lesions were observed in 3 patients. In a per-biopsy analysis, Barrett's-oesophagus-associated neoplasia could be predicted with an accuracy of 98.1%. The agreement between endomicroscopic and histological results was substantial (κ=0.76).

CONCLUSIONS

This study suggests that endomicroscopy can provide in vivo diagnosis of Barrett's oesophagus-associated neoplasia. Because it allows for the study of larger surface areas of the mucosa, endomicroscopy may lead to significant improvements in the in vivo screening and surveillance of Barrett's oesophagus.

Barrett's esophagus: review of diagnosis and treatment

Barrett's esophagus (BE) is an acquired condition characterized by replacement of stratified squamous epithelium by a cancer predisposing metaplastic columnar epithelium. Endoscopy with systemic biopsy protocols plays a vital role in diagnosis. Technological advancements in dysplasia detection improves outcomes in surveillance and treatment of patients with BE and dysplasia. These advances in endoscopic technology radically changed the treatment for dysplastic BE and early cancer from being surgical to organ-sparing endoscopic therapy. A multimodal treatment approach combining endoscopic resection of visible and/or raised lesions with ablation techniques for flat BE mucosa, followed by long-term surveillance improves the outcomes of BE. Safe and effective endoscopic treatment can be either tissue acquiring as in endoscopic mucosal resection and endoscopic submucosal dissection or tissue ablative as with photodynamic therapy, radiofrequency ablation and cryotherapy. Debatable issues such as durability of response, recognition and management of sub-squamous BE and optimal management strategy in patients with low-grade dysplasia and non-dysplastic BE need to be studied further. Development of safer wide field resection techniques, which would effectively remove all BE and obviate the need for long-term surveillance, is another research goal. Shared decision making between the patient and physician is important while considering treatment for dysplasia in BE.

Advanced precancerous lesions in the lower oesophageal mucosa: high-grade dysplasia and intramucosal carcinoma in Barrett's oesophagus

Adenocarcinoma developed in Barrett's oesophagus is a tumour with an increasing incidence and still a poor prognosis. The only marker that can be used for surveillance remains dysplasia (intraepithelial neoplasia), especially when it is high-grade, that precedes intramucosal carcinoma. New forms of dysplasia have been described in complement to the classical intestinal type (foveolar dysplasia, basal crypt dysplasia). High-grade dysplasia and intramucosal carcinoma are diagnosed on biopsies taken during endoscopy. Standard endoscopy is now challenged by various techniques that represent recent major technical improvements (chromoendoscopy, virtual chromoendoscopy, optical frequency domain imaging, confocal laser endomicroscopy). In numerous cases, high-grade dysplasia and intramucosal carcinoma can be treated by endoscopic procedures, allowing a precise histopathological diagnosis on the resected specimen (endoscopic mucosal resection, submucosal endoscopic dissection) or destroying the neoplastic tissue. Radiofrequency ablation is currently considered as the best available technique for treatment of flat high grade dysplasia and for eradication of residual Barrett's mucosa after focal endoscopic mucosal resection.

Endoscopic resection (endoscopic submucosal dissection/endoscopic mucosal resection) for superficial Barrett's esophageal cancer

Recently developed endoscopic resection (endoscopic submucosal dissection [ESD]/ endoscopic mucosal resection) has dramatically changed the therapeutic approach for Barrett's esophageal cancer. The rationale for endoscopic resection is that lesions confined to the mucosal layer have negligible risk for developing lymph node metastasis and can be successfully eradicated by endoscopic treatment as a curative treatment with minimal invasiveness. According to some reports that analyzed the rate of lymph-node involvement relative to the depth of mucosal or submucosal tumor infiltration, endoscopic resection is clearly indicated for intramucosal carcinoma and might be extended to lesions with invasion into the submucosa (<200 μm, sm1) because of the low risk for lymph node metastasis. Most Japanese experts recommend ESD for Barrett's esophageal cancer after accurate diagnosis of the margin of cancer using narrow band imaging with magnifying endoscopy because of its high curative rate. However, few studies have evaluated the long-term outcomes of endoscopic resection for Barrett's esophageal cancer in Japan. Further investigations should be conducted to establish endoscopic resection for Barrett's esophageal cancer.

Indications, stains and techniques in chromoendoscopy

Early detection of malignancies within the gastrointestinal tract is essential to improve the prognosis and outcome of affected patients. However, conventional white light endoscopy has a miss rate of up to 25% for gastrointestinal pathology, specifically in the context of small and flat lesions within the colon. Chromoendoscopy and other advanced imaging techniques aim at facilitating the visualization and detection of neoplastic lesions and have been applied throughout the gastrointestinal tract. Chromoendoscopy, particularly in combination with magnifying endoscopy has significantly improved means to detect neoplastic lesions in the gastrointestinal mucosa, particularly in ulcerative colitis and Crohn's colitis. In addition, chromoendoscopy is beneficial in the upper gastrointestinal tract, especially when evaluating Barrett's oesophagus (BO) for the presence of dysplasia. Furthermore, it also improves characterization, differentiation and diagnosis of endoscopically detected suspicious lesions, and helps to delineate the extent of neoplastic lesions that may be amenable to endoscopic resection. This review discusses the dyes, indications and advanced endoscopic imaging methods used in various chromoendoscopic techniques, and presents a critical overview of the existing evidence supporting their use in current practice with a particular emphasis on the role in inflammatory bowel disease and BO.

Diagnosis and management of Barrett’s metaplasia: What’s new

Barrett’s esophagus (BE) is a complication of gastroesophageal reflux disease, and a premalignant lesion for esophageal adenocarcinoma (EAC). Observational studies suggest that endoscopic surveillance is associated with the detection of dysplasia and EAC at an early stage along with improved survival, but controversies still remain. The management of patients with BE involves endoscopic surveillance, preventive and clinical measures for cancer, and endoscopic and surgical approaches to treatment. Deciding upon the most appropriate treatment is a challenge. This study presents the results and the effectiveness of these practices.

Endotherapy for Barrett's esophagus

Endotherapy is now the mainstay of therapy for Barrett's associated neoplasia. The approach should begin with confirmation of neoplasia by a gastrointestinal pathologist, patient counseling, and appropriate endoscopic work up. Detailed examination with high-resolution white light endoscopy is the most important tool for detection of neoplasia. Further validation studies are needed for many enhanced imaging modalities before being recommended as part of the standard work up and assessment of patients with Barrett's esophagus (BE). Endoscopic mucosal resection is required for any visible lesion in the setting of dysplasia for accurate histological diagnosis. The remainder of the epithelium may be treated with resection or ablative therapy, followed by adequate surveillance. Patients with nondysplastic Barrett's require further risk stratification before incorporation of ablative therapy for this population. The future will fortify the endoscopic role in Barrett's with validation trials for endoscopic assessment, further long-term results for each of the treatment modalities, potential risk stratification for patients with BE, and improved guidelines for surveillance after therapy.

Frequent occurrence of mitochondrial DNA mutations in Barrett's metaplasia without the presence of dysplasia

Background

Barrett's esophagus (BE) is one of the most common premalignant lesions and can progress to esophageal adenocarcinoma (EA). The numerous molecular events may play a role in the neoplastic transformation of Barrett’s mucosa such as the change of DNA ploidy, p53 mutation and alteration of adhesion molecules. However, the molecular mechanism of the progression of BE to EA remains unclear and most studies of mitochondrial DNA (mtDNA) mutations in BE have performed on BE with the presence of dysplasia.

Methods/Findings

Thus, the current study is to investigate new molecular events (Barrett’s esophageal tissue-specific-mtDNA alterations/instabilities) in mitochondrial genome and causative factors for their alterations using the corresponding adjacent normal mucosal tissue (NT) and tissue (BT) from 34 patients having Barrett’s metaplasia without the presence of dysplasia. Eighteen patients (53%) exhibited mtDNA mutations which were not found in adjacent NT. mtDNA copy number was about 3 times higher in BT than in adjacent NT. The activity of the mitochondrial respiratory chain enzyme complexes in tissues from Barrett’s metaplasia without the presence of dysplasia was impaired. Reactive oxygen species (ROS) level in BT was significantly higher than those in corresponding samples.

Conclusion/Significance

High ROS level in BT may contribute to the development of mtDNA mutations, which may play a crucial role in disease progression and tumorigenesis in BE.

Use of in vivo real-time optical imaging for esophageal neoplasia

Esophageal adenocarcinoma carries a poor prognosis, as it typically presents at a late stage. Thus, a major research priority is the development of novel diagnostic-imaging strategies that can detect neoplastic lesions earlier and more accurately than current techniques. Advances in optical imaging allow clinicians to obtain real-time histopathologic information with instant visualization of cellular architecture and the potential to identify neoplastic tissue. The various endoscopic imaging modalities for esophageal neoplasia can be grouped into 2 major categories: (1) wide-field imaging, a comparatively lower-resolution view for imaging larger surface areas, and (2) high-resolution imaging, which allows individual cells to be visualized. This review will provide an overview of the various forms of real-time optical imaging in the diagnosis and management of Barrett's esophagus and esophageal adenocarcinoma.

Emerging technologies in endoscopic imaging

Endoscopic imaging is in part responsible for the recent drop in deaths from gastrointestinal cancers and also for detecting pre-cancerous and non-cancerous conditions and allowing them to be treated effectively, although techniques are far from perfect. Endoscopic imaging has evolved considerably from fiber optic systems 50 years ago to high resolution and high definition systems used at present. Moreover, image enhancement using filters and processors has led to the technique of 'electronic chromoendoscopy' to visualize mucosal blood vessels and surface pit patterns clearly. Magnification by optical zoom or confocal laser microscopy has enabled real time diagnosis and 'virtual histology'. These techniques have contributed to the early detection, assessment and treatment of various gastrointestinal pathologies. The focus of future research is directed towards molecular targeted imaging.

Endoscopic management of Barrett esophagus

Endoscopy has a vital role in the diagnosis, screening, surveillance and treatment of Barrett esophagus. Over the past few decades, tremendous advances have been made in endoscopic technology, and the management of dysplasia and early cancer in Barrett esophagus has changed radically from being surgical to organ-sparing endoscopic therapy. Proper endoscopic techniques and systematic biopsy protocols improve dysplasia detection, and endoscopic surveillance improves outcomes in patients with Barrett esophagus and dysplasia. Endoscopic treatment can be tissue acquiring (as in endoscopic mucosal resection and endoscopic submucosal dissection) or ablative (as with photodynamic therapy, radiofrequency ablation and cryotherapy). Treatment is usually multimodal, combining endoscopic resection of visible lesions with one or more mucosal ablation techniques, followed by long-term surveillance. Such treatment is safe and effective. Shared decision-making between the patient and physician is important while considering treatment for dysplasia in Barrett esophagus. Issues such as durability of response, importance of subsquamous Barrett epithelium and the optimal management strategy in patients with low-grade dysplasia and nondysplastic Barrett esophagus need to be studied further. Development of safer wide-field resection techniques, which would effectively remove all Barrett esophagus and obviate the need for long-term surveillance, is needed.

[Endoscopic technique in endobrachyoesophagus diagnosis: Chromoendoscopy and acetic acid]

Screening for complications of neoplastic Barrett's oesophagus requires a tedious blind standardized protocol biopsies quadrant every 1 to 2cm depending on the morphology of the Barrett's epithelium (Protocol of Seattle). To achieve that biopsies targeted to areas suspicious of dysplasia, a method of high sensitivity is required. Chromoendoscopy has been developed in this direction. Acetic acid combined with high resolution endoscopy and zooming represents an aid in the preparation of the oesophageal mucosa for visualization of suspicious anomalies. It is safe, cheap and easy to use. Acetic acid has proven its value in improving the visibility of the pit pattern. Several vital dyes have been tested, including methylene blue, indigo carmine and crystal violet, with mixed results. The FICE(®) and NBI(®), immediate, reversible and attractive virtual chromoendoscopy techniques represent interesting tools for improving sensitivity in screening for Barrett's oesophagus and its complications. Confocal endomicroscopy, which is similar as a "per-endoscopic real time histological examination", seems to be equally a promising technique in detection of Barrett's oesophagus associated neoplasia. But these tools which are capable of improvement so far, have not proved their use on a large population. For this, the systematic biopsy protocol Seattle remains the "gold standard" in monitoring the Barrett's oesophagus.

Endoscopic methods

Endoscopic methods to recognise and treat early gastrointestinal malignancies have increased in recent years. This has resulted in more lesions being diagnosed at an early stage and a shift away from invasive surgery towards endoscopic resection. However, it is necessary for the endoscopist to understand the key principles behind advanced endoscopic diagnosis and the new therapeutic options available. This chapter will review the advances in endoscopic techniques and methods which are changing the way we diagnose and treat these cancers. It will examine the general principles behind advanced endoscopy and then examine their application in Barrett's neoplasia, gastric cancer and the dysplasia associated lesions or masses associated with ulcerative colitis. It will focus on the best techniques for each of the above pathology.

Endoscopic evaluation and advanced imaging of Barrett's esophagus

Enhanced visualization techniques are available for Barrett's esophagus and have promise in the detection of dysplasia and cancer. Several of these techniques, such as narrow band imaging and chromoendoscopy, are being applied clinically. These techniques will allow the endoscopist to screen the surface of the Barrett's esophagus to detect areas of neoplasia. Once detected, it is hoped that either magnification techniques, such as confocal laser endomicroscopy, or spectroscopic techniques can be of value in allowing in vivo real-time diagnostic capabilities.

Endoscopy in gastro-oesophageal reflux disease

Although gastro-oesophageal reflux disease is basically a clinical diagnosis, oesophago-gastroduodenoscopy is essential to assess the type and severity of tissue damage. The main role for endoscopy is to detect metaplastic or premalignant changes complicating gastro-oesophageal reflux, and allow for surveillance. Routine biopsies are potentially useful to increase the diagnostic precision in case of minimal mucosal abnormalities. Management algorithms should include endoscopy to be performed early in the course of disease in most patients, even in the absence of alarm symptoms. Routine use of the Los Angeles classification of oesophagitis and the Prague classification for metaplasia is necessary for a precise description and biopsy sampling. Magnification chromoendoscopy is particularly useful in the hands of experienced endoscopists, whereas novel technologies including confocal laser endomicroscopy may become an important method in specialised centres to optimise the surveillance of premalignant mucosa.

Diagnostic challenges in the pathologic evaluation of Barrett esophagus

CONTEXT

Barrett esophagus represents an unstable epithelium resulting from chronic gastroesophageal reflux disease. Patients with Barrett esophagus routinely undergo endoscopic examination to detect dysplasia and early carcinoma. Although appropriate classification of Barrett esophagus and neoplasia is usually straightforward, persistent esophageal inflammation may induce epithelial changes that mimic, or mask, dysplasia. Recent data also indicate that specific molecular changes occur in nondysplastic Barrett mucosa and herald the development of dysplasia and/or carcinoma.

OBJECTIVE

To describe problematic aspects of biopsy interpretation in tissue samples of the gastroesophageal junction and distal esophagus, including the diagnostic criteria for Barrett esophagus, the importance of the gastric cardia, and pitfalls to the diagnosis of dysplasia. Ancillary studies that have recently emerged as potential adjuncts to the evaluation of patients with Barrett esophagus will be briefly discussed.

DATA SOURCES

A comprehensive review of the relevant literature indexed in PubMed (National Library of Medicine) was performed.

CONCLUSIONS

Barrett esophagus is currently defined as the presence of intestinal metaplasia in samples obtained from an endoscopically evident abnormality in the distal esophagus. Diagnosis and grading of dysplasia in mucosal biopsies remain the most reliable method to assess risk for neoplastic progression, but its classification may be hindered by superimposed inflammatory changes and suffers from considerable interobserver variability. Therefore, immunohistochemical studies and molecular assessment for TP53, CDKN2A , and DNA content abnormalities have emerged as potential adjuncts to the detection of dysplasia.

Era of Barrett’s surveillance: Does equipment matter?

Barrett’s esophagus is a consequence of long standing gastro-esophageal reflux disease and predisposes to the development of esophageal adenocarcinoma. Regular surveillance endoscopies can detect curable early neoplasia in asymptomatic patients, which in turn could improve the prognosis compared to symptomatic cancer. Early neoplastic lesions, which are amenable for local therapy, could be treated endoscopically, avoiding a major surgery. However, in the absence of obvious mucosal lesions, random four quadrant biopsies are done, which is associated with significant sampling error. Newer imaging modalities, such as autofluorescence endoscopy, are helpful in detecting subtle lesions that could be examined in detail with narrow band imaging to characterize and target biopsies. This has the potential benefit of reducing the number of random biopsies with a better yield of dysplasia. Confocal endomicroscopy provides “optical biopsies” and is a valuable tool in targeting biopsies to improve dysplasia detection; however, this is technically challenging. Fuji intelligent chromoendoscopy and I-Scan are recent additions to the imaging armamentarium that have produced notable early results. While all these additional new imaging techniques are promising, a thorough examination by high resolution white light endoscopy after clearing the mucosa with mucolytics should be the minimum standard to improve dysplasia detection during Barrett’s surveillance.

Endoscopic techniques for recognizing neoplasia in Barrett's esophagus: which should the clinician use?

PURPOSE OF REVIEW

The key to prevention and cure of esophageal adenocarcinoma is the detection and eradication of neoplasia in patients with Barrett's esophagus. Multiple tools and technologies are emerging for this purpose.

RECENT FINDINGS

A detailed white light examination with high-resolution endoscopy and recognition of lesions is paramount. A variety of imaging modalities are being studied for the detection of neoplasia in Barrett's esophagus. Chromoendoscopy, narrow band imaging, and autofluorescence provide a way to target suspicious areas. Confocal endomicroscopy and optical coherence tomography are means to pinpoint imaging to obtain information about the tissue microarchitecture.

SUMMARY

The key to detection of neoplasia is a careful white light examination with high-resolution endoscopy and recognition of lesion characteristics. Additional imaging modalities may enhance targeting of lesions or provide more information at a focused level. Many of these modalities have yet to be validated in prospective randomized, multicenter trials.

Confocal laser endomicroscopy: potential in the management of Barrett's esophagus

Confocal laser endomicroscopy (CLE) can serve as a useful adjunct imaging modality for targeted endoscopic biopsies during surveillance of Barrett's esophagus (BE). In addition, CLE may also have potential roles during therapeutic procedures that include localization of pathology, targeting of resections, guiding which therapy to use, and determining adequacy of treatment. This case series illustrates a range of cases in which endomicroscopy was performed during the procedure and offers possibilities of real-time decision-making to select specific therapies in patients with known high-grade dysplasia (HGD) and intramucosal carcinoma in the setting of BE presented for endoscopic treatment or follow-up. Patients with BE with HGD and intramucosal carcinoma presented for management for initial treatment or follow-up. Examinations were performed sequentially with detailed white light endoscopy, narrow band imaging (NBI), acetic acid, and CLE. This is a retrospective case series describing the characteristics of the exam findings and illustrating the role of endomicroscopy on real-time case management. Seven patients with Barrett-associated neoplasia underwent endomicroscopy as part of their endoscopic examination. CLE confirmed findings of neoplasia seen with red flag techniques such as NBI, and in one case independently suggested findings of neoplasia. In the majority of cases, these findings were incorporated into the decision of which modality of treatment was used. Future prospective studies should be done to validate the role of endomicroscopy in BE.

Barrett esophagus: histology and pathology for the clinician

The incidence of adenocarcinoma of the esophagus and gastroesophageal junction has increased dramatically over the past 30 years. The major precursor to this type of adenocarcinoma is Barrett esophagus, which is defined as the conversion of normal squamous epithelium into metaplastic columnar epithelium. Abundant evidence suggests that adenocarcinoma in the setting of Barrett esophagus develops via a progressive sequence of histological and molecular events. Consequently, patients with Barrett esophagus routinely undergo endoscopic surveillance for early detection of neoplasia. Histological evaluation of mucosal biopsy samples from the esophagus and gastroesophageal junction for identification of goblet cells and evaluation of the presence, grade and extent of dysplasia is the mainstay of risk assessment for these patients. This Review provides physicians with a summary of the pertinent, clinically relevant histological features of Barrett esophagus and its neoplastic complications. The histology of Barrett esophagus and the gastroesophageal junction is summarized, and an overview of information necessary to interpret pathology reports from patients either with or without endoscopic evidence of Barrett esophagus is provided to appropriately guide management of patients. Close interaction between the clinician and the pathologist is essential for proper interpretation of biopsy results and to provide optimal surveillance or treatment strategies.

Mucosal ablation of Barrett esophagus

The management of Barrett esophagus is evolving with the emergence of new endoscopic technologies. Traditionally, patients with high-grade dysplasia or cancer were referred for esophagectomy. However, with the advent of endoscopic ablative therapies for Barrett esophagus, the treatment paradigm has shifted. Patients with high-grade dysplasia and intramucosal carcinoma are increasingly offered esophagus-sparing therapies. Endoscopic ablative therapies can be categorized into tissue-acquiring and non-tissue-acquiring modalities. Visible lesions in the setting of dysplasia should be treated with a tissue-acquiring modality to stage and resect the lesion appropriately. One or more modalities may be used to eradicate the entire region of affected esophagus totally. Total eradication treats all of the at-risk epithelium and, therefore, treats any metachronous or synchronous lesions. Success of treatment may be gauged by complete remission of cancer, dysplasia, or Barrett esophagus. In addition to procedure-related complications, the risk of residual Barrett esophagus or subsquamous Barrett esophagus remains to be addressed. Endoscopic surveillance and acid suppression is still currently required after ablation.

Optimal approach to obtaining mucosal biopsies for assessment of inflammatory disorders of the gastrointestinal tract

Endoscopic evaluation and mucosal biopsy analysis have assumed important roles in the clinical management of patients with symptoms related to the gastrointestinal tract. Several common inflammatory diseases, including eosinophilic esophagitis, Barrett's esophagus, Helicobacter pylori infection, celiac disease, lymphocytic colitis, collagenous colitis, and inflammatory bowel disease, may display a patchy or discontinuous distribution and, thus, multiple mucosal samples may be required to obtain diagnostic tissue in some cases. Not surprisingly, clinicians and pathologists are increasingly challenged to determine the optimum number of procedures and tissue samples necessary to detect, or exclude, the presence of inflammatory disorders of the gastrointestinal tract. Unfortunately, clinical practice varies widely with respect to tissue sample procurement in the evaluation of these disorders, particularly when the endoscopic appearance of the gastrointestinal mucosa is normal or shows only minimal changes. Guidelines concerning the appropriate number of tissue samples are well established for some diseases, such as Barrett's esophagus and chronic gastritis, but are not clear in other instances. The purpose of this review is to discuss the available literature pertaining to appropriate endoscopic sampling in the assessment of medical diseases of the gastrointestinal tract, and to develop recommendations regarding the clinical evaluation of common gastrointestinal disorders.

Barrett's esophagus: can biomarkers predict progression to malignancy?

Barrett's esophagus (BE) is one of the most common premalignant lesions and can progress to esophageal adenocarcinoma. It is characterized histologically by a specialized intestinal metaplasia that replaces the squamous epithelium of the distal esophagus, and is associated with chronic gastroesophageal reflux disease and obesity. Similar to the adenoma-carcinoma sequence of colorectal carcinomas, esophageal adenocarcinoma develops through progression from BE to low- and high-grade dysplasia, then to adenocarcinoma with accumulation of genetic and epigenetic abnormalities. The exact malignancy potential of BE is uncertain. Dysplasia is the most predictive marker for risk of esophageal adenocarcinoma, whereas endoscopic and histological diagnoses are still the gold standard for surveillance of patients with BE. However, both are limited, either by sampling errors in biopsies or by differences in histological interpretation. Several studies have identified candidate biomarkers that may have predictive value and may serve as additional factors for the risk assessment of esophageal adenocarcinoma. This review discusses the role of biomarkers in the progression from BE to adenocarcinoma, focusing on clinical and molecular markers.

Meta-analysis: narrow band imaging for lesion characterization in the colon, oesophagus, duodenal ampulla and lung

BACKGROUND

Narrow band imaging is a new endoscopic technology that highlights mucosal surface structures and microcapillaries, which may be indicative of neoplastic change.

AIM

To assess the diagnostic precision of narrow band imaging for the diagnosis of epithelial neoplasia compared to conventional histology both overall and in specific organs.

METHODS

We performed a meta-analysis of studies which compared narow band imaging-based diagnosis of neoplasia with histopathology as the gold standard. Search terms: 'endoscopy' and 'narrow band imaging'.

RESULTS

Five hundred and eighty-two patients and 1108 lesions in 11 studies were included. Overall, sensitivity was 0.94 (95% confidence interval 0.92-0.95), specificity 0.83 (0.80-0.86); weighted area under the curve was 0.96 (standard error 0.02), diagnostic odds ratio (DOR) 72.74 (34.11-155.15). DORs were 66.65 (25.84-171.90), 61.19 (7.09-527.97), 69.74 (8.04-605.24) for colon, oesophagus and lung respectively. Studies with more than 50 patients had higher diagnostic precision, relative DOR 4.96 (1.28-19.27), P = 0.022. There was no difference in accuracy between microvessel and mucosal (pit) pattern based measures, relative DOR 1.29 (0.05-35.16), P = 0.87. There was significant heterogeneity overall between studies, Q = 31.2, P = 0.003.

CONCLUSION

Narrow band imaging is accurate with high diagnostic precision for in vivo diagnosis of neoplasia across a range of organs, using simple microvessel-based measures.

Novel imaging modalities in the detection of oesophageal neoplasia

The prognosis of oesophageal neoplasia is dependent on the stage of the disease at the time of detection. Early lesions have an excellent prognosis in contrast to more advanced stages that usually have a dismal prognosis. Therefore, the early detection of these lesions is of the utmost importance. In recent years, several new techniques have been introduced to improve the endoscopic detection of early lesions. The most important improvement, in general, has been the introduction of high-resolution/high-definition endoscopy into daily clinical practice. The value of superimposing techniques such as chromoendoscopy, narrow band imaging and computed virtual chromoendoscopy onto high-resolution/high-definition endoscopy will have to be proven in randomised cross-over trials comparing these techniques with standard techniques. Important future adjuncts to white-light endoscopy serving as 'red-flag' techniques for the detection of early neoplasia may be broad field functional imaging techniques such as video autofluorescence endoscopy. In addition, real-time histopathology during endoscopy has become possible with endocytoscopy and confocal endomicroscopy. The clinical value of these techniques needs to be ascertained in the coming years.

Tethered capsule endoscopy, a low-cost and high-performance alternative technology for the screening of esophageal cancer and Barrett's esophagus

Esophageal cancer is currently the fastest growing cancer in the United States. To help combat the recent rise in morbidity, our laboratory has developed a low-cost tethered capsule endoscope system (TCE) aimed at improving early detection of esophageal cancer. The TCE contains a resonant fiberoptic laser scanner (1.6 mm O.D.) which fits into 6.4-mm easy-to-swallow capsule at the distal tip. The tethered portion contains a single mode optical fiber multiplexed to three laser diodes at the proximal end. This design offers two main advantages over current endoscope technology. First, because of its small size, the TCE can be swallowed with minimal patient discomfort, thereby obviating sedation. Second, by imaging via directed laser light, the TCE is strategically positioned to employ several burgeoning laser-based diagnostic technologies, such as narrow-band, hyperspectral, and fluorescence imaging. It is believed that the combination of such imaging techniques with novel biomarkers of dysplasia will greatly assist in identifying precancerous conditions such as Barrett's esophagus (BE). As the probe is swallowed, the fiber scanner captures high resolution, wide-field color images of the gastroesophageal junction (500 lines at 0.05-mm resolution) currently at 15-Hz frame rate. Video images are recorded as the capsule is slowly retracted by its tether. Accompanying software generates panoramic images from the video output by mosaicing individual frames to aid in pattern recognition. This initial report describes the rationale for the unique TCE system design, results from preliminary testing in vitro and in vivo, and discussion on the merits of this new platform technology as a basis for developing a low-cost screening program for esophageal cancer.

Chromoendoscopy and narrow-band imaging compared with high-resolution magnification endoscopy in Barrett's esophagus

BACKGROUND & AIMS

The aim of this study was to compare magnified still images obtained with high-resolution white light endoscopy, indigo carmine chromoendoscopy, acetic acid chromoendoscopy, and narrow-band imaging to determine the best technique for use in Barrett's esophagus.

METHODS

We obtained magnified images from 22 areas with the 4 aforementioned techniques. Seven endoscopists with no specific expertise in Barrett's esophagus or advanced imaging techniques and 5 international experts in this field evaluated these 22 areas for overall image quality, mucosal image quality, and vascular image quality. In addition, the regularity of mucosal and vascular patterns and the presence of abnormal blood vessels were evaluated, and this was correlated with histology.

RESULTS

The interobserver agreement for the 3 features of mucosal morphology with white light images ranged from kappa = 0.51 (95% confidence interval [CI]: 0.46-0.55) to kappa = 0.53 (95% CI: 0.50-0.57) for all observers, from kappa = 0.43 (95% CI: 0.33-0.54) to kappa = 0.53 (95% CI: 0.41-0.64) for experts, and from kappa = 0.51 (95% CI: 0.15-0.33) to kappa = 0.64 (95% CI: 0.58-0.70) for nonexperts. The interobserver agreement in these groups did not improve by adding one of the enhancement techniques. The yield for identifying early neoplasia with white light images was 86% for all observers, 90% for experts, and 84% for nonexperts. The addition of enhancement techniques did not improve the yield neoplasia.

CONCLUSIONS

The addition of indigo carmine chromoendoscopy, acetic acid chromoendoscopy, or narrow-band imaging to white light images did not improve interobserver agreement or yield identifying early neoplasia in Barrett's esophagus.

Columnar lined (Barrett's) esophagus: future perspectives

Columnar lined esophagus (CLE) or Barrett's esophagus is the precursor for esophageal adenocarcinoma. Future advances in understanding and management of this condition as well as improving the quality of care of CLE patients depends on answering essential questions. It is important to standardize the criteria for CLE definition. The rapid increase in incidence of CLE and adenocarcinoma raises serious concerns that the current management of gastroesophageal reflux disease (GERD) needs reassessment. The risk factors that determine who will and will not develop CLE are as yet undetermined. There is a need to develop a clinical risk stratification tool, which will help in determining who should be screened. The impact of elimination of GERD on the natural history of CLE is one important area for future research. The benefit of surveillance strategies remains unproven and the ideal endoscopic frequency, protocols and markers of cancer risk are unknown. Dysplasia may not provide the gold standard marker of cancer risk because of some inherited problems. A better technique than the current endoscopic pinch biopsy protocol is needed. To overcome the limitations of histological markers, many other markers of cancer risk needs to be developed and validated. The key question as to whether cancer risk is actually reduced by the new ablation modalities remains unanswered. The natural history of dysplasia and its management needs to be clarified. Although many questions have to be answered, it seems, however, that at least some answers exist, and these and proposals for answering some of these questions are underlined throughout this review.

Technology insight: endoscopic submucosal dissection of gastrointestinal neoplasms

Gastrointestinal neoplasms can be cured by local resection as long as the lesions are in the early stage and have not metastasized. Endoscopic resection is a minimally invasive treatment for early-stage gastrointestinal neoplasms, and endoscopic submucosal dissection (ESD) is one type of endoscopic resection that has been developed in the past 10 years. For ESD to be a reliable, curative treatment for gastrointestinal neoplasms, it is necessary for the endoscopist to detect the lesion early, make a precise pretreatment diagnosis, ensure that the patient has the correct indication for endoscopic resection, and have the skill to perform ESD. For early lesion detection, endoscopists should pay attention to subtle changes in the surface structure, the color of the mucosa and the visibility of underlying submucosal vessels. Chromoendoscopy and magnifying endoscopy are useful for determining the margin of the lesions for pretreatment diagnosis, and endoscopic ultrasonography and magnifying endoscopy are useful for determining the depth of invasion. For ESD to be successful, local injection of sodium hyaluronate helps maintain mucosal elevation during dissection. Selecting the appropriate knife, using transparent hoods wisely, employing a good strategy that uses gravity, and having good control of bleeding are all needed to make ESD reliable.

Screening for and surveillance of Barrett's esophagus is clinically indicated

Barrett's esophagus (BE) is a complication of chronic gastroesophageal reflux disease (GERD) and is the precursor of esophageal adenocarcinoma (EA), through a progression from intestinal metaplasia (IM), through high-grade dysplasia (HGD). Although the progression from BE to EA seems to be infrequent (0.5% per year), endoscopic and bioptic surveillance would play a significant role in the evaluation of HGD and the detection of EA in early, curable stage, improving survival rates after treatments. The severity and the duration of GERD could be helpful in the assessment of the risk for BE and to enroll these subjects into screening protocols to detect any dysplastic or neoplastic change. The benefits of screening-surveillance programs could be furthermore enhanced by an improvement in diagnostic methods, such as high-resolution endoscopic techniques and the use of biomarkers for the histological examination seems to play a primary role in the cancer risk stratification; in such way, endoscopic resection techniques (mucosal resection and submucosal dissection) can be considered as a helpful method to stage dysplastic changes in BE.