Comparison of methylene blue-directed biopsies and conventional biopsies in the detection of intestinal metaplasia and dysplasia in Barrett's esophagus: a preliminary study

Current Status of Image-Enhanced Endoscopy for Early Identification of Esophageal Neoplasms

Advanced esophageal cancer is known to have a poor prognosis. The early detection of esophageal neoplasms, including esophageal dysplasia and early esophageal cancer, is highly important for the accurate treatment of the disease. However, esophageal dysplasia and early esophageal cancer are usually subtle and can be easily missed. In addition to the early detection, proper pretreatment evaluation of the depth of invasion of esophageal cancer is very important for curative treatment. The progression of non-invasive diagnosis via image-enhanced endoscopy techniques has been shown to aid the early detection and estimate the depth of invasion of early esophageal cancer and, as a result, may provide additional opportunities for curative treatment. Here, we review the advancement of image-enhanced endoscopy-related technologies and their role in the early identification of esophageal neoplasms.

Quicker, deeper and stronger imaging: A review of tumor-targeted, near-infrared fluorescent dyes for fluorescence guided surgery in the preclinical and clinical stages

Cancer is a public health problem and the main cause of human mortality and morbidity worldwide. Complete removal of tumors and metastatic lymph nodes in surgery is significantly beneficial for the prognosis of patients. Tumor-targeted, near-infrared fluorescent (NIRF) imaging is an emerging field of real-time intraoperative cancer imaging based on tumor-targeted NIRF dyes. Targeted NIRF dyes contain NIRF fluorophores and specific binding ligands such as antibodies, peptides and small molecules. The present article reviews recently updated tumor-targeted NIRF dyes for the molecular imaging of malignant tumors in the preclinical stage and clinical trials. The strengths and challenges of NIRF agents with tumor-targeting ability are also summarized. Smaller ligands, near infrared II dyes, dual-modality dyes and activatable dyes may contribute to quicker, deeper, stronger imaging in the nearest future. In this review, we highlighted tumor-targeted NIRF dyes for fluorescence-guided surgery and their potential clinical translation.

Advances in the Endoscopic Diagnosis of Barrett Esophagus

BACKGROUND

Barrett esophagus (BE) continues to be a major risk factor for developing esophageal adenocarcinoma.

METHODS

We review the risk factors, diagnosis, and management of BE, with an emphasis on the most current endoscopic diagnostic modalities for BE.

RESULTS

Novel diagnostic modalities have emerged to address the inadequacies of standard, untargeted biopsies, such as dye-based and virtual chromoendoscopy, endoscopic mucosal resection, molecular biomarkers, optical coherence tomography, confocal laser endomicroscopy, volumetric laser endomicroscopy, and endocytoscopy. Treatment of BE depends on the presence of intramucosal cancer or dysplasia, particularly high-grade dysplasia with or without visible mucosal lesions.

CONCLUSIONS

Recent advances in endoscopic diagnostic tools demonstrate promising results and help to mitigate the shortcomings of the Seattle protocol. Future research as well as refining these tools may help aid them in replacing standard untargeted biopsies.

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.

Endoscopic imaging of Barrett’s esophagus

The incidence of esophageal adenocarcinoma (EAC) has dramatically increased in the United States as well as Western European countries. The majority of esophageal adenocarcinomas arise from a backdrop of Barrett’s esophagus (BE), a premalignant lesion that can lead to dysplasia and cancer. Because of the increased risk of EAC, GI society guidelines recommend endoscopic surveillance of patients with BE. The emphasis on early detection of dysplasia in BE through surveillance endoscopy has led to the development of advanced endoscopic imaging technologies. These techniques have the potential to both improve mucosal visualization and characterization and to detect small mucosal abnormalities which are difficult to identify with standard endoscopy. This review summarizes the advanced imaging technologies used in evaluation of BE.

Advances in the endoscopic diagnosis and treatment of Barrett's neoplasia

Barrett's oesophagus is a well-recognised precursor of oesophageal adenocarcinoma. The incidence of oesophageal adenocarcinoma is continuing to rise in the Western world with dismal survival rates. In recent years, efforts have been made to diagnose Barrett's earlier and improve surveillance techniques in order to pick up cancerous changes earlier. Recent advances in endoscopic therapy for early Barrett's cancers have shifted the paradigm away from oesophagectomy and have yielded excellent results.

Emerging optical methods for surveillance of Barrett's oesophagus

The rapid rise in incidence of oesophageal adenocarcinoma has motivated the need for improved methods for surveillance of Barrett's oesophagus. Early neoplasia is flat in morphology and patchy in distribution and is difficult to detect with conventional white light endoscopy (WLE). Light offers numerous advantages for rapidly visualising the oesophagus, and advanced optical methods are being developed for wide-field and cross-sectional imaging to guide tissue biopsy and stage early neoplasia, respectively. We review key features of these promising methods and address their potential to improve detection of Barrett's neoplasia. The clinical performance of key advanced imaging technologies is reviewed, including (1) wide-field methods, such as high-definition WLE, chromoendoscopy, narrow-band imaging, autofluorescence and trimodal imaging and (2) cross-sectional techniques, such as optical coherence tomography, optical frequency domain imaging and confocal laser endomicroscopy. Some of these instruments are being adapted for molecular imaging to detect specific biological targets that are overexpressed in Barrett's neoplasia. Gene expression profiles are being used to identify early targets that appear before morphological changes can be visualised with white light. These targets are detected in vivo using exogenous probes, such as lectins, peptides, antibodies, affibodies and activatable enzymes that are labelled with fluorescence dyes to produce high contrast images. This emerging approach has potential to provide a 'red flag' to identify regions of premalignant mucosa, outline disease margins and guide therapy based on the underlying molecular mechanisms of cancer progression.

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.

Multiple-Band Imaging Provides Better Value Than White-light Endoscopy in Detection of Dysplasia in Patients With Barrett's Esophagus

BACKGROUND & AIMS

Surveillance of patients with Barrett's esophagus usually is performed with standard white-light endoscopy (SDWLE) and the collection of 4 biopsy specimens (every 1-2 cm of the metaplastic segment), based on Seattle protocol. New endoscopic techniques are used routinely, but have been validated based only on low-grade evidence. We aimed to validate the use of high-definition magnifying endoscopy with multiple-band imaging (HDMEMBI) with a targeted biopsy collection for the detection of dysplasia, using SDWLE with quadrant biopsy collection as the reference.

METHODS

In a cross-over study, patients with suspected or histologically verified BE (without known neoplasia) seen at a tertiary referral high-volume endoscopy center in Sweden, from November 2009 through November 2012, were assigned randomly to undergo HDMEMBI (n = 63) or SDWLE (n = 47) as the initial procedure, followed by the other procedure in 1 to 4 months. The primary end point was the total number of subjects found to have low-grade dysplasia or high-grade dysplasia (HGD) by each technique. Secondary end points included the number of biopsy specimens taken and the duration of each procedure.

RESULTS

There was no significant difference between groups in diagnostic yield for low-grade dysplasia (14 in HDMEMBI vs. 13 in SDWLE) or HGD. Four HGDs were found: 3 using HDMEMBI and 1 using SDWLE. Significantly fewer biopsy specimens were collected during the HDMEMBI procedure (P < .001). The diagnostic yield for the detection of dysplasia per biopsy specimen collected therefore was significantly higher for HDMEMBI than SDWLE (0.25 vs. 0.07; P = .018). There was no significant difference in the duration of procedures.

CONCLUSIONS

There is no significant difference in the detection of dysplastic lesions using HDMEMBI with targeted collection of biopsy specimens vs SDWLE with 4-quadrant biopsy specimen collection. However, HDMEMBI requires the collection of significantly fewer biopsy specimens, providing better value for health care providers. ClinicalTrials.gov number: NCT01694511.

Endoscopic imaging in Barrett's esophagus

Barrett's esophagus is the only known precursor that predisposes patients to the development of esophageal adenocarcinoma. The current recommended surveillance method is targeted biopsies of any abnormalities followed by random four-quadrant biopsies every 2 cm using standard white light endoscopy. Compliance with this and sampling error are two of the biggest problems. Several novel imaging technologies have been developed to aid the diagnosis of early neoplasia in Barrett's esophagus. There are emerging data that some of these new modalities can increase the yield of detecting dysplasia. This review will discuss some of the present available techniques and technologies including chromoendoscopy, narrow-band imaging, autofluorescence imaging, optical coherence tomography, confocal endomicroscopy and endocytoscopy. Based on the current evidence, these imaging modalities appear to be promising as adjunctive tools to white light endoscopy. A few of them, nevertheless, remain experimental due to expense, lack of expertise, generalizability as well as reproducibility of results.

Diffuse reflectance spectroscopy in Barrett's esophagus: developing a large field-of-view screening method discriminating dysplasia from metaplasia

We evaluated diffuse reflectance spectroscopy implemented as a small field-of-view technique for discrimination of dysplasia from metaplasia in Barrett's esophagus as an adjuvant to autofluorescence endoscopy. Using linear discriminant analysis on 2579 spectra measured in 54 patients identified an optimum a 4-wavelength classifier (at 485, 513, 598 and 629 nm). Sensitivity and specificity for a test data set were 0.67 and 0.85, respectively. Spectroscopic results show that this technique could be implemented in wide-field imaging mode to improve the accuracy of existing endoscopy techniques for finding early pre-malignant lesions in Barrett's esophagus. Results show that the discrimination occurs likely due to redistribution of blood content in the tissue sensed by the optical probing with the wavelength-dependent sampling depth.

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.

Advanced imaging technologies increase detection of dysplasia and neoplasia in patients with Barrett's esophagus: a meta-analysis and systematic review

BACKGROUND & AIMS

US guidelines recommend surveillance of patients with Barrett's esophagus (BE) to detect dysplasia. BE conventionally is monitored via white-light endoscopy (WLE) and a collection of random biopsy specimens. However, this approach does not definitively or consistently detect areas of dysplasia. Advanced imaging technologies can increase the detection of dysplasia and cancer. We investigated whether these imaging technologies can increase the diagnostic yield for the detection of neoplasia in patients with BE, compared with WLE and analysis of random biopsy specimens.

METHODS

We performed a systematic review, using Medline and Embase, to identify relevant peer-review studies. Fourteen studies were included in the final analysis, with a total of 843 patients. Our metameter (estimate) of interest was the paired-risk difference (RD), defined as the difference in yield of the detection of dysplasia or cancer using advanced imaging vs WLE. The estimated paired-RD and 95% confidence interval (CI) were obtained using random-effects models. Heterogeneity was assessed by means of the Q statistic and the I(2) statistic. An exploratory meta-regression was performed to look for associations between the metameter and potential confounders or modifiers.

RESULTS

Overall, advanced imaging techniques increased the diagnostic yield for detection of dysplasia or cancer by 34% (95% CI, 20%-56%; P < .0001). A subgroup analysis showed that virtual chromoendoscopy significantly increased the diagnostic yield (RD, 0.34; 95% CI, 0.14-0.56; P < .0001). The RD for chromoendoscopy was 0.35 (95% CI, 0.13-0.56; P = .0001). There was no significant difference between virtual chromoendoscopy and chromoendoscopy, based on Student t test analysis (P = .45).

CONCLUSIONS

Based on a meta-analysis, advanced imaging techniques such as chromoendoscopy or virtual chromoendoscopy significantly increase the diagnostic yield for identification of dysplasia or cancer in patients with BE.

Red flag imaging techniques in Barrett's esophagus

The key to detection and treatment of early neoplasia in Barrett's esophagus (BE) is thorough and careful inspection of the Barrett's segment. The greatest role for red flag techniques is to help identify neoplastic lesions for targeted biopsy and therapy. High-definition white light endoscopy (HD-WLE) can potentially improve endoscopic imaging of BE compared with standard endoscopy, but little scientific evidence supports this. The addition of autofluorescence imaging to HD-WLE and narrow band imaging increases sensitivity and the false-positive rate without significantly improving overall detection of BE-related neoplasia.

Determination of the optimal time for premedication with pronase, dimethylpolysiloxane, and sodium bicarbonate for upper gastrointestinal endoscopy

GOALS AND BACKGROUND

Premedication with pronase, dimethylpolysiloxane, and sodium bicarbonate improves visibility during upper gastrointestinal (UGI) endoscopy. However, the optimal time for this combination to take effect is unknown. We investigated the optimal time of pre-UGI endoscopy medication.

STUDY

A randomized, investigator-blind, controlled trial. The 300 patients who were to receive premedication were randomized into 3 groups according to the following medication time before UGI endoscopy: 10 minutes (group A, n=98), 10 to 30 minutes (group B, n=97), and 30 minutes premedication (group C, n=99). Visibility scores (range, 1 to 4, with lower scores indicating better gastric mucosal visibility) were assessed for the antrum, lower body, upper body, and fundus and compared, including the sum of the scores, between the 3 groups.

RESULTS

Group B had significantly lower visibility scores for the lower body, upper body, and fundus than group C (P=0.001, 0.009, and 0.002, respectively). Group A obtained significantly lower scores for the antrum and lower body than group C (P=0.007 and 0.005, respectively). The total visibility scores of groups A and B were significantly lower compared with those of group C (P=0.001, 0.003, respectively).

CONCLUSIONS

Administration of pronase, dimethylpolysiloxane, and sodium bicarbonate within 30 minutes before UGI endoscopy significantly improved endoscopic visualization. However, the optimal time to achieve the best visibility was between 10 to 30 minutes before UGI endoscopy.

Confocal endomicroscopy (CEM) improves efficiency of Barrett surveillance

BACKGROUND

Endoscopists with extensive experience with confocal endomicroscopy (CEM) have demonstrated that this technology is useful for Barrett's esophagus (BE) surveillance. However, data on endoscopists with minimal experience with this technique are limited.

HYPOTHESIS

For BE surveillance, an endoscopist with minimal experience in CEM-guided biopsy would achieve a similar diagnostic yield with fewer biopsies when compared to the random 4-quadrant biopsy protocol.

OBJECTIVE

To compare the diagnostic yields of CEM-guided biopsy technique with the random 4-quadrant biopsy protocol.

DESIGN

Randomized controlled trial.

SETTING

Tertiary care center.

PATIENTS

Patients with BE.

METHODS

Out of 18 patients who underwent routine BE surveillance, 11 and 7 were randomly assigned to group A (CEM-guided) and to group B (random 4-quadrant biopsy), respectively. The pathologists were blinded to all clinical information.

RESULTS

Mean length of endoscopic Barrett was similar in both groups, (5.1 vs. 6.3 cm, p=0.51). The diagnostic yields for detecting SIM (63.6% vs. 59.5%, p=0.5), low grade dysplasia (11. 6% vs. 11.2%, p=NS), high grade dysplasia (10.1% vs. 11.5%, p=0.88). Although the total number of individual mucosal biopsy performed were 52% lower in the CEM group (129 vs. 269), the overall diagnostic yield (85.3% vs. 82.2%, p=0.53) was similar in both groups.

LIMITATIONS

Small sample size.

CONCLUSIONS

For BE surveillance, limited data suggested that endoscopists with minimal experience in CEM can effective use this technology for "smart" biopsy to decrease the need for intense tissue sampling but without lowering the diagnostic yield in detecting dysplasia.

Advanced endoscopic imaging in Barrett's oesophagus: A review on current practice

Over the last few years, improvements in endoscopic imaging technology have enabled identification of dysplasia and early cancer in Barrett’s oesophagus. New techniques should exhibit high sensitivities and specificities and have good interobserver agreement. They should also be affordable and easily applicable to the community gastroenterologist. Ideally, these modalities must exhibit the capability of imaging wide areas in real time whilst enabling the endoscopist to specifically target abnormal areas. This review will specifically focus on some of the novel endoscopic imaging modalities currently available in routine practice which includes chromoendoscopy, autofluorescence imaging and narrow band imaging.

Real-time increased detection of neoplastic tissue in Barrett's esophagus with probe-based confocal laser endomicroscopy: final results of an international multicenter, prospective, randomized, controlled trial

BACKGROUND

Probe-based confocal laser endomicroscopy (pCLE) allows real-time detection of neoplastic Barrett's esophagus (BE) tissue. However, the accuracy of pCLE in real time has not yet been extensively evaluated.

OBJECTIVE

To compare the sensitivity and specificity of pCLE in addition to high-definition white-light endoscopy (HD-WLE) with HD-WLE alone for the detection of high-grade dysplasia (HGD) and early carcinoma (EC) in BE.

DESIGN

International, prospective, multicenter, randomized, controlled trial.

SETTING

Five tertiary referral centers.

PATIENTS

A total of 101 consecutive BE patients presenting for surveillance or endoscopic treatment of HGD/EC.

INTERVENTIONS

All patients were examined by HD-WLE, narrow-band imaging (NBI), and pCLE, and the findings were recorded before biopsy samples were obtained. The order of HD-WLE and NBI was randomized and performed by 2 independent, blinded endoscopists. All suspicious lesions on HD-WLE or NBI and 4-quadrant random locations were documented. These locations were examined by pCLE, and a presumptive diagnosis of benign or neoplastic (HGD/EC) tissue was made in real time. Finally, biopsies were taken from all locations and were reviewed by a central pathologist, blinded to endoscopic and pCLE data.

MAIN OUTCOME MEASUREMENTS

Diagnostic characteristics of pCLE.

RESULTS

The sensitivity and specificity for HD-WLE were 34.2% and 92.7%, respectively, compared with 68.3% and 87.8%, respectively, for HD-WLE or pCLE (P = .002 and P < .001, respectively). The sensitivity and specificity for HD-WLE or NBI were 45.0% and 88.2%, respectively, compared with 75.8% and 84.2%, respectively, for HD-WLE, NBI, or pCLE (P = .01 and P = .02, respectively). Use of pCLE in conjunction with HD-WLE and NBI enabled the identification of 2 and 1 additional HGD/EC patients compared with HD-WLE and HD-WLE or NBI, respectively, resulting in detection of all HGD/EC patients, although not statistically significant.

LIMITATIONS

Academic centers with enriched population.

CONCLUSIONS

pCLE combined with HD-WLE significantly improved the ability to detect neoplasia in BE patients compared with HD-WLE. This may allow better informed decisions to be made for the management and subsequent treatment of BE patients. (

CLINICAL TRIAL REGISTRATION NUMBER

NCT00795184.).

State of the art in the endoscopic imaging and ablation of Barrett's esophagus

Barrett's esophagus is the result of long-term acid reflux and is a precursor to esophageal adenocarcinoma. Surgical resection of the esophagus has been the mainstay of treatment for high grade dysplasia and early cancer. However, recent advances in the endoscopic imaging and ablation technologies have made esophagectomy avoidable in patients with dysplasia and superficial neoplasia. In this article, we review the most relevant endoscopic imaging technologies, such as chromoendoscopy, narrow band and autofluorescence imaging, and confocal laser endomicroscopy. We also review the various endoscopic ablation technologies, such as endoscopic mucosal resection, photodynamic therapy, radiofrequency ablation, and cryotherapy. Finally, we focus on the studies that evaluate the efficacy of these imaging and ablation technologies in finding and eradicating neoplastic Barrett's esophagus.

[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 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.

Classification of histological severity of Helicobacter pylori-associated gastritis by confocal laser endomicroscopy

AIM: To classify the histological severity of Helicobacter pylori (H. pylori) infection-associated gastritis by confocal laser endomicroscopy (CLE).

METHODS: Patients with upper gastrointestinal symptoms or individuals who were screened for gastric cancer were enrolled in this study. Histological severity of H. pylori infection-associated gastritis was graded according to the established CLE criteria. Diagnostic value of CLE for histological gastritis was investigated and compared with that of white light endoscopy (WLE). Targeted biopsies from the sites observed by CLE were performed.

RESULTS: A total of 118 consecutive patients with H. pylori infection-associated gastritis were enrolled in this study. Receiver operating characteristic curve analysis showed that the sensitivity and specificity of CLE were 82.9% and 90.9% for the diagnosis of H. pylori infection, 94.6% and 97.4% for predicting gastric normal mucosa, 98.5% and 94.6% for predicting histological active inflammation, 92.9% and 95.2% for predicting glandular atrophy, 98.6% and 100% for diagnosing intestinal metaplasia, respectively. Post-CLE image analysis showed that goblet cells and absorptive cells were the two most common parameters on the CLE-diagnosed intestinal metaplasia (IM) images (P < 0.001). More histological lesions of the stomach could be found by CLE than by WLE (P < 0.001).

CONCLUSION: CLE can accurately show the histological severity of H. pylori infection-associated gastritis. Mapping IM by CLE has a rather good diagnostic accuracy.

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.

Endoscopic imaging for the detection of esophageal dysplasia and carcinoma

Numerous endoscopic imaging modalities have been developed and introduced into clinical practice to enhance diagnostic capabilities. In the past, detection of dysplasia and carcinoma of the esophagus has been dependent on biopsies taken during standard white-light endoscopy. Recent important developments in biophonotics have improved visualization of these subtle lesions sufficiently for cellular details to be seen in vivo during endoscopy. These improvements allow diagnosis to be made in gastrointestinal endoscopy units, thereby avoiding the cost, risk, and time delay involved in tissue biopsy and resection. Chromoendoscopy, narrow-band imaging, high-yield white-light endoscopy, Fujinon intelligent color enhancement, and point enhancement such as confocal laser endomicroscopy are examples of enhanced imaging technologies that are being used in daily practice. This article reviews endoscopic-based imaging techniques for the detection of esophageal dysplasia and carcinoma from the perspective of routine clinical practice.

New technologies for imaging of Barrett's esophagus

There have been many developments in endoscopy-based imaging for the detection of Barrett's syndrome, dysplasia, and neoplasia in patients with Barrett's esophagus. This article reviews the studies on and compares the efficacy of several important endoscopic imaging modalities. Some of these technologies have already achieved regulatory approval, commercial availability, and establishment of clinical utility and practical application. The future of imaging for Barrett's syndrome likely rests with the development of molecular targeting with dysplasiatargeted probes that have been conjugated to dyes or nanoparticles.

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.

Diagnostic yield of methylene blue chromoendoscopy for detecting specialized intestinal metaplasia and dysplasia in Barrett's esophagus: a meta-analysis

BACKGROUND

The reported yield of methylene-blue (MB) chromoendoscopy targeted biopsy in detecting specialized intestinal metaplasia (SIM) and, more importantly, dysplasia in patients with Barrett's esophagus (BE) has shown variable results.

OBJECTIVE

To perform a meta-analysis of published studies for assessment of the diagnostic yield of techniques of chromoendoscopy compared with conventional 4-quadrant random biopsy (RB) in detection of SIM and dysplasia in patients with BE.

DESIGN

A literature search of the MEDLINE, EMBASE, and the Cochrane Databases was performed, along with a search of PubMed and a manual search of cross-references of eligible articles. Data on yield of both modalities were extracted and analyzed to estimate weighted incremental yield (IY) and 95% CIs of MB over RB using a fixed-effects or random-effects model, as appropriate, based on whether homogeneity or heterogeneity, respectively, was indicated by Cochrane's Q chi(2) test.

PATIENTS

A total of 450 patients with BE were reported in 9 studies included in the meta-analysis.

RESULTS

There was no significant IY with MB over RB for detection of SIM (IY 4%; 95% CI, -7% to 16%; 6 studies, n = 251), dysplasia (IY 9%; 95% CI, -1% to 20%; 9 studies, n = 450), and high-grade dysplasia and/or early cancer (IY 5%; 95% CI, -1% to 10%; 8 studies, n = 405).

LIMITATIONS

Only data on MB were analyzed because of limited availability of data for other chromoendoscopy dyes, minor variations in inclusion and exclusion criteria, and the small sample size, and because differences in application technique could have led to an underestimation of the diagnostic yield of MB chromoendoscopy.

CONCLUSION

The technique of MB chromoendoscopy has only a comparable yield with RB for the detection of SIM and dysplasia during endoscopic evaluation of patients with BE.

Chromoendoscopy

Chromoendoscopy involves the use of stains or dyes during endoscopy to improve the visualization and characterization of the gastrointestinal mucosa. Its main clinical application is the detection of dysplasia or early cancer of the gastrointestinal tract in individuals with pre-malignant conditions or hereditary and environmental factors that predispose them to cancer. The utility of chromoendoscopy has been mostly studied in squamous cell carcinoma of the esophagus, Barrett's esophagus, gastric cancer, colorectal polyps, and chronic ulcerative colitis. Although chromoendoscopy has been shown to be feasible and safe, several limitations have prevented its widespread use in endoscopy. Despite this, chromoendoscopy remains a useful adjunct to standard white light endoscopy in the visualization of mucosal lesions, which may potentially improve tissue diagnosis and impact patient care.

Barrett's esophagus: where do we stand?

Barrett's esophagus (BE) is a precursor for esophageal adenocarcinoma, which has an increased incidence rate over the last few decades. Its importance stems from the poor five-year survival of esophageal adenocarcinoma and current data that suggest a survival benefit when surveillance programs are implemented. In this review, we will cover the pathophysiology and natural history of BE and the different endoscopic findings. The prevalence of BE in different geographic areas and the incidence of high-grade dysplasia and adenocarcinoma in this patient population is reviewed. Recent recommendation for screening and surveillance of BE has been covered in this review as well as the efficacy of nonconventional imaging modalities and endoscopic ablation therapies.

Advances in endoscopic imaging of the esophagus

The introduction of flexible fiberoptic endoscopy in the 1960s was a major step forward in the diagnosis and management of various esophageal disorders. Since then, there has been steady progress in the development of novel gastrointestinal endoscopy techniques. Magnification and high-resolution endoscopy, chromoendoscopy, narrow-band imaging, autofluorescence imaging, and confocal laser endomicroscopy are some of the recent advances that have shown promise in the diagnosis of squamous cell carcinoma, gastroesophageal reflux disease, Barrett's esophagus, and adenocarcinoma of the esophagus. The purpose of this review is to summarize the recent advances in endoscopic imaging of the esophagus and their practical application for the gastroenterologist.

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.

Prospective, controlled tandem endoscopy study of narrow band imaging for dysplasia detection in Barrett's Esophagus

BACKGROUND & AIMS

High-resolution endoscopy with narrow band imaging (NBI) enhances the visualization of mucosal glandular and vascular structures. This study assessed whether narrow band targeted biopsies could detect advanced dysplasia using fewer biopsy samples compared with standard resolution endoscopy.

METHODS

We conducted a prospective, blinded, tandem endoscopy study in a tertiary care center with 65 patients with Barrett's esophagus undergoing evaluation for previously detected dysplasia. Standard resolution endoscopy was used first to detect visible lesions. Narrow band endoscopy was then used by another gastroenterologist to detect and biopsy areas suspicious for dysplasia. The lesions initially detected by standard resolution endoscopy were then disclosed and biopsied, after biopsy of the lesions targeted with NBI. Finally, random 4-quadrant biopsies were taken throughout the segment of Barrett's mucosa.

RESULTS

Higher grades of dysplasia were found by NBI in 12 patients (18%), compared with no cases (0%) in whom standard resolution white light endoscopy with random biopsy detected a higher grade of histology (P < .001). Correspondingly, narrow band directed biopsies detected dysplasia in more patients (n = 37; 57%) compared with biopsies taken using standard resolution endoscopy (n = 28; 43%). In addition, more biopsies were taken using standard resolution endoscopy with random biopsy compared with narrow band targeted biopsies (mean 8.5 versus 4.7; P < .001).

CONCLUSIONS

In patients evaluated for Barrett's esophagus with dysplasia, NBI detected significantly more patients with dysplasia and higher grades of dysplasia with fewer biopsy samples compared with standard resolution endoscopy.

The usefulness of chromoendoscopy with methylene blue in Barrett's metaplasia and early esophageal carcinoma

BACKGROUND

Barrett's esophagus is a condition that is premalignant for adenocarcinoma of the esophagus and the esophagogastric junction. Early detection of Barrett's metaplasia and dysplasia is very important to decrease the mortality and morbidity from esophageal adenocarcinoma cancer. This study aimed to evaluate the effectiveness of methylene blue-targeted biopsies in the differential diagnosis of intestinal metaplasia, dysplasia, and superficial esophageal carcinoma.

METHODS

A total of 109 patients (43 women and 66 men; average age, 62.32 +/- 10.61 years; range, 33-82 years) were enrolled for the study. Four groups were designed before endoscopic examinations. The patients for these groups were selected at the conventional endoscopy, and then chromoendoscopy was performed. The esophagus was stained with methylene blue, after which six biopsies were taken from stained and unstained areas.

RESULTS

Conventional and chromoendoscopic assessments were compared with histopathologic examination. The sensitivity of chromoendoscopy for Barrett's epithelium was superior to that of conventional endoscopy (p < 0.05). However, there was no statistical difference between the two methods in the diagnosis of esophagitis or esophageal carcinoma (p > 0.05). Stained biopsies were superior to unstained biopsies in terms of sensitivity for Barrett's epithelium and esophageal carcinoma (p < 0.001).

CONCLUSION

Chromoendoscopy is useful for delineating Barrett's epithelium and for indicating the correct location for securing biopsies where dysplasia or early esophageal cancer is suspected.

A randomized comparison of methylene blue-directed biopsy versus conventional four-quadrant biopsy for the detection of intestinal metaplasia and dysplasia in patients with long-segment Barrett's esophagus

OBJECTIVES

Methylene blue (MB) selectively stains specialized intestinal metaplasia (SIM) and may assist in surveying a columnar-lined esophagus for Barrett's esophagus associated dysplasia.

METHODS

This is a prospective, randomized crossover study comparing 4-quadrant random biopsies (4QB) versus MB-directed biopsies for the detection of SIM and dysplasia in 48 patients with long segment Barrett's esophagus (LSBE). Patients randomly underwent two endoscopies over a 4-wk time period with either 4QB or MB-directed biopsies as their first or second exam. Our aim was to correlate stain intensity with histology.

RESULTS

The sensitivity of MB for SIM and dysplasia was 75.2% and 83.1%, respectively. The yield of 4QB for identifying nondysplasia SIM was 57.6% (523/917) and for dysplasia was 12% (111/917). Dark staining was significantly associated with histologic grade (P < 0.007). The final diagnosis was correct in 43 (90%) patients using MB and in 45 (94%) using 4QB. The 4QB technique missed dysplasia in 3 of 21 patients while MB biopsies missed dysplasia in 5 of 21 patients. The discordance between the two techniques was not significant (P= 0.727, McNemar's test). The mean number of biopsies taken during 4QB was 18.92 +/- 6.36 and with MB was 9.23 +/- 2.89 (P < 0.001).

CONCLUSION

MB requires significantly fewer biopsies than 4QB to evaluate for SIM and dysplasia. Dark staining correlates more with HGD than LGD in our experience. While MB is not more accurate than 4QB, MB may help to define areas to target for biopsy during surveillance endoscopy in patients with LSBE.

American Gastroenterological Association (AGA) Institute technology assessment on image-enhanced endoscopy

This document presents the official recommendations of the American Gastroenterological Association (AGA) Institute Technology Assessment on "Image-Enhanced Endoscopy." It was approved by the Clinical Practice and Economics Committee on August 3, 2007, and by the AGA Institute Governing Board September 27, 2007.

Barrett's Esophagus: Diagnosis, Screening, Surveillance, and Controversies

Barrett's esophagus (BE) is a frequent complication of gastroesophageal reflux disease, an acquired condition resulting from persistent mucosal injury to the esophagus. The incidence of Barrett's metaplasia and Barrett's adenocarcinoma has been increasing, but the prognosis of Barrett's adenocarcinoma is worse because individuals present at a late stage. Attempts have been made to intervene at early stage using surveillance programmes, although proof of efficacy of endoscopic surveillance is lacking. There is much to be learned about BE. Whether adequate control of gastroesophageal reflux early in the disease alters the natural history of Barrett's change once it has developed remains unanswered. Thus there is great need for carefully designed large randomised controlled trials to address these issues in order to determine how best to manage patients with BE. The AspECT and BOSS clinical trials proride this basis.

Acetic acid allows effective selection of areas for obtaining biopsy samples in Barrett's esophagus

OBJECTIVE

The aim of this study was to determine whether macroscopic changes resulting from acetic acid application on the surface of columnar-lined esophagus allow regular, nonmagnifying, endoscopic identification of areas presenting dysplasia and/or cancer in Barrett's esophagus.

PATIENTS AND METHODS

A total of 100 patients (mean age, 53 years; range, 27-86 years) under surveillance because of short-segment (n=71) and long-segment (n=29) Barrett's esophagus, with no alterations of columnar-lined esophagus on standard endoscopy, were enrolled. After endoscopic examination, 3% acetic acid was sprayed on columnar-lined esophagus. The subsequent appearance of the mucosa was classified as: (1) Normal pattern: uniform reticulum along the entire columnar-lined esophagus. (2) Abnormal pattern: reticulum presenting areas of rough or irregular appearance. Biopsy samples were obtained from areas of normal and abnormal patterns, and the results of the corresponding histological studies were compared. All endoscopies were performed by the same investigator.

RESULTS

The endoscopic appearance, after acetic acid application, corresponded to a normal pattern in 85% of cases and an abnormal pattern in 15%. The percentage of dysplasia and adenocarcinoma in biopsy specimens was significantly higher in patients with rough or irregular areas (86.7%) than in those with normal uniform reticulum (0%) (P< 0.001). Sensitivity for the identification of areas of dysplasia or adenocarcinoma was 100% (95% confidence interval: 71.7-100%). Specificity was 97.7% (95% confidence interval: 91.2-99.6%).

CONCLUSIONS

This prospective study shows that acetic acid test is useful for standard, nonmagnifying, endoscopic detection of dysplasia and cancer in Barrett's esophagus.

Premedication with pronase or N-acetylcysteine improves visibility during gastroendoscopy: An endoscopist-blinded, prospective, randomized study

AIM: To assess the efficacy of premedicaton with pronase or N-acetylcysteine (NAC) at 20 min before upper gastrointestinal (UGI) endoscopy and to determine whether pronase or NAC pretreatment influences the reliability of the rapid urease test.

METHODS: A total of 146 patients were prospectively and randomly assigned into the study groups according to different premedications before endoscopy. One endoscopist assessed mucosal visibility (MV) with scores ranged from 1 to 4 at four sites in the stomach. The sum of the MV scores from these four locations was defined as the total mucosal visibility (TMV) score. Identification of H pylori was performed using CLO test, histology, and serology.

RESULTS: The Group with pronase premedication had a significantly lower TMV score than did the groups with gascon and gascon water (p < 0.001 and p < 0.01, respectively). The group with NAC had a significantly lower TMV score than the group with gascon (p < 0.01) and a trend of a lower MV score than the group with gascon water (p = 0.06). The TMV score did not significantly differ between the group with pronase and the group with NAC (p = 0.39 and p = 0.14, respectively). The sensitivity and specificity of the CLO test were 92.5% and 93.9%, respectively, in groups premedicated with pronase and NAC together.

CONCLUSION: Premedication with pronase or NAC at 20 min before UGI endoscopy improves the mucosal visibility of the stomach. Neither pronase nor NAC produces any obvious interference with the CLO test for the identification of H pylori infection.

Comparison of methylene blue-directed biopsies and four-quadrant biopsies in the detection of high-grade intraepithelial neoplasia and early cancer in Barrett's oesophagus

BACKGROUND

Barrett's oesophagus embodies the risk of malignant transformation. High-grade intraepithelial neoplasia and early cancer in Barrett's oesophagus are often discrete or macroscopically occult lesions and show a patchy distribution and therefore, directed biopsies in combination with four-quadrant random biopsies are the gold standard for surveillance.

AIMS

The aim of this prospective study was to compare methylene blue staining and random biopsies in patients with early Barrett's neoplasia.

PATIENTS AND METHODS

Eighty-six patients (mean age 65+/-8 years) with histologically proven but macroscopically in evident high-grade intraepithelial neoplasia (n=17) or early cancer in Barrett's oesophagus (n=69) on HR-endoscopy with all together 98 lesions, were included. In the first step, four-quadrant random biopsies were taken during routine endoscopy (group I). In a second step, staining was performed with a 0.5% solution of methylene blue with a spray catheter. Biopsies of focal areas with decreased stain, heterogeneity of stain or absence stain were taken (group II).

RESULTS

In 75/86 patients, high-grade intraepithelial neoplasia or early cancer in Barrett's oesophagus could be diagnosed in the methylene blue group while 56 patients were determined in the random biopsies group (P=0.053). High-grade intraepithelial neoplasia or early cancer was diagnosed in significantly more methylene blue-directed biopsies (80.9% versus 26.4%, P<0.005) and also significantly more lesions could be identified in the methylene blue group (96/98; 98%) while in the random biopsies group only 58/98 lesions (59%) could be localised (P<0.05). When methylene blue was used (1217 versus 562, P<0.0001), the average number of specimens taken with methylene blue per patient was about half of that with random biopsy (6.5 versus 14.1, P<0.0001).

CONCLUSIONS

Chromoendoscopy with methylene blue diagnosed significantly more patients and lesions with intraepithelial neoplasia or early cancer in Barrett's oesophagus compared to random biopsies. In addition, significantly less biopsies were needed with methylene blue compared to random biopsies. The use of methylene blue-directed biopsies appears to improve the detection of intraepithelial neoplasia and early cancer in Barrett's oesophagus.