Acetic acid chromoendoscopy for the diagnosis of early neoplasia and specialized intestinal metaplasia in Barrett's esophagus: a meta-analysis

A Survey of Expert Practice and Attitudes Regarding Advanced Imaging Modalities in Surveillance of Barrett's Esophagus

BACKGROUND

Published guidelines do not address what the minimum incremental diagnostic yield (IDY) for detection of dysplasia/cancer is required over the standard Seattle protocol for an advanced imaging modality (AIM) to be implemented in routine surveillance of Barrett's esophagus (BE) patients. We aimed to report expert practice patterns and attitudes, specifically addressing the minimum IDY in the use of AIMs in BE surveillance.

METHODS

An international group of BE experts completed an anonymous electronic survey of domains relevant to surveillance practice patterns and use of AIMs. The evaluated AIMs were conventional chromoendoscopy (CC), virtual chromoendoscopy (VC), volumetric laser endomicroscopy (VLE), confocal laser endomicroscopy (CLE), and wide-area transepithelial sampling (WATS3D). Responses were recorded using five-point balanced Likert items and analyzed as continuous variables.

RESULTS

The survey response rate was 84% (61/73)-41 US and 20 non-US. Experts were most comfortable with and routinely use VC and CC, and least comfortable with and rarely use VLE, CLE, and WATS3D. Experts rated data from randomized controlled trials (1.4 ± 0.9) and guidelines (2.6 ± 1.2) as the two most influential factors for implementing AIMs in clinical practice. The minimum IDY of AIMs over standard biopsies to be considered of clinical benefit was lowest for VC (15%, IQR 10-29%) and highest for VLE (30%, IQR 20-50%). Compared to US experts, non-US experts reported higher use of CC for BE surveillance (p < 0.001).

CONCLUSION

These results should inform benchmarks that need to be met for guidelines to recommend the routine use of AIMs in the surveillance of BE patients.

Blue laser imaging with acetic acid enhancement improved the detection rate of gastric intestinal metaplasia

Our aim was to evaluate the ability of blue laser imaging (BLI) combined with acetic acid (BLI-AA) to detect gastric intestinal metaplasia (GIM). Participants undergoing gastroscopy from July 2017 to February 2018 in our hospital were enrolled prospectively. The abilities of white light imaging endoscopy, BLI endoscopy, and BLI-AA to detect GIM were compared. One hundred six patients undergoing gastroscopy met the inclusion criteria. GIM was diagnosed in 41 patients. For BLI-AA, the sensitivity, specificity, positive predictive, and negative predictive values were 85.4%, 84.6%, 77.8%, and 90.2% respectively. The diagnostic accuracy rate for BLI-AA was 84.9%, which was higher than that of white light imaging endoscopy and BLI endoscopy. For target biopsy, the GIM detection rate for the BLI-AA mode was significantly higher (77.8%, 105/135) than that for the BLI mode (58.3%, 84/144) or the white light endoscopy mode (40.4%, 57/141) (p < 0.05). BLI-AA is an efficient and simple method for the detection of GIM.

How to get the most out of costly Barrett's oesophagus surveillance

Current endoscopic surveillance protocols for Barrett's oesophagus have several limitations, mainly the poor cost-effectiveness and high miss rate. However, there is sufficient evidence that patients enrolled in a surveillance program have better survival chances of oesophageal cancer due to earlier tumor stages at diagnosis compared to patients with de novo diagnosed oesophagus cancer. Risk stratifications aim to identify patients at highest risk of developing adenocarcinoma of the oesophagus; most of them base on the length of the Barrett's segment and the presence of dysplasia. This review discusses prognostic factors and provides practical guidance on how to improve the efficacy and outcome in Barrett's surveillance programs.

How Should We Report Endoscopic Results in Patient's with Barrett's Esophagus?

Barrett's esophagus is the only known pre-cancerous lesion for esophageal adenocarcinoma and is diagnosed by high-definition white light endoscopy demonstrating a columnar-lined esophagus along with biopsy evidence of intestinal metaplasia. With accurate performance and reporting of the endoscopic procedure, an evidence-based management strategy can be developed for treatment of Barrett's dysplasia. However, cross-sectional data demonstrate that there is still inconsistency among gastroenterologists in performance and reporting of endoscopic findings in patients with Barrett's esophagus. Here, we present an evidence-based review of how to report endoscopic findings in Barrett's esophagus.

Emerging optical methods for endoscopic surveillance of Barrett's oesophagus

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

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

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Development of Image-enhanced Endoscopy of the Gastrointestinal Tract: A Review of History and Current Evidences

Endoscopy imaging of the gastrointestinal (GI) tract has evolved tremendously over the last few decades. Key milestones in the development of endoscopy imaging include the use of various dyes for chromoendoscopy, the application of optical magnification in endoscopy, the introduction of high-definition image capturing and display technology and the application of altered illuminating light to achieve vascular and surface enhancement. Aims of this review paper are to summarize the development and evolution of modern endoscopy imaging and in particular, imaged-enhanced endoscopy (IEE), to promote appropriate usage, and to guide future development of good endoscopy practice. A search of PubMed database was performed to identify articles related to IEE of the GI tract. Where appropriate, landmark trials and high-quality meta-analyses and systematic reviews were used in the discussion. In this review, the developments and evolutions in endoscopy imaging and in particular, IEE, were summarized into discernible eras and the literature evidence with regard to the strengths and weaknesses in term of their detection and characterization capability in each of these eras were discussed. It is in the authors' opinion that IEE is capable of fairly good detection and accurate characterization of various GI lesions but such benefits may not be readily reaped by those who are new in the field of luminal endoscopy. Exposure and training in making confident diagnoses using these endoscopy imaging technologies are required in tandem with these new developments in order to fully embrace and adopt the benefits.

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

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

Endoscopic treatment for Barrett's oesophagus dysplasia and early cancer

Endoscopic treatment of early Barrett's oesophagus neoplasia is now proven to be a safe and effective alternative to oesophagectomy. An ideal candidate for endoscopic treatment should have dysplasia or carcinoma limited to the mucosa or superficial submucosa without lymphovascular invasion or poor differentiation. Two main types of endoscopic therapies are used: (1) endoscopic resection, which comprises of endoscopic mucosal resection or endoscopic submucosal dissection for removal of visible lesions en bloc and (2) endoscopic ablation utilising argon plasma coagulation, radiofrequency ablation or, more recently, cryotherapy. Although endoscopic resection is the cornerstone for Barrett's endotherapy, ablative techniques are complementary in achieving complete eradication of the columnar epithelium and dysplasia.

Endoscopic management of Barrett's and early oesophageal neoplasia

Barrett's oesophagus (BO) is the only known precursor to oesophageal adenocarcinoma (OAC). Dysplasia and intramucosal cancer arising in BO can safely be treated with endoscopic eradication therapy (EET) due to the low risk of subsequent lymph node metastasis. Treatment at an early stage is paramount due to the ongoing poor prognosis and outcomes of patients with advanced OAC. The mainstay of treatment is endoscopic resection of visible lesions for accurate staging followed by ablation therapy to all remaining columnar-lined epithelium, most commonly with radiofrequency ablation. Successful eradication of dysplasia can be achieved in >95% of patients with this EET combined approach.

Role of endoscopy in early oesophageal cancer

Incidence of oesophageal adenocarcinoma has increased exponentially in the West over the past few decades. Following detection of advanced cancers, 5-year survival rates remain bleak, making identification of early neoplasia, which has a better outcome, important. Detection of subtle oesophageal lesions during endoscopy can be challenging, and advanced imaging techniques might improve their detection. High-definition endoscopy has become a standard in most endoscopy centres, and this technology probably provides better delineation of mucosal features than standard-definition endoscopy. Various image enhancement techniques are now available with the development of new electronics and software systems. Image enhancement with chromoendoscopy using dyes has been a cost-effective option for many years, yet these techniques have been replaced in some contexts by electronic chromoendoscopy, which can be used with the press of a button. However, Lugol's chromoendoscopy remains the gold standard to identify squamous dysplasia. Identification and characterization of subtle neoplastic lesions could help to target biopsies and perform endoscopic resection for better local staging and definitive therapy. In vivo histology with techniques such as confocal endomicroscopy could make endotherapy feasible within a shorter timescale than when relying on histology on tissue samples. Once early neoplasia is identified, treatments include endoscopic resection, endoscopic submucosal dissection or various ablative techniques. Endotherapy has the advantage of being a less invasive technique than oesophagectomy, and is associated with lower mortality and morbidity. Endoscopic ablation therapies have evolved over the past few years, with radiofrequency ablation showing the best results in terms of success rates and complications in Barrett dysplasia.

Acetic acid chromoendoscopy: Improving neoplasia detection in Barrett's esophagus

Barrett’s esophagus (BE) is an important condition given its significant premalignant potential and dismal five-year survival outcomes of advanced esophageal adenocarcinoma. It is therefore suggested that patients with a diagnosis of BE undergo regular surveillance in order to pick up dysplasia at an earlier stage to improve survival. Current “gold-standard” surveillance protocols suggest targeted biopsy of visible lesions followed by four quadrant random biopsies every 2 cm. However, this method of Barrett’s surveillance is fraught with poor endoscopist compliance as the procedures are time consuming and poorly tolerated by patients. There are also significant miss-rates with this technique for the detection of neoplasia as only 13% of early neoplastic lesions appear as visible nodules. Despite improvements in endoscope resolution these problems persist. Chromoendoscopy is an extremely useful adjunct to enhance mucosal visualization and characterization of Barrett’s mucosa. Acetic acid chromoendoscopy (AAC) is a simple, non-proprietary technique that can significantly improve neoplasia detection rates. This topic highlight summarizes the current evidence base behind AAC for the detection of neoplasia in BE and provides an insight into the direction of travel for further research in this area.

Radiofrequency ablation for low-grade dysplasia in Barrett's esophagus

PURPOSE OF REVIEW

The diagnosis and management of low-grade dysplasia (LGD) in Barrett's esophagus continue to evolve and vary in practice. Radiofrequency ablation (RFA) is now an acceptable option for the treatment of LGD. Therefore, the purpose of this review article is to present current literature on the diagnosis and management of LGD, and to explore when to optimally pursue RFA for the treatment of LGD.

RECENT FINDINGS

The challenge of the management of LGD begins with its diagnosis. Because of high interobserver variability among pathologists in the diagnosis of dysplasia, it is recommended that an expert gastrointestinal pathologist confirms the diagnosis of LGD. Endoscopic mucosal resection is indicated to remove visible lesions in the setting of dysplasia to obtain an accurate diagnosis, especially regarding T staging. Management options include intense surveillance and endoscopic eradication therapy. RFA provides a reasonable method to eradicate flat Barrett's mucosa. Endoscopic eradication of confirmed LGD has been demonstrated to reduce the risk of progression to esophageal cancer. Additional data about the risk factors associated with progression, and the benefits and risks of treatment are discussed, and can be incorporated in patient counseling and decision making.

SUMMARY

Endoscopic eradication therapy with RFA may be an appropriate treatment option for LGD in Barrett's esophagus after the benefits and risks have been discussed in detail with the patient.