Systematic review of narrow-band imaging for the detection and differentiation of abnormalities in the esophagus and stomach (with video)

Multifunctional Ablative Gastrointestinal Imaging Capsule (MAGIC) for Esophagus Surveillance and Interventions

Objective and Impact Statement: A clinically viable technology for comprehensive esophagus surveillance and potential treatment is lacking. Here, we report a novel multifunctional ablative gastrointestinal imaging capsule (MAGIC) technology platform to address this clinical need. The MAGIC technology could also facilitate the clinical translation and adoption of the tethered capsule endomicroscopy (TCE) technology. Introduction: Recently developed optical coherence tomography (OCT) TCE technologies have shown a promising potential for surveillance of Barrett's esophagus and esophageal cancer in awake patients without the need for sedation. However, it remains challenging with the current TCE technology for detecting early lesions and clinical adoption due to its suboptimal resolution, imaging contrast, and lack of visual guidance during imaging. Methods: Our technology reported here integrates dual-wavelength OCT imaging (operating at 800 and 1300 nm), an ultracompact endoscope camera, and an ablation laser, aiming to enable comprehensive surveillance, guidance, and potential ablative treatment of the esophagus. Results: The MAGIC has been successfully developed with its multimodality imaging and ablation capabilities demonstrated by imaging swine esophagus ex vivo and in vivo. The 800-nm OCT imaging offers exceptional resolution and contrast for the superficial layers, well suited for detecting subtle changes associated with early neoplasia. The 1300-nm OCT imaging provides deeper penetration, essential for assessing lesion invasion. The built-in miniature camera affords a conventional endoscopic view for assisting capsule deployment and laser ablation. Conclusion: By offering complementary and clinically viable functions in a single device, the reported technology represents an effective solution for endoscopic screening, diagnosis, and potential ablation treatment of the esophagus of a patient in an office setting.

CLELNet: A continual learning network for esophageal lesion analysis on endoscopic images

BACKGROUND AND OBJECTIVE

A deep learning-based intelligent diagnosis system can significantly reduce the burden of endoscopists in the daily analysis of esophageal lesions. Considering the need to add new tasks in the diagnosis system, a deep learning model that can train a series of tasks incrementally using endoscopic images is essential for identifying the types and regions of esophageal lesions.

METHOD

In this paper, we proposed a continual learning-based esophageal lesion network (CLELNet), in which a convolutional autoencoder was designed to extract representation features of endoscopic images among different esophageal lesions. The proposed CLELNet consists of shared layers and task-specific layers. Shared layers are used to extract common features among different lesions while task-specific layers can complete different tasks. The first two tasks trained by the CLELNet are the classification (task 1) and the segmentation (task 2). We collected a dataset of esophageal endoscopic images from Macau Kiang Wu Hospital for training and testing the CLELNet.

RESULTS

The experimental results showed that the classification accuracy of task 1 was 95.96%, and the Intersection Over Union and the Dice Similarity Coefficient of task 2 were 65.66% and 78.08%, respectively.

CONCLUSIONS

The proposed CLELNet can realize task-incremental learning without forgetting the previous tasks and thus become a useful computer-aided diagnosis system in esophageal lesions analysis.

Quality in diagnostic upper gastrointestinal endoscopy for the detection and surveillance of gastric cancer precursor lesions: Position paper of AEG, SEED and SEAP

This position paper, sponsored by the Asociación Española de Gastroenterología [Spanish Association of Gastroenterology], the Sociedad Española de Endoscopia Digestiva [Spanish Gastrointestinal Endoscopy Society] and the Sociedad Española de Anatomía Patológica [Spanish Anatomical Pathology Society], aims to establish recommendations for performing an high quality upper gastrointestinal endoscopy for the screening of gastric cancer precursor lesions (GCPL) in low-incidence populations, such as the Spanish population. To establish the quality of the evidence and the levels of recommendation, we used the methodology based on the GRADE system (Grading of Recommendations Assessment, Development and Evaluation). We obtained a consensus among experts using a Delphi method. The document evaluates different measures to improve the quality of upper gastrointestinal endoscopy in this setting and makes recommendations on how to evaluate and treat the identified lesions. We recommend that upper gastrointestinal endoscopy for surveillance of GCPL should be performed by endoscopists with adequate training, administering oral premedication and use of sedation. To improve the identification of GCPL, we recommend the use of high definition endoscopes and conventional or digital chromoendoscopy and, for biopsies, NBI should be used to target the most suspicious areas of intestinal metaplasia. Regarding the evaluation of visible lesions, the risk of submucosal invasion should be evaluated with magnifying endoscopes and endoscopic ultrasound should be reserved for those with suspected deep invasion. In lesions amenable to endoscopic resection, submucosal endoscopic dissection is considered the technique of choice.

Advanced endoscopic methods in gastrointestinal diseases: a systematic review

Endoscopic imaging is the main method for detecting gastrointestinal diseases, which adversely affect human health. White light endoscopy (WLE) was the first method used for endoscopic examination and is still the preliminary step in the detection of gastrointestinal diseases during clinical examination. However, it cannot accurately diagnose gastrointestinal diseases owing to its poor correlation with histopathological diagnosis. In recent years, many advanced endoscopic methods have emerged to improve the detection accuracy by endoscopy. Chromoendoscopy (CE) enhances the contrast between normal and diseased tissues using biocompatible dye agents. Narrow band imaging (NBI) can improve the contrast between capillaries and submucosal vessels by changing the light source acting on the tissue using special filters to realize the visualization of the vascular structure. Flexible spectral imaging color enhancement (FICE) technique uses the reflectance spectrum estimation technique to obtain individual spectral images and reconstructs an enhanced image of the mucosal surface using three selected spectral images. The i-Scan technology takes advantage of the different reflective properties of normal and diseased tissues to obtain images, and enhances image contrast through post-processing algorithms. These abovementioned methods can be used to detect gastrointestinal diseases by observing the macroscopic structure of the digestive tract mucosa, but the ability of early cancer detection is limited with low resolution. However, based on the principle of confocal imaging, probe-based confocal laser endomicroscopy (pCLE) can enable cellular visualization with high-performance probes, which can present cellular morphology that is highly consistent with that shown by biopsy to provide the possibility of early detection of cancer. Other endoscopic imaging techniques including endoscopic optical coherence tomography (EOCT) and photoacoustic endoscopy (PAE), are also promising for diagnosing gastrointestinal diseases. This review focuses on these technologies and aims to provide an overview of different technologies and their clinical applicability.

An Asian consensus on standards of diagnostic upper endoscopy for neoplasia

BACKGROUND

This is a consensus developed by a group of expert endoscopists aiming to standardise the preparation, process and endoscopic procedural steps for diagnosis of early upper gastrointestinal (GI) cancers.

METHOD

The Delphi method was used to develop consensus statements through identification of clinical questions on diagnostic endoscopy. Three consensus meetings were conducted to consolidate the statements and voting. We conducted a systematic literature search on evidence for each statement. The statements were presented in the second consensus meeting and revised according to comments. The final voting was conducted at the third consensus meeting on the level of evidence and agreement.

RESULTS

Risk stratification should be conducted before endoscopy and high risk endoscopic findings should raise an index of suspicion. The presence of premalignant mucosal changes should be documented and use of sedation is recommended to enhance detection of superficial upper GI neoplasms. The use of antispasmodics and mucolytics enhanced visualisation of the upper GI tract, and systematic endoscopic mapping should be conducted to improve detection. Sufficient examination time and structured training on diagnosis improves detection. Image enhanced endoscopy in addition to white light imaging improves detection of superficial upper GI cancer. Magnifying endoscopy with narrow-band imaging is recommended for characterisation of upper GI superficial neoplasms. Endoscopic characterisation can avoid unnecessary biopsy.

CONCLUSION

This consensus provides guidance for the performance of endoscopic diagnosis and characterisation for early gastric and oesophageal neoplasia based on the evidence. This will enhance the quality of endoscopic diagnosis and improve detection of early upper GI cancers.

Narrow band imaging and serology in the assessment of premalignant gastric pathology

BACKGROUND

Patient outcomes in gastric adenocarcinoma are poor due to late diagnosis. Detecting and treating at the premalignant stage has the potential to improve this. Helicobacter pylori is also a strong risk factor for this disease.

AIMS

Primary aims were to assess the diagnostic accuracy of magnified narrow band imaging (NBI-Z) endoscopy and serology in detecting normal mucosa, H. pylori gastritis and gastric atrophy. Secondary aims were to compare the diagnostic accuracies of two classification systems using both NBI-Z and white light endoscopy with magnification (WLE-Z) and evaluate the inter-observer agreement.

METHODS

Patients were prospectively recruited. Images of gastric mucosa were stored with histology and serum for IgG H. pylori and Pepsinogen (PG) I/II ELISAs. Blinded expert endoscopists agreed on mucosal pattern. Mucosal images and serological markers were compared with histology. Kappa statistics determined inter-observer variability for randomly allocated images among four experts and four non-experts.

RESULTS

116 patients were prospectively recruited. Diagnostic accuracy of NBI-Z for determining normal gastric mucosa was 0.87(95%CI 0.82-0.92), H. pylori gastritis 0.65(95%CI 0.55-0.75) and gastric atrophy 0.88(95%CI 0.81-0.94). NBI-Z was superior to serology at detecting gastric atrophy: NBI-Z gastric atrophy 0.88(95%CI 0.81-0.94) vs PGI/II ratio < 3 0.74(95%CI 0.62-0.85) p<.0001. Overall NBI-Z was superior to WLE-Z in detecting disease using two validated classifications. Inter-observer agreement was 0.63(95%CI 0.51-0.73).

CONCLUSIONS

NBI-Z accurately detects changes in the GI mucosa which currently depend on histology. NBI-Z is useful in the detection of precancerous conditions, potentially improving patient outcomes with early intervention to prevent gastric cancer.

Efficacy of narrow-band imaging in detecting early esophageal cancer and risk factors for its occurrence

OBJECTIVE

The aim of this study is to evaluate the efficacy of narrow-band imaging (NBI) in the detecting early esophageal cancer and precancerous lesions and to investigate the risk factors for its occurrence.

METHODS

The esophagus was examined with ordinary endoscopy, NBI, and iodine staining. All the lesions were confirmed by histopathologically as the gold standard; NBI and intrapapillary capillary scale (IPCL) scale were compared with pathologic diagnosis. The accuracy, sensitivity, specificity, positive and negative predictive values (PPV, NPV) were calculated. Subgroup analysis was performed between the elderly vs. younger group, and head and neck squamous cell cancer (HNSCC) vs. non-HNSCC patients.

RESULTS

Ninety lesions were detected with ordinary endoscopy, 108 with NBI, and 120 with iodine staining. All esophageal cancers were detected both by NBI and by iodine staining. Accuracy, sensitivity, and specificity for esophageal cancer and precancerous lesion were 67.8%, 58.1%, and 76.6%; 92%, 89.7%, and 96%; 93.4%, 93.4%, and 93.2%, respectively. NBI endoscopy and iodine staining were superior to ordinary endoscopy for detecting esophageal cancer and precancerous lesions (p < 0.05). NBI showed better detection of esophageal neoplasms in the elderly patients (p < 0.001). The incidence of multiple squamous cell cancers (SCCs) was significantly higher in non-elderly group (p = 0.009). NBI can also detect more esophageal neoplastic lesions in patients with head and neck cancers (p = 0.003).

CONCLUSIONS

NBI endoscopy appears as effective as Lugol staining to detect and screen the early esophageal cancer. NBI shows better detection of esophageal neoplasms in the elderly patients. The incidence of multiple SCCs was much higher in non-elderly patients.

Beyond Dysplasia Grade: The Role of Biomarkers in Stratifying Risk

Gastroenterology society guidelines recommend endoscopic surveillance as a means to detect early stage cancer in Barrett's esophagus. However, the incidence of esophageal adenocarcinoma in Western countries continues to increase, suggesting that this strategy may be inadequate. Current surveillance methods rely on the endoscopist's ability to identify suspicious areas of Barrett's esophagus to biopsy, random biopsies, and on the histopathologic diagnosis of dysplasia. This review highlights the challenges of using dysplasia to stratify cancer risk and addresses the development and use of molecular biomarkers and in vivo molecular imaging to detect early neoplasia in Barrett's esophagus.

Diagnostic Performance of Narrow Band Imaging for Laryngeal Cancer: A Systematic Review and Meta-analysis

Objective

To evaluate the performance of narrow band imaging (NBI) for the diagnosis of laryngeal cancer and to compare the diagnostic value of NBI with that of white light endoscopy.

Data Sources

PubMed, Embase, Cochrane Library, and CNKI databases.

Review Methods

Data analyses were performed with Meta-DiSc. The updated Quality Assessment of Diagnostic Accuracy Studies–2 tool was used to assess study quality and potential bias. Publication bias was assessed with the Deeks’s asymmetry test. The protocol used in this article has been published on PROSPERO and is in accordance with the PRISMA checklist. The registry number for this study is CRD42015025866.

Results

Six studies including 716 lesions were included in this meta-analysis. The pooled sensitivity, specificity, and diagnostic odds ratio for the NBI diagnosis of laryngeal cancer were 0.94 (95% confidence interval [95% CI]: 0.91-0.96), 0.89 (95% CI: 0.85-0.92), and 142.12 (95% CI: 46.42-435.15), respectively, and the area under receiver operating characteristics curve was 0.97. Among the 6 studies, 3 evaluated the diagnostic value of white light endoscopy, with a sensitivity of 0.81 (95% CI: 0.76-0.86), a specificity of 0.92 (95% CI: 0.88-0.95), and a diagnostic odds ratio of 33.82 (95% CI: 14.76-77.49). The evaluation of heterogeneity, calculated per the diagnostic odds ratio, gave an I2 of 66%. No marked publication bias ( P = .84) was detected in this meta-analysis.

Conclusion

The sensitivity of NBI is superior to white light endoscopy, and the potential value of NBI needs to be validated in future studies.

Novel insights into esophageal diagnostic procedures

The 21st century offers new advances in diagnostic procedures and protocols in the management of esophageal diseases. This review highlights the most recent advances in esophageal diagnostic technologies, including clinical applications of novel endoscopic devices, such as ultrathin endoscopy and confocal laser endomicroscopy for diagnosis and management of Barrett's esophagus; novel parameters and protocols in high-resolution esophageal manometry for the identification and better classification of motility abnormalities; innovative connections between esophageal motility disorder diagnosis and detection of gastroesophageal reflux disease (GERD); impedance-pH testing for detecting the various GERD phenotypes; performance of distensibility testing for better pathophysiological knowledge of the esophagus and other gastrointestinal abnormalities; and a modern view of positron emission tomography scanning in metastatic disease detection in the era of accountability as a model for examining other new technologies. We now have better tools than ever for the detection of esophageal diseases and disorders, and emerging data are helping to define how well these tools change management and provide value to clinicians. This review features novel insights from multidisciplinary perspectives, including both surgical and medical perspectives, into these new tools, and it offers guidance on the use of novel technologies in clinical practice and future directions for research.

Development and Validation of a Classification System to Identify High-Grade Dysplasia and Esophageal Adenocarcinoma in Barrett's Esophagus Using Narrow-Band Imaging

BACKGROUND & AIMS

Although several classification systems have been proposed for characterization of Barrett's esophagus (BE) surface patterns based on narrow-band imaging (NBI), none have been widely accepted. The Barrett's International NBI Group (BING) aimed to develop and validate an NBI classification system for identification of dysplasia and cancer in patients with BE.

METHODS

The BING working group, composed of NBI experts from the United States, Europe, and Japan, met to develop a validated, consensus-driven NBI classification system for identifying dysplasia and cancer in BE. The group reviewed 60 NBI images of nondysplastic BE, high-grade dysplasia, and esophageal adenocarcinoma to characterize mucosal and vascular patterns visible by NBI; these features were used to develop the BING criteria. We then recruited adult patients undergoing surveillance or endoscopic treatment for BE at 4 institutions in the United States and Europe, obtaining high-quality NBI images and performing histologic analysis of biopsies. Experts individually reviewed 50 NBI images to validate the BING criteria, and then evaluated 120 additional NBI images (not previously viewed) to determine whether the criteria accurately predicted the histology results.

RESULTS

The BING criteria identified patients with dysplasia with 85% overall accuracy, 80% sensitivity, 88% specificity, 81% positive predictive value, and 88% negative predictive value. When dysplasia was identified with a high level of confidence, these values were 92%, 91%, 93%, 89%, and 95%, respectively. The overall strength of inter-observer agreement was substantial (κ = 0.681).

CONCLUSIONS

The BING working group developed a simple, internally validated system to identify dysplasia and EAC in patients with BE based on NBI results. When images are assessed with a high degree of confidence, the system can classify BE with >90% accuracy and a high level of inter-observer agreement.

Endoscopic diagnosis of early esophageal carcinoma

Esophageal carcinoma is one of the common malignant tumors in the world and China has the highest incidence and mortality rates. With the development of endoscopic techniques, the diagnosis rate of early esophageal carcinoma is greatly improved in recent years, and endoscopic techniques have been accepted as the first choice for diagnosis of early esophageal carcinoma. This paper reviews endoscopic diagnosis methods, including chromoendoscopy, narrow-band imaging, endoscopic ultrasonography, magnification endoscopy, fluorescence endoscopy, confocal laser endomicroscopy, Fujinon intelligent chromoendoscopy, I-Scan, endocytoscopy, optical coherence tomography, three-dimensional endoscopic imaging, endoscopic capsule endoscopy, and elastic scattering spectroscopy.

Neutrophil infiltration and the distribution of intestinal metaplasia is associated with metachronous gastric cancer following endoscopic submucosal dissection

BACKGROUND

Endoscopic submucosal dissection (ESD) of early gastric cancer is a minimally invasive procedure. However, the risk for metachronous cancers after successful cancer treatment remains high and the risk factors for metachronous cancers have not been elucidated.

OBJECTIVE

To evaluate the risk factors for metachronous gastric cancers after ESD with a long-term follow-up.

METHODS

A total of 155 consecutive patients (119 men, 36 women, mean age 68.9 years) were treated with ESD between September 2000 and September 2009. Biopsy specimens were obtained from the greater curvature of the antrum and middle corpus to evaluate gastric mucosal status, including Helicobacter pylori, intestinal metaplasia (IM) and neutrophil infiltration (NI) before ESD. Follow-up endoscopy after ESD was scheduled at two and six months, one year and annually thereafter. H pylori eradication was recommended when possible.

RESULTS

The median follow-up period was 4.2 years. Metachronous gastric cancers were found in 23 of 155 patients (3.5% per year). No local recurrences were observed. The cumulative incidence of metachronous gastric cancer was significantly high in IM and NI in the corpus (P=0.0093 and P=0.0025, respectively [log-rank test]). The ORs for IM and NI in the corpus were 2.65 and 3.06, respectively, according to the Cox proportional hazards model (P=0.024 and P=0.0091, respectively).

CONCLUSIONS

The presence of IM and NI in the corpus was closely related to the development of metachronous gastric cancer after ESD.

Red flag imaging in Barrett's esophagus: does it help to find the needle in the haystack?

Esophageal Adenocarcinoma (EAC) has suffered a sharp increase on its incidence for the last decades, and it is associated with a poor prognosis. Barrett's Esophagus (BE) is the most important identifiable risk factor for the progression to esophageal adenocarcinoma. The key to prevent and provide a curative treatment of esophageal adenocarcinoma is the detection and eradication of early neoplasia in patients with esophagus. Endoscopic surveillance is evolving from a blind or random four quadrant biopsies protocol (Seattle protocol) to a more targeted approach. A detailed white light examination with high-resolution endoscopy is the cornerstone for recognition of early neoplastic lesions in BE. Additional imaging modalities may enhance targeting of lesions or provide more information at a focused level. There are emerging data that some of these new modalities can increase the yield of detecting dysplasia, although its routine use has yet to be validated.

Endoscopic assessment and management of early esophageal adenocarcinoma

Esophageal carcinoma affects more than 450000 people worldwide and the incidence is rapidly increasing. In the United States and Europe, esophageal adenocarcinoma has superseded esophageal squamous cell carcinoma in its incidence. Esophageal cancer has a high mortality rates secondary to the late presentation of most patients at advanced stages. Endoscopic screening is recommended for patients with multiple risk factors for cancer in Barrett’s esophagus. These risk factors include chronic gastroesophageal reflux disease, hiatal hernia, advanced age, male sex, white race, cigarette smoking, and obesity. The annual risk of esophageal cancer is approximately 0.25% for patients without dysplasia and 6% for patients with high-grade dysplasia. Twenty percent of all esophageal adenocarcinoma in the United States is early stage with disease confined to the mucosa or submucosa. The significant morbidity and mortality of esophagectomy make endoscopic treatment an attractive option. The American Gastroenterological Association recommends endoscopic eradication therapy for patients with high-grade dysplasia. Endoscopic modalities for treatment of early esophageal adenocarcinoma include endoscopic resection techniques and endoscopic ablative techniques such as radiofrequency ablation, photodynamic therapy and cryoablation. Endoscopic therapy should be precluded to patients with no evidence of lymphovascular invasion. Local tumor recurrence is low after endoscopic therapy and is predicted by poor differentiation of tumor, positive lymph node and submucosal invasion. Surgical resection should be offered to patients with deep submucosal invasion.

Endoscopic molecular imaging of cancer

White light endoscopy has proven to be a very powerful tool in oncology. There is still, however, a need for better endoscopic techniques to overcome the current limitations of white light optics. New technologies that allow higher sensitivity, improved microanatomy and molecular characterization have been available for in vitro microscopy and are now being translated into in vivo endoscopy. Endoscopic molecular imaging is still in its infancy but holds the promise for enhancing sensitivity for early lesions, thus allowing earlier diagnosis and enabling early image-guided endoscopic intervention. A key feature of endoscopic molecular imaging is its increased sensitivity and specificity, which will be illustrated in this article, as well as describing perspectives on its future use in oncologic surgery.

Third-generation autofluorescence endoscopy for the detection of early neoplasia in Barrett's esophagus: a pilot study

In Barrett's esophagus (BE), second-generation autofluorescence imaging (AFI-II) improves targeted detection of high-grade intra-epithelial neoplasia (HGIN) and early cancer (EC), yet suffers from high false-positive (FP) rates. The newest generation AFI (AFI-III) specifically targets fluorescence in malignant cells and may therefore improve detection of early neoplasia and reduce FP rate. The aim was to compare AFI-III with AFI-II for endoscopic detection of early neoplasia in BE. BE patients with endoscopically inconspicuous neoplasia underwent two diagnostic endoscopies (AFI-II/AFI-III) in a single session. End-points: number of patients and lesions with HGIN/EC detected with AFI-II and AFI-III after white-light endoscopy (WLE) and the value of reinspection of AFI-positive areas with WLE and narrow-band imaging. Forty-five patients were included (38 males, age 65 years). Nineteen patients showed HGIN/EC. AFI-II inspection after WLE increased detection of HGIN/EC from 9 to 15 patients (47 to 79%); AFI-III increased detection from 9 to 17 patients (47 to 89%). WLE plus random biopsies diagnosed 13/19 (68%) HGIN/EC patients. One hundred and four abnormal AFI areas were inspected; 23 (22%) showed HGIN/EC. AFI-II increased detection of HGIN/EC from 10 to 18 lesions (43 to 78%). AFI-III increased detection from 10 to 20 lesions (43-87%). FP rate was 86% for AFI-II and AFI-III. Reinspection with WLE or narrow-band imaging reduced FP rate to 21% and 22%, respectively, but misclassified HGIN/EC lesions as unsuspicious in 54% and 31%, respectively. This first feasibility study on third-generation AFI again showed improved targeted detection of HGIN/EC in BE. However, the results do not suggest AFI-III performs significantly better than conventional AFI-II.

High definition endoscopy and "narrow band imaging" in the diagnosis of gastroesophageal reflux disease

INTRODUCTION

The gastroesophageal reflux disease is a common condition in the western world but less than half of patients present endoscopic abnormalities, making a standard procedure unsuitable for diagnosis. High definition endoscopy coupled with narrow band imaging has shown potential for differentiation of lesions and possible biopsy, allowing early diagnosis and treatment.

METHODS

This review describes the principles of biotic and their influence in obtaining images with better definition of the vessels in the mucosa, through the narrow band imaging. Selected papers using it in patients with reflux disease and Barrett's esophagus are analyzed in several ways, highlighting the findings and limitations.

CONCLUSION

The meaning of the narrow band imaging in the endoscopic diagnosis of reflux disease will be defined by large scale studies, with different categories of patients, including assessment of symptoms and response to treatment.

Systematic review of the diagnosis of gastric premalignant conditions and neoplasia with high-resolution endoscopic technologies

AIM. The aim of the article is to systematically review the current evidence on the diagnostic use of narrow band imaging (NBI), flexible spectral imaging color enhancement (FICE) and endoscopic image enhancement technology i-scan endoscopies for gastric precancerous and cancerous lesions. MATERIALS AND METHODS. Original manuscripts were searched in PubMed until October 2012. Pertinent data were collected and pooled diagnostic accuracy measures were estimated when possible. RESULTs. In total, 38 studies were evaluated. Thirty-one studies were included for NBI and 7 studies for FICE assessment in this systematic review. No article was found meeting inclusion criteria for i-scan endoscopy. The most defined and evaluated outcomes were cancer-related (n = 26). Quality Assessment of Diagnostic Accuracy Studies score varied from 9 to 12 (out of 14). Only few studies assessed the interobserver reliability. On a patient level analysis, NBI's pooled sensitivity, specificity and diagnostic odds ratio were 0.67 (95% CI: 0.61-0.73), 0.81 (95% CI: 0.76-0.85) and 22.71 (95% CI: 12.53-41.1), respectively for diagnosing normal mucosa; 0.86 (95% CI: 0.82-0.90), 0.77 (95% CI: 0.73-0.80) and 17.01 (95% CI: 1.4-207.2) for intestinal metaplasia and 0.90 (95% CI: 0.84-0.94), 0.83 (95% CI: 0.80-0.86) and 47.61 (95% CI: 4.61-491.34) for dysplasia. Owing to the insufficient data and different definitions, we could not aggregate the results for FICE. CONCLUSION. Gastric pattern descriptions have been proposed for NBI and FICE studies by gathering all descriptions in one single description. The classification systems varied between studies, a single description of gastric mucosal features with HR--scopes or at least per technology--will have to be agreed on.

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.

Screening and surveillance for Barrett's esophagus: current issues and future directions

PURPOSE OF REVIEW

Our article discusses the current understanding of screening and surveillance options for Barrett's esophagus and emerging concepts that have the potential to improve the effectiveness and cost-effectiveness of surveillance.

RECENT FINDINGS

Although endoscopic surveillance of patients with Barrett's esophagus is commonly practiced in order to detect high-grade dysplasia and early esophageal adenocarcinoma (EAC), the reported incidence of EAC in Barrett's esophagus patients varies widely. Recent studies found the risk of progression from Barrett's esophagus to EAC to be significantly lower than previously reported, raising concerns regarding the limitations of current surveillance strategies. Advances in imaging techniques and their enhanced diagnostic accuracy may improve the value of endoscopic surveillance. Additionally, various efforts are ongoing to identify biomarkers that identify individuals at higher risk of cancer, possibly allowing for individual risk stratification.

SUMMARY

These new data highlight some of the opportunities to revise and improve surveillance in patients with Barrett's esophagus. The incorporation of new advances such as imaging techniques and biomarkers has the potential to improve the effectiveness and cost-effectiveness of new surveillance regimens.

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.

Helpfulness of the combination of acetic acid and FICE in the detection of Barrett's epithelium and Barrett's associated neoplasias

AIM: To investigate the mucosal morphology in Barrett’s oesophagus by chromo and magnifying endoscopy.

METHODS: A prospective pilot study at a tertiary medical centre was conducted to evaluate the use of acetic acid pulverisation combined with virtual chromoendoscopy using Fujinon intelligent chromoendoscopy (FICE) for semiological characterization of the mucosal morphology in Barrett’s oesophagus and its neoplastic complications. Upper endoscopy using high definition white light, 2% acid acetic pulverisation and FICE with high definition videoendoscopy were performed in 20 patients including 18 patients who presented with aspects of Barrett’s oesophagus at endoscopy examination. Two patients used as controls had normal endoscopy and histological results. Prospectively, videos were watched blind from histological results by three trained FICE technique endoscopists.

RESULTS: The videos of patients with high-grade dysplasia showed an irregular mucosal pattern in 14% using high definition white light endoscopy and in 100% using acid acetic-FICE combined. Videos did not identify irregular vascular patterns using high definition white light endoscopy, while acid acetic-FICE combined visualised one in 86% of cases.

CONCLUSION: Combined acetic acid and FICE is a promising method for screening high-grade dysplasia and early cancer in Barrett’s oesophagus.

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.

Upper and Lower Gastrointestinal Findings in PTEN Mutation-Positive Cowden Syndrome Patients Participating in an Active Surveillance Program

OBJECTIVES:

Cowden syndrome (CS), associated with germline PTEN mutations, is an autosomal-dominant disorder with increased frequencies of thyroid and breast cancers. Recent reports document the occurrence of gastrointestinal (GI) polyps and increased risk of colon cancer in PTEN mutation carriers. Studies to date, however, have not been based on mutation carriers undergoing active, systematic, routine-interval GI surveillance. Our objective is to document the upper and lower GI findings in CS patients undergoing such an active GI surveillance program.

METHODS:

In a 5-year period, 3,000 consecutive patients were referred to our high-risk GI cancer clinic for various reasons. Of these 3,000, 10 met full-blown clinical criteria for the diagnosis of CS. Individuals with identified PTEN mutations underwent annual upper and lower endoscopy surveillance programs using dual white light and narrow-band imaging. All biopsies including archived materials were reviewed by a single dedicated GI pathologist.

RESULTS:

Ten PTEN mutation carriers from different ethnic backgrounds were invited and all participated in the active GI surveillance program. Eight patients had colonic polyps, mostly hyperplastic (eight patients) and hamartomatous (five patients), but also adenomatous (three patients), ganglioneuromatous (three patients), and juvenile polyps (two patients). One patient (10%) had an early-onset rectal cancer (aged 44 years), which was null for PTEN expression on immunohistochemistry. All patients had gastric polyps and nine (90%) had duodenal polyps, mostly hyperplastic and hamartomatous. Additional three patients (30%) had adenomatous duodenal polyps.

CONCLUSIONS:

PTEN mutation–positive CS patients have a higher frequency of upper GI polyps than previously believed. They appear prone to develop adenomatous upper and lower tract dysplastic polyps and cancer. Thus, the polyps encountered during upper or lower endoscopy in these patients should not be automatically considered innocent hamartomas without malignant potential. Active surveillance programs in specialized centers should be considered in these patients.

[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.

Novel risk markers for gastric cancer screening: Present status and future prospects

Initial identification of populations at high risk of gastric cancer (GC) is important for endoscopic screening of GC. As serum pepsinogen (PG) test-positive subjects with progression of chronic atrophic gastritis (CAG) show a high likelihood of future cancer development, this population warrants careful follow-up observation as a high-risk GC group. By combining the PG test with Helicobacter pylori (HP) antibody titers, the HP-related chronic gastritis stage can be classified, thus identifying not only a GC high-risk group but also a low-risk group. Among PG test-negative patients without CAG, those with high serum PG II levels and HP antibody titers are thought to have severe gastric mucosal inflammation and the risk of diffuse-type GC is also high. Meanwhile, in gastric mucosae obtained by endoscopic biopsy, HP infection induces aberrant DNA methylation in CpG islands in multiple gene regions and the extent of methylation clearly correlates with GC risk. By quantifying aberrant DNA methylation in suitable gene markers, we can determine the extent of the epigenetic field for cancerization. These novel concepts and risk markers will have many clinical applications in gastrointestinal endoscopy, including more efficient endoscopic GC screening and a strategic approach to metachronous multiple GCs after endoscopic treatment.

Endomicroscopy of intestinal metaplasia and gastric cancer

In vivo histologic diagnosis of gastric intestinal metaplasia (GIM) and gastric cancer (GC) can be achieved by confocal laser endomicroscopy (CLE). This review describes the endomicroscopic features of GIM and GC and reviews their clinical applications. Differentiation of phenotypes of GIM and GC by using CLE is also discussed.

Autofluorescence and narrow band imaging in Barrett's esophagus

This review discusses the application of 2 novel imaging techniques in Barrett's esophagus: autofluorescence imaging and narrow band imaging (NBI). Autofluorescence as well as NBI may help to direct endoscopic therapy for early neoplasia in Barrett's esophagus; their value in daily practice, however, seems to be limited and needs further evaluation.

Advances in endoscopic diagnosis and treatment of Barrett's esophagus

Barrett's esophagus (BE) is defined as abnormal specialized columnar metaplasia with intestinalization in place of the normal squamous esophageal epithelium. Gastroesophageal reflux disease is a known risk factor for BE; nonetheless BE is also detected in asymptomatic individuals. Other risk factors for BE include smoking, male gender, age over 50 and obesity. Patients diagnosed with BE (without dysplasia) are recommended to undergo endoscopic surveillance every 3-5 years. Advances in imaging techniques (such as narrow band imaging, autofluorescence imaging and confocal laser endomicroscopy) have the potential to improve the detection of dysplasia and early cancer, thus making surveillance a more cost-effective endeavor. Patients with high grade dysplasia (HGD) and early cancer have a high rate of progression to invasive adenocarcinoma and traditionally these patients were treated with esophagectomy. The rapid advancement of endoscopic therapeutic techniques along with a low risk of complications have made endoscopic therapy an acceptable alternative to an esophagectomy in patients with HGD and early cancer. Several endoscopic treatment techniques such as endoscopic mucosal resection, multipolar electrocoagulation, photodynamic therapy, argon plasma coagulation, cryotherapy, and radiofrequency ablation have been studied for endoscopic treatment.

Autofluorescence imaging with a transparent hood for detection of colorectal neoplasms: a prospective, randomized trial

BACKGROUND

Colonoscopy is one of the most reliable methods for detection of colorectal neoplasms, but conventional colonoscopy can miss some lesions.

OBJECTIVE

To evaluate the efficacy of autofluorescence imaging (AFI) with a transparent hood (TH) for detection of colorectal neoplasms.

DESIGN

A 2 × 2 factorial designed, prospective, randomized, controlled trial.

SETTING

This study was conducted at the Osaka Medical Center for Cancer and Cardiovascular Diseases, a tertiary cancer center.

PATIENTS

A total of 561 patients.

INTERVENTIONS

Patients were allocated to 1 of 4 groups: (1) white light imaging (WLI) alone--colonoscopy using WLI without a TH; (2) WLI+TH--colonoscopy using WLI with a TH; (3) AFI alone--colonoscopy using AFI without a TH; and (4) AFI+TH--colonoscopy using AFI with a TH. Eight colonoscopists used each allocated method.

MAIN OUTCOME MEASUREMENT

The difference in neoplasm detection rate (number of detected neoplasms per patient) between the WLI alone and AFI+TH groups.

RESULTS

Neoplasm detection rate (95% confidence interval) in the AFI+TH group was significantly higher than in the WLI alone group (1.96 [1.50-2.43] vs 1.19 [0.93-1.44]; P = .023, Tukey-Kramer multiple comparison test). Relative detection ratios (95% confidence interval) for polypoid neoplasms based on Poisson regression model were significantly increased by mounting a TH (1.69 [1.34-2.12], P < .001), and relative detection ratios for flat neoplasms were significantly increased by AFI observation (1.83 [1.24-2.71], P = .002).

LIMITATIONS

Open trial performed in single cancer referral center.

CONCLUSION

AFI colonoscopy with a TH detected significantly more colorectal neoplasms than did conventional WLI colonoscopy without a TH.

Wide-field fluorescence lifetime imaging of cancer

Optical imaging of tissue autofluorescence has the potential to provide rapid label-free screening and detection of surface tumors for clinical applications, including when combined with endoscopy. Quantitative imaging of intensity-based contrast is notoriously difficult and spectrally resolved imaging does not always provide sufficient contrast. We demonstrate that fluorescence lifetime imaging (FLIM) applied to intrinsic tissue autofluorescence can directly contrast a range of surface tissue tumors, including in gastrointestinal tissues, using compact, clinically deployable instrumentation achieving wide-field fluorescence lifetime images of unprecedented clarity. Statistically significant contrast is observed between cancerous and healthy colon tissue for FLIM with excitation at 355 nm. To illustrate the clinical potential, wide-field fluorescence lifetime images of unstained ex vivo tissue have been acquired at near video rate, which is an important step towards real-time FLIM for diagnostic and interoperative imaging, including for screening and image-guided biopsy applications.

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.

[Virtual chromoendoscopy]

Precise endoscopic assessment of gastrointestinal mucosal features is important in order to detect neoplastic lesions at an early stage. Electronic virtual chromoendoscopy markedly improves capillary pattern contrast and is an in vivo method for visualizing microvessel morphological changes in superficial neoplastic lesions. The scientific basis for this technique is that short wavelength light falls within the hemoglobin absorption band, thereby facilitating clearer visualization of vascular structures and pit pattern. Narrow Band Imaging (NBI, Olympus) and Multi-Band Imaging (FICE) are real-time, on-demand endoscopic imaging techniques available with high-definition endoscope. Potential indications include both the detection of premalignant lesions and differentiation between neoplastic and non-neoplastic lesions. The ease and readiness of use and the routine availability of virtual chromoendoscopy will probably contribute to its popularity. This does not alleviate the need to better define the role of these techniques in daily endoscopy practice by conducting well-designed prospective studies.