Chromoendoscopy with methylene blue and associated DNA damage in Barrett's oesophagus

Endoscopic imaging of Barrett’s esophagus

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

Management of Barrett's esophagus: From screening to newer treatments

Barrett's esophagus is a premalignant condition of the esophagus in which the squamous epithelium of the lower end of the esophagus is replaced with columnar epithelium. Since the incidence of esophageal adenocarcinoma is on the rise, the major gastroenterology societies have come up with their recommendations for screening and surveillance. Specific factors like obesity, white race, age over 50 years, early age of onset of GERD, smoking and hiatal hernia have been identified as increasing the risk of Barrett's esophagus and adenocarcinoma. The diagnosis requires both endoscopic identification of columnar-lined mucosa and histological confirmation with biopsy. Most medical societies recommend screening people with GERD and other risk factors with endoscopy, but other alternatives employing less invasive methods are currently being studied. Surveillance strategies vary depending on the endoscopic findings and the Seattle biopsy protocol with random 4-quadrant sampling is recommended. Biomarkers have shown promising results, but more studies are needed in the future. White light endoscopy is the standard practice, but other advanced imaging modalities have shown variable results and hence more studies are awaited for further validation. Endoscopic eradication techniques, including both resection and ablation, have shown good but variable results for treating dysplastic lesions confined to the mucosa. Resection procedures to remove visible lesions followed by ablation of the dysplastic mucosa have shown the best results with higher eradication rates and lower recurrence rates. Surgical management is reserved for lesions with sub-mucosal invasion and lymph node spread with increased risk of metastasis.

White-Light or Narrow-Band Imaging Colonoscopy in Surveillance of Ulcerative Colitis: A Prospective Multicenter Study

BACKGROUND & AIMS

Early detection of neoplastic lesions is essential in patients with long-standing ulcerative colitis but the best technique of colonoscopy still is controversial.

METHODS

We performed a prospective multicenter study in patients with long-standing ulcerative colitis. Two colonoscopies were performed in each patient within 3 weeks to 3 months. In white-light (WL) colonoscopy, stepwise random biopsy specimens (4 biopsy specimens every 10 cm), segmental random biopsies (2 biopsy specimens in 5 segments), and targeted biopsy specimens were taken. In NBI colonoscopy, segmental and targeted biopsy specimens were taken. The sequence of WL and NBI colonoscopy was randomized.

RESULTS

In 36 of 159 patients enrolled (22.6%), 54 lesions with intraepithelial neoplasia (IN) were found (51 low-grade, 3 high-grade). In WL colonoscopy we found 11 IN in stepwise biopsy specimens, 4 in segmental biopsy specimens, and 15 in targeted biopsy specimens. In NBI colonoscopy 7 IN were detected in segmental biopsy specimens and 24 IN were detected in targeted biopsy specimens. Almost all IN were found with one technique alone (κ value of WL vs NBI, -0.86; P < .001). Statistically equivalent numbers of IN were found in NBI colonoscopy with targeted and segmental biopsy specimens as in WL colonoscopy with targeted and stepwise biopsy specimens, but with fewer biopsy specimens (11.9 vs 38.6 biopsy specimens, respectively; P < .001), and less withdrawal time was necessary (23 vs 13 min, respectively; P < .001).

CONCLUSIONS

Stepwise biopsy specimens are indispensable in WL colonoscopy. The combination of targeted and segmental biopsy specimens in the NBI technique is as sensitive as targeted together with stepwise biopsy specimens in WL colonoscopy, but requires fewer biopsy specimens and less time. The highest sensitivity should be reached by combining the WL and NBI techniques by switching between the modes.

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

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

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.

Chromocolonoscopy

Chromoendoscopy techniques improve the visualization of mucosal structures. This article reviews and summarizes key studies addressing the impact of chromoendoscopy on colonic neoplasia detection and differentiation of neoplastic from non-neoplastic polyps in average and high-risk populations, including patients with colonic inflammatory bowel disease (IBD). In this context, there are convincing data that chromoendoscopy differentiates neoplastic from non-neoplastic polyps in average-risk populations with high accuracy. Moreover, dye-based chromoendoscopy improves neoplasia detection in colonic IBD surveillance.

Synergistic in vitro photodynamic antimicrobial activity of methylene blue and chitosan against Helicobacter pylori 26695

BACKGROUND

Photodynamic therapy (PDT) is a method for killing cells (bacterial, fungal and cancer cells) or virus using photosensitizers (PS) and light of various wavelengths. In vitro PDT using endoscopic light against H. pylori was effective at a concentration of 0.2mg/mL of MB. The purpose of this study was to increase the effect of photodynamic modality against H. pylori by addition of chitosan to MB.

METHODS

The bactericidal effect was measured by counting viable cells after PDT. The degree of damage to DNA was confirmed using alkaline gel electrophoresis. Cellular DNA damage was demonstrated by ethidium bromide monoazide-quantitative polymerase chain reaction (EMA-qPCR).

RESULTS

In the groups treated with either 0.04 mg/mL MB alone or 0.02 mg/mL MB with endoscopic light for 15 min, viable cells were decreased approximately tenfold. The group treated with 0.04 mg/mL of MB with light, showed more effective bactericidal activity than 0.02 mg/mL of MB treatment. By 0.05% chitosan pre-treatment followed with 0.04 mg/mL of MB and light irradiation, viable cells were decreased 10(7)-fold. The DNA damage caused by PDT as demonstrated by alkaline gel electrophoresis was greater in the MB plus chitosan-treated group than in control and MB-treated groups. Cellular DNA damage demonstrated by EMA-qPCR was also greater in the group treated with MB plus chitosan than in the MB-treated group.

CONCLUSION

The bactericidal effects with PDT using MB were increased with the concentration of photosensitizer and chitosan treatment, peculiarly before endoscopic light irradiation.

Toxicity of imine-iminium dyes and pigments: electron transfer, radicals, oxidative stress and other physiological effects

Although conjugation is well known as an important contributor to color, there is scant recognition concerning involvement of imine and iminium functions in the physiological effects of this class of dyes and pigments. The group includes the dyes methylene blue, rhodamine, malachite green, fuchsin, crystal violet, auramine and cyanins, in addition to the pigments consisting of pyocyanine, phthalocyanine and pheophytin. The physiological effects consist of both toxicity and beneficial aspects. The unifying theme of electron transfer-reactive oxygen species-oxidative stress is used as the rationale in both cases. Toxicity is frequently prevented or alleviated by antioxidants. The apparent dichotomy of methylene blue action as both oxidant and antioxidant is rationalized based on similar previous cases. This mechanistic approach may have practical benefit. This review is important in conveying, for the first time, a unifying mechanism for toxicity based on electron transfer-reactive oxygen species-oxidative stress arising from imine-iminium.

Implementation of image-enhanced endoscopy into solo and group practices for dysplasia detection in Crohn's disease and ulcerative colitis

Enhanced surveillance colonoscopy techniques for dysplasia detection in ulcerative colitis have successfully been implemented into group and solo practices. Chromoendoscopy (CE), in particular, has been shown to significantly increase dysplasia detection in surveillance of patients with inflammatory bowel disease. CE can be learned and is reproducible, with an associated modest increase in procedure time.

Image-enhanced endoscopy is critical in the surveillance of patients with colonic IBD

Cancer risk in patients with inflammatory bowel disease (IBD) involving the colon is high and increases with time. The quality and efficacy of colonoscopic surveillance is variable. Chromoendoscopy with targeted biopsies is superior to standard white light endoscopy with random biopsies. Although commonly practiced, the technique of random colonic biopsies has poor yield for dysplasia and has little clinical consequence. Studies have shown a limited role for electronic-based image-enhanced endoscopy, including narrow band imaging, in detecting IBD dysplasia. Efforts should focus on the dissemination of the technique of chromoendoscopy in routine clinical practice through training and quality metrics.

Endoscopic Optical Coherence Tomography for Clinical Gastroenterology

Optical coherence tomography (OCT) is a real-time optical imaging technique that is similar in principle to ultrasonography, but employs light instead of sound waves and allows depth-resolved images with near-microscopic resolution. Endoscopic OCT allows the evaluation of broad-field and subsurface areas and can be used ancillary to standard endoscopy, narrow band imaging, chromoendoscopy, magnification endoscopy, and confocal endomicroscopy. This review article will provide an overview of the clinical utility of endoscopic OCT in the gastrointestinal tract and of recent achievements using state-of-the-art endoscopic 3D-OCT imaging systems.

Double staining with crystal violet and methylene blue is appropriate for colonic endocytoscopy: an in vivo prospective pilot study

BACKGROUND AND AIM

Endocytoscopy (EC) at ultra-high magnification enables in vivo visualization of cellular atypia of gastrointestinal mucosae. Clear images are essential for precise diagnosis by EC. The aim of the present study was to evaluate the optimal staining method for EC in the colon.

METHODS

Thirty prospectively enrolled patients were allocated 1:1:1 to three distinct staining methods: 0.05% crystal violet (CV) alone, 1% methylene blue (MB) alone, or CV+MB (CM double). Normal rectal mucosae were stained with each dye and videos of EC images were recorded. Visibility of nuclei and gland formation after staining were evaluated as 'recognizable' or 'not recognizable'. Time for each parameter to become 'recognizable' was measured, and the average times for the three staining regimens were compared.

RESULTS

MB alone and CM double staining resulted in 'recognizable' (102 ± 27 vs 89 ± 22 s, P=0.263) nuclei within comparable periods of time, whereas CV alone was unable to identify nuclei. Gland formation became 'recognizable' sooner after CM double staining than after MB alone (61 ± 16 vs 108 ± 24 s, P<0.001).

CONCLUSIONS

Double staining with CV and MB, which rapidly provided recognizable images of both nuclei and gland formation, is an appropriate staining regimen for colonic EC.

Narrow band imaging: application for early-stage gastrointestinal neoplasia

Narrow-band imaging (NBI) is an imaging technique for endoscopy using optical filters to narrow the bandwidth of spectral transmittance. Through this narrow spectrum, NBI contrasts surface structure and microvascular architecture of various lesions. In this article we focus on the application of NBI for early-stage neoplasia in the esophagus, stomach and colon with a three-step strategy of endoscopic diagnosis: (i) the detection of abnormality; (ii) the differentiation between non-neoplasia and neoplasia; and (iii) staging for tumor extension and depth of invasion.

Endoscopic diagnosis of early Barrett's neoplasia: perspectives for advanced endoscopic technology

Barrett's esophagus (BE) is a metaplastic condition that occurs secondary to gastroesophageal reflux disease. BE is also a precursor to esophageal adenocarcinoma, which, although still rare in Japan, is one of the most rapidly increasing cancers in Western countries. However, the prevalence of gastroesophageal reflux disease has increased significantly over the past few decades in Japan, possibly leading to an incremental rise in BE and the associated inherent risk of adenocarcinoma. Given the poor prognosis of advanced-stage Barrett's adenocarcinoma, endoscopic surveillance is recommended for subjects with BE to detect early neoplasias including dysplasia. However, endoscopic identification of dysplastic lesions is still not sufficiently reliable or subjective, making targeted therapy extremely difficult. Over the past few years, improvements in image resolution, image processing software, and optical filter technology have enabled identification of dysplasia and early cancer in BE patients. We retrieved as many studies on advanced endoscopic technologies in BE as possible from MEDLINE and PubMed. The present review focuses on the emergent clinically available technologies to provide an overview of the technologies, their practical applicability, current status, and future challenges.

Diagnostic yield of the light blue crest sign in gastric intestinal metaplasia: a meta-analysis

BACKGROUND

The diagnostic yield of light blue crest(LBC) sign, which was observed by narrow band imaging with magnification endoscopy(NBI-ME), in detecting gastric intestinal metaplasia(IM) has shown variable results.

OBJECTIVE

We aimed to assess the diagnostic value of LBC under NBI-ME for detecting gastric IM.

METHODS

We performed a literature search of the Medline/PubMed, Embase, Web of Science, Science Direct and the Cochrane Library Databases; and a meta-analysis of pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and SROC area under the curve, using fixed- and random-effects models, for the accuracy of LBC-based IM diagnosis.

RESULTS

We initially included 4 articles, but excluded 1 article to counter significant heterogeneity. When pooled, the remaining 3 articles, which included 247 patients with 721 lesions, showed the following patterns in IM diagnosis: sensitivity: 0.90 (95% confidence interval [CI] 0.86-0.92); specificity: 0.90 (95% CI 0.86-0.93), positive likelihood ratio: 8.98 (95% CI 6.42-12.58), negative likelihood ratio: 0.12 (95% CI 0.09-0.16), and SROC area under the curve: 0.9560.

LIMITATIONS

As the studies varied by their definitions for positive LBC, endoscopy types, biopsy protocols, race of patient cohort, and physicians' proficiency, some sample sizes were limited so that subgroup analyses could not be performed.

CONCLUSION

We concluded that observing LBC under NBI-ME is an accurate and precise means of diagnosing gastric IM.

Accuracy and interrater reliability for the diagnosis of Barrett's neoplasia among users of a novel, portable high-resolution microendoscope

The high-resolution microendoscope (HRME) is a novel imaging modality that may be useful in the surveillance of Barrett's esophagus in low-resource or community-based settings. In order to assess accuracy and interrater reliability of microendoscopists in identifying Barrett's-associated neoplasia using HRME images, we recruited 20 gastroenterologists with no microendoscopic experience and three expert microendoscopists in a large academic hospital in New York City to interpret HRME images. They prospectively reviewed 40 HRME images from 28 consecutive patients undergoing surveillance for metaplasia and low-grade dysplasia and/or evaluation for high-grade dysplasia or cancer. Images were reviewed in a blinded fashion, after a 4-minute training with 11 representative images. All imaged sites were biopsied and interpreted by an expert pathologist. Sensitivity of all endoscopists for identification of high-grade dysplasia or cancer was 0.90 (95% confidence interval [CI]: 0.88-0.92) and specificity was 0.82 (95% CI: 0.79-0.85). Positive and negative predictive values were 0.72 (95% CI: 0.68-0.77) and 0.94 (95% CI: 0.92-0.96), respectively. No significant differences in accuracy were observed between experts and novices (0.90 vs. 0.84). The kappa statistic for all raters was 0.56 (95% CI: 0.54-0.58), and the difference between groups was not significant (0.64 vs. 0.55). These data suggest that gastroenterologists can diagnose Barrett's-related neoplasia on HRME images with high sensitivity and specificity, without the aid of prior microendoscopy experience.

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

BACKGROUND & AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Review article: newer optical and digital chromoendoscopy techniques vs. dye-based chromoendoscopy for diagnosis and surveillance in inflammatory bowel disease

BACKGROUND

Recent innovations in gastrointestinal endoscopy have changed our traditional approach to diagnosis and therapy in patients with inflammatory bowel diseases (IBD). While traditionally used dye-based chromoendoscopy (DBC) techniques suffer from several limitations that reduce their utility in daily routine practice, newer 'dye-less' chromoendoscopy (DLC) techniques offer a great potential to overcome most of these limitations.

AIM

To review available optical and digital chromoendoscopy techniques, by critically discussing their potential for diagnostic and surveillance colonoscopy in patients with IBD.

METHODS

A literature search on the use of dye-less and dye-based chromoendoscopy in IBD patients was performed.

RESULTS

In long-standing IBD, DBC improves detection of dysplasia (diagnostic odds ratio = 17.5, 95% CI = 1.2-247.1) as well as prediction of inflammatory disease activity and extent of disease compared with standard video-colonoscopy. Narrow band imaging (NBI) shows no improvement in dysplasia detection rates compared with white-light endoscopy and DBC (P = 0.6). Moreover, NBI results in a suboptimal differentiation of dysplastic from nondysplastic lesions. No data regarding digital DLC techniques (i.e. FICE, i-scan) for dysplasia detection in IBD are yet available. Both NBI and i-scan are superior to white-light endoscopy in assessing the activity and extent of colorectal IBD.

CONCLUSIONS

Although the potential benefits of newer optical and digital dye-less chromoendoscopy techniques over traditionally used DBC are substantial, only DBC can currently be recommended to improve dysplasia detection in long-standing IBD. In contrast, DLC has the potential to quantify disease activity and mucosal healing in IBD.

Overcoming challenges in IBD management: management of colonic dysplastic lesions

The aim of any screening or surveillance program must be to identify early lesions to enable treatment and prevention before the development of invasive cancer. A surveillance program must be acceptable to patients and practically possible to implement. There is a move away from using random colonic biopsies towards targeted biopsies aimed at abnormal areas identified by newer colonoscopic techniques (narrow band imaging, chromoendoscopy, confocal microendoscopy). However, the attitude towards a patient with a dysplastic lesion is not well established. Bowel cancer screening in the general population relies on identification of adenomatous lesions which can be resected before they transform into carcinoma. The therapeutic approach to such lesions, the patient groups at risk and the intervals of surveillance are reasonably established. In contrast, inflammatory bowel disease (IBD)-colorectal cancer (CRC) poses different challenges: dysplastic lesions do not follow the adenoma-carcinoma sequence, they can be difficult to see (flat lesions), difficult to resect completely, and multifocal. Prophylactic proctocolectomy eliminates the risk of CRC, but this strategy is not acceptable to most patients or physicians. Moreover, IBD patients can harbor dysplastic lesions related to the sporadic CRC pathway, the clinical significance of which differs clearly from colitis-associated dysplastic lesions. Nowadays, therapeutic recommendations for the management of dysplasia in IBD are based on macroscopic pattern and microscopic characteristics. As an example, consensus guidelines state that adenoma-like lesions can be adequately treated by polypectomy unlike non-adenoma-like raised lesions or flat high-grade dysplasia that should undergo colectomy. The present article is aimed to summarize the existing evidence on this thorny matter.

Red flag imaging techniques in Barrett's esophagus

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

Narrow-band imaging with magnifying endoscopy is accurate for detecting gastric intestinal metaplasia

AIM

To investigate the predictive value of narrow-band imaging with magnifying endoscopy (NBI-ME) for identifying gastric intestinal metaplasia (GIM) in unselected patients.

METHODS

We prospectively evaluated consecutive patients undergoing upper endoscopy for various indications, such as epigastric discomfort/pain, anaemia, gastro-oesophageal reflux disease, suspicion of peptic ulcer disease, or chronic liver diseases. Patients underwent NBI-ME, which was performed by three blinded, experienced endoscopists. In addition, five biopsies (2 antrum, 1 angulus, and 2 corpus) were taken and examined by two pathologists unaware of the endoscopic findings to determine the presence or absence of GIM. The correlation between light blue crest (LBC) appearance and histology was measured. Moreover, we quantified the degree of LBC appearance as less than 20% (+), 20%-80% (++) and more than 80% (+++) of an image field, and the semiquantitative evaluation of LBC appearance was correlated with IM percentage from the histological findings.

RESULTS

We enrolled 100 (58 F/42 M) patients who were mainly referred for gastro-esophageal reflux disease/dyspepsia (46%), cancer screening/anaemia (34%), chronic liver disease (9%), and suspected celiac disease (6%); the remaining patients were referred for other indications. The prevalence of Helicobacter pylori (H. pylori) infection detected from the biopsies was 31%, while 67% of the patients used proton pump inhibitors. LBCs were found in the antrum of 33 patients (33%); 20 of the cases were classified as LBC+, 9 as LBC++, and 4 as LBC+++. LBCs were found in the gastric body of 6 patients (6%), with 5 of them also having LBCs in the antrum. The correlation between the appearance of LBCs and histological GIM was good, with a sensitivity of 80% (95%CI: 67-92), a specificity of 96% (95%CI: 93-99), a positive predictive value of 84% (95%CI: 73-96), a negative predictive value of 95% (95%CI: 92-98), and an accuracy of 93% (95%CI: 90-97). The NBI-ME examination overlooked GIM in 8 cases, but the GIM was less than 5% in 7 of the cases. Moreover, in the 6 false positive cases, the histological examination showed the presence of reactive gastropathy (4 cases) or H. pylori active chronic gastritis (2 cases). The semiquantitative correlation between the rate of LBC appearance and the percentage of GIM was 79% (P < 0.01).

CONCLUSION

NBI-ME achieved good sensitivity and specificity in recognising GIM in an unselected population. In routine clinical practice, this technique can reliably target gastric biopsies.

Advanced precancerous lesions in the lower oesophageal mucosa: high-grade dysplasia and intramucosal carcinoma in Barrett's oesophagus

Adenocarcinoma developed in Barrett's oesophagus is a tumour with an increasing incidence and still a poor prognosis. The only marker that can be used for surveillance remains dysplasia (intraepithelial neoplasia), especially when it is high-grade, that precedes intramucosal carcinoma. New forms of dysplasia have been described in complement to the classical intestinal type (foveolar dysplasia, basal crypt dysplasia). High-grade dysplasia and intramucosal carcinoma are diagnosed on biopsies taken during endoscopy. Standard endoscopy is now challenged by various techniques that represent recent major technical improvements (chromoendoscopy, virtual chromoendoscopy, optical frequency domain imaging, confocal laser endomicroscopy). In numerous cases, high-grade dysplasia and intramucosal carcinoma can be treated by endoscopic procedures, allowing a precise histopathological diagnosis on the resected specimen (endoscopic mucosal resection, submucosal endoscopic dissection) or destroying the neoplastic tissue. Radiofrequency ablation is currently considered as the best available technique for treatment of flat high grade dysplasia and for eradication of residual Barrett's mucosa after focal endoscopic mucosal resection.

Screening for precancerous lesions of upper gastrointestinal tract: from the endoscopists' viewpoint

Upper gastrointestinal tract cancers are one of the most important leading causes of cancer death worldwide. Diagnosis at late stages always brings about poor outcome of these malignancies. The early detection of precancerous or early cancerous lesions of gastrointestinal tract is therefore of utmost importance to improve the overall outcome and maintain a good quality of life of patients. The desire of endoscopists to visualize the invisibles under conventional white-light endoscopy has accelerated the advancements in endoscopy technologies. Nowadays, image-enhanced endoscopy which utilizes optical- or dye-based contrasting techniques has been widely applied in endoscopic screening program of gastrointestinal tract malignancies. These contrasting endoscopic technologies not only improve the visualization of early foci missed by conventional endoscopy, but also gain the insight of histopathology and tumor invasiveness, that is so-called optical biopsy. Here, we will review the application of advanced endoscopy technique in screening program of upper gastrointestinal tract cancers.

Indications, stains and techniques in chromoendoscopy

Early detection of malignancies within the gastrointestinal tract is essential to improve the prognosis and outcome of affected patients. However, conventional white light endoscopy has a miss rate of up to 25% for gastrointestinal pathology, specifically in the context of small and flat lesions within the colon. Chromoendoscopy and other advanced imaging techniques aim at facilitating the visualization and detection of neoplastic lesions and have been applied throughout the gastrointestinal tract. Chromoendoscopy, particularly in combination with magnifying endoscopy has significantly improved means to detect neoplastic lesions in the gastrointestinal mucosa, particularly in ulcerative colitis and Crohn's colitis. In addition, chromoendoscopy is beneficial in the upper gastrointestinal tract, especially when evaluating Barrett's oesophagus (BO) for the presence of dysplasia. Furthermore, it also improves characterization, differentiation and diagnosis of endoscopically detected suspicious lesions, and helps to delineate the extent of neoplastic lesions that may be amenable to endoscopic resection. This review discusses the dyes, indications and advanced endoscopic imaging methods used in various chromoendoscopic techniques, and presents a critical overview of the existing evidence supporting their use in current practice with a particular emphasis on the role in inflammatory bowel disease and BO.

Inflammatory bowel disease cancer risk, detection and surveillance

Ulcerative colitis (UC) is a chronic and relapsing inflammation of the colonic mucosa with variable extension from the rectum towards the cecum. The aim of medical treatment is to induce and maintain clinical remission. If no remission can be achieved, continuous inflammation may repeatedly destroy the epithelial cells. This has to be compensated by epithelial increased proliferation which finally can lead to inflammation-associated colorectal cancer (CRC). The risk of colitis-associated CRC is increased after a long disease duration, especially in patients with chronic active disease. This risk may be lower if long-lasting mucosal healing can be achieved. To detect the development of dysplasia/intraepithelial neoplasia and colitis-associated CRC early, surveillance programs have been installed. However, the evidence of success for those surveillance programs is limited. This is partially due to problems of detecting precancerous lesions in the colonic mucosa during those surveillance programs. The specific problems of surveillance programs for the prevention of CRC and specific aspects of patient care in UC are reviewed in this article.

Diagnosis and management of Barrett’s metaplasia: What’s new

Barrett’s esophagus (BE) is a complication of gastroesophageal reflux disease, and a premalignant lesion for esophageal adenocarcinoma (EAC). Observational studies suggest that endoscopic surveillance is associated with the detection of dysplasia and EAC at an early stage along with improved survival, but controversies still remain. The management of patients with BE involves endoscopic surveillance, preventive and clinical measures for cancer, and endoscopic and surgical approaches to treatment. Deciding upon the most appropriate treatment is a challenge. This study presents the results and the effectiveness of these practices.

Barrett's esophagus: A review of diagnostic criteria, clinical surveillance practices and new developments

Barrett's esophagus is defined by metaplastic glandular changes to the distal esophagus and is linked to an increased risk of esophageal adenocarcinoma. Controversy exists whether the definition should be limited to intestinal type glands with goblet cells or should be expanded to include non-goblet cell columnar epithelium. Barrett's esophagus may be asymptomatic in a large proportion of the population but screening should be considered for those with certain clinical findings. The diagnosis of Barrett's should be based on the combination of careful endoscopic evaluation and histologic review of the biopsy material. Continued surveillance biopsies may be necessary in cases of indeterminate or low grade dysplasia. Clinical follow-up of patients with high grade dysplasia should be tailored to the individual patient. Development of newer endoscopy techniques including chemoendoscopy, chromoendoscopy and use of biomarkers on frozen tissue have shown some promise of identifying patients at risk for malignancy.

Frontiers in bronchoscopic imaging

Bronchoscopy is a minimally invasive method for diagnosis of diseases of the airways and the lung parenchyma. Standard bronchoscopy uses the reflectance/scattering properties of white light from tissue to examine the macroscopic appearance of airways. It does not exploit the full spectrum of the optical properties of bronchial tissues. Advances in optical imaging such as optical coherence tomography (OCT), confocal endomicroscopy, autofluorescence imaging and laser Raman spectroscopy are at the forefront to allow in vivo high-resolution probing of the microscopic structure, biochemical compositions and even molecular alterations in disease states. OCT can visualize cellular and extracellular structures at and below the tissue surface with near histological resolution, as well as to provide three-dimensional imaging of the airways. Cellular and subcellular imaging can be achieved using confocal endomicroscopy or endocytoscopy. Contrast associated with light absorption by haemoglobin can be used to highlight changes in microvascular structures in the subepithelium using narrow-band imaging. Blood vessels in the peribronchial space can be displayed using Doppler OCT. Biochemical compositions can be analysed with laser Raman spectroscopy, autofluorescence or multispectral imaging. Clinically, autofluorescence and narrow-band imaging have been found to be useful for localization of preneoplastic and neoplastic bronchial lesions. OCT can differentiate carcinoma in situ versus microinvasive cancer. Endoscopic optical imaging is a promising technology that can expand the horizon for studying the pathogenesis and progression of airway diseases such as COPD and asthma, as well as to evaluate the effect of novel therapy.

Chromoendoscopy in inflammatory bowel disease

Chromoendoscopy with methylene blue or indigo carmine significantly increases the diagnostic yield of finding intraepithelial neoplasia in patients with longstanding colitis. The number needed to treat is 14 for panchromoendoscopy to identify 1 additional patient with dysplasia. Chromoendoscopy can greatly facilitate the identification of flat lesions harboring intraepithelial neoplasia. Chromoendoscopy can guide biopsies and clearly reduces the amount of biopsies that are needed per patient. Magnifying endoscopy or CLE are additional techniques, which can be used in conjunction with chromoendoscopy to further reduce the amount of biopsies and to further increase the diagnostic yield. Chromoendoscopy is an established clinical procedure and recommended by many gastroenterological societies for surveillance of patients with longstanding ulcerative colitis. Thus, intravital staining should be an essential part of the diagnostic armamentarium of every colonoscopist.

Innovation in cancer imaging

Cancer is rapidly becoming the worldwide leading cause of premature death. Iconographic techniques have traditionally provided information on tumor anatomy. The recent introduction of functional and molecular imaging techniques allows probing tumor physiology and biology in addition to mere anatomical description. In addition to the research implications, these novel imaging techniques offer early response assessment and target visualization which, in the era of personalized medicine, may offer significant advances in cancer therapy. Here, we provide an overview of the most important developments in cancer imaging, with a focus on the clinical applications.

Use of in vivo real-time optical imaging for esophageal neoplasia

Esophageal adenocarcinoma carries a poor prognosis, as it typically presents at a late stage. Thus, a major research priority is the development of novel diagnostic-imaging strategies that can detect neoplastic lesions earlier and more accurately than current techniques. Advances in optical imaging allow clinicians to obtain real-time histopathologic information with instant visualization of cellular architecture and the potential to identify neoplastic tissue. The various endoscopic imaging modalities for esophageal neoplasia can be grouped into 2 major categories: (1) wide-field imaging, a comparatively lower-resolution view for imaging larger surface areas, and (2) high-resolution imaging, which allows individual cells to be visualized. This review will provide an overview of the various forms of real-time optical imaging in the diagnosis and management of Barrett's esophagus and esophageal adenocarcinoma.

The diagnostic accuracy of chromoendoscopy for dysplasia in ulcerative colitis: meta-analysis of six randomized controlled trials

AIM

The diagnostic accuracy of chromoendoscopy for dysplasia in ulcerative colitis (UC) was systematically evaluated.

METHOD

  Original studies in any language were searched from PubMed and Embase. Meta-analysis of prospective studies that compared chromoendoscopy with histological diagnosis was carried out. Sensitivity, specificity, and diagnostic odds ratio (DOR) were calculated for each study and pooled together; summary receiver operating characteristic (ROC) and subgroup analyses were performed, while the quality of the study and heterogeneity were assessed.

RESULTS

Six randomized controlled trials were included, which used methylene blue or indigo carmine dye spray. The meta-analysis demonstrated a pooled sensitivity of 83.3% (95% confidence interval (CI), 35.9-99.6%), specificity of 91.3% (95% CI, 43.8-100%), and DOR of 17.544 (95% CI, 1.245-247.14). Subgroup analyses revealed that both the methylene blue dye spray subgroup and the unspecified endoscopist subgroup include the same studies, and their pooled sensitivity and specificity were 0.737 and 0.917, respectively. The other subgroup, which used indigo carmine dye spray, had overall higher sensitivity (0.930) and lower specificity (0.910).

CONCLUSION

Chromoendoscopy has medium to high sensitivity and a high diagnostic accuracy for dysplastic lesions in UC.

Recent advancement of observing living cells in the esophagus using CM double staining: endocytoscopic atypia classification

Magnification endoscopy enables in vivo evaluation of gastrointestinal mucosa. Furthermore, endocytoscopy (ECS) with ultra-high magnification enables in vivo observation of cellular atypia during routine endoscopic examination. The purpose of this study is to clarify the efficacy of ECS and endocytoscopic atypia (ECA) classification in various types of benign and malignant pathology in the esophagus. Consecutive 110 patients, who underwent ECS in our institution from March 2003 to December 2009, were included in this study. One hundred and forty-six esophageal lesions were classified according to ECA classification, and these endocytoscopic images were compared with histological images. We categorized endocytoscopic images into five categories according to size and uniformity of nuclei, number of cells and regularity of cellular arrangement. Eighty-one out of 89 ECA-1 to ECA-3 lesions (91.0%) corresponded to Vienna categories 1 to 3. Seventy-one out of 84 ECA-4 or ECA-5 lesions (91.2%) corresponded to Vienna category 4 or 5. Overall accuracy of ECS was 91.3%, providing images similar to conventional hematoxylin and eosin staining. In addition, with ECS, we can take an 'optical biopsy' even in patients with cardiovascular disease without interrupting anticoagulant therapy. A newly designed single charge-coupled device endocytoscope allows observation of target tissue noninvasibly from regular magnification to ultra-high magnification. The development of ECS has opened the door to in vivo cellular imaging, enabling endoscopic diagnosis of tissue cytological atypia during routine endoscopic examination.

Magnifying endoscopy in upper gastroenterology for assessing lesions before completing endoscopic removal

Any prognosis of gastrointestinal (GI) cancer is closely related to the stage of the disease at diagnosis. Endoscopic submucosal dissection (ESD) and en bloc endoscopic mucosal resection (EMR) have been performed as curative treatments for many early-stage GI lesions in recent years. The technologies have been widely accepted in many Asian countries because they are minimally invasive and supply thorough histopathologic evaluation of the specimens. However, before engaging in endoscopic therapy, an accurate diagnosis is a precondition to effecting the complete cure of the underlying malignancy or carcinoma in situ. For the past few years, many new types of endoscopic techniques, including magnifying endoscopy with narrow-band imaging (ME-NBI), have emerged in many countries because these methods provide a strong indication of early lesions and are very useful in determining treatment options before ESD or EMR. However, to date, there is no comparable classification equivalent to “Kudo’s Pit Pattern Classification in the colon”, for the upper GI, there is still no clear internationally accepted classification system of magnifying endoscopy. Therefore, in order to help unify some viewpoints, here we will review the defining optical imaging characteristics and the current representative classifications of microvascular and microsurface patterns in the upper GI tract under ME-NBI, describe the accurate relationship between them and the pathological diagnosis, and their clinical applications prior to ESD or en bloc EMR. We will also discuss assessing the differentiation and depth of invasion, defying the lateral spread of involvement and targeting biopsy in real time.

Advances in endoscopic diagnosis of early esophageal cancer

Esophageal cancer is one of the most common malignancies in China. The prognosis of esophageal carcinoma is closely related to the stage of the disease at the time of detection. Patients with early lesions have an excellent prognosis, whereas those with more advanced stages of the disease usually have a poor prognosis. Therefore, the early detection of these lesions is of the greatest importance for treatment. Recently, many endoscopic methods have been developed, such as fluorescence endoscopy, confocal endoscopy, optical coherence tomography (OCT), and electronic staining imaging technology which includes narrow band imaging (NBI), Fujinon intelligent chromoendoscopy (FICE) and I-Scan. However, the clinical value of these techniques needs to be ascertained in the coming years. This paper reviews the progress of endoscopic diagnosis of early esophageal cancer.

Toluidine blue staining in the diagnosis of endometrial pathologies: a preliminary study before chromohysteroscopy

OBJECTIVE

To assess the efficacy of toluidine blue (TBlue) staining in the detection of endometrial premalignant or malignant lesions in uterine specimens obtained from hysterectomies. We hoped that the results of this preliminary study would help us in our future studies which may be on chromohysteroscopy.

STUDY DESIGN

We developed an endometrium staining technique in which TBlue solution was used as a vital dye. The study enrolled 50 patients. Of these, 20 patients known to have a premalign or malign lesion of the uterus constituted the study group and 30 patients were recruited as the control group who were operated for leiomyoma of the uterus. Immediately after hysterectomy, all specimens were dyed with TBlue solution and a frozen section procedure was performed on the positively stained areas. The pre- and post-operative histopathological diagnoses of the participants were compared and the reliability of the new method was calculated.

RESULTS

The sensitivity of TBlue staining in the determination of endometrial pathologies was 100% (95%, CI 0.83-1) with a specificity of 90% (95%, CI 0.74-0.96). As a diagnostic test, the positive predictive value (PPV) was 87% with a negative predictive value (NPV) of 100%. The positive likelihood ratio (+LR) was 10 (95%, CI 3.41-29.2).

CONCLUSIONS

Our preliminary results demonstrated that TBlue staining of endometrium is a reliable and highly sensitive technique that may be used in the frozen section examination of uterine specimens if a malignancy is suspected. Moreover, TBlue staining of endometrium may prove useful in hysteroscopy, although the technique, interpretation, and indications require further studies.

Predictability of Gastric Intestinal Metaplasia by Mottled Patchy Erythema Seen on Endoscopy

BACKGROUND

Intestinal metaplasia (IM) is regarded as a premalignant lesion. However, endoscopic diagnosis of IM has been considered difficult. Using endoscopy, we found a unique pattern of erythema, "Mottled Patchy Erythema (MPE)," which includes severe IM. Helicobacter pylori (Hp) infection itself can cause erythema, which reflects histologic changes in the gastric mucosa. Therefore we enrolled Hp eradication patients to validate the relation between MPE and pathologic findings.

METHODS

We enrolled patients with chronic gastritis who underwent successful Hp eradication at least 6 months before the study. We defined MPE as multiple flat or depressed erythematous lesions. When encountering MPE on endoscopy, we performed biopsy on both the MPE site and non-MPE site. The non-MPE site was defined as an adjacent mucosa located within 3 cm of the MPE site. All biopsy specimens were evaluated immunohistochemically for IM subtype using MUC2, MUC5AC, MUC6, CD10, and CDX2 stains. The degree of IM was defined according to the Updated Sydney System. The diagnostic accuracy of the MPE findings for pathologic IM was calculated. The relation between MPE and IM subtype was also assessed.

RESULTS

A total of 102 patients were selected for the study. Of these, 55 (54%) patients had MPE. Biopsy specimens were taken from the MPE sites and non-MPE sites from these 55 patients. The IM percentages and median scores of IM were both significantly higher at the MPE sites (P < 0.001) than at the non-MPE sites. The sensitivity and specificity for MPE in the detection of histologic IM were 72.7% and 84.1%, respectively. No significant associations were observed in the expression of MUC2, MUC5AC, MUC6, CD10, and CDX2 between the MPE sites and non-MPE sites. There were no significant differences in the ratios (complete/incomplete) of IM subtypes between the two groups.

CONCLUSIONS

MPE is a useful endoscopic finding to detect histologic IM without the use of chromoendoscopy and magnifying endoscopy. However, the IM subtype is difficult to identify. In the era of Hp eradication, MPE has the potential to become a predictive finding for the risk of gastric cancer.

Enhanced endoscopic imaging and gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) and GERD-related symptoms are common, and affect 25% to 30% of the general population. Upper gastrointestinal endoscopy of the esophagus has been the most widely used modality for the diagnosis and grading of reflux disease. Endoscopic imaging today has evolved beyond the confines of routine white light endoscopy (WLE) to advanced optical imaging with a precise and real time endoscopic diagnosis. These technological advances have helped circumvent the limitation of WLE in reflux disease by a) improved detection of subtle irregularities, b) characterization of anomalies, and c) possible optical biopsies providing real-time diagnosis. This review attempts to define the current status of these newer technologies vis-a-vis the diagnosis and management of gastroesophageal reflux disease.

Cancer surveillance strategies in ulcerative colitis: the need for modernization

The risk of colorectal cancer is increased in patients with long-standing ulcerative colitis. Traditional surveillance has centered around regular standard white-light colonoscopy, with multiple biopsies aimed at detecting dysplasia or the identification of early cancer. This has resulted in only a modest reduction in cancer incidence and mortality. A better understanding of disease risk factors may allow endoscopic resources to be more focused on patients at higher risk. In addition, advanced endoscopic techniques have the potential to improve dysplasia detection, minimize the need for routine biopsies, and allow for the removal of dysplastic lesions, avoiding the need for surgery. Techniques such as magnification colonoscopy, chromoendoscopy, narrow band imaging, autofluorescence, and confocal endomicroscopy may all have a role to play in improving the benefits of endoscopic surveillance. Revised endoscopic surveillance strategies are proposed, incorporating aspects of risk stratification, a well-established practice in noncolitis-related colorectal cancer screening, and some of these new technologies.

Current status of chromoendoscopy and narrow band imaging in colonoscopy

Colonoscopy, the preferred procedure for colon cancer screening, has well-documented limitations. To improve colonoscopy's effectiveness, augmented endoscopy techniques, such as chromoendoscopy and narrow band imaging (NBI) have been evaluated. Both techniques are inexpensive, safe, and relatively easy to perform. Chromoendoscopy has an increasingly important role in surveillance of IBD, but significant work is needed to determine the optimal staining techniques and mucosal surface pattern analysis before this technique can be incorporated into routine clinical practice. NBI is a much newer technology with far less data. Well-designed prospective randomized controlled trials have failed to identify a benefit of NBI in screening colonoscopy, in surveillance for high-risk populations or as an adjunct for therapeutic procedures.

Role of narrow band imaging in Barrett's esophagus

The present recommended strategy for detection of dysplasia and cancer in Barrett's esophagus is by randomly carrying out four quadrant biopsies every 2 cm. This approach is however prone to sampling error. Narrow band imaging has been routinely available for clinical use for more than half a decade now. This review will focus on the available data to date on the role of narrow band imaging in the detection and characterization of specialized intestinal metaplasia, high grade dysplasia and intramucosal cancer in Barrett's esophagus.

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

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

[Endoscopic technique in endobrachyoesophagus diagnosis: Chromoendoscopy and acetic acid]

Screening for complications of neoplastic Barrett's oesophagus requires a tedious blind standardized protocol biopsies quadrant every 1 to 2cm depending on the morphology of the Barrett's epithelium (Protocol of Seattle). To achieve that biopsies targeted to areas suspicious of dysplasia, a method of high sensitivity is required. Chromoendoscopy has been developed in this direction. Acetic acid combined with high resolution endoscopy and zooming represents an aid in the preparation of the oesophageal mucosa for visualization of suspicious anomalies. It is safe, cheap and easy to use. Acetic acid has proven its value in improving the visibility of the pit pattern. Several vital dyes have been tested, including methylene blue, indigo carmine and crystal violet, with mixed results. The FICE(®) and NBI(®), immediate, reversible and attractive virtual chromoendoscopy techniques represent interesting tools for improving sensitivity in screening for Barrett's oesophagus and its complications. Confocal endomicroscopy, which is similar as a "per-endoscopic real time histological examination", seems to be equally a promising technique in detection of Barrett's oesophagus associated neoplasia. But these tools which are capable of improvement so far, have not proved their use on a large population. For this, the systematic biopsy protocol Seattle remains the "gold standard" in monitoring the Barrett's oesophagus.

Non-sequential narrow band imaging for targeted biopsy and monitoring of gastric intestinal metaplasia

AIM: To evaluate the efficacy of non-sequential narrow band imaging (NBI) for a better recognition of gastric intestinal metaplasia (GIM).

METHODS: Previously diagnosed GIM patients underwent targeted biopsy from areas with and without GIM, as indicated by NBI, twice at an interval of 1 year. The authors compared the endoscopic criteria such as light blue crest (LBC), villous pattern (VP), and large long crest (LLC) with standard histology. The results from two surveillance endoscopies were compared with histology results for sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and likelihood ratio of positive test (LR+). The number of early gastric cancer cases detected was also reported.

RESULTS: NBI targeted biopsy was performed in 38 and 26 patients during the first and second surveillance endoscopies, respectively. There were 2 early gastric cancers detected in the first endoscopy. No cancer was detected from the second study. Surgical and endoscopic resections were successfully performed in each patient. Sensitivity, specificity, PPV, NPV, and LR+ of all 3 endoscopic criteria during the first/second surveillances were 78.8%/91.3%, 82.5%/89.1%, 72.8%/77.8%, 86.8%/96.1, and 4.51/8.4, respectively. LBC provided the highest LR+ over VP and LLC.

CONCLUSION: Non-sequential NBI is useful for GIM targeted biopsy. LBC provides the most sensitive reading. However, the optimal duration between two surveillances requires further study.