Usefulness of cytopathology and histology in the evaluation of Barrett's esophagus in a community hospital

Towards screening Barrett's oesophagus: current guidelines, imaging modalities and future developments

Barrett's oesophagus is the only known precursor to oesophageal adenocarcinoma (OAC). Although guidelines on the screening and surveillance exist in Barrett's oesophagus, the current strategies are inadequate. Oesophagogastroduodenoscopy (OGD) is the gold standard method in screening for Barrett's oesophagus. This invasive method is expensive with associated risks negating its use as a current screening tool for Barrett's oesophagus. This review explores current definitions, epidemiology, biomarkers, surveillance, and screening in Barrett's oesophagus. Imaging modalities applicable to this condition are discussed, in addition to future developments. There is an urgent need for an alternative non-invasive method of screening and/or surveillance which could be highly beneficial towards reducing waiting times, alleviating patient fears and reducing future costs in current healthcare services. Vibrational spectroscopy has been shown to be promising in categorising Barrett's oesophagus through to high-grade dysplasia (HGD) and OAC. These techniques need further validation through multicentre trials.

Barrett's esophagus: novel strategies for screening and surveillance

Barrett’s esophagus is the precursor lesion for esophageal adenocarcinoma. Screening and surveillance of Barrett’s esophagus are undertaken with the goal of earlier detection and lowering the mortality from esophageal adenocarcinoma. The widely used technique is standard esophagogastroduodenoscopy with biopsies per the Seattle protocol for screening and surveillance of Barrett’s esophagus. Surveillance intervals vary depending on the degree of dysplasia with endoscopic eradication therapy confined to patients with Barrett’s esophagus and confirmed dysplasia. In this review, we present various novel techniques for screening of Barrett’s esophagus such as unsedated transnasal endoscopy, cytosponge with trefoil factor-3, balloon cytology, esophageal capsule endoscopy, liquid biopsy, electronic nose, and oral microbiome. In addition, advanced imaging techniques such as narrow band imaging, dye-based chromoendoscopy, confocal laser endomicroscopy, volumetric laser endomicroscopy, and wide-area transepithelial sampling with computer-assisted three-dimensional analysis developed for better detection of dysplasia are also reviewed.

Role of cytopathology in the diagnosis and management of gastrointestinal tract cancers

Cytology of gastro-intestinal (GI) tract lesions can be used successfully to diagnose neoplastic and non-neoplastic conditions, especially when combined with biopsies. Cytologic evaluation is widely accepted as a cost-effective method that allows rapid interpretation and triaging of material. Technical advances over the years have allowed simultaneous visualization of abnormal tissue and procurement of needle aspirates, brushings and biopsies from mucosal and deeper seated lesions. Successful cytologic examination of the GI tract is highly dependent on the skill of the endoscopist, specimen preparation, the expertise of the pathologist, and the recognition of the limitations of cytology. This article reviews the key cytologic features of important GI tract lesions, differential diagnoses, and pitfalls, and addresses the advantages and limitations of different collection techniques.

Relevance of the detection of intestinal metaplasia in non-dysplastic columnar-lined oesophagus

OBJECTIVE

In the USA, detection of intestinal metaplasia is a requirement for enrollment in surveillance programmes for dysplasia or adenocarcinoma in columnar-lined oesophagus. In the UK, it is believed that failure to detect intestinal metaplasia at index endoscopy does not imply its absence within the columnarized segment or that the tissue is not at risk of neoplastic transformation. The aim of this study was to investigate the factors predicting the probability of detection of intestinal metaplasia in the columnarized segment.

MATERIAL AND METHODS

Demonstration of intestinal metaplasia was analysed in 3568 biopsies of non-dysplastic columnar-lined oesophagus from 1751 patients from 7 centres in the UK. Development of dysplasia and adenocarcinoma was analysed in 322 patients without intestinal metaplasia and compared with that in 612 patients with intestinal metaplasia.

RESULTS

Intestinal metaplasia was more commonly detected in males than in females (odds ratio 1.244), longer segment length (10.3% increase per centimetre) and increasing number of biopsies taken (24% increase per unit increase). After 5 years of follow-up, 54.8% of patients without intestinal metaplasia at index endoscopy demonstrated intestinal metaplasia, and 90.8% after 10 years. There was no significant difference in the rate of development of dysplasia or adenocarcinoma between patients with or without intestinal metaplasia detection at index endoscopy.

CONCLUSIONS

Detection of intestinal metaplasia is subject to significant sampling error. It increases with segment length and number of biopsies taken. In the majority of patients, if sufficient biopsies are taken over time, intestinal metaplasia will be demonstrated. The decision to offer surveillance should not be based upon the presence or absence of intestinal metaplasia at index endoscopy as the risk of dysplasia and adenocarcinoma is similar in both groups.

Gastrointestinal tract cytology: advancing horizons

Tide and ebb of interest in gastrointestinal tract cytology has followed technical advances in this field over the last 60 years. Cytologic samples can be obtained using gastric lavage, abrasive balloons, mucosal brushing, and fine needle aspiration (under percutaneous image guidance, endoscope and endoscopic ultrasound guidance). These advances now allow simultaneous performance of brushing the abnormal mucosa, obtaining fine needle aspirates and excising mucosal biopsy samples for evaluation. Use of endoscopic ultrasound guided fine needle aspirates now help to obtain diagnosis of submucosal lesions, preoperative staging of gastrointestinal tract malignancies and help determine further management of patients. Such advances have brought pathologists to the forefront of the patient management team for the treatment of gastrointestinal tract lesions. This manuscript reviews the advantages and limitations of each cytology associated technique as well as reviews the salient diagnostic features, differential diagnosis and diagnostic pitfalls of gastrointestinal tract lesions. Finally, it suggests the modalities best suited to obtain diagnosis for various gastrointestinal tract lesions.

Cytology in Barrett's esophagus

Brush cytology is complementary to endoscopic biopsy and is recommended by some to be part of the routine endoscopic surveillance of patients with BE. Advantages of cytology include the ability to sample a greater area of involved epithelium, preferential exfoliation of the less cohesive dysplastic cells, simplicity, and lower cost. There are clear cytologic criteria for dysplasia, and biomarker studies can be performed on cytologic specimens. Despite these advantages, cytology is used by only 17% of gastroenterologists in the United States today. Limited data are available on the usefulness of cytology in the diagnosis and surveillance of BE. Cytology has good sensitivity for the detection of adenocarcinoma and HGD and good specificity for the detection of IM without dysplasia. Furthermore, cytology may detect abnormalities missed by biopsy. Cytology has problems in the detection of LGD, however. For cytology to become a useful surveillance option, its sensitivity for low-grade lesions must be improved. One potential way to accomplish this is to add biomarkers to routine cytologic specimens to define patients at increased risk of progression to cancer. If simple prognostic biomarkers could be developed and validated in histology and cytologic specimens, this would provide additional support for the utility of cytologic brushings in the surveillance of BE. Cytology could then conceivably accomplish the goals of improved efficiency, risk stratification, and decreased costs in BE surveillance programs.

Screening for esophageal adenocarcinoma: an evidence-based approach

Adenocarcinoma of the esophagus and the gastroesophageal junction is the twentieth most common malignancy in the United States. In developed countries, the incidence of esophageal adenocarcinoma is increasing 5% to 10% per year. Despite the use of endoscopy for earlier detection, mortality from esophageal adenocarcinoma has not declined. Using an evidence-based approach, we review screening methods for esophageal adenocarcinoma, including the use of a symptom questionnaire, identification of patients with a family history of Barrett's esophagus, peroral or transnasal endoscopy, barium swallow, fecal occult blood testing, and brush and balloon cytology. Screening has not been shown to reduce rate of progression of Barrett's esophagus to esophageal cancer. Many treatment options for dysplastic Barrett's esophagus or early carcinoma appear effective, but long-term follow-up data are not available. There is currently insufficient evidence supporting population-based screening for Barrett's esophagus. Several risk factors, including severe reflux symptoms, male sex, and obesity, may identify patients with gastroesophageal reflux disease who are at the greatest risk of the development of cancer.

Barrett's esophagus

Barrett's esophagus is an acquired condition resulting from severe esophageal mucosal injury. It still remains unclear why some patients with gastroesophageal reflux disease develop Barrett's esophagus whereas others do not. The diagnosis of Barrett's esophagus is established if the squamocolumnar junction is displaced proximal to the gastroesophageal junction and if intestinal metaplasia is detected by biopsy. Despite this seemingly simple definition, diagnostic inconsistencies remain a problem, especially in distinguishing short segment Barrett's esophagus from intestinal metaplasia of the gastric cardia. Barrett's esophagus would be of little importance were it not for its well-recognized association with adenocarcinoma of the esophagus. The incidence of esophageal adenocarcinoma continues to increase and the 5-year survival rate for this cancer remains dismal. However, cancer risk for a given patient with Barrett's esophagus is lower than previously estimated. Current strategies for improved survival in patients with esophageal adenocarcinoma focus on cancer detection at an early and potentially curable stage. This can be accomplished either by screening more patients for Barrett's esophagus or with endoscopic surveillance of patients with known Barrett's esophagus. Current screening and surveillance strategies are inherently expensive and inefficient. New techniques to improve the efficiency of cancer surveillance are evolving rapidly and hold the promise to change clinical practice in the future. Treatment options include aggressive acid suppression, antireflux surgery, chemoprevention, and ablation therapy, but there is still no clear consensus on the optimal treatment for these patients.

Endoscopy in Barrett's esophagus. Surveillance during reflux management and new advances in the diagnosis and early detection of dysplasia

Given the alarming rise in the incidence of esophageal cancer and the fact that Barrett's esophagus is clearly a precursor to this disease, effective surveillance is desirable. Endoscopic surveillance is recommended by major endoscopic and gastrointestinal societies based on the available data and hypothetic models suggest that the costs of endoscopic surveillance for Barrett's esophagus may be reasonable when compared with other commonly applied cancer screening strategies. Although, however, most implicated physicians agree that surveillance is warranted, recommended guidelines often are not followed. This occurrence may reflect the importance of some of the practical limitations inherent to carrying out intensive endoscopic biopsy protocols in large numbers of eligible patients. In an effort to improve the surveillance process, several new techniques have been tested and are in development. These techniques are aimed at facilitating the histologic sampling of larger areas of metaplastic epithelium, at better targeting sites more likely to harbor dysplasia and cancer, and at replacing endoscopic biopsies with nonhistologic tissue analysis. Although many of these newer techniques are promising, however, none are currently close to widespread clinical application. The current standard for surveillance remains the use of systematic endoscopic biopsies, with the frequency of surveillance endoscopies determined by the severity of any dysplastic changes that are found. Given the large number of patients that are likely to be eligible for screening and the current constraints in terms of physician availability and health-care resources, endoscopic biopsy will remain the cornerstone of Barrett's esophagus surveillance strategies unless newer alternatives are clearly advantageous in terms of accuracy, cost, availability, and ease of application. In the future, however, advances in techniques for minimally invasive ablation of Barrett's epithelium may make endoscopic surveillance obsolete altogether.

The diagnosis of dysplasia and malignancy in Barrett's oesophagus

Barrett's metaplasia is associated with an increased risk for adenocarcinoma. Adenocarcinoma develops through a multistep process characterized by defects in genes and morphological abnormalities. The early morphological changes of the process are called 'dysplasia'. Dysplasia is defined as an unequivocal neoplastic (premalignant) transformation confined within the basement membrane. For most Western pathologists malignancy is defined as invasion and characterized by a breach through the basement membrane. Japanese pathologists rely on cytological atypia and complex branching of crypts. Cytological and architectural abnormalities allow identification of dysplasia on routinely stained sections. A distinction is made between low- and high-grade dysplasia. The differential diagnosis between low-grade dysplasia and reactive changes can be difficult. Therefore a second opinion is strongly recommended, not only for high-grade dysplasia but also for low-grade. Immunohistochemistry for p53 and flow cytometry for detection of aneuploidy can support the diagnosis. Identification of dysplasia and malignancy depends on the number of biopsy samples examined. The minimum number of biopsies required has not yet been determined and depends partly on the length of the metaplastic segment. It has been proposed to sample with four quadrant biopsies at 20-mm intervals. New endoscopic techniques can increase the diagnostic yield. Endoscopically visible lesions increase the risk of finding malignancy. The time sequence for the progression of dysplasia is not known but progression from low- to high-grade and cancer has been shown to occur over a period of years although it may not be inevitable.