Meta-analysis of the effects of endoscopy with narrow band imaging in detecting dysplasia in Barrett's esophagus

Endoscopic Advances in the Diagnosis and Management of Gastroesophageal Reflux Disease

Gastroesophageal reflux disease (GERD) is one of the most common diseases that occurs secondary to failure of the antireflux barrier system, resulting in the frequent and abnormal reflux of gastric contents to the esophagus. GERD is diagnosed in routine clinical practice based on the classic symptoms of heartburn and regurgitation. However, a subset of patients with atypical symptoms can pose challenges in diagnosing GERD. An esophagogastroduodenoscopy (EGD) is the most common initial diagnostic test used in the assessment for GERD, although half of these patients will not have any positive endoscopic findings suggestive of GERD. The advanced endoscopic techniques have improved the diagnostic yield of GERD diagnosis and its complications, such as Barrett's esophagus and early esophageal adenocarcinoma. These newer endoscopic tools can better detect subtle irregularities in the mucosa and vascular structures. The management options for GERD include lifestyle modifications, pharmacological therapy, and endoscopic and surgical interventions. The latest addition to the armamentarium is the minimally invasive endoscopic interventions in carefully selected patients, including the electrical stimulation of the LES, Antireflux mucosectomy, Radiofrequency therapy, Transoral Incisionless Fundoplication, Endoscopic Full-Thickness plication (GERDx™), and suturing devices. With the emergence of these advanced endoscopic techniques, it is crucial to understand their selection criteria, advantages, and disadvantages.

Advanced endoscopic imaging for detection of Barrett's esophagus

Barrett's esophagus (BE) is the precursor to esophageal adenocarcinoma (EAC), and is caused by chronic gastroesophageal reflux. BE can progress over time from metaplasia to dysplasia, and eventually to EAC. EAC is associated with a poor prognosis, often due to advanced disease at the time of diagnosis. However, if BE is diagnosed early, pharmacologic and endoscopic treatments can prevent progression to EAC. The current standard of care for BE surveillance utilizes the Seattle protocol. Unfortunately, a sizable proportion of early EAC and BE-related high-grade dysplasia (HGD) are missed due to poor adherence to the Seattle protocol and sampling errors. New modalities using artificial intelligence (AI) have been proposed to improve the detection of early EAC and BE-related HGD. This review will focus on AI technology and its application to various endoscopic modalities such as high-definition white light endoscopy, narrow-band imaging, and volumetric laser endomicroscopy.

Identification of visible lesions during surveillance endoscopy for Barrett's esophagus: a video-based survey study

BACKGROUND AND AIMS

Visible lesion (VL) detection is essential in patients with Barrett's esophagus (BE). We sought to assess the rate of VL detection by academic and community endoscopists using high-definition white-light endoscopy (HD-WLE) and narrow-band imaging (NBI) during surveillance endoscopy.

METHODS

Fifty endoscopists were invited to participate in a prospective video survey study. Participants viewed 25 standardized clips of patients referred for endoscopic therapy. Participants noted identification of anatomic landmarks and VLs using HD-WLE and NBI and reported practice-level data. The criterion standard of VL identification was established by consensus of 5 BE experts. Our primary outcome was the rate of VL identification using HD-WLE and NBI.

RESULTS

Forty-four of 50 participants completed the study (22 academic and 22 community). Compared with the criterion standard, participants did not identify 28% (HD-WLE) and 31% (NBI) of VLs. Community endoscopists had more experience (>5 years in practice: community 85% vs academic 54.5%, P = .041; >5 surveillance endoscopies a month: community 85% vs academic 31.8%, P = .046). Across all participants, VL detection using NBI improved significantly with a minimum of 5 surveillance endoscopies per month (area under the curve = .72; 95% confidence interval, .56-.85; P = .006).

CONCLUSIONS

Despite improved endoscope resolution and availability of virtual chromoendoscopy, the overall rate of VL detection remains low. Identification of VLs using NBI may be volume dependent. Further education and training efforts focused on VL detection during BE surveillance endoscopy are needed.

Need for improvement in the evaluation of pre-malignant upper gastro-intestinal lesions in India: Results of a nationwide survey

BACKGROUND AND AIM

Gastric and esophageal cancers are associated with high morbidity in India. In the absence of formal screening programs in India, it is essential that all elective esophago-gastro-duodenoscopies (EGDs), irrespective of indication, be also considered an opportunity to screen for premalignant lesions. With this premise, we tried to assess the adherence to best practices in the detection of premalignant upper gastro-intestinal lesions (PMUGIL) among endoscopists in India. We also evaluated the adequacy of training, availability of appropriate facilities, and differences between teaching and non-teaching centers.

METHODS

We disbursed a survey among endoscopists working in India, through the membership database of the Society of Gastrointestinal Endoscopists of India, by email and instant messaging. The responses were collected and subsequently analyzed.

RESULTS

We obtained a total of 422 eligible responses. The adherence to best practices assessed was lower than the set threshold in all except one parameter in both teaching centers and non-teaching centers. Only 58.5% of endoscopists had received training in the detection of PMUGIL. Appropriate image enhanced endoscopy (IEE) facilities were available to only 58.05% of surveyed endoscopists.

CONCLUSIONS

Strategies to improve detection of PMUGIL should be directed at improving adherence to best practices, ensuring adequate training of endoscopists in the evaluation of PMUGIL and improving infrastructure.

Advanced imaging and artificial intelligence for Barrett's esophagus: What we should and soon will do

Barrett’s esophagus (BE) is a well-established risk factor for esophageal adenocarcinoma. It is recommended that patients have regular endoscopic surveillance, with the ultimate goal of detecting early-stage neoplastic lesions before they can progress to invasive carcinoma. Detection of both dysplasia or early adenocarcinoma permits curative endoscopic treatments, and with this aim, thorough endoscopic assessment is crucial and improves outcomes. The burden of missed neoplasia in BE is still far from being negligible, likely due to inappropriate endoscopic surveillance. Over the last two decades, advanced imaging techniques, moving from traditional dye-spray chromoendoscopy to more practical virtual chromoendoscopy technologies, have been introduced with the aim to enhance neoplasia detection in BE. As witnessed in other fields, artificial intelligence (AI) has revolutionized the field of diagnostic endoscopy and is set to cover a pivotal role in BE as well. The aim of this commentary is to comprehensively summarize present evidence, recent research advances, and future perspectives regarding advanced imaging technology and AI in BE; the combination of computer-aided diagnosis to a widespread adoption of advanced imaging technologies is eagerly awaited. It will also provide a useful step-by-step approach for performing high-quality endoscopy in BE, in order to increase the diagnostic yield of endoscopy in clinical practice.

Advanced Endoscopic Imaging and Interventions in GERD: An Update and Future Directions

Gastroesophageal reflux disease (GERD) is one of the most common gastrointestinal diseases encountered in primary care and gastroenterology clinics. Most cases of GERD can be diagnosed based on clinical presentation and risk factors; however, some patients present with atypical symptoms, which can make diagnosis difficult. An esophagogastroduodenoscopy can be used to assist in diagnosis of GERD, though only half of these patients have visible endoscopic findings on standard white light endoscopy. This led to the development of new advanced endoscopic techniques that enhanced the diagnosis of GERD and related complications like squamous cell dysplasia, Barrett's esophagus, and early esophageal adenocarcinoma. This is conducted by improved detection of subtle irregularities in the mucosa and vascular structures through optical biopsies in real-time. Management of GERD includes lifestyle modifications, pharmacological therapy, endoscopic and surgical intervention. Minimally invasive endoscopic intervention can be an option in selected patients with small hiatal hernia and without complications of GERD. These endoscopic interventions include endoscopic fundoplication, endoscopic mucosal resection techniques, ablative techniques, creating mechanical barriers, and suturing and stapling devices. As these new advanced endoscopic techniques are emerging, data surrounding the indications, advantages and disadvantages of these techniques need a thorough understanding.

Recent advances in early esophageal cancer: diagnosis and treatment based on endoscopy

Esophageal cancer (EC) often cannot be discovered in time because of its asymptomatic or symptom-atypical characteristics in early stage. The risk and probability of lymph node metastasis and distant metastasis increase correspondingly as the cancer aggressively invades deeper layers. Treatment regimens may be shifted to surgery and chemoradiotherapy (CRT) from endoscopic eradication therapy (EET) with poor quality of life and prognosis. It is imperative to identify dysplasia and EC early and enable early curative endoscopic treatments. Newer methods have been attempted in the clinical setting to achieve early detection at a more microscopic and precise level. Newer imaging techniques and artificial intelligence (AI) technology have been involved in targeted biopsies and will gradually unveil the visualization of pathology in the future. Early detection and diagnosis are the prerequisite to choose personal and precise treatment regimens. EET has also been undergoing development and improvement to benefit more patients as the first option or the firstly chosen alternative therapy, when compared with esophagectomy. More clinical studies are needed to provide more possibilities for EET.

Barrett's Esophagus and Intestinal Metaplasia

Intestinal metaplasia refers to the replacement of the differentiated and mature normal mucosal epithelium outside the intestinal tract by the intestinal epithelium. This paper briefly describes the etiology and clinical significance of intestinal metaplasia in Barrett’s esophagus. This article summarizes the impact of intestinal metaplasia on the diagnosis, monitoring, and treatment of Barrett’s esophagus according to different guidelines. We also briefly explore the basis for the endoscopic diagnosis of intestinal metaplasia in Barrett’s esophagus. The identification techniques of goblet cells in Barrett’s esophagus are also elucidated by some scholars. Additionally, we further elaborate on the current treatment methods related to Barrett’s esophagus.

Advanced Imaging and Sampling in Barrett's Esophagus: Artificial Intelligence to the Rescue?

Because the current Barrett's esophagus (BE) surveillance protocol suffers from sampling error of random biopsies and a high miss-rate of early neoplastic lesions, many new endoscopic imaging and sampling techniques have been developed. None of these techniques, however, have significantly increased the diagnostic yield of BE neoplasia. In fact, these techniques have led to an increase in the amount of visible information, yet endoscopists and pathologists inevitably suffer from variations in intra- and interobserver agreement. Artificial intelligence systems have the potential to overcome these endoscopist-dependent limitations.

Curriculum for optical diagnosis training in Europe: European Society of Gastrointestinal Endoscopy (ESGE) Position Statement

This manuscript represents an official Position Statement of the European Society of Gastrointestinal Endoscopy (ESGE) aiming to guide general gastroenterologists to develop and maintain skills in optical diagnosis during endoscopy. In general, this requires additional training beyond the core curriculum currently provided in each country. In this context, ESGE have developed a European core curriculum for optical diagnosis practice across Europe for high quality optical diagnosis training. 1:  ESGE suggests that every endoscopist should have achieved general competence in upper and/or lower gastrointestinal (UGI/LGI) endoscopy before commencing training in optical diagnosis of the UGI/LGI tract, meaning personal experience of at least 300 UGI and/or 300 LGI endoscopies and meeting the ESGE quality measures for UGI/LGI endoscopy. ESGE suggests that every endoscopist should be able and competent to perform UGI/LGI endoscopy with high definition white light combined with virtual and/or dye-based chromoendoscopy before commencing training in optical diagnosis. 2:  ESGE suggests competency in optical diagnosis can be learned by attending a validated optical diagnosis training course based on a validated classification, and self-learning with a minimum number of lesions. If no validated training course is available, optical diagnosis can only be learned by attending a non-validated onsite training course and self-learning with a minimum number of lesions. 3:  ESGE suggests endoscopists are competent in optical diagnosis after meeting the pre-adoption and learning criteria, and meeting competence thresholds by assessing a minimum number of lesions prospectively during real-time endoscopy. ESGE suggests ongoing in vivo practice by endoscopists to maintain competence in optical diagnosis. If a competent endoscopist does not perform in vivo optical diagnosis on a regular basis, ESGE suggests repeating the learning and competence phases to maintain competence.Key areas of interest were optical diagnosis training in Barrett's esophagus, esophageal squamous cell carcinoma, early gastric cancer, diminutive colorectal lesions, early colorectal cancer, and neoplasia in inflammatory bowel disease. Condition-specific recommendations are provided in the main document.

Diffuse endoscopically visible, predominantly low grade dysplasia in Barrett's esophagus (with video)

Background  Low grade dysplasia (LGD) in Barrett's esophagus (BE) has generally been considered as undetectable endoscopically. Aim  To describe a phenotype which consists of diffuse, endoscopically visible, predominantly low grade dysplasia in Barrett's esophagus (DEVLB), with often subtle but visible endoscopic changes seen with high definition white light (HDWL) and narrow-band imaging (NBI). Method  A systematic search of a prospectively collected database for patients satisfying predefined criteria for DEVLB and a review of endoscopic and histological features of biopsies and endoscopic mucosal resection (EMR) specimens. Results  Out of a total of 419 patients referred to our expert center for assessment of dysplastic Barrett's esophagus during the period January 2009 to March 2018, there were 7 patients (1.7 %) who satisfied the criteria defined for DEVLB, identified on their initial assessment endoscopy. All patients were treated by EMR of visible abnormal mucosa during their assessment endoscopy at our tertiary referral center. There was a total of 47 EMR specimens obtained, with a median of 6 (IQR 5-9) EMR resection pieces per patient, of which 36 (77 %) contained LGD, 8 (17 %) high grade dysplasia (HGD), 2 (4 %) non-dysplastic Barrett's esophagus (NDBE), and 1 (2 %) contained early esophageal adenocarcinoma (EAC). Conclusion  DEVLB is a distinct phenotype seen in a small but significant proportion of individuals with dysplastic Barrett's esophagus. Patients with DEVLB have widespread LGD, with many having areas of focal HGD or early cancer within this area. We believe these patients are best treated with extensive EMR of the visibly abnormal area.

Evaluation and Management of Premalignant Conditions of the Esophagus: A Systematic Survey of International Guidelines

Esophageal cancer represents one of the most lethal forms of malignancy. The growing incidence of esophageal adenocarcinoma represents an emerging public health concern. This review article summarizes current diagnostic, management, and therapeutic practices of premalignant conditions of the esophagus including Barrett's esophagus, tylosis, granular cell tumors, achalasia, and the ingestion of caustic substances. Our report provides clinicians and academics with a global clinical perspective regarding presentation, surveillance guidelines, and therapeutic management of these esophageal conditions.

Economic value of narrow-band imaging versus white light endoscopy for the diagnosis and surveillance of Barrett's esophagus: Cost-consequence model

Barrett’s esophagus (BE) is an abnormality arising from gastroesophageal reflux disease that can progressively evolve into a sequence of dysplasia and adenocarcinoma. Progression of Barrett’s esophagus into dysplasia is monitored with endoscopic surveillance. The current surveillance standard requests random biopsies plus targeted biopsies of suspicious lesions under white-light endoscopy, known as the Seattle protocol. Recently, published evidence has shown that narrow-band imaging (NBI) can guide targeted biopsies to identify dysplasia and reduce the need for random biopsies. We aimed to assess the health economic implications of adopting NBI-guided targeted biopsy vs. the Seattle protocol from a National Health Service England perspective. A decision tree model was developed to undertake a cost-consequence analysis. The model estimated total costs (i.e. staff and overheads; histopathology; adverse events; capital equipment) and clinical implications of monitoring a cohort of patients with known/suspected BE, on an annual basis. In the simulation, BE patients (N = 161,657 at Year 1; estimated annual increase: +20%) entered the model every year and underwent esophageal endoscopy. After 7 years, the adoption of NBI with targeted biopsies resulted in cost reduction of £458.0 mln vs. HD-WLE with random biopsies (overall costs: £1,966.2 mln and £2,424.2 mln, respectively). The incremental investment on capital equipment to upgrade hospitals with NBI (+£68.3 mln) was offset by savings due to the reduction of histological examinations (-£505.2 mln). Reduction of biopsies also determined savings for avoided adverse events (-£21.1 mln). In the base-case analysis, the two techniques had the same accuracy (number of correctly identified cases: 1.934 mln), but NBI was safer than HD-WLE. Budget impact analysis and cost-effectiveness analyses confirmed the findings of the cost-consequence analysis. In conclusion, NBI-guided targeted biopsies was a cost-saving strategy for NHS England, compared to current practice for detection of dysplasia in patients with BE, whilst maintaining at least comparable health outcomes for patients.

Virtual Histology in Everyday Gastrointestinal Endoscopy

Advances in imaging technologies have demonstrated promise in the early detection of dysplasia and cancer. They have also provided the ability to assess submucosal and vascular structures, helping differentiate neoplastic from non-neoplastic tissue. The aim of this concise case-based review is to discuss how optical imaging can impact patient management decisions during endoscopy, using real- life scenarios.

Point-Counterpoint: Screening and Surveillance for Barrett's Esophagus, Is It Worthwhile?

The exponential rise in incidence of esophageal adenocarcinoma (EAC), paired with persistently poor survival, continues to drive efforts to improve and optimize screening and surveillance practices. While advancements in endoscopic therapy have generated a shift in management and significantly improved the outcomes of patients with early-stage EAC, the majority of prevalent EAC continues to be diagnosed at advanced stages, remaining ineligible for curative therapy. Barrett's esophagus (BE) screening, when applied to high-yield target populations, using minimally or noninvasive accurate tests, followed by endoscopic surveillance to detect prevalent or incident dysplasia/EAC (which can then be treated successfully) is the cornerstone of the current BE management paradigm. While supported by some empiric evidence and attractive, this approach faces a number of challenges, which are also balanced by numerous recent advances in these areas. In this manuscript, we review the rationale, supportive evidence, current challenges, and recent progress in BE screening and surveillance.

Emerging optical methods for endoscopic surveillance of Barrett's oesophagus

Barrett's oesophagus is an acquired metaplastic condition that predisposes patients to the development of oesophageal adenocarcinoma, prompting the use of surveillance regimes to detect early malignancy for endoscopic therapy with curative intent. The currently accepted surveillance regime uses white light endoscopy together with random biopsies, but has poor sensitivity and discards information from numerous light-tissue interactions that could be exploited to probe structural, functional, and molecular changes in the tissue. Advanced optical methods are now emerging that are highly sensitive to these changes and hold potential to improve surveillance of Barrett's oesophagus if they can be applied endoscopically. The next decade will see some of these exciting new methods applied to surveillance of Barrett's oesophagus in new device architectures for the first time, potentially leading to a long-awaited improvement in the standard of care.

Impact of advanced endoscopic imaging on Barrett's esophagus in daily clinical practice

BACKGROUND AND AIMS

Several advanced imaging techniques have been proposed to improve the visualization of dysplastic regions within Barrett's epithelium, with some evidence for the use of narrow-band imaging (NBI) and acetic acid chromoendoscopy (AAC).

METHODS

We retrospectively analyzed consecutive cases of Barrett's esophagus, diagnosed using white-light endoscopy and confirmed histologically by the presence of intestinal metaplasia, between April 2007 and April 2010 in a large community hospital. A change in practice was then instituted, whereby a Barrett's team consisting of specialist endoscopists was formed in an attempt to standardize and improve the quality of surveillance. Barrett's epithelium was inspected with both white-light imaging and NBI in all patients. Where the length of Barrett's epithelium was 3 cm or more, AAC was also used. One and a half percent acetic acid was sprayed onto the Barrett's segment and loss of aceto-whitening observed after a 2-minute period. Any abnormal areas noted during advanced imaging underwent target biopsy sampling. We subsequently compared the dysplasia detection rate in Barrett's epithelium identified between April 2011 and April 2014 after these changes. Observed differences between the cohorts were analyzed with the Fisher exact test and the Student t test.

RESULTS

From 2007 to 2010 Barrett's esophagus was identified during 560 gastroscopies in 392 individual patients. The mean maximal Barrett's esophagus recorded length was 4.4 cm (range, 1-10), with an average of 4.7 esophageal biopsy specimens taken per endoscopy. In comparison, from 2011 to 2014 Barrett's esophagus was identified during 856 endoscopies in 630 patients. From 2011 to 2014 the Barrett's team performed 85% of all procedures using the aforementioned techniques. The mean maximal Barrett's esophagus length was 3.8 cm (range, 1-16), with an increased average of 5.8 biopsy specimens per endoscopy taken (P < .01). Both cohorts were comparable in age and gender distribution. Our data demonstrated no significant difference in the relative frequencies of occurrence of dysplasia detected between both cohorts of patients. From 2007 to 2010 dysplasia was detected in 11.0% (n = 43) of patients. This consisted of low-grade dysplasia in 7.7% of patients and high-grade dysplasia or cancer 3.3%. From 2011 to 2014 this compared with dysplasia in 11.3% (n = 71) of patients, with low-grade dysplasia in 9.4% and high-grade dysplasia or cancer in 1.9%.

CONCLUSIONS

Our data show that the use of NBI and AAC in the imaging of Barrett's esophagus did not result in an increased detection rate of dysplasia in routine clinical practice. These findings concur with the recommendations of existing Barrett's esophagus surveillance guidelines, which advocate the continued use of quadratic biopsy sampling within general surveillance programs.

Narrow-Band Imaging: Clinical Application in Gastrointestinal Endoscopy

Narrow-band imaging is an advanced imaging system that applies optic digital methods to enhance endoscopic images and improves visualization of the mucosal surface architecture and microvascular pattern. Narrow-band imaging use has been suggested to be an important adjunctive tool to white-light endoscopy to improve the detection of lesions in the digestive tract. Importantly, it also allows the distinction between benign and malignant lesions, targeting biopsies, prediction of the risk of invasive cancer, delimitation of resection margins, and identification of residual neoplasia in a scar. Thus, in expert hands it is a useful tool that enables the physician to decide on the best treatment (endoscopic or surgical) and management. Current evidence suggests that it should be used routinely for patients at increased risk for digestive neoplastic lesions and could become the standard of care in the near future, at least in referral centers. However, adequate training programs to promote the implementation of narrow-band imaging in daily clinical practice are needed. In this review, we summarize the current scientific evidence on the clinical usefulness of narrow-band imaging in the diagnosis and characterization of digestive tract lesions/cancers and describe the available classification systems.

Evaluation of a novel infra-red endoscopy system in the assessment of early neoplasia in Barretts esophagus: pilot study from a single center

Infrared endoscopy (IRE) has been shown to be useful in detecting submucosal (SM) invasion in early gastric cancer. Its role in the endoscopic assessment of Barrett's neoplasia has not been reported to date. We aimed in this study to evaluate the role of IRE in the detection and characterization of early neoplastic lesions within Barrett's esophagus (BE). The secondary aim was to explore its usefulness for the assessment of the presence of submucosal invasion in these early neoplastic Barrett's lesions. We included in the study patients with dysplastic BE who were referred to our institution for endoscopic therapy of a previously diagnosed early Barrett's neoplasia. An examination with white light high resolution endoscopy (HRE) and near IRE after intravenous injection of indocyanine green was performed for all patients using an infrared endoscope prototype. Staining on IRE and correlation with final histological staging by endoscopic mucosal resection/surgery or histological diagnosis on mapping biopsies was analyzed. A total of 23 patients were enrolled in our study: 17 of them with 19 visible lesions and 6 patients with flat BE and no lesions. Staining on IRE was noted in 18 cases: 17 (94%) had at least high grade dysplasia (HGD). No stain was noted in 7 cases: final histology was <HGD in 5 (71%) and ≥HGD in 2 (29%). There was statistically significant difference between cases with no stain and any staining on IRE with regard to the presence of ≥HGD [2/7 (29%) vs. 17/18 (94%) P = 0.0022]. Stain was reported as faint in 12 and dense in 6. All 6 cases with dense staining had at least HGD. We concluded that IRE can provide additional information to the currently available white light endoscopy for detecting early neoplastic lesions within BE. IRE also allows detecting HGD and most advanced histology in BE. Usefulness of IRE to detect submucosal involvement in early Barrett's neoplastic lesions needs to be assessed further in larger cohort studies.

Comparison of narrow-band imaging and confocal laser endomicroscopy for the detection of neoplasia in Barrett's esophagus: A meta-analysis

AIMS

Barrett's esophagus (BE) predisposes to the development of esophageal neoplasia, including high-grade dysplasia (HGD) and esophageal adenocarcinoma (EAC). A systematic literature review and meta-analysis were performed to assess the accuracy of within-patient comparisons of narrow band imaging (NBI) and confocal laser endomicroscopy (CLE) for diagnosis of HGD/EAC in patients with BE.

METHODS

The following databases were examined up to April 2016 without language restriction: PubMed, Embase, Medline, Web of Science and the Cochrane Library. The QUADAS-2 tool for assessing the quality of included studies was used. The meta-analysis included pooled additional detection rate (ADR), diagnostic accuracy, and 95% confidence intervals (CI). The I² and Q-test were used to determine study heterogeneity.

RESULTS

Five studies involving 251 patients, reported within-patient comparisons of NBI and CLE, were eligible for meta-analysis. Compared with NBI, pooled ADR of CLE for per-lesion detection of neoplasia in patients with BE was 19.3% (95% CI: 0.05-0.33, I²=74.6%). The pooled sensitivity of NBI was 62.8% (95% CI: 0.56-0.69, I²=94.6%), which was lower (not significantly) than that of CLE (72.3%, 95% CI: 0.66-0.78, I²=89.3%). The pooled specificity of NBI and CLE were similar [85.3% (95% CI: 0.84-0.87, I²=92.1%) vs 83.8% (95% CI: 0.82-0.85, I²=96.8%)].

CONCLUSIONS

When compared with NBI, CLE significantly increased the per-lesion detection rate of esophageal neoplasia, HGD, and EAC in BE patients. Whether CLE is superior to NBI in neoplasia detection at per-patient level needs to be further investigated.

The value of narrow band imaging in diagnosis of head and neck cancer: a meta-analysis

Head and neck cancer is difficult to diagnose early. We aimed to estimate the diagnosis value of narrow band imaging(NBI) in head and neck cancers. We identified relevant studies through a search of PubMed, Embase and the Cochrane Library. We used a random effect model. Subgroup analysis and meta-regression analysis were performed to estimate the factors which may influence the sensitivity and specificity of the NBI. We included 25 studies with total 6187 lesions. The pooled sensitivity, specificity, positive likelihood rate, negative likelihood rate and diagnostic odds ratios of NBI were 88.5%, 95.6%, 12.33, 0.11 and 121.26, respectively. The overall area under the curve of SROC was 96.94%. The location, type of assessment, type of endoscope system and high definition were not significant sources of heterogeneity (P > 0.05). However, magnification may be related to the source of heterogeneity (P = 0.0065). Therefore, NBI may be a promising endoscopic tool in the diagnosis of head and neck cancer.

Multispectral light scattering endoscopic imaging of esophageal precancer

Esophageal adenocarcinoma is the most rapidly growing cancer in America. Although the prognosis after diagnosis is unfavorable, the chance of a successful outcome increases tremendously if detected early while the lesion is still dysplastic. Unfortunately, the present standard-of-care, endoscopic surveillance, has major limitations, since dysplasia is invisible, often focal, and systematic biopsies typically sample less than one percent of the esophageal lining and therefore easily miss malignancies. To solve this problem we developed a multispectral light scattering endoscopic imaging system. It surveys the entire esophageal lining and accurately detects subcellular dysplastic changes. The system combines light scattering spectroscopy, which detects and identifies invisible dysplastic sites by analyzing light scattered from epithelial cells, with rapid scanning of the entire esophageal lining using a collimated broadband light beam delivered by an endoscopically compatible fiber optic probe. Here we report the results of the first comprehensive multispectral imaging study, conducted as part of routine endoscopic procedures performed on patients with suspected dysplasia. In a double-blind study that characterized the system's ability to serve as a screening tool, 55 out of 57 patients were diagnosed correctly. In addition, a smaller double-blind comparison of the multispectral data in 24 patients with subsequent pathology at locations where 411 biopsies were collected yielded an accuracy of 90% in detecting individual locations of dysplasia, demonstrating the capability of this method to serve as a guide for biopsy.

Endoscopic Management of Early Adenocarcinoma and Squamous Cell Carcinoma of the Esophagus: Screening, Diagnosis, and Therapy

Because the esophagus is easily accessible with endoscopy, early diagnosis and curative treatment of esophageal cancer is possible. However, diagnosis is often delayed because symptoms are not specific during early stages of tumor development. The onset of dysphagia is associated with advanced disease, which has a survival at 5 years lower than 15%. Population screening by endoscopy is not cost-effective, but a number of alternative imaging and cell analysis technologies are under investigation. The ideal screening test should be inexpensive, well tolerated, and applicable to primary care. Over the past 10 years, significant progress has been made in endoscopic diagnosis and treatment of dysplasia (squamous and Barrett's), and early esophageal cancer using resection and ablation technologies supported by evidence from randomized controlled trials. We review the state-of-the-art technologies for early diagnosis and minimally invasive treatment, which together could reduce the burden of disease.

Usefulness of Non-magnifying Narrow Band Imaging in EVIS EXERA III Video Systems and High-Definition Endoscopes to Diagnose Dysplasia in Barrett's Esophagus Using the Barrett International NBI Group (BING) Classification

BACKGROUND

Narrow band imaging (NBI) allows identification of abnormal areas of Barrett's esophagus (BE) and could facilitate targeted biopsies.

AIMS

We evaluated the diagnostic accuracy for dysplasia prediction using non-magnifying NBI in Evis Exera III processors and high-definition endoscopes using the Barrett International NBI Group (BING) classification, as well as inter/intraobserver agreement for dysplasia prediction and mucosal/vascular patterns.

METHODS

Eight observers (4 staff endoscopists and 4 trainee endoscopists) evaluated 100 images selected from an anonymized bank of 470 photographs using the BING classification. Observers were to assign their individual assessment of the mucosal and vascular pattern, and prediction for dysplasia. Accuracy for dysplasia prediction and intra/interobserver agreement was calculated.

RESULTS

Dysplasia prediction had an accuracy of 81.1%, sensitivity of 48.4%, and a specificity of 91%. Positive predictive value and negative predictive value (NPV) were 61.4 and 85.5%, respectively. Dysplasia prediction done with a high degree of confidence (vs. low degree of confidence) had better diagnostic accuracy (85.8 vs. 70.7%). Interobserver concordance for dysplasia was weak: Κ = 0.40. Agreement for mucosal and vascular patterns was 0.39 and 0.30, respectively. Intraobserver concordance (assessed 6 months after initial test) for mucosal pattern, vascular pattern, and dysplasia prediction was moderate: Κ = 0.56, Κ = 0.47 and Κ = 0.60, respectively.

CONCLUSIONS

Our results showed that NBI had a significant accuracy in BE assessment for dysplasia prediction, high specificity (>90%), and NPV (>85%), with suboptimal sensitivity. NBI could be a useful additional tool for BE inspection and targeted biopsies, but cannot avoid the need for biopsies following the Seattle protocol.

A guide to multimodal endoscopy imaging for gastrointestinal malignancy - an early indicator

Multimodality imaging is an essential aspect of endoscopic surveillance for the detection of neoplastic lesions, such as dysplasia or intramucosal cancer, because it improves the efficacy of endoscopic surveillance and therapeutic procedures in the gastrointestinal tract. This approach reveals mucosal abnormalities that cannot be detected by standard endoscopy. Currently, these imaging techniques are divided into those for primary detection and those for targeted imaging and characterization, the latter being used to visualize areas of interest in detail and permit histological evaluation. This Review outlines the use of virtual chromoendoscopy, narrow-band imaging, autofluorescence imaging, optical coherence tomography, confocal endomicroscopy and volumetric laser endomicroscopy as new imaging techniques for diagnostic investigation of the gastrointestinal tract. Insights into use of multimodal endoscopic imaging for early disease detection, in particular for pre-malignant lesions, in the oesophagus, stomach and colon are described.

The Role of Adjunct Imaging in Endoscopic Detection of Dysplasia in Barrett's Esophagus

Advances in imaging technologies have demonstrated promise in early detection of dysplasia and cancer in Barrett's esophagus (BE). Optical chromoendoscopy, dye-based chromoendoscopy, and novel technologies have provided the opportunity to visualize the cellular and subcellular structures. Only narrow-band imaging and acetic acid chromoendoscopy have reached benchmarks for clinical use. Volumetric laser endomicroscopy and molecular imaging are not established for routine use. Best practice in management of BE should be focused on careful endoscopic examination, resection, or ablation of the entire abnormal lesion, as well as the use of available imaging technique that has good diagnostic accuracy.

Recent Advances in Non-invasive Esophageal Tissue Sampling

PURPOSE OF REVIEW

The costs to society and accuracy of screening for esophageal cancer and other esophageal diseases with standard endoscopy are formidable. As a result, the applicability of endoscopy as a general screening tool has been challenged.

RECENT FINDINGS

To maintain accuracy but reduce the price of endoscopy on society, multiple adjunct or replacement technologies are being developed that are less expensive and more easily applied. These devices include image-enhancing techniques that more reliably identify dysplasia and cancer reducing the need for extensive biopsy sampling during standard endoscopy. They also include ambulatory forms for procuring esophageal imaging including smaller endoscopes and capsule endoscopy. Finally, some of the newer methods either obtain samples of esophageal tissue through bedside maneuvers not requiring endoscopy or retrieve information about mucosal inflammation and function without the need to procure esophageal tissue. There is an exciting future for esophageal diagnosis with tools that will save cost and/or provide greater accuracy and safety for some of the most common esophageal disorders.

Emerging endoscopic techniques for the identification of esophageal disease

Esophageal diseases, both benign and malignant, impose an increasing burden to global health. In the West, gastroesophageal reflux disease (GERD) and Barrett's esophagus are increasing in prevalence and impact. In the East, squamous esophageal cancer remains a large burden, but increasingly, precancerous lesions related to GERD are recognized. We review the various advanced endoscopic techniques that have been developed to improve the accuracy of endoscopic identification of esophageal disease. These techniques are designed to increase the sensitivity of detecting disease and high-risk lesions, enable targeted biopsies, decrease total number of biopsies and costs for surveillance, but also guide therapy in real-time. After proper clinical validation, the widespread use of these technologies will lead to improved outcomes, mostly in cancer prevention.

Review: Surveillance of patients with Barrett oesophagus

There has been a rapid increase in the incidence of oesophageal adenocarcinoma in most Western countries over the past thirty years. Barrett's oesophagus (BE) is a common premalignant lesion of oesophageal adenocarcinoma, although the risk of developing cancer in BE remains low. Therefore, screening is not recommended in the general population. Surveillance of BE is recommended to detect high grade dysplasia or carcinoma in an early stage, although there is no clear evidence that surveillance leads to a reduced mortality. This review discusses the several screening and surveillance techniques, including chromoendoscopy, narrow band imaging, autofluorescence imaging and confocal laser endomicroscopy, pointing out the areas that are well established as well as the new techniques that require more research.

A preliminary feasibility study: Narrow-band imaging targeted versus standard white light endoscopy non-targeted biopsies in a surveillance Barrett's population

BACKGROUND

Narrow band imaging (NBI) is used in the detection of intestinal metaplasia (IM) and dysplasia in patients with Barrett's oesophagus (BE).

AIMS

The study compared the usefulness of NBI with white-light standard endoscopy (WLSE) for the detection of dysplasia and IM in BE and determined the prediction of the histological diagnosis according to the mucosal and vascular patterns obtained by NBI.

PATIENTS AND METHODS

A total of 84 patients were prospectively enrolled in the study. Every patient underwent a WLSE with random biopsies and after 4-6 weeks, a NBI examination was performed.

RESULTS

NBI detected significant more IM positive biopsies than WLSE (74.5% vs. 35.9%; p<0.0001) and significant more patients with low grade dysplasia (LGD) (7.1% vs. 0%; p=0.03). Taking biopsy samples from the villous pattern determined the diagnosis of IM (80%) and biopsies from the area covered by the irregular pattern lead to the identification of LGD in 45.4% of the cases and indefinite dysplasia (ID) in 18.2% of the cases.

CONCLUSION

A thorough analysis of NBI patterns may lead to real-time IM diagnosis in the absence of the histological examination and may require targeted biopsies from the areas with an irregular pattern for diagnosing dysplasia.

Asia-Pacific consensus on the management of gastro-oesophageal reflux disease: an update focusing on refractory reflux disease and Barrett's oesophagus

OBJECTIVE

Since the publication of the Asia-Pacific consensus on gastro-oesophageal reflux disease in 2008, there has been further scientific advancement in this field. This updated consensus focuses on proton pump inhibitor-refractory reflux disease and Barrett's oesophagus.

METHODS

A steering committee identified three areas to address: (1) burden of disease and diagnosis of reflux disease; (2) proton pump inhibitor-refractory reflux disease; (3) Barrett's oesophagus. Three working groups formulated draft statements with supporting evidence. Discussions were done via email before a final face-to-face discussion. We used a Delphi consensus process, with a 70% agreement threshold, using Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria to categorise the quality of evidence and strength of recommendations.

RESULTS

A total of 32 statements were proposed and 31 were accepted by consensus. A rise in the prevalence rates of gastro-oesophageal reflux disease in Asia was noted, with the majority being non-erosive reflux disease. Overweight and obesity contributed to the rise. Proton pump inhibitor-refractory reflux disease was recognised to be common. A distinction was made between refractory symptoms and refractory reflux disease, with clarification of the roles of endoscopy and functional testing summarised in two algorithms. The definition of Barrett's oesophagus was revised such that a minimum length of 1 cm was required and the presence of intestinal metaplasia no longer necessary. We recommended the use of standardised endoscopic reporting and advocated endoscopic therapy for confirmed dysplasia and early cancer.

CONCLUSIONS

These guidelines standardise the management of patients with refractory gastro-oesophageal reflux disease and Barrett's oesophagus in the Asia-Pacific region.

Design and validation of a near-infrared fluorescence endoscope for detection of early esophageal malignancy

Barrett’s esophagus is a known precursor lesion to esophageal adenocarcinoma. In these patients, early detection of premalignant disease, known as dysplasia, allows curative minimally invasive endoscopic therapy, but is confounded by a lack of contrast in white light endoscopy. Imaging fluorescently labeled lectins applied topically to the tissue has the potential to more accurately delineate dysplasia, but tissue autofluorescence limits both sensitivity and contrast when operating in the visible region. To overcome this challenge, we synthesized near-infrared (NIR) fluorescent wheat germ agglutinin (WGA-IR800CW) and constructed a clinically translatable bimodal NIR and white light endoscope. Images of NIR and white light with a field of view of 63 deg and an image resolution of 182  μm are coregistered and the honeycomb artifact arising from the fiber bundle is removed. A minimum detectable concentration of 110 nM was determined using a dilution series of WGA-IR800CW. We demonstrated ex vivo that this system can distinguish between gastric and squamous tissue types in mouse stomachs (p=0.0005) and accurately detect WGA-IR800CW fluorescence in human esophageal resections (compared with a gold standard imaging system, rs>0.90). Based on these findings, future work will optimize the bimodal endoscopic system for clinical trials in Barrett’s surveillance.

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

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Advances in the 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.

White Paper AGA: Advanced Imaging in Barrett's Esophagus

Enhanced imaging technologies such as narrow band imaging, flexible spectral imaging color enhancement, i-Scan, confocal laser endomicroscopy, and optical coherence tomography are readily available for use by endoscopists in routine clinical practice. In November 2014, the American Gastroenterological Association's Center for GI Innovation and Technology conducted a 2-day workshop to discuss endoscopic image enhancement technologies, focusing on their role in 2 specific clinical conditions (colon polyps and Barrett's esophagus) and on issues relating to training and implementation of these technologies (white papers). Although the majority of the studies that use enhanced imaging technologies have been positive, these techniques ideally need to be validated in larger cohorts and in community centers. As it stands today, detailed endoscopic examination with high-definition white-light endoscopy and random 4-quadrant biopsy remains the standard of care. However, the workshop panelists agreed that in the hands of endoscopists who have met the preservation and incorporation of valuable endoscopic innovation thresholds (diagnostic accuracy) with enhanced imaging techniques (specific technologies), use of the technique in Barrett's esophagus patients is appropriate.

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.

Endoscopic imaging

OPINION STATEMENT

The most important tools are the eye and the brain. A detailed white-light high-resolution examination and ability to recognize subtle lesions provide the foundation of the ability to detect lesions in the gastrointestinal tract. Novel technologies are now available to provide additional information with the goals of detection, delineation, or classification often with a focus on neoplasia in the gastrointestinal tract. The observer using these new tools must still recognize, interpret, and then make a clinically relevant conclusion. Therefore, the assessment of these tools may focus on both the technical feasibility to use the respective equipment to obtain an image and then also the associated cognitive-based criteria for image interpretation.

Developments in flexible endoscopic surgery: a review

Flexible endoscopy is increasingly developing into a therapeutic instead of a purely diagnostic discipline. Improved visualization makes early lesions easily detectable and allows us to decide ad hoc on the required treatment. Deep enteroscopy allows the exploration of even the small bowel - for long a "white spot" for gastrointestinal endoscopy - and to perform direct treatment. Endoscopic submucosal dissection is a considerable step forward in oncologically correct endoscopic treatment of (early) malignant lesions. Though still technically challenging, it is increasingly facilitated by new manipulation techniques and tools that are being steadily optimized. Closure of wall defects and hemostasis could be improved significantly. Even the anatomy beyond the gastrointestinal wall is being explored by the therapeutic use of endoluminal ultrasound. Endosonographic-guided surgery is not only a suitable fallback solution if conventional endoscopic retrograde cholangiopancreatography fails, but even makes necrosectomy procedures, abscess drainage, and neurolysis feasible for the endoscopist. Newly developed endoscopic approaches aim at formerly distinctive surgical domains like gastroesophageal reflux disease, appendicitis, and cholecystitis. Combined endoscopic/laparoscopic interventional techniques could become the harbingers of natural orifice transluminal endoscopic surgery, whereas pure natural orifice transluminal endoscopic surgery is currently still in its beginnings.

Esophageal cancer: Recent advances in screening, targeted therapy, and management

The incidence of esophageal cancer remains on the rise worldwide and despite aggressive research in the field of gastrointestinal oncology, the survival remains poor. Much remains to be defined in esophageal cancer, including the development of an effective screening tool, identifying a good tumor marker for surveillance purposes, ways to target esophageal cancer stem cells as well as circulating tumor cells, and developing minimally invasive protocols to treat early-stage disease. The goal of this chapter is to highlight some of the recent advances and ongoing research in the field of esophageal cancer.