The Seattle protocol does not more reliably predict the detection of cancer at the time of esophagectomy than a less intensive surveillance protocol

PARP1-targeted fluorescence molecular endoscopy as novel tool for early detection of esophageal dysplasia and adenocarcinoma

BACKGROUND

Esophageal cancer is one of the 10 most common cancers worldwide and its incidence is dramatically increasing. Despite some improvements, the current surveillance protocol with white light endoscopy and random untargeted biopsies collection (Seattle protocol) fails to diagnose dysplastic and cancerous lesions in up to 50% of patients. Therefore, new endoscopic imaging technologies in combination with tumor-specific molecular probes are needed to improve early detection. Herein, we investigated the use of the fluorescent Poly (ADP-ribose) Polymerase 1 (PARP1)-inhibitor PARPi-FL for early detection of dysplastic lesions in patient-derived organoids and transgenic mouse models, which closely mimic the transformation from non-malignant Barrett's Esophagus (BE) to invasive esophageal adenocarcinoma (EAC).

METHODS

We determined PARP1 expression via immunohistochemistry (IHC) in human biospecimens and mouse tissues. We also assessed PARPi-FL uptake in patient- and mouse-derived organoids. Following intravenous injection of 75 nmol PARPi-FL/mouse in L2-IL1B (n = 4) and L2-IL1B/IL8Tg mice (n = 12), we conducted fluorescence molecular endoscopy (FME) and/or imaged whole excised stomachs to assess PARPi-FL accumulation in dysplastic lesions. L2-IL1B/IL8Tg mice (n = 3) and wild-type (WT) mice (n = 2) without PARPi-FL injection served as controls. The imaging results were validated by confocal microscopy and IHC of excised tissues.

RESULTS

IHC on patient and murine tissue revealed similar patterns of increasing PARP1 expression in presence of dysplasia and cancer. In human and murine organoids, PARPi-FL localized to PARP1-expressing epithelial cell nuclei after 10 min of incubation. Injection of PARPi-FL in transgenic mouse models of BE resulted in the successful detection of lesions via FME, with a mean target-to-background ratio > 2 independently from the disease stage. The localization of PARPi-FL in the lesions was confirmed by imaging of the excised stomachs and confocal microscopy. Without PARPi-FL injection, identification of lesions via FME in transgenic mice was not possible.

CONCLUSION

PARPi-FL imaging is a promising approach for clinically needed improved detection of dysplastic and malignant EAC lesions in patients with BE. Since PARPi-FL is currently evaluated in a phase 2 clinical trial for oral cancer detection after topical application, clinical translation for early detection of dysplasia and EAC in BE patients via FME screening appears feasible.

Third-Generation High-Vision Ultrathin Endoscopy Using Texture and Color Enhancement Imaging and Narrow-Band Imaging to Evaluate Barrett's Esophagus

It remains unclear whether texture- and color-enhancement imaging (TXI) and narrow-band imaging (NBI) provide an advantage over white-light imaging (WLI) in Barrett’s esophagus. We compared endoscopic findings and color differences between WLI and image-enhanced endoscopy (IEE) using a third-generation ultrathin endoscope. We retrospectively enrolled 40 patients who evaluated Barrett’s esophagus using WLI, TXI, and NBI. Color differences determined using the International Commission on Illumination 1976 (L∗, a∗, b∗) color space among Barrett’s epithelium, esophageal, and gastric mucosa were compared among the endoscopic findings. As the secondary outcome, we assessed the subjective visibility score among three kinds of endoscopic findings. The prevalence of Barrett’s esophagus and gastroesophageal reflux disease (GERD) in WLI was 82.5% and 47.5%, respectively, and similar among WLI, TXI, and NBI. Color differences between Barrett’s epithelium and esophageal or gastric mucosa on NBI were significantly greater than on WLI (all p < 0.05). However, the color difference between Barrett’s epithelium and esophageal mucosa was significantly greater on NBI than TXI (p < 0.001), and the visibility score of Barrett’s epithelium detection was significantly greater on TXI than NBI (p = 0.022), and WLI (p = 0.016). High-vision, third-generation ultrathin endoscopy using NBI and TXI is useful for evaluating Barrett’s epithelium and GERD compared with WLI alone.

Using texture and colour enhancement imaging to evaluate gastrointestinal diseases in clinical practice: a review

White light imaging (WLI) is the most common endoscopic technique used for screening of gastrointestinal diseases. However, despite the advent of a new processor that offers sufficient clear illumination and other advanced developments in endoscopic instrumentation, WLI alone is inadequate for detecting all gastrointestinal diseases with abnormalities in mucosal discoloration and morphological changes to the mucosal surface. The recent development of image-enhanced endoscopy (IEE) has dramatically improved the detection of gastrointestinal diseases. Texture and colour enhancement imaging (TXI) is a new type of IEE that enhances brightness, surface irregularities, such as elevations or depressions, and subtle colour changes. TXI with two modes, namely modes 1 and 2, can selectively enhance brightness in dark areas of an endoscopic image and subtle tissue differences such as slight morphological or colour changes while simultaneously preventing over-enhancement. Several clinical studies have investigated the efficacy of TXI for detecting and visualizing gastrointestinal diseases, including oesophageal squamous cell carcinoma (ESCC), Barret's epithelium, gastric cancer, gastric mucosal atrophy and intestinal metaplasia. Although TXI is often more useful for detecting and visualizing gastrointestinal diseases than WLI, it remains unclear whether TXI outperforms other IEEs, such as narrow-band imaging (NBI), in similar functions, and whether the performance of TXI modes 1 and 2 are comparable. Therefore, large-scale prospective studies are needed to compare the efficacy of TXI to WLI and other IEEs for endoscopic evaluation of patients undergoing screening endoscopy. Here, we review the characteristics and efficacy of TXI for the detection and visualization of gastrointestinal diseases.Key MessagesTXI mode 1 can improve the visibility of gastrointestinal diseases and qualitative diagnosis, especially for diseases associated with colour changes.The enhancement of texture and brightness with TXI mode 2 enables the detection of diseases, and is ideal for use in the first screening of gastrointestinal tract.

Esophageal OCT Imaging Using a Paddle Probe Externally Attached to Endoscope

BACKGROUND AND AIMS

Endoscopic surveillance of Barrett's esophagus (BE) by white light examination is insufficient to diagnose dysplastic change. In this work, we describe an optical imaging method to obtain high-resolution cross-sectional imaging using a paddle-shaped probe affixed to the endoscope tip.

METHODS

We integrated Optical Coherence Tomography (OCT), an optical imaging method that produces cross-sectional images, into a paddle probe attached to video endoscope. We acquired images of esophageal epithelium from patients undergoing routine upper GI endoscopy. Images were classified by a reviewer blinded to patient identity and condition, and these results were compared with clinical diagnosis.

RESULTS

We successfully captured epithelial OCT images from 30 patients and identified features consistent with both squamous epithelium and Barrett's esophagus. Our blinded image reviewer classified BE versus non-BE with 91.5% accuracy (65/71 image regions), including sensitivity of 84.6% for BE (11/13) and a specificity of 93.1% (54/58). However, in 16 patients, intubation of the probe into the esophagus could not be achieved.

CONCLUSIONS

A paddle probe is a feasible imaging format for acquiring cross-sectional OCT images from the esophagus and can provide a structural assessment of BE and non-BE tissue. Probe form factor is the current limiting obstacle, but could be addressed by further miniaturization.

In vivo microscopy as an adjunctive tool to guide detection, diagnosis, and treatment

SIGNIFICANCE

There have been numerous academic and commercial efforts to develop high-resolution in vivo microscopes for a variety of clinical use cases, including early disease detection and surgical guidance. While many high-profile studies, commercialized products, and publications have resulted from these efforts, mainstream clinical adoption has been relatively slow other than for a few clinical applications (e.g., dermatology).

AIM

Here, our goals are threefold: (1) to introduce and motivate the need for in vivo microscopy (IVM) as an adjunctive tool for clinical detection, diagnosis, and treatment, (2) to discuss the key translational challenges facing the field, and (3) to propose best practices and recommendations to facilitate clinical adoption.

APPROACH

We will provide concrete examples from various clinical domains, such as dermatology, oral/gastrointestinal oncology, and neurosurgery, to reinforce our observations and recommendations.

RESULTS

While the incremental improvement and optimization of IVM technologies should and will continue to occur, future translational efforts would benefit from the following: (1) integrating clinical and industry partners upfront to define and maintain a compelling value proposition, (2) identifying multimodal/multiscale imaging workflows, which are necessary for success in most clinical scenarios, and (3) developing effective artificial intelligence tools for clinical decision support, tempered by a realization that complete adoption of such tools will be slow.

CONCLUSIONS

The convergence of imaging modalities, academic-industry-clinician partnerships, and new computational capabilities has the potential to catalyze rapid progress and adoption of IVM in the next few decades.

The development and clinical application of microscopic endoscopy for in vivo optical biopsies: Endocytoscopy and confocal laser endomicroscopy

Endoscopies are crucial for detecting and diagnosing diseases in gastroenterology, pulmonology, urology, and other fields. To accurately diagnose diseases, sample biopsies are indispensable and are currently considered the gold standard. However, random 4-quadrant biopsies have sampling errors and time delays. To provide intraoperative real-time microscopic images of suspicious lesions, microscopic endoscopy for in vivo optical biopsy has been developed, including endocytoscopy and confocal laser endomicroscopy. This article reviews recent advances in technology and clinical applications, as well as their shortcomings and future directions.

Outcome of Sleeve Gastrectomy Converted to Roux-en-Y Gastric Bypass and One-Anastomosis Gastric Bypass

Purpose

Sleeve gastrectomy (SG) is the commonest bariatric procedure worldwide but there is also a high conversion rate mainly due to weight regain and gastroesophageal reflux disease (GERD) reported in studies with long-term follow-up. The aim of this study is to highlight benefits and limitations of converting SG patients to Roux-en-Y gastric bypass (RYGB) and one-anastomosis gastric bypass (OAGB).

Setting

Retrospective cross-sectional-study, medical university clinic setting.

Methods

This study includes all patients converted from primary SG to RYGB or OAGB by 12/2018 at the Medical University of Vienna. Patients were examined using gastroscopy, esophageal manometry, 24-h pH-metry, and questionnaires.

Results

Fifty-eight patients were converted from SG to RYGB (n = 45) or OAGB (n = 13). Total weight loss of patients converted to RYGB and OAGB was 41.5% and 44.8%, respectively, at nadir. Six patients had Barrett’s esophagus (BE) after SG. In four out of these six patients, a complete remission of BE after conversion to RYGB was observed; nevertheless, two patients after RYGB and one after OABG newly developed BE. Clinical GERD improved at a higher rate after RYGB than after OAGB. Both revisional procedures improved associated medical problems.

Conclusion

Conversion to RYGB is probably the best option for patients with GERD after SG. OAGB has shown a low potential to cure patients from GERD symptoms after SG. In terms of additional weight loss and remission of associated medical problems, both procedures studied were equal. Surveillance gastroscopies every 5 years after SG revisions are recommended.

Graphical abstract

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.

Deep Learning for Whole-Slide Tissue Histopathology Classification: A Comparative Study in the Identification of Dysplastic and Non-Dysplastic Barrett's Esophagus

The gold standard of histopathology for the diagnosis of Barrett's esophagus (BE) is hindered by inter-observer variability among gastrointestinal pathologists. Deep learning-based approaches have shown promising results in the analysis of whole-slide tissue histopathology images (WSIs). We performed a comparative study to elucidate the characteristics and behaviors of different deep learning-based feature representation approaches for the WSI-based diagnosis of diseased esophageal architectures, namely, dysplastic and non-dysplastic BE. The results showed that if appropriate settings are chosen, the unsupervised feature representation approach is capable of extracting more relevant image features from WSIs to classify and locate the precursors of esophageal cancer compared to weakly supervised and fully supervised approaches.

SCREENING FOR BARRETT'S ESOPHAGUS WITH PROBE-BASED CONFOCAL LASER ENDOMICROSCOPY VIDEOS

Histologic diagnosis of Barrett's esophagus and esophageal malignancy via probe-based confocal laser endomicroscopy (pCLE) allows for real-time examination of epithelial architecture and targeted biopsy sampling. Although pCLE demonstrates high specificity, sensitivity remains low. This study employs deep learning architectures in order to improve the accuracy of pCLE in diagnosing esophageal cancer and its precursors. pCLE videos are curated and annotated as belonging to one of the three classes: squamous, Barrett's (intestinal metaplasia without dysplasia), or dysplasia. We introduce two novel video architectures, AttentionPooling and Multi-Module AttentionPooling deep networks, that outperform other models and demonstrate a high degree of explainability.

Validation of the use of a fluorescent PARP1 inhibitor for the detection of oral, oropharyngeal and oesophageal epithelial cancers

For oral, oropharyngeal and oesophageal cancer, the early detection of tumours and of residual tumour after surgery are prognostic factors of recurrence rates and patient survival. Here, we report the validation, in animal models and a human, of the use of a previously described fluorescently labelled small-molecule inhibitor of the DNA repair enzyme poly(ADP-ribose) polymerase 1 (PARP1) for the detection of cancers of the oral cavity, pharynx and oesophagus. We show that the fluorescent contrast agent can be used to quantify the expression levels of PARP1 and to detect oral, oropharyngeal and oesophageal tumours in mice, pigs and fresh human biospecimens when delivered topically or intravenously. The fluorescent PARP1 inhibitor can also detect oral carcinoma in a patient when applied as a mouthwash, and discriminate between fresh biopsied samples of the oral tumour and the surgical resection margin with more than 95% sensitivity and specificity. The PARP1 inhibitor could serve as the basis of a rapid and sensitive assay for the early detection and for the surgical-margin assessment of epithelial cancers of the upper intestinal tract.

Development and validation of the international Blue Light Imaging for Barrett's Neoplasia Classification

BACKGROUND AND AIMS

Detecting subtle Barrett's neoplasia during surveillance endoscopy can be challenging. Blue-light imaging (BLI) is a novel advanced endoscopic technology with high-intensity contrast imaging that may improve the identification of Barrett's neoplasia. The aim of this study was to develop and validate the first classification to enable characterization of neoplastic and non-neoplastic Barrett's esophagus using BLI.

METHODS

In phase 1, descriptors pertaining to neoplastic and non-neoplastic Barrett's esophagus were identified to form the classification, named the Blue Light Imaging for Barrett's Neoplasia Classification (BLINC). Phase 2 involved validation of these component criteria by 10 expert endoscopists assessing 50 BLI images. In phase 3, a web-based training module was developed to enable 15 general (nonexpert) endoscopists to use BLINC. They then validated the classification with an image assessment exercise in phase 4, and their pre- and post-training results were compared.

RESULTS

In phase 1 the descriptors were grouped into color, pit, and vessel pattern categories to form the classification. In phase 2 the sensitivity of neoplasia identification was 96.0% with a very good level of agreement among the experts (κ = .83). In phase 3, 15 general endoscopists completed the training module. In phase 4 their pretraining sensitivity (85.3%) improved significantly to 95.7% post-training with a good level of agreement (κ = .67).

CONCLUSIONS

We developed and validated a new classification system (BLINC) for the optical diagnosis of Barrett's neoplasia using BLI. Despite the limitations of this image-based study with a high prevalence of neoplasia, we believe it has the potential to improve the optical diagnosis of Barrett's neoplasia given the high degree of sensitivity (96%) noted. It is also a promising tool for training in Barrett's esophagus optical diagnosis using BLI.

Modeling clinical assessor intervariability using deep hypersphere encoder–decoder networks

In medical imaging, a proper gold-standard ground truth as, e.g., annotated segmentations by assessors or experts is lacking or only scarcely available and suffers from large intervariability in those segmentations. Most state-of-the-art segmentation models do not take inter-observer variability into account and are fully deterministic in nature. In this work, we propose hypersphere encoder–decoder networks in combination with dynamic leaky ReLUs, as a new method to explicitly incorporate inter-observer variability into a segmentation model. With this model, we can then generate multiple proposals based on the inter-observer agreement. As a result, the output segmentations of the proposed model can be tuned to typical margins inherent to the ambiguity in the data. For experimental validation, we provide a proof of concept on a toy data set as well as show improved segmentation results on two medical data sets. The proposed method has several advantages over current state-of-the-art segmentation models such as interpretability in the uncertainty of segmentation borders. Experiments with a medical localization problem show that it offers improved biopsy localizations, which are on average 12% closer to the optimal biopsy location.

Challenges to diagnostic standardization of Barrett's esophagus in Asia

Barrett's esophagus (BE), a premalignant condition of the lower esophagus, is increasingly prevalent in Asia. However, endoscopic and histopathological criteria vary widely between studies across Asia, making it challenging to assess comparability between geographical regions. Furthermore, guidelines from various societies worldwide provide differing viewpoints and definitions, leading to diagnostic challenges that affect prognostication of the condition. In this review, the authors discuss the controversies surrounding the diagnosis of BE, particularly in Asia. Differences between guidelines worldwide are summarized with further discussion regarding various classifications of BE used, different definitions of gastroesophageal junction used across geographical regions and the clinical implications of intestinal metaplasia in the setting of BE. Although many guidelines recommend the Seattle protocol as the preferred approach regarding dysplasia surveillance in BE, some limitations exist, leading to poor adherence. Newer technologies, such as acetic acid-enhanced magnification endoscopy, narrow band imaging, Raman spectroscopy, molecular approaches and the use of artificial intelligence appear promising in addressing these problems, but further studies are required before implementation into routine clinical practice. The Asian Barrett's Consortium also outlines its ongoing plans to tackle the challenge of standardizing the diagnosis of BE in Asia.

Update: 10 Years of Sleeve Gastrectomy-the First 103 Patients

BACKGROUND

Sleeve gastrectomy (SG) has been the most frequently performed bariatric procedure worldwide since 2014. Therefore, it is vital to look at its outcomes in a long-term follow-up based on a large patient collective. Main points of discussion are weight regain, reflux, and patients' quality of life at 10+ years after the procedure.

OBJECTIVES

The aim of this study is to present an update of data that have been published recently and, thus, achieve more conclusive results. The number of patients has been doubled, and the length of the follow-up is still 10+ years.

SETTING

Multi-center study, medical university clinic, Austria METHODS: This study includes all patients who had SG before December 2006 at the participating bariatric centers. At 10+ years, non-converted patients (67%) were examined using gastroscopy, manometry, 24-hour pH-metry, and questionnaires. Patients' history of weight, comorbidities, and reflux were established through interviews.

RESULTS

At 10+ years after SG, the authors found a conversion rate of 33%, an %EWL in non-converted patients of 50.0 ± 22.5, reflux in 57%, and Barrett's metaplasia in 14% of non-converted patients. Gastroscopies revealed that patients with reflux were significantly more likely to have de-novo hiatal hernia. A significantly lower quality of life was detected through GIQLI and BAROS in patients with reflux.

CONCLUSION

The authors recommend gastroscopies at 5-year intervals after SG to detect the possible sequelae of reflux at an early stage. Conversion to Roux-en-Y-gastric bypass (RYGB) works well to cure patients from reflux but may not be as efficient at treating weight regain.

Anatomic location of Barrett's esophagus recurrence after endoscopic eradication therapy: development of a simplified surveillance biopsy strategy

BACKGROUND AND AIMS

Surveillance endoscopy is recommended after endoscopic eradication therapy (EET) for Barrett's esophagus (BE) because of the risk of recurrence. Currently recommended biopsy protocols are based on expert opinion and consist of sampling visible lesions followed by random 4-quadrant biopsy sampling throughout the length of the original BE segment. Despite this protocol, some recurrences are not visibly identified. We aimed to identify the anatomic location and histology of recurrences after successful EET with the goal of developing a more efficient and evidence-based surveillance biopsy protocol.

METHODS

We performed an analysis of a large multicenter database of 443 patients who underwent EET and achieved complete eradication of intestinal metaplasia (CE-IM) from 2005 to 2015. The endoscopic location of recurrence relative to the squamocolumnar junction (SCJ), visible recurrence identified during surveillance endoscopy, and time to recurrence after CE-IM were assessed.

RESULTS

Fifty patients with BE recurrence were studied in the final analysis. Seventeen patients (34%) had nonvisible recurrences. In this group, biopsy specimens demonstrating recurrence were taken from within 2 cm of the SCJ in 16 of these 17 patients (94%). Overall, 49 of 50 recurrences (98%) occurred either within 2 cm of the SCJ or at the site of a visible lesion. Late recurrences (>1 year) were more likely to be visible than early (<1 year) recurrences (P = .006).

CONCLUSIONS

Recurrence after EET detected by random biopsy sampling is identified predominately in the distal esophagus and occurs earlier than visible recurrences. As such, we suggest a modified biopsy protocol with targeted sampling of visible lesions followed by random biopsy sampling within 2 cm of the SCJ to optimize detection of recurrence after EET. (Clinical trial registration number: NCT02634645.).

International development and validation of a classification system for the identification of Barrett's neoplasia using acetic acid chromoendoscopy: the Portsmouth acetic acid classification (PREDICT)

BACKGROUND

Barrett's oesophagus is an established risk factor for developing oesophageal adenocarcinoma. However, Barrett's neoplasia can be subtle and difficult to identify. Acetic acid chromoendoscopy (AAC) is a simple technique that has been demonstrated to highlight neoplastic areas but lesion recognition with AAC remains a challenge, thereby hampering its widespread use.

OBJECTIVE

To develop and validate a simple classification system to identify Barrett's neoplasia using AAC.

DESIGN

The study was conducted in four phases: phase 1-development of component descriptive criteria; phase 2-development of a classification system; phase 3-validation of the classification system by endoscopists; and phase 4-validation of the classification system by non-endoscopists.

RESULTS

Phases 1 and 2 led to the development of a simplified AAC classification system based on two criteria: focal loss of acetowhitening and surface patterns of Barrett's mucosa. In phase 3, the application of PREDICT (Portsmouth acetic acid classification) by endoscopists improved the sensitivity and negative predictive value (NPV) from 79.3% and 80.2% to 98.1% and 97.4%, respectively (p<0.001). In phase 4, the application of PREDICT by non-endoscopists improved the sensitivity and NPV from 69.6% and 75.5% to 95.9% and 96.0%, respectively (p<0.001).

CONCLUSION

We developed and validated a classification system known as PREDICT for the diagnosis of Barrett's neoplasia using AAC. The improvement seen in the sensitivity and NPV for detection of Barrett's neoplasia in phase 3 demonstrates the clinical value of PREDICT and the similar improvement seen among non-endoscopists demonstrates the potential for generalisation of PREDICT once proven in real time.

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.

Fluorescence Imaging for Cancer Screening and Surveillance

The advent of fluorescence imaging (FI) for cancer cell detection in the field of oncology is promising for both cancer screening and surgical resection. Particularly, FI in cancer screening and surveillance is actively being evaluated in many new clinical trials with over 30 listed on Clinical Trials.gov . While surgical resection forms the foundation of many oncologic treatments, early detection is the cornerstone for improving outcomes and reducing cancer-related morbidity and mortality. The applications of FI are twofold as it can be applied to high-risk patients in addition to those undergoing active surveillance. This technology has the promise of highlighting lesions not readily detected by conventional imaging or physical examination, allowing disease detection at an earlier stage of development. Additionally, there is a persistent need for innovative, cost-effective imaging modalities to ameliorate healthcare disparities and the global burden of cancer worldwide. In this review, we outline the current utility of FI for screening and detection in a range of cancer types.

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.

Acetic acid-guided biopsies in Barrett's surveillance for neoplasia detection versus non-targeted biopsies (Seattle protocol): A feasibility study for a randomized tandem endoscopy trial. The ABBA study

BACKGROUND AND STUDY AIMS

Barrett's esophagus is a potentially pre-cancerous condition, affecting 375,000 people in the UK. Patients receive a 2-yearly endoscopy to detect cancerous changes, as early detection and treatment results in better outcomes. Current treatment requires random mapping biopsies along the length of Barrett's, in addition to biopsy of visible abnormalities. As only 13 % of pre-cancerous changes appear as visible nodules or abnormalities, areas of dysplasia are often missed. Acetic acid chromoendoscopy (AAC) has been shown to improve detection of pre-cancerous and cancerous tissue in observational studies, but no randomized controlled trials (RCTs) have been performed to date.

PATIENTS AND METHODS

A "tandem" endoscopy cross-over design. Participants will be randomized to endoscopy using mapping biopsies or AAC, in which dilute acetic acid is sprayed onto the surface of the esophagus, highlighting tissue through an whitening reaction and enhancing visibility of areas with cellular changes for biopsy. After 4 to 10 weeks, participants will undergo a repeat endoscopy, using the second method. Rates of recruitment and retention will be assessed, in addition to the estimated dysplasia detection rate, effectiveness of the endoscopist training program, and rates of adverse events (AEs). Qualitative interviews will explore participant and endoscopist acceptability of study design and delivery, and the acceptability of switching endoscopic techniques for Barrett's surveillance.

RESULTS

Endoscopists' ability to diagnose dysplasia in Barrett's esophagus can be improved. AAC may offer a simple, universally applicable, easily-acquired technique to improve detection, affording patients earlier diagnosis and treatment, reducing endoscopy time and pathology costs. The ABBA study will determine whether a crossover "tandem" endoscopy design is feasible and acceptable to patients and clinicians and gather outcome data to power a definitive trial.

Application of a multi-gene next-generation sequencing panel to a non-invasive oesophageal cell-sampling device to diagnose dysplastic Barrett's oesophagus

The early detection and endoscopic treatment of patients with the dysplastic stage of Barrett's oesophagus is a key to preventing progression to oesophageal adenocarcinoma. However, endoscopic surveillance protocols are hampered by the invasiveness of repeat endoscopy, sampling bias, and a subjective histopathological diagnosis of dysplasia. In this case-control study, we investigated the use of a non-invasive, pan-oesophageal cell-sampling device, the Cytosponge™, coupled with a cancer hot-spot panel to identify patients with dysplastic Barrett's oesophagus. Formalin-fixed, paraffin-embedded (FFPE) Cytosponge™ samples from 31 patients with non-dysplastic and 28 with dysplastic Barrett's oesophagus with good available clinical annotation were selected for inclusion. Samples were microdissected and amplicon sequencing performed using a panel covering >2800 COSMIC hot-spot mutations in 50 oncogenes and tumour suppressor genes. Strict mutation criteria were determined and duplicates were run to confirm any mutations with an allele frequency <12%. When compared with endoscopy and biopsy as the gold standard the panel achieved a 71.4% sensitivity (95% CI 51.3-86.8) and 90.3% (95% CI 74.3-98.0) specificity for diagnosing dysplasia. TP53 had the highest rate of mutation in 14/28 dysplastic samples (50%). CDKN2A was mutated in 6/28 (21.4%), ERBB2 in 3/28 (10.7%), and 5 other genes at lower frequency. The only gene from this panel found to be mutated in the non-dysplastic cases was CDKN2A in 3/31 cases (9.7%) in keeping with its known loss early in the natural history of the disease. Hence, it is possible to apply a multi-gene cancer hot-spot panel and next-generation sequencing to microdissected, FFPE samples collected by the Cytosponge™, in order to distinguish non-dysplastic from dysplastic Barrett's oesophagus. Further work is required to maximize the panel sensitivity.

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.

Molecular endoscopy for targeted imaging in the digestive tract

Endoscopy uses optical imaging methods to investigate tissue in a non-destructive manner with high resolution over a broad range of wavelengths, thus providing a powerful tool to rapidly visualise mucosal surfaces in the digestive tract. Molecular imaging is an important advancement that has been clinically demonstrated for early cancer detection and guidance of therapy. With this approach, imaging can be used to observe expression patterns of molecular targets to improve understanding of key biological mechanisms that drive disease progression. Prototype devices that collect fluorescence for wide-field or microscopic images have been developed. Several targeting moieties, including enzyme-activatable probes, antibodies, peptides, and lectins, have been administered in preclinical and clinical imaging studies in vivo. These emerging technologies provide useful approaches to study molecular events in different signalling pathways, producing insights that could lead to improved interventions to prevent and treat gastrointestinal diseases. In this Review, we introduce the basic concepts that form the foundation for development of molecular endoscopy and summarise key results from preclinical and clinical studies.

Diagnosis and Surveillance of Barrett's Esophagus: Addressing the Transatlantic Divide

BACKGROUND

Barrett's esophagus is a premalignant condition of the esophagus leading to esophageal adenocarcinoma. No consensus exists between the UK and USA concerning the diagnosis of Barrett's esophagus. Although the diagnostic procedure is common, the required findings and diagnostic criteria vary. Both guidelines require endoscopy showing columnar epithelia lining the esophagus, but the US guidelines require the additional finding of intestinal metaplasia on biopsy to confirm diagnosis. Achievement of a consensus is of particular importance due to the established progression from Barrett's esophagus to esophageal adenocarcinoma. Of further importance is the increasing incidence of esophageal adenocarcinoma, a condition with poor overall survival, leading to various opinions on the utility of surveillance in patients.

DISCUSSION

A review of the vast array of literature revealed that substantial evidence exists in favor of both diagnostic criteria; hence, there is no easy way to identify the "correct" method of diagnosing Barrett's esophagus. USA recommends surveillance of Barrett's esophagus, whereas UK does not advocate it unless dysplasia is present. Surveillance was found to be effective, but this varied as did cost-effectiveness. Further research into diagnostic methods for Barrett's esophagus is needed to address areas of limited understanding, such that agreement can be reached and practice standardized. Surveillance was generally advocated, but with different criteria and time intervals, and new methods are being evaluated.

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.

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.

Yield of Repeat Endoscopy in Barrett's Esophagus with No Dysplasia and Low-Grade Dysplasia: A Population-Based Study

BACKGROUND

The yield of early repeat endoscopy in patients with Barrett's esophagus (BE) is not well established.

AIMS

To determine how often early repeat endoscopy detected missed dysplasia or esophageal adenocarcinoma (EAC) in a population-based cohort of patients with BE. Secondary aims were to identify risk factors for missed dysplasia/EAC and compare detection of prevalent versus incident HGD/EAC.

METHODS

A population-based cohort of BE subjects in Olmsted County, MN, was studied. Patients with initial non-dysplastic BE or low-grade dysplasia (LGD) who underwent repeat endoscopy within 24 months were included. Those with a worse histologic diagnosis on repeat endoscopy were considered to have missed dysplasia/EAC. Baseline characteristics among patients with and without missed dysplasia/EAC were compared. The absolute numbers of asymptomatic prevalent or missed, and incident HGD/EAC in the entire cohort were ascertained.

RESULTS

Of 488 BE cases, 210 were included for the primary aim of this study. Repeat endoscopy revealed four HGD/EAC (1.9 %) and 16 LGD (8.8 %) for a combined miss rate of 9.5 %. Long-segment BE (LSBE) and lack of PPI use were predictors of missed dysplasia/EAC (P = 0.008), but adherence to biopsy protocol was not. Increased prevalent HGD/EAC (n = 30) rather than incident HGD/EAC (n = 22) was identified during a median 4.8 years of follow-up in this cohort.

CONCLUSIONS

Dysplasia/EAC is commonly missed at initial BE diagnosis, particularly in patients with LSBE and no PPI use. Efforts should be made to enhance the sensitivity of detecting dysplasia/neoplasia around the time of initial BE diagnosis.

High definition versus standard definition white light endoscopy for detecting dysplasia in patients with Barrett's esophagus

High-definition endoscopy systems provide superior image resolution. The aim of this study was to assess the utility of high definition compared with standard definition endoscopy system for detecting dysplastic lesions in patients with Barrett's esophagus. A retrospective cohort study of patients with non-dysplastic Barrett's esophagus undergoing routine surveillance was performed. Data were retrieved from the central hospital electronic database. Procedures performed for non-surveillance indications, Barrett's esophagus Prague C0M1 classification with no specialized intestinal metaplasia on histology, patients diagnosed with any dysplasia or cancer on index endoscopy, and procedures using advanced imaging techniques were excluded. Logistic regression models were constructed to estimate adjusted odds ratios and 95% confidence intervals comparing outcomes with standard definition and high-definition systems. The high definition was superior to standard definition system in targeted detection of all dysplastic lesions (odds ratio 3.27, 95% confidence interval 1.27-8.40) as well as overall dysplasia detected on both random and target biopsies (odds ratio 2.36, 95% confidence interval 1.50-3.72). More non-dysplastic lesions were detected with the high-definition system (odds ratio 1.16, 95% confidence interval 1.01-1.33). There was no difference between high definition and standard definition endoscopy in the overall (random and target) high-grade dysplasia or cancers detected (odds ratio 0.93, 95% confidence interval 0.83-1.04). Trainee endoscopists, number of biopsies taken, and male sex were all significantly associated with a higher yield for dysplastic lesions. The use of the high-definition endoscopy system is associated with better targeted detection of any dysplasia during routine Barrett's esophagus surveillance. However, high-definition endoscopy cannot replace random biopsies at present time.

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.

Spatial predisposition of dysplasia in Barrett's esophagus segments: a pooled analysis of the SURF and AIM dysplasia trials

OBJECTIVES

Surveillance endoscopy detects dysplasia within Barrett's esophagus (BE) and dictates treatment. Current biopsy regimens recommend uniformly spaced random biopsies. We assessed the distribution of dysplasia in BE to develop evidence-based biopsy regimens.

METHODS

We performed analysis of the distribution of dysplasia within BE using pretreatment biopsy data from two randomized controlled trials (RCTs) of radiofrequency ablation for dysplastic BE: the SURF (Surveillance vs. Radiofrequency Ablation) trial and the AIM Dysplasia (Ablation of Intestinal Metaplasia (AIM) Containing Dysplasia) trial. We used generalized linear models with generalized estimating equations (GEE) to estimate prevalence differences for dysplasia depending on the standardized location of biopsies. We performed Monte Carlo simulation of biopsy regimens to estimate their yield for any dysplasia within segments.

RESULTS

Dysplasia preferentially resides in the proximal-most half of the BE segment that is almost twice as likely to demonstrate dysplasia as the distal-most quartile. In pooled analysis, compared with the distal-most quarter, the prevalence difference in the proximal-most quarter was 22.6%, in the second proximal-most quarter 23.1%, and in the second distal-most quarter 15.3%. The best performing biopsy regimen in simulation studies acquired 8 biopsies in the most proximal cm of BE, 8 biopsies in the second cm, and 2 biopsies in each cm thereafter (q1cm: 8, 8, 2, 2…). A slightly simpler q2cm (every 2 cm) regimen (q2cm: 12, 12, 4…) was nearly as effective.

CONCLUSIONS

The post hoc analysis of two RCTs reveals a substantially increased prevalence of dysplasia proximally in BE segments. Our simulations suggest an altered biopsy regimen could increase sensitivity of biopsies in short-segment BE by >30%.

Endoscopic Management of Early Esophageal Cancer

The absolute incidence of esophageal adenocarcinoma has increased 7-fold over the past 5 decades, and esophageal adenocarcinoma is the most rapidly increasing epithelial malignancy in the United States. The incidence of early esophageal cancer has also increased proportionately. In the past decade, radiofrequency ablation has become the standard first-line therapy for high-grade dysplasia when found in the precursor lesion to esophageal adenocarcinoma, Barrett's esophagus. Success in the endoscopic management of high-grade dysplasia has furthered efforts to treat early esophageal cancers endoscopically. Although surgery remains the mainstay of treatment for more advanced tumors, national guidelines now recommend endoscopic mucosal resection followed by radiofrequency ablation for intramucosal carcinomas and T1a cancers. T1b cancers represent a more challenging group-very good results have been reported in highly selected subsets of patients with T1b tumors; however, many recommendations favor individualization or a surgical approach for this stage. This review examines the current data and recommendations regarding the endoscopic management of early esophageal adenocarcinomas.

Confocal foveated endomicroscope for the detection of esophageal carcinoma

By mimicking the variable resolution of the human eye, a newly designed foveated endomicroscopic objective shows the potential to improve current endoscopic based techniques of identifying abnormal tissue in the esophagus and colon. The prototype miniature foveated objective is imaged with a confocal microscope to provide large field of view images combined with a high resolution central region to rapidly observe morphological structures associated with cancer development in a mouse model.

Screening of a specific peptide binding to esophageal squamous carcinoma cells from phage displayed peptide library

To select a specifically binding peptide for imaging detection of human esophageal squamous cell carcinoma (ESCC), a phage-displayed 12-mer peptide library was used to screen the peptide that bind to ESCC cells specifically. After four rounds of bio-panning, the phage recovery rate gradually increased, and specific phage clones were effectively enriched. The 60 randomly selected phage clones were tested using cellular enzyme-linked immunosorbent assay (ELISA), and 41 phage clones were identified as positive clones with the over 2.10 ratio of absorbance higher than other clones, IRP and PBS controls. From the sequencing results of the positive clones, 14 peptide sequences were obtained and ESCP9 consensus sequence was identified as the peptide with best affinity to ESCC cells via competitive inhibition, fluorescence microscopy, and flow cytometry. The results indicate that the peptide ESCP9 can bind to ESCC cells specifically and sensitively, and it is a potential candidate to be developed as an useful molecule to the imaging detection and targeting therapy for ESCC.

TGM2: a cell surface marker in esophageal adenocarcinomas

INTRODUCTION

Esophageal adenocarcinomas (EAC) are aggressive cancers that are increasing in incidence and associated with a poor prognosis. The identification of highly expressed genes in EAC relative to metaplastic Barrett's esophagus (BE) may provide new targets for novel early cancer detection strategies using endoscopically administered, fluorescently labeled peptides.

METHODS

Gene expression analysis of BE and EACs were used to identify the cell surface marker transglutaminase 2 (TGM2) as overexpressed in cancer. The expression of two major isoforms of TGM2 was determined by qRT-polymerase chain reaction in an independent cohort of 128 EACs. Protein expression was confirmed by tissue microarrays and immunoblot analysis of EAC cell lines. TGM2 DNA copy number was assessed using single nucleotide polymorphism microarrays and confirmed by qPCR. TGM2 expression in neoadjuvantly treated EACs and following small interfering RNA-mediated knockdown in cisplatin-treated EAC cells was used to determine its possible role in chemoresistance.

RESULTS

TGM2 is overexpressed in 15 EACs relative to 26 BE samples. Overexpression of both TGM2 isoforms was confirmed in 128 EACs and associated with higher tumor stage, poor differentiation, and increased inflammatory and desmoplastic response. Tissue microarrays and immunohistochemistry confirmed elevated TGM2 protein expression in EAC. Single nucleotide polymorphism and qPCR analysis revealed increased TGM2 gene copy number as one mechanism underlying elevated TGM2 expression. TGM2 was highly expressed in resistant EAC after patient treatment with neoadjuvant chemotherapy/radiation suggesting a role for TGM2 in chemoresistance.

CONCLUSION

TGM2 may be a useful cell surface biomarker for early detection of EAC.

Minimally invasive esophagectomy for dysplastic Barrett's esophagus

A substantial portion of patients diagnosed preoperatively with high grade dysplasia (HGD) alone will have occult esophageal adenocarcinoma on analysis of the surgical specimen. Therefore, because of an increased risk of disease progression and malignancy, patients with HGD should be referred for esophagectomy promptly when endoscopic therapy has failed. The required extent of lymphadenectomy in this cohort of patients is unknown because of the variable incidence of submucosal cancer observed. Improvements in perioperative care, adoption of a minimally invasive surgical approach, and centralization of esophageal cancer services have substantially reduced the rates of mortality and morbidity associated with esophagectomy in recent years. Minimally invasive esophagectomy should be considered the treatment of choice in patients with dysplastic Barrett's esophagus that is refractory to endoscopic therapy or those at high risk of invasive cancer.

Endoscopic assessment and management of early esophageal adenocarcinoma

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

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.

Targeted imaging of esophageal neoplasia with a fluorescently labeled peptide: first-in-human results

Esophageal adenocarcinoma is rising rapidly in incidence and usually develops from Barrett's esophagus, a precursor condition commonly found in patients with chronic acid reflux. Premalignant lesions are challenging to detect on conventional screening endoscopy because of their flat appearance. Molecular changes can be used to improve detection of early neoplasia. We have developed a peptide that binds specifically to high-grade dysplasia and adenocarcinoma. We first applied the peptide ex vivo to esophageal specimens from 17 patients to validate specific binding. Next, we performed confocal endomicroscopy in vivo in 25 human subjects after topical peptide administration and found 3.8-fold greater fluorescence intensity for esophageal neoplasia compared with Barrett's esophagus and squamous epithelium with 75% sensitivity and 97% specificity. No toxicity was attributed to the peptide in either animal or patient studies. Therefore, our first-in-human results show that this targeted imaging agent is safe and may be useful for guiding tissue biopsy and for early detection of esophageal neoplasia and potentially other cancers of epithelial origin, such as bladder, colon, lung, pancreas, and stomach.

Optical coherence tomography in Barrett's esophagus

The incidence of Barrett's-related adenocarcinoma of the esophagus continues to increase at an alarming rate. Studies to date show great promise for optical coherence tomography (OCT) in screening, surveillance, and guiding management of Barrett's esophagus. With continued innovation in rapid, accurate scanning systems, such as volumetric laser endomicroscopy or optical frequency domain imaging, advanced OCT seems likely to have an important impact. The next few years are likely to see the initiation of large clinical studies that will define the extent and significance of this impact.

Endocytoscopic visualization of squamous cell islands within Barrett's epithelium

AIM

To study the endocytoscopic visualization of squamous cell islands within Barrett's epithelium.

METHODS

Endocytoscopy (ECS) has been studied in the surveillance of Barrett's esophagus, with controversial results. In initial studies, however, a soft catheter type endocytoscope was used, while only methylene blue dye was used for the staining of Barrett's mucosa. Integrated type endocytoscopes (GIF-Q260 EC, Olympus Corp, Tokyo, Japan) have been recently developed, with the incorporation of a high-power magnifying endocytoscope into a standard endoscope together with narrow-band imaging (NBI). Moreover, double staining with a mixture of 0.05% crystal violet and 0.1% of methylene blue (CM) during ECS enables higher quality images comparable to conventional hematoxylin eosin histopathological images.

RESULTS

In vivo endocytoscopic visualization of papillary squamous cell islands within glandular Barrett's epithelium in a patient with long-segment Barrett's esophagus is reported. Conventional white light endoscopy showed typical long-segment Barrett's esophagus, with small squamous cell islands within normal Barrett's mucosa, which were better visualized by NBI endoscopy. ECS after double CM staining showed regular Barrett's esophagus, while higher magnification (× 480) revealed the orifices of glandular structures better. Furthermore, typical squamous cell papillary protrusion, classified as endocytoscopic atypia classification (ECA) 2 according to ECA, was identified within regular glandular Barrett's mucosa. Histological examination of biopsies taken from the same area showed squamous epithelium within glandular Barrett's mucosa, corresponding well to endocytoscopic findings.

CONCLUSION

To our knowledge, this is the first report of in vivo visualization of esophageal papillary squamous cell islands surrounded by glandular Barrett's epithelium.

Synthesis and characterization of anti-EGFR fluorescent nanoparticles for optical molecular imaging

Molecular imaging, the visualization of molecular and cellular markers, is a promising method for detection of dysplasia and early cancer in the esophagus and can potentially be used to identify regions of interest for biopsy or tumor margins for resection. EGFR is a previously reported cell surface receptor with stepwise increases in expression during the progression from Barrett's metaplasia to adenocarcinoma. In this work, a 200 nm fluorescent nanoparticle contrast agent was synthesized for targeted imaging of EGFR through a series of surface modifications to dye-encapsulated polystyrene particles. Amino-functionalized polystyrene particles were PEGylated using a heterobifunctional PEG linker. Subsequently, thiolated M225 antibodies were conjugated to maleimide functional groups on attached PEGs for EGFR targeting. In vitro binding studies using flow cytometry demonstrated specific binding of M225-PEG-NP to EGFR-expressing cells with minimal nonspecific binding in EGFR(-) cells. Binding was shown to increase proportionally with the number of conjugated M225 antibodies. Adsorbed formulations with unmodified M225 antibodies, M225 + PEG-NP, were synthesized using the same antibody feeds used in M225-PEG-NP synthesis to determine the contribution of adsorbed antibodies to EGFR targeting. Adsorbed antibodies were less efficient at mediated nanoparticle targeting to EGFR than conjugated antibodies. Finally, M225-PEG-NP demonstrated binding to EGFR-expressing regions in human esophageal tissue sections.

Improved detection of incident dysplasia by probe-based confocal laser endomicroscopy in a Barrett's esophagus surveillance program

BACKGROUND

Probe-based confocal laser endomicroscopy (pCLE) is a new technique allowing in vivo detection of neoplastic tissue using a standard endoscope.

AIMS

Our aim was to compare the incident dysplasia detection rate of biopsies obtained by high-definition white light endoscopy (HD-WLE) or by pCLE in a cohort of patients with Barrett's esophagus (BE) participating in a surveillance program.

METHODS

Fifty of 100 patients underwent pCLE in addition to HD-WLE. Four-quadrant biopsy specimens according to the Seattle biopsy protocol were obtained in all patients to ensure standard-of-care. Diagnosis of dysplasia/neoplasia was made by a blinded gastrointestinal pathologist.

RESULTS

Incident high-grade dysplasia (HGD) and low-grade dysplasia (LGD) were diagnosed in 3/100 and in 16/100 cases. In the HD-WLE group, areas suspicious for neoplasia were not observed and dysplasia was diagnosed in 5/50 (10%) patients (one with HGD). In the pCLE group, areas suspicious for neoplasia were observed by pCLE in 21/50 (42%) patients; dysplasia was confirmed in 14 cases (28%) (two with HGD). The dysplasia detection rate was significantly higher in the pCLE group than in the HD-WLE group (P = 0.04). The sensitivity, specificity, positive and negative predictive values of pCLE for dysplasia were 100, 83, 67, and 100%, respectively.

CONCLUSIONS

Incident dysplasia can be more frequently detected by pCLE than by HD-WLE in BE. The higher dysplasia detection rate provided by pCLE could improve the efficacy of BE surveillance programs.