Probe-based confocal laser endomicroscopy compared with standard four-quadrant biopsy for evaluation of neoplasia in Barrett's esophagus

National Institute for Health and Care Excellence (NICE) guidance on monitoring and management of Barrett's oesophagus and stage I oesophageal adenocarcinoma

Barrett's oesophagus is the only known precursor to oesophageal adenocarcinoma, a cancer with very poor prognosis. The main risk factors for Barrett's oesophagus are a history of gastro-oesophageal acid reflux symptoms and obesity. Men, smokers and those with a family history are also at increased risk. Progression from Barrett's oesophagus to cancer occurs via an intermediate stage, known as dysplasia. However, dysplasia and early cancer usually develop without any clinical signs, often in individuals whose symptoms are well controlled by acid suppressant medications; therefore, endoscopic surveillance is recommended to allow for early diagnosis and timely clinical intervention. Individuals with Barrett's oesophagus need to be fully informed about the implications of this diagnosis and the benefits and risks of monitoring strategies. Pharmacological treatments are recommended for control of symptoms, but not for chemoprevention. Dysplasia and stage 1 oesophageal adenocarcinoma have excellent prognoses, since they can be cured with endoscopic or surgical therapies. Endoscopic resection is the most accurate staging technique for early Barrett's-related oesophageal adenocarcinoma. Endoscopic ablation is effective and indicated to eradicate Barrett's oesophagus in patients with dysplasia. Future research should focus on improved accuracy for dysplasia detection via new technologies and providing more robust evidence to support pathways for follow-up and treatment.

Optical Biopsy of Dysplasia in Barrett's Oesophagus Assisted by Artificial Intelligence

Optical biopsy in Barrett's oesophagus (BE) using endocytoscopy (EC) could optimize endoscopic screening. However, the identification of dysplasia is challenging due to the complex interpretation of the highly detailed images. Therefore, we assessed whether using artificial intelligence (AI) as second assessor could help gastroenterologists in interpreting endocytoscopic BE images. First, we prospectively videotaped 52 BE patients with EC. Then we trained and tested the AI pm distinct datasets drawn from 83,277 frames, developed an endocytoscopic BE classification system, and designed online training and testing modules. We invited two successive cohorts for these online modules: 10 endoscopists to validate the classification system and 12 gastroenterologists to evaluate AI as second assessor by providing six of them with the option to request AI assistance. Training the endoscopists in the classification system established an improved sensitivity of 90.0% (+32.67%, p < 0.001) and an accuracy of 77.67% (+13.0%, p = 0.020) compared with the baseline. However, these values deteriorated at follow-up (-16.67%, p < 0.001 and -8.0%, p = 0.009). Contrastingly, AI-assisted gastroenterologists maintained high sensitivity and accuracy at follow-up, subsequently outperforming the unassisted gastroenterologists (+20.0%, p = 0.025 and +12.22%, p = 0.05). Thus, best diagnostic scores for the identification of dysplasia emerged through human-machine collaboration between trained gastroenterologists with AI as the second assessor. Therefore, AI could support clinical implementation of optical biopsies through EC.

The Use of Confocal Laser Endomicroscopy in Diagnosing Barrett’s Esophagus and Esophageal Adenocarcinoma

Confocal laser endomicroscopy (CLE) is a diagnostic technique that enables real-time microscopic imaging during microscopic examination and evaluation of epithelial structures with 1000-fold magnification. CLE can be used in the diagnosis of various pathologies, in pneumology, and in urology, and it is very widely utilized in gastroenterology, most importantly in the diagnosis of Barrett’s esophagus (BE), esophageal adenocarcinoma (EAC), biliary strictures, and cystic pancreatic lesions. A literature search was made in MEDLINE/PubMed and Google Scholar databases while focusing on diagnostics using CLE of BE and EAC. We then examined randomized and observational studies, systematic reviews, and meta-analyses relating to the utilization of CLE in BE and EAC diagnostics. Here, we discuss whether CLE can be a suitable diagnostic method for surveillance of BE. Even though many studies have proven that CLE increases diagnostic accuracy in detecting neoplastic transformation of BE, CLE is still not used as a standard diagnostic tool in BE surveillance due to a deficiency of scientific evidence. More studies and data are needed if CLE is to find a place as a new technique in BE surveillance.

Endoscopic Diagnosis and Management of Barrett's Esophagus with Low-Grade Dysplasia

Barrett’s Esophagus is a common condition associated with chronic gastroesophageal reflux disease. It is well known that it has an association with a higher incidence of esophageal adenocarcinoma, but this neoplastic transformation is first preceded by the onset of low and high-grade dysplasia. The evaluation of low grade dysplastic esophageal mucosa is still controversial; although endoscopic surveillance is preferred, several minimally invasive endoscopic therapeutic approaches are available. Endoscopic mucosal resection and radiofrequency ablation are the most used endoscopic treatments for the eradication of low-grade dysplasia, respectively, for nodular and flat dysplasia. Novel endoscopic treatments are cryotherapy ablation and argon plasma coagulation, that have good rates of eradication with less complications and post-procedural pain.

Barrett's esophagus: The pathomorphological and molecular genetic keystones of neoplastic progression

Barrett's esophagus is a widespread chronically progressing disease of heterogeneous nature. A life threatening complication of this condition is neoplastic transformation, which is often overlooked due to lack of standardized approaches in diagnosis, preventative measures and treatment. In this essay, we aim to stratify existing data to show specific associations between neoplastic transformation and the underlying processes which predate cancerous transition. We discuss pathomorphological, genetic, epigenetic, molecular and immunohistochemical methods related to neoplasia detection on the basis of Barrett's esophagus. Our review sheds light on pathways of such neoplastic progression in the distal esophagus, providing valuable insight into progression assessment, preventative targets and treatment modalities. Our results suggest that molecular, genetic and epigenetic alterations in the esophagus arise earlier than cancerous transformation, meaning the discussed targets can help form preventative strategies in at-risk patient groups.

The evolution of endoscopic therapy for Barrett's esophagus

Barrett’s esophagus is the condition in which a metaplastic columnar epithelium replaces the stratified squamous epithelium that normally lines the distal esophagus. The condition develops as a consequence of chronic gastroesophageal reflux disease and predisposes the patient to the development of esophageal adenocarcinoma. The diagnosis and management of Barrett’s esophagus have undergone dramatic changes over the years and continue to evolve today. Endoscopic eradication therapy has revolutionized the management of dysplastic Barrett’s esophagus and early esophageal adenocarcinoma by significantly reducing the morbidity and mortality associated with the prior gold standard of therapy, esophagectomy. The purpose of this review is to highlight current principles in the management and endoscopic treatment of this disease.

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.

Probe-Based Confocal Laser Endomicroscopy and Barrett's Esophagus: Just a Scientific Toy or Significant Improvement in Diagnosis?

BACKGROUND

Barrett's esophagus (BE) requires surveillance to identify potential neoplasia at an early stage. The standard surveillance regimen includes random 4-quadrant biopsies by Seattle protocol. Main limitations of random biopsies are high risk of sampling error, difficulties in histology interpretation, common inadequate classification of pathohistological changes, increased risk of bleeding, and time necessary to acquire the final diagnosis. Probe-based confocal laser endomicroscopy (pCLE) has emerged as a potential tool with an aim to overcome these obvious limitations.

SUMMARY

pCLE represents a real-time microscopic imaging method that offers evaluation of epithelial and subepithelial structures with 1,000-fold magnification. In theory, pCLE has potential to eliminate the need for biopsy in BE patients. The main advantages would be real-time diagnosis and decision-making, greater diagnostic accuracy, and evaluation of larger area compared to random biopsies. Clinical pCLE studies in the esophagus show high diagnostic accuracy, and its high negative predictive value offers high reliability and confidence to exclude dysplastic and neoplastic lesions. However, it still cannot replace histopathology due to lower positive predictive value and sensitivity. Key Messages: Despite promising results, its role in routine use in patients with BE remains questionable primarily due to lack of well-organized double-blind randomized trials.

Deep learning systems detect dysplasia with human-like accuracy using histopathology and probe-based confocal laser endomicroscopy

Probe-based confocal laser endomicroscopy (pCLE) allows for real-time diagnosis of dysplasia and cancer in Barrett's esophagus (BE) but is limited by low sensitivity. Even the gold standard of histopathology is hindered by poor agreement between pathologists. We deployed deep-learning-based image and video analysis in order to improve diagnostic accuracy of pCLE videos and biopsy images. Blinded experts categorized biopsies and pCLE videos as squamous, non-dysplastic BE, or dysplasia/cancer, and deep learning models were trained to classify the data into these three categories. Biopsy classification was conducted using two distinct approaches-a patch-level model and a whole-slide-image-level model. Gradient-weighted class activation maps (Grad-CAMs) were extracted from pCLE and biopsy models in order to determine tissue structures deemed relevant by the models. 1970 pCLE videos, 897,931 biopsy patches, and 387 whole-slide images were used to train, test, and validate the models. In pCLE analysis, models achieved a high sensitivity for dysplasia (71%) and an overall accuracy of 90% for all classes. For biopsies at the patch level, the model achieved a sensitivity of 72% for dysplasia and an overall accuracy of 90%. The whole-slide-image-level model achieved a sensitivity of 90% for dysplasia and 94% overall accuracy. Grad-CAMs for all models showed activation in medically relevant tissue regions. Our deep learning models achieved high diagnostic accuracy for both pCLE-based and histopathologic diagnosis of esophageal dysplasia and its precursors, similar to human accuracy in prior studies. These machine learning approaches may improve accuracy and efficiency of current screening protocols.

Deep learning systems detect dysplasia with human-like accuracy using histopathology and probe-based confocal laser endomicroscopy

Probe-based confocal laser endomicroscopy (pCLE) allows for real-time diagnosis of dysplasia and cancer in Barrett's esophagus (BE) but is limited by low sensitivity. Even the gold standard of histopathology is hindered by poor agreement between pathologists. We deployed deep-learning-based image and video analysis in order to improve diagnostic accuracy of pCLE videos and biopsy images. Blinded experts categorized biopsies and pCLE videos as squamous, non-dysplastic BE, or dysplasia/cancer, and deep learning models were trained to classify the data into these three categories. Biopsy classification was conducted using two distinct approaches-a patch-level model and a whole-slide-image-level model. Gradient-weighted class activation maps (Grad-CAMs) were extracted from pCLE and biopsy models in order to determine tissue structures deemed relevant by the models. 1970 pCLE videos, 897,931 biopsy patches, and 387 whole-slide images were used to train, test, and validate the models. In pCLE analysis, models achieved a high sensitivity for dysplasia (71%) and an overall accuracy of 90% for all classes. For biopsies at the patch level, the model achieved a sensitivity of 72% for dysplasia and an overall accuracy of 90%. The whole-slide-image-level model achieved a sensitivity of 90% for dysplasia and 94% overall accuracy. Grad-CAMs for all models showed activation in medically relevant tissue regions. Our deep learning models achieved high diagnostic accuracy for both pCLE-based and histopathologic diagnosis of esophageal dysplasia and its precursors, similar to human accuracy in prior studies. These machine learning approaches may improve accuracy and efficiency of current screening protocols.

SAGES TAVAC safety and efficacy analysis confocal laser endomicroscopy

BACKGROUND

Confocal laser endomicroscopy (CLE) is a novel endoscopic adjunct that allows real-time in vivo histological examination of mucosal surfaces. By using intravenous or topical fluorescent agents, CLE highlights certain mucosal elements that facilitate an optical biopsy in real time. CLE technology has been used in different organ systems including the gastrointestinal tract. There has been numerous studies evaluating this technology in gastrointestinal endoscopy, our aim was to evaluate the safety, value, and efficacy of this technology in the gastrointestinal tract.

METHODS

The Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) Technology and Value Assessment Committee (TAVAC) performed a PubMed/Medline database search of clinical studies involving CLE in May of 2018. The literature search used combinations of the keywords: confocal laser endomicroscopy, pCLE, Cellvizio, in vivo microscopy, optical histology, advanced endoscopic imaging, and optical diagnosis. Bibliographies of key references were searched for relevant studies not covered by the PubMed search. Case reports and small case series were excluded. The manufacturer's website was also used to identify key references. The United States Food and Drug Administration (U.S. FDA) Manufacturer And User facility and Device Experience (MAUDE) database was searched for reports regarding the device malfunction or injuries.

RESULTS

The technology offers an excellent safety profile with rare adverse events related to the use of fluorescent agents. It has been shown to increase the detection of dysplastic Barrett's esophagus, gastric intraepithelial neoplasia/early gastric cancer, and dysplasia associated with inflammatory bowel disease when compared to standard screening protocols. It also aids in the differentiation and classification of colorectal polyps, indeterminate biliary strictures, and pancreatic cystic lesions.

CONCLUSIONS

CLE has an excellent safety profile. CLE can increase the diagnostic accuracy in a number of gastrointestinal pathologies.

Probe-based confocal laser endomicroscopy versus biopsies in the diagnostics of oesophageal and gastric lesions: A prospective, pathologist-blinded study

BACKGROUND AND AIM

Probe-based confocal laser endomicroscopy (pCLE) provides real-time microscopic visualisation. Our aim was to compare the diagnostic accuracy of pCLE with standard biopsies in patients with visible oesophageal or gastric lesions.

METHODS

This was a single-centre, prospective, pathologist-blinded study. Patients underwent high-resolution endoscopy, and lesions were examined by pCLE followed by standard biopsies. A definitive diagnosis was determined from resection specimen. Main outcomes were overall diagnostic accuracy, sensitivity, specificity and positive and negative predictive values.

RESULTS

We examined 74 lesions in 67 patients. Definitive diagnoses revealed 34 malignant and 40 non-malignant lesions. pCLE diagnosis was correct in 89.2% (66/74), while diagnosis based on biopsy was correct in 85% (57/67; p = 0.6). The overall diagnostic accuracy of biopsies was 85% (76-94%) and that of pCLE was 89% (79-96%). pCLE correctly diagnosed malignant lesions, comprising oesophageal adenocarcinoma, oesophageal squamous-cell cancer or gastric adenocarcinoma, in 88.2% (30/34) of cases, while biopsy was correctly diagnosed in 75.9% (22/29; p = 0.3). Sensitivity and specificity to diagnose a malignant lesion were 75.9% (95% confidence interval (CI) 56-89%) and 100% (95% CI 90-100%) for biopsies and 88.2% (95% CI 72-97%) and 92% (95% CI 79-98%) for pCLE. No differences between biopsies and pCLE were found with regard to sensitivity, specificity to diagnose dysplastic and benign lesions (p > 0.2).

CONCLUSION

pCLE provides satisfactory diagnostic accuracy comparable with standard biopsies in patients with oesophageal or gastric lesions. ClinicalTrials.gov identifier: NCT0292049).

Early Esophageal Cancer: A Gastroenterologist's Disease

Traditionally, early esophageal cancer (i.e., cancer limited to the mucosa or superficial submucosa) was managed surgically; the gastroenterologist's role was primarily to diagnose the tumor. Over the last decade, advances in endoscopic imaging, ablation, and resection techniques have resulted in a paradigm shift-diagnosis, staging, treatment, and surveillance are within the endoscopist's domain. Yet, there are few reviews that provide a focused, evidence-based approach to early esophageal cancer, and highlight areas of controversy for practicing gastroenterologists. In this manuscript, we will discuss the following: (1) utility of novel endoscopic technologies to identify high-grade dysplasia and early esophageal cancer, (2) role of endoscopic resection and imaging to stage early esophageal cancer, (3) endoscopic therapies for early esophageal cancer, and (4) indications for surgical and multidisciplinary management.

Imaging for Barrett's esophagus: state of the art

PURPOSE OF REVIEW

Barrett's esophagus is the premalignant condition for esophageal cancer and the diagnosis of esophageal adenocarcinoma on index endoscopy is increasing. Many advanced endoscopic techniques are available and aim to identify Barrett's esophagus-associated neoplasia earlier, thereby preventing progression into malignancy.

RECENT FINDINGS

It is well established adherence to Seattle protocol increases dysplasia detection but leaves large portions of mucosa unsampled. Recent attention has been given to wide-area transepithelial sampling as an additional means of biopsy and shows increased dysplasia detection rates. Many endoscopic techniques aim to increase the success of diagnosis of Barrett's esophagus-associated neoplasia, including probe confocal endomicroscopy, volumetric laser endomicroscopy, and virtual chromoendoscopy. Interestingly, volumetric laser endomicroscopy may also be useful in delineating margins during endoscopic mucosal resection, leading to both diagnostic and therapeutic applications.

SUMMARY

Advanced endoscopic techniques are available to increase detection of Barrett's esophagus-associated neoplasia; however, these remain localized to academic centers of excellence. With recent advancements in both sampling techniques and the potential application of imaging to therapeutics, these techniques are becoming more accessible to community endoscopists.

A miniaturized, tethered, spectrally-encoded confocal endomicroscopy capsule

BACKGROUND AND OBJECTIVE

The tethered spectrally-encoded confocal endomicroscopy (SECM) capsule is an imaging device that once swallowed by an unsedated patient can visualize cellular morphologic changes associated with gastrointestinal (GI) tract diseases in vivo. Recently, we demonstrated a tethered SECM capsule for counting esophageal eosinophils in patients with eosinophilic esophagitis (EoE) in vivo. Yet, the current tethered SECM capsule is far too long to be widely utilized for imaging pediatric patients, who constitute a major portion of the EoE patient population. In this paper, we present a new tethered SECM capsule that is 33% shorter, has an easier and repeatable fabrication process, and produces images with reduced speckle noise.

MATERIALS AND METHODS

The smaller SECM capsule utilized a miniature condenser to increase the fiber numerical aperture and reduce the capsule length. A custom 3D-printed holder was developed to enable easy and repeatable device fabrication. A dual-clad fiber (DCF) was used to reduce speckle noise.

RESULTS

The fabricated SECM capsule (length = 20 mm; diameter = 7 mm) had a similar size and shape to a pediatric dietary supplement pill. The new capsule achieved optical sectioning thickness of 13.2 μm with a small performance variation between devices of 1.7 μm. Confocal images of human esophagus obtained in vivo showed the capability of this new device to clearly resolve microstructural epithelial details with reduced speckle noise.

CONCLUSIONS

We expect that the smaller size and better image performance of this new SECM capsule will greatly facilitate the clinical adoption of this technology in pediatric patients and will enable more accurate assessment of EoE-suspected tissues. Lasers Surg. Med. 51:452-458, 2019. © 2019 Wiley Periodicals, Inc.

Real-time diagnosis of Barrett's esophagus: a prospective, multicenter study comparing confocal laser endomicroscopy with conventional histology for the identification of intestinal metaplasia in new users

INTRODUCTION

Endoscopic evaluation with high-definition white light endoscopy and random 4-quadrant biopsy (Seattle Protocol) is the current standard of care for the detection of Barrett's esophagus (BE). Recently, enhanced imaging technologies have become available to provide real-time diagnosis of intestinal metaplasia (IM) and dysplasia, reducing the need for tissue biopsy. Probe-based confocal laser endomicroscopy (pCLE) provides dynamic microscopic mucosal views, rapidly capturing digital images that become optical biopsies. This study examined the role of pCLE in BE screening and surveillance as compared to the Seattle Protocol.

METHODS

Patients undergoing BE screening or surveillance endoscopy were enrolled at eight US centers. Optical biopsy using pCLE was interpreted in real time. Endoscopists performing pCLE were new users with a median experience of 8.5 months and no formal training in surgical pathology. Seattle Protocol biopsies were then taken. Recorded pCLE images were reviewed by a blinded expert in optical biopsy interpretation.

RESULTS

Early pCLE users identified significantly more patients with IM than the Seattle Protocol overall (99/172 vs. 46/172, p < 0.0001). Early users of pCLE also identified significantly more patients with IM than the Seattle Protocol in the patients with visible columnar lined esophagus (75 vs. 31, p < 0.0001), but not in the 76 patients without columnar lined esophagus (24 vs. 15, p = 0.067). There was no statistically significant difference between early pCLE users and expert review.

CONCLUSION

Optical biopsy using pCLE technology allows for the real-time evaluation of entire segments of columnar lined esophagus. Consequently, pCLE is considerably more sensitive in the detection of BE than the Seattle Protocol, which leaves a majority of epithelium unexamined. This effect is seen even in new users and increases with experience. Overall, pCLE provides a promising advance in Barrett's detection which will likely result in superior identification of individuals at risk for esophageal adenocarcinoma.

Molecular imaging in gastroenterology: A route for personalized endoscopy

With the rapid expansion and diversification of the repertoire of biological agents utilized in inflammatory bowel diseases and cancer and the increase in oncological patients in gastroenterology, visualization of single receptor or molecular target expression and the subsequent initiation of expression tailored therapy are gaining increasing attention. Through the combination of utilizing fluorescently labeled probes with high specificity towards defined molecular targets and their subsequent detection and visualization with endoscopic devices, molecular imaging is a new emerging field focusing on the receptor expression within the mucosa on a cellular level rather than on macroscopic changes. In the past years various new technological and molecular probes have been successfully utilized for molecular imaging. Within this review, we summarize different technologies as well as molecular probes applied in molecular imaging and review current and past approaches for functional imaging with molecular endoscopy within the GI Tract and resulting clinical applications. It can be expected that molecular imaging allows for individualized diagnostic approaches and patient tailored medicine in the future.

Targeted Optical Imaging Agents in Cancer: Focus on Clinical Applications

Molecular imaging is an emerging strategy for in vivo visualization of cancer over time based on biological mechanisms of disease activity. Optical imaging methods offer a number of advantages for real-time cancer detection, particularly in the epithelium of hollow organs and ducts, by using a broad spectral range of light that spans from visible to near-infrared. Targeted ligands are being developed for improved molecular specificity. These platforms include small molecule, peptide, affibody, activatable probes, lectin, and antibody. Fluorescence labeling is used to provide high image contrast. This emerging methodology is clinically useful for early cancer detection by identifying and localizing suspicious lesions that may not otherwise be seen and serves as a guide for tissue biopsy and surgical resection. Visualizing molecular expression patterns may also be useful to determine the best choice of therapy and to monitor efficacy. A number of these imaging agents are overcoming key challenges for clinical translation and are being validated in vivo for a wide range of human cancers.

Accuracy of probe-based confocal laser endomicroscopy (pCLE) compared to random biopsies during endoscopic surveillance of Barrett's esophagus

BACKGROUND

 For surveillance of Barrett's esophagus (BE), the current standard of random 4-quadrant biopsies misses 10 - 50 % of esophageal neoplasms, and does not permit real-time decision-making. Probe-based confocal laser endomicroscopy (pCLE) permits real-time in vivo histologic assessment of esophageal mucosa during upper endoscopy. Prospective studies comparing the accuracy of pCLE to 4-quadrant biopsies in routine clinical practice are lacking.

METHODS

 Consecutive patients with BE underwent high definition white light and narrow-band imaging followed by pCLE and targeted biopsy or mucosal resection. Four-quadrant biopsies were obtained during the same session. Baseline variables, real-time pCLE interpretation, and histology results were prospectively recorded. Blinded expert review of pCLE sequences and histology specimens was performed. A sample size of 64 patients was calculated a priori based on 3 % estimated prevalence of high grade dysplasia (HGD) or cancer.

RESULTS

 In total, 66 patients were included in the study. The prevalence of HGD or cancer was 4.55 %. Both real-time and blinded pCLE correctly identified all cases of cancer. For the primary outcome, real-time pCLE was 98 % specific but only 67 % sensitive for HGD/cancer compared to non-blinded pathologist interpretation. For HGD and cancer, inter-observer agreement was substantial between real-time and blinded endomicroscopists (kappa = 0.6). pCLE identified dysplasia in 75 % of cases where both blinded and unblinded pathology interpretation was low grade dysplasia.

CONCLUSIONS

 pCLE demonstrates high specificity for detecting dysplasia and cancer, but lower sensitivity may limit its utility in routine BE surveillance. pCLE may have a role in confirming LGD in real-time before eradication therapy.

Developments in optical imaging for gastrointestinal surgery

To improve outcomes for patients with cancer, in terms of both survival and a reduction in the morbidity and mortality that results from surgical resection and treatment, there are two main areas that require improvement. Accurate early diagnosis of the cancer, at a stage where curative and, ideally, minimally invasive treatment is achievable, is desired as well as identification of tumor margins, lymphatic and distant disease, enabling complete, but not unnecessarily extensive, resection. Optical imaging is making progress in achieving these aims. This review discusses the principles of optical imaging, focusing on fluorescence and spectroscopy, and the current research that is underway in GI tract carcinomas.

Probe-based confocal laser endomicroscopy for in vivo evaluation of the tumor vasculature in gastric and rectal carcinomas

Probe-based Confocal Laser Endomicroscopy (pCLE) is a powerful imaging technique that allows to perform gastrointestinal endomicroscopy at subcellular resolution. The aim of this study was to assess the use of pCLE to evaluate tumor angiogenesis in rectal and gastric cancers. A total of 35 consecutive patients with gastric and 91 with rectal carcinomas underwent endoscopy and pCLE during the same examination. Vascular assessment was based on vessel shape and size, vessel permeability and blood flow, and allowed the creation of an angiogenic score ranging from 0, for normal vasculature, to 4, for aberrant vasculature. A significant difference for the presence of vessels with large diameter and defective blood flow was found between rectal and gastric cancers. Overall, rectal cancers displayed a higher angiogenic score compared to gastric cancers. Conventional therapy induced a striking reduction in the angiogenic score only in rectal cancer patients. Taken together, our findings suggest that the pCLE technology is suitable for the evaluation of the tumor microvasculature abnormalities. Therefore, the real-time assessment of the vasculature status may represent a promising approach to predict the efficacy of the treatments and improve the clinical management of patients with gastric or rectal carcinomas.

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.

Probe confocal laser endomicroscopy in the therapeutic endoscopic management of Barrett's dysplasia

Background

Endoscopic management of Barrett’s esophagus (BE) depends on the histological stage of BE and includes the following: follow up, endotherapy with thermal ablation, and piecemeal or monobloc endoscopic resection (ER). We know that biopsies are unreliable in 20-75% of cases. The aim of our study was to evaluate the efficiency of probe confocal laser endomicroscopy (pCLE) in the diagnosis of the histological stage of BE, compared with the final histological results after ER.

Methods

This retrospective study was based on a prospective registry of patients referred for management of BE-associated dysplasia. The inclusion criteria were dysplasia associated with BE on pre-resection biopsy and endoscopic resection of the examined areas. CLE examinations (pCLEs) were performed using the Gastroflex^® probe (Maunakea company). ER was sufficient to ensure that the target area was resected. The following four potential diagnoses were considered: normal or inflammatory mucosa, metaplasia (BE), low-grade dysplasia (LGD), and high-grade dysplasia/esophageal adenocarcinoma (HGD/EAC).

Results

The sensitivity, specificity, and accuracy in the detection of HGD/EAC were 92.9%, 71.4% and 80% for pCLE, and 78.6%, 61.9%, and 68.6% for histological biopsy, respectively. The differences in favor of pCLE were not statistically significant (P=0.2); however, in 13 patients with irregularities of the mucosa without elevated or depressed lesions (2 HGD/EAC and 11 non-HGD/EAC), pCLE led to positive redirection of therapy in 70% (9/13) of cases.

Conclusion

In the absence of visible lesions, pCLE appears to lead to correct diagnoses and to aid real-time decisions regarding therapeutic management.

Endomicroscopy for Computer and Robot Assisted Intervention

Endomicroscopy is a new technique that allows human tissue to be characterized in vivo and in situ, circumventing the need for conventional biopsy and histology. Despite increased application and growing research interests in this area, the clinical application of endomicroscopy, however, is limited by difficulties in ergonomic control, consistent probe-tissue contact, large area surveillance, and retargeting. Recently, advances in high-speed imaging, mosaicing, and robotics have aimed to address these difficulties. The development of robot-assisted devices in particular has shown great promises in extending the clinical potential of endomicroscopy. Issues related to miniaturization, adaptation to tissue deformation, control stability, force and position compensation, cost, and sterility are being pursued by both research and commercial communities. In this review, recent clinical and technical developments in different aspects of computer and robotic assisted endomicroscopy interventions including instrumentation, multiscale integration, and high-speed imaging techniques are presented. We further address emerging trends and new research opportunities toward more widespread clinical acceptance of robotically assisted endomicroscopy technologies.

Diagnostic performance of confocal laser endomicroscopy for optical diagnosis of gastric intestinal metaplasia: a meta-analysis

BACKGROUND

Gastric intestinal metaplasia (IM) is generally considered as a precancerous condition, a related risk factor for intestinal-type gastric cancer. However, an accurate endoscopic diagnosis of IM is a clinical challenge. Confocal Laser Endomicroscopy (CLE) is a newly technique that can provide real-time magnified images and visualize tissues at cellular or subcellular levels. The aim of this study is to clarify the diagnostic value of CLE in detection of IM in patients at high risk of gastric cancer.

METHODS

Systematic literature searches up to April 2015 in PubMed, Embase, Web of Science, Cochrane Library databases were conducted by two reviewers independently. The Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool was applied to assess study quality and to reduce potential bias. A meta-analysis using Meta-Disc (version 1.4) and STATA software (version 13) was performed.

RESULTS

A total of four studies enrolled 218 patients and 579 lesions were included in this meta-analysis. On per-lesion basis, the pooled sensitivity and specificity of CLE were 0.97(95 % confidence interval (CI) = 0.94-0.98) and 0.94 (95 % CI = 0.91-0.97) respectively. The pooled positive likelihood ratio (PLR) and negative likelihood ratio (NLR) were 15.20 (95 % CI = 9.46-24.41) and 0.04 (95 % CI = 0.02-0.07) respectively. The pooled diagnostic odds ratio (DOR) was 479.59 (95 % CI = 205.64-1118.51) and summary receiver operating curve (SROC) area under the curve was 0.9884. There was no statistical significance of publication bias.

CONCLUSION

CLE is a promising endoscopic tool in the detection of IM with the relatively high diagnostic value in patients at high risk of gastric cancer.

A meta-analysis of confocal laser endomicroscopy for the detection of neoplasia in patients with Barrett's esophagus

BACKGROUND AND AIMS

Barrett's esophagus (BE) is considered the most important risk factor for development of esophageal adenocarcinoma. Confocal laser endomicroscopy (CLE) is a recently developed technique used to diagnose neoplasia in BE. This meta-analysis was performed to assess the accuracy of CLE for diagnosis of neoplasia in BE.

METHODS

We searched EMBASE, PubMed, Cochrane Library, and Web of Science to identify relevant studies for all articles published up to June 27, 2015 in English. The quality of included studies was assessed using QUADAS-2. Per-patient and per-lesion pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio with 95% confidence intervals (CIs) were calculated.

RESULTS

In total, 14 studies were included in the final analysis, covering 789 patients with 4047 lesions. Seven studies were included in the per-patient analysis. Pooled sensitivity and specificity were 89% (95% CI: 0.82-0.94) and 83% (95% CI: 0.78-0.86), respectively. Ten studies were included in the per-lesion analysis. Compared with the PP analysis, the corresponding pooled sensitivity declined to 77% (95% CI: 0.73-0.81) and specificity increased to 89% (95% CI: 0.87-0.90). Subgroup analysis showed that probe-based CLE (pCLE) was superior to endoscope-based CLE (eCLE) in pooled specificity [91.4% (95% CI: 89.7-92.9) vs 86.1% (95% CI: 84.3-87.8)] and AUC for the sROC (0.885 vs 0.762).

CONCLUSION

Confocal laser endomicroscopy is a valid method to accurately differentiate neoplasms from non-neoplasms in BE. It can be applied to BE surveillance and early diagnosis of esophageal adenocarcinoma.

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.

Confocal Laser Endomicroscopy in Gastrointestinal and Pancreatobiliary Diseases: A Systematic Review and Meta-Analysis

Confocal laser endomicroscopy (CLE) is an endoscopic-assisted technique developed to obtain histopathological diagnoses of gastrointestinal and pancreatobiliary diseases in real time. The objective of this systematic review is to analyze the current literature on CLE and to evaluate the applicability and diagnostic yield of CLE in patients with gastrointestinal and pancreatobiliary diseases. A literature search was performed on MEDLINE, EMBASE, Scopus, and Cochrane Oral Health Group Specialized Register, using pertinent keywords without time limitations. Both prospective and retrospective clinical studies that evaluated the sensitivity, specificity, or accuracy of CLE were eligible for inclusion. Of 662 articles identified, 102 studies were included in the systematic review. The studies were conducted between 2004 and 2015 in 16 different countries. CLE demonstrated high sensitivity and specificity in the detection of dysplasia in Barrett's esophagus, gastric neoplasms and polyps, colorectal cancers in inflammatory bowel disease, malignant pancreatobiliary strictures, and pancreatic cysts. Although CLE has several promising applications, its use has been limited by its low availability, high cost, and need of specific operator training. Further clinical trials with a particular focus on cost-effectiveness and medicoeconomic analyses, as well as standardized institutional training, are advocated to implement CLE in routine clinical practice.

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.

Use of probe-based confocal laser endomicroscopy (pCLE) in gastrointestinal applications. A consensus report based on clinical evidence

BACKGROUND

Probe-based confocal laser endomicroscopy (pCLE) provides microscopic imaging during an endoscopic procedure. Its introduction as a standard modality in gastroenterology has brought significant progress in management strategies, affecting many aspects of clinical care and requiring standardisation of practice and training.

OBJECTIVE

This study aimed to provide guidance on the standardisation of its practice and training in Barrett's oesophagus, biliary strictures, colorectal lesions and inflammatory bowel diseases.

METHODS

Initial statements were developed by five group leaders, based on the available clinical evidence. These statements were then voted and edited by the 26 participants, using a modified Delphi approach. After two rounds of votes, statements were validated if the threshold of agreement was higher than 75%.

RESULTS

Twenty-six experts participated and, among a total of 77 statements, 61 were adopted (79%) and 16 were rejected (21%). The adoption of each statement was justified by the grade of evidence.

CONCLUSION

pCLE should be used to enhance the diagnostic arsenal in the evaluation of these indications, by providing microscopic information which improves the diagnostic performance of the physician. In order actually to implement this technology in the clinical routine, and to ensure good practice, standardised initial and continuing institutional training programmes should be established.

Advanced Imaging in Barrett's Esophagus

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

Comparison between two types of confocal laser endomicroscopy in gastrointestinal tract

OBJECTIVES

Confocal laser endomicroscopy (CLE) consists of endoscope-based CLE (eCLE) and probe-based CLE (pCLE). This study aimed to compare eCLE and pCLE in their diagnostic yield in different parts of the gastrointestinal (GI) tract.

METHODS

Consecutive patients were scheduled for CLE examination due to GI symptoms. All patients were randomly assigned to eCLE or pCLE group and underwent a programmed procedure using one type of CLE. Differences in procedure time, complication rate, CLE image quality and image acquisition feasibility between these two types of CLE for esophagogastroduodenoscopy (EGD) and colonoscopy were calculated.

RESULTS

Altogether 513 CLE procedures were performed, including 324 EGD and 189 colonoscopy. The procedure time of pCLE was significantly shorter than that of eCLE both in EGD and colonoscopy (16.78 min vs 18.13 min for EGD, P = 0.027; 32.48 min vs 39.89 min for colonoscopy, P < 0.001). No significant difference was found between these two types of CLE in diagnostic utility, including the detection and prediction of histopathological results of the lesions. The CLE image quality of both eCLE and pCLE were comparable in the stomach and colon, but eCLE seemed to be superior to pCLE in examining the esophagus. Colonoscopy using pCLE had a higher complete rate than that of eCLE, although the difference was not statistically significant (P = 0.065).

CONCLUSIONS

pCLE is more flexible in diagnosing GI diseases with a shorter procedure time than eCLE regardless of comparable diagnostic yields, except the diagnosis of esophageal diseases in which eCLE provides better image quality.

Endoscopy for diagnosis and treatment in esophageal cancers: high-technology assessment

The following, from the 12th OESO World Conference: Cancers of the Esophagus, includes commentaries on the endoscopic tools to recognize squamous cell dysplasia; confocal laser endomicroscopy for Barrett's esophagus; confocal microscopy in the cancer patient; optical coherence tomography in the assessment of subsquamous Barrett's metaplasia; endoscopic mucosal resection for high-grade dysplasia in Barrett's esophagus; HALO in the treatment of squamous dysplasia; and the use of fluorescence in situ hybridization to detect dysplasia and adenocarcinoma in patients with Barrett's esophagus.

Emerging enhanced imaging technologies of the esophagus: spectroscopy, confocal laser endomicroscopy, and optical coherence tomography

BACKGROUND

Despite advances in diagnoses and therapy, esophageal adenocarcinoma remains a highly lethal neoplasm. Hence, a great interest has been placed in detecting early lesions and in the detection of Barrett esophagus (BE). Advanced imaging technologies of the esophagus have then been developed with the aim of improving biopsy sensitivity and detection of preplastic and neoplastic cells. The purpose of this article was to review emerging imaging technologies for esophageal pathology, spectroscopy, confocal laser endomicroscopy (CLE), and optical coherence tomography (OCT).

METHODS

We conducted a PubMed search using the search string "esophagus or esophageal or oesophageal or oesophagus" and "Barrett or esophageal neoplasm" and "spectroscopy or optical spectroscopy" and "confocal laser endomicroscopy" and "confocal microscopy" and "optical coherence tomography." The first and senior author separately reviewed all articles. Our search identified: 19 in vivo studies with spectroscopy that accounted for 1021 patients and 4 ex vivo studies; 14 clinical CLE in vivo studies that accounted for 941 patients and 1 ex vivo study with 13 patients; and 17 clinical OCT in vivo studies that accounted for 773 patients and 2 ex vivo studies.

RESULTS

Human studies using spectroscopy had a very high sensitivity and specificity for the detection of BE. CLE showed a high interobserver agreement in diagnosing esophageal pathology and an accuracy of predicting neoplasia. We also found several clinical studies that reported excellent diagnostic sensitivity and specificity for the detection of BE using OCT.

CONCLUSIONS

Advanced imaging technology for the detection of esophageal lesions is a promising field that aims to improve the detection of early esophageal lesions. Although advancing imaging techniques improve diagnostic sensitivities and specificities, their integration into diagnostic protocols has yet to be perfected.

A pilot study of the endomicroscopic assessment of tumor extension in Barrett's esophagus-associated neoplasia before endoscopic resection

BACKGROUND AND STUDY AIMS

Barrett's esophagus (BE) - associated neoplasia can be treated endoscopically, but accurate assessment before intervention is challenging. This study aimed to investigate the role of confocal laser endomicroscopy (CLE) as an adjunct in the endoscopic treatment of BE-associated neoplasia by assessing lateral tumor and subsquamous tumor (SST) extension.

PATIENTS AND METHODS

In the context of a prospective, single-arm pilot clinical trial, patients referred for endoscopic resection of BE-associated neoplasia (high grade dysplasia and esophageal adenocarcinoma) underwent high definition, white light endoscopy with narrow-band imaging (NBI). Then, CLE mapping of suspected neoplastic lesions was performed by another endoscopist, partially blinded to the previous findings, before the patients underwent endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD), depending on lesion size and anticipated histology.

RESULTS

In 7 of 38 patients (18 %), CLE revealed additional neoplastic tissue compared with prior white light endoscopy and NBI: 2 concomitant lesions, 2 cases of lateral tumor extension within the Barrett's epithelium, and 3 cases of previously undetected SST extension. Overall, en bloc resection (tumor-free lateral margin) was achieved in 28 of 34 neoplastic lesions (82 %), and complete resection (tumor-free lateral and basal margins) in 21 of 34 neoplastic lesions (62 %).

CONCLUSIONS

CLE-assisted endoscopic resection of BE-associated neoplasia was safe and effective in this study, as proved by a high additional diagnostic yield of CLE (including visualization of occult SST extension) and a favorable rate of en bloc resection. The clinical value of CLE for assisting endoscopic therapy of BE-associated neoplasia deserves further evaluation in randomized controlled trials.

State of the art in advanced endoscopic imaging for the detection and evaluation of dysplasia and early cancer of the gastrointestinal tract

Ideally, endoscopists should be able to detect, characterize, and confirm the nature of a lesion at the bedside, minimizing uncertainties and targeting biopsies and resections only where necessary. However, under conventional white-light inspection – at present, the sole established technique available to most of humanity – premalignant conditions and early cancers can frequently escape detection. In recent years, a range of innovative techniques have entered the endoscopic arena due to their ability to enhance the contrast of diseased tissue regions beyond what is inherently possible with standard white-light endoscopy equipment. The aim of this review is to provide an overview of the state-of-the-art advanced endoscopic imaging techniques available for clinical use that are impacting the way precancerous and neoplastic lesions of the gastrointestinal tract are currently detected and characterized at endoscopy. The basic instrumentation and the physics behind each method, followed by the most influential clinical experience, are described. High-definition endoscopy, with or without optical magnification, has contributed to higher detection rates compared with white-light endoscopy alone and has now replaced ordinary equipment in daily practice. Contrast-enhancement techniques, whether dye-based or computed, have been combined with white-light endoscopy to further improve its accuracy, but histology is still required to clarify the diagnosis. Optical microscopy techniques such as confocal laser endomicroscopy and endocytoscopy enable in vivo histology during endoscopy; however, although of invaluable assistance for tissue characterization, they have not yet made transition between research and clinical use. It is still unknown which approach or combination of techniques offers the best potential. The optimal method will entail the ability to survey wide areas of tissue in concert with the ability to obtain the degree of detailed information provided by microscopic techniques. In this respect, the challenging combination of autofluorescence imaging and confocal endomicroscopy seems promising, and further research is awaited.

Confocal laser endomicroscopy for detection of neoplasia in Barrett's esophagus: a meta-analysis

Barrett's esophagus (BE) is associated with an increased risk of esophageal adenocarcinoma, and the recommended guideline for detection of neoplasia is surveillance endoscopy with random four-quadrant biopsies. Recently, a novel technique, confocal laser endomicroscopy (CLE), has emerged and enabled the endoscopist to perform a real-time histologic assessment of the gastrointestinal tract. We aimed to assess the accuracy of CLE in diagnosing BE-associated neoplasia by pooling data of existing trials. Databases including PubMed, EMBASE, the Cochrane Library, the Science Citation Index and momentous meeting abstracts were searched and evaluated by two reviewers independently. Meta-analysis was performed. Pooling data were conducted in a fixed effect model or a random effects model. Eight studies involving 709 patients and 4008 specimens were analyzed. In a per-patient analysis, the pooled sensitivity of CLE for detection of neoplasia was 89% (95% confidence interval [CI], 0.80-0.95), and the specificity was 75% (95% CI, 0.69-0.81). The area under the curve under the summary receiver operating characteristic was 0.9472. In a per-location analysis, the pooled sensitivity of CLE for detection of neoplasia was 70% (95% CI, 0.65-0.74), and the specificity was 91% (95% CI, 0.90-0.92). The area under the curve under the summary receiver operating characteristic was 0.9509. CLE is a reasonable, promising modality for management of patients with BE; more prospective trials need doing to determine whether it is superior to traditional method in diagnosing BE-associated neoplasia.

Role of endoscopy in GERD

Endoscopy is commonly performed for the diagnosis and management of gastroesophageal reflux disease (GERD). Endoscopy allows the physician to evaluate esophageal mucosa for evidence of esophagitis and Barrett esophagus, to obtain mucosal biopsies for evaluation of such conditions as eosinophilic esophagitis and diagnosis and grading of Barrett esophagus, and to apply various therapies. In a patient with suboptimal response to GERD therapy, endoscopy excludes other etiologies as a cause of patients' symptoms. Newer endoscopic therapies for GERD are available or are in development. Advances in imaging techniques in development will improve the diagnostic yield of endoscopy and may replace the need for mucosal biopsies.

In vivo endomicroscopy improves detection of Barrett's esophagus-related neoplasia: a multicenter international randomized controlled trial (with video)

BACKGROUND

Confocal laser endomicroscopy (CLE) enables in vivo microscopic imaging of the GI tract mucosa. However, there are limited data on endoscope-based CLE (eCLE) for imaging Barrett's esophagus (BE).

OBJECTIVE

To compare high-definition white-light endoscopy (HDWLE) alone with random biopsy (RB) and HDWLE + eCLE and targeted biopsy (TB) for diagnosis of BE neoplasia.

DESIGN

Multicenter, randomized, controlled trial.

SETTING

Academic medical centers.

PATIENTS

Adult patients with BE undergoing routine surveillance or referred for early neoplasia.

INTERVENTION

Patients were randomized to HDWLE + RB (group 1) or HDWLE + eCLE + TB (group 2). Real-time diagnoses and management plans were recorded after HDWLE in both groups and after eCLE in group 2. Blinded expert pathology diagnosis was the reference standard.

MAIN OUTCOME MEASUREMENTS

Diagnostic yield, performance characteristics, clinical impact.

RESULTS

A total of 192 patients with BE were studied. HDWLE + eCLE + TB led to a lower number of mucosal biopsies and higher diagnostic yield for neoplasia (34% vs 7%; P < .0001), compared with HDWLE + RB but with comparable accuracy. HDWLE + eCLE + TB tripled the diagnostic yield for neoplasia (22% vs 6%; P = .002) and would have obviated the need for any biopsy in 65% of patients. The addition of eCLE to HDWLE increased the sensitivity for neoplasia detection to 96% from 40% (P < .0001) without significant reduction in specificity. In vivo CLE changed the treatment plan in 36% of patients.

LIMITATIONS

Tertiary-care referral centers and expert endoscopists limit generalizability.

CONCLUSION

Real-time eCLE and TB after HDWLE can improve the diagnostic yield and accuracy for neoplasia and significantly impact in vivo decision making by altering the diagnosis and guiding therapy. (

CLINICAL TRIAL REGISTRATION NUMBER

NCT01124214.).

Advanced imaging technologies for the detection of dysplasia and early cancer in barrett esophagus

Advanced esophageal adenocarcinomas arising from Barrett esophagus (BE) are tumors with an increasing incidence and poor prognosis. The aim of endoscopic surveillance of BE is to detect dysplasia, particularly high-grade dysplasia and intramucosal cancers that can subsequently be treated endoscopically before progression to invasive cancer with lymph node metastases. Current surveillance practice standards require the collection of random 4-quadrant biopsy specimens over every 1 to 2 cm of BE (Seattle protocol) to detect dysplasia with the assistance of white light endoscopy, in addition to performing targeted biopsies of recognizable lesions. This approach is labor-intensive but should currently be considered state of the art. Chromoendoscopy, virtual chromoendoscopy (e.g., narrow band imaging), and confocal laser endomicroscopy, in addition to high-definition standard endoscopy, might increase the diagnostic yield for the detection of dysplastic lesions. Until these modalities have been demonstrated to enhance efficiency or cost effectiveness, the standard protocol will remain careful examination using conventional off the shelf high-resolution endoscopes, combined with as longer inspection time which is associated with increased detection of dysplasia.

Confocal laser endomicroscopy and molecular imaging in barrett esophagus and stomach

Detection of premalignant lesions in the upper gastrointestinal tract may facilitate endoscopic treatment and improve survival. Despite technological advances in white light endoscopy, its ability to detect premalignant lesions remains limited. Early detection could be improved by using advanced endoscopic imaging techniques, such as magnification endoscopy, narrow band imaging, i-scanning, flexible spectral imaging color enhancement, autofluorescence imaging, and confocal laser endomicroscopy (CLE), as these techniques may increase the rate of detection of mucosal abnormalities and allow optical diagnosis. The present review focuses on advanced endoscopic imaging techniques based on the use of CLE for diagnosing premalignant lesions in Barrett esophagus and stomach.

Enhanced mucosal imaging and the esophagus--ready for prime time?

Innovation of endoscopic technology has recently been introduced to improve real-time visualization of mucosal architecture and subepithelial vascular structures. Since the esophagus is easily accessible using endoscopy and the length of required observation is limited, many different types of new imaging modalities have been reported and showing promising data. Early detection of neoplastic changes in the esophagus is devoted to the treatment in early stage cancer and theoretically leads to better prognosis. This review will focus on the emerging endoscopic technologies for the management of esophageal cancer.

Microscopic imaging in endoscopy: endomicroscopy and endocytoscopy

Performing real-time microscopy has been a vision of endoscopists since the very early phases of gastrointestinal endoscopy. Confocal endomicroscopy, an adaption of confocal laser scanning microscopy, and endocytoscopy, an adaption of white-light microscopy, have been introduced into the endoscopic armamentarium in the past decade. Both techniques yield on-site histological information. Multiple trials have demonstrated the ability of gastroenterologists to obtain and interpret microscopic images from the upper and lower gastrointestinal tract, and also the hepatobiliary-pancreatic system, during endoscopy. Such microscopic information has been successfully used in expert hands to minimize sampling error by 'smart', microscopically targeted biopsies and to guide endoscopic interventions. However, endomicroscopy is also unique in its ability to dynamically visualize cellular processes in their native environment free of artefacts. This ability enables fundamental insights into mechanisms of human diseases in clinical and translational science.

Endoscopic mucosal imaging of gastrointestinal neoplasia in 2013

The holy grail of gastrointestinal endoscopy consists of the detection, in vivo characterization, and endoscopic removal of early or premalignant mucosal lesions. While our ability to achieve this goal has improved substantially since the development of the modern video-endoscope, inadequate visual inspection, errors of interpretation, and lesion subtlety all contribute to the continued suboptimal detection and assessment of early neoplasia. A myriad of new technologies has thus emerged that may help resolve these shortcomings; high magnification endoscopes, as well as the techniques of dye-based and virtual chromoendoscopy, are now widely available, while confocal laser endomicroscopy and endocystoscopy, optical coherence tomography, and autofluorescence imaging are generally applicable only in a research setting. Such technologies can be broadly categorized according to whether they potentially afford endoscopists improved detection, or real-time characterization, of mucosal lesions. Enhanced detection of otherwise "invisible" lesions, such as a flat area of intramucosal adenocarcinoma within Barrett's esophagus, carries the potential of an endoscopic cure prior to the development into a more advanced or metastatic disease. The ability to characterize a lesion to achieve an in vivo diagnosis, such as a colonic polyp, potentially affords endoscopists the ability to decide which lesions require removal and which can be safely left behind or discarded without histological assessment. Furthermore targeted biopsies, such as in the surveillance of chronic colitis, may prove to be more accurate and efficacious than the current protocol of random biopsies. An important caveat in the discussion of developing technologies in early cancer detection is the fundamental importance of a health-care system that promotes screening programs to recruit at-risk individuals. The ideal tool to optimize the use of endoscopy in population screening would be a panel of reliable biomarkers (blood, stool, or urine) that could effectively select a high-risk group, thus reducing the indiscriminate use of an expensive technology. The following review summarizes the current endoscopic imaging techniques available, and in development, for the early identification of gastrointestinal neoplasia.

Practice patterns among U.S. gastroenterologists regarding endoscopic management of Barrett's esophagus

BACKGROUND

Endoscopic management of Barrett's esophagus (BE) has evolved over the past decade; however, the practice patterns for managing BE among gastroenterologists remain unclear.

OBJECTIVE

To assess practice patterns for management of BE among gastroenterologists working in various practice settings.

DESIGN

A random questionnaire-based survey of practicing gastroenterologists in the United States. The questionnaire contained a total of 10 questions pertaining to practice setting, physician demographics, and strategies used for managing BE.

SETTING

Survey of gastroenterologists working in various practice settings.

INTERVENTION

Questionnaire.

MAIN OUTCOME MEASUREMENTS

Practice patterns for endoscopic imaging and management of BE.

RESULTS

The response rate was 45% (236/530). The majority (85%) were gastroenterologists in community practice, 72% were aged 41 to 60 years, 80% had >10 years of experience, and 81% had attended postgraduate courses and/or seminars on BE management. A total of 78% did not use the Prague C & M classification, and about a third used advanced endoscopic imaging routinely (37%) or in selected cases (31%). For nondysplastic BE, 86% practiced surveillance, 12% performed ablation, and 3% did no intervention. For BE with low-grade dysplasia, 56% practiced surveillance, 26% performed endoscopic ablation in all low-grade dysplasia cases, and 18% performed endoscopic ablation in only selected patients with low-grade dysplasia. The majority of respondents (58%) referred their patients with high-grade dysplasia to centers with BE expertise, 13% performed endoscopic ablation in all patients with high-grade dysplasia, 25% performed endoscopic ablation in selected cases only, and 3% referred these patients for surgery. The most frequently used endoscopic eradication therapy was radiofrequency ablation (39%) followed by EMR (17%).

LIMITATIONS

The sample may be unrepresentative, participation in the study was voluntary, and responses may be skewed toward following the guidelines.

CONCLUSION

Results from this survey show that the majority of practicing gastroenterologists in the United States practice surveillance endoscopy in patients with nondysplastic BE and provide endoscopic therapy for those with high-grade dysplasia. The Prague C & M classification and advanced imaging techniques are used by less than a third of gastroenterologists. Practice patterns did not appear to be affected by respondent age or duration of clinical practice.