Methylene blue-directed biopsies improve detection of intestinal metaplasia and dysplasia in Barrett's esophagus

Interventional endoscopy in the diagnosis and staging of upper gastrointestinal malignancy

Increased population longevity as well as an emphasis on earlier diagnosis and more effective treatment of cancer have created an environment for new technologies and techniques to flourish. Some of the endoscopic entities discussed in this article have not been fully validated in clinical practice. Innovative spectroscopic modalities hold a great deal of promise, but are years away from general applicability. In contrast, many interventional endoscopic techniques are currently available and confer heightened levels of diagnostic and staging accuracy for gastric and esophageal malignancies. Earlier diagnosis can identify patients who may be eligible for less-invasive treatment options such as EMR. Minimally invasive treatment options and maximum staging accuracy are more important for patients who are marginal surgical candidates and for accurate comparison of clinical trials studying treatment options. Our challenge for the future is to properly integrate these technologic advances with the science of good medical practice.

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.

Appearance and prognosis of dysplasia in Barrett's esophagus

Dysplasia in a patient who has Barrett's esophagus (BE) is the first step in the neoplastic process. The grade of dysplasia correlates with the likelihood of developing adenocarcinoma of the esophagus during follow-up surveillance endoscopy and biopsy. Surveillance intervals are proposed based on the existing data of the likelihood of developing adenocarcinoma. In the future these intervals will be refined as a result of better definition of the risk factors the development of adenocarcinoma of the esophagus. Risk stratification of the individual patients by age, gender, grade of dysplasia, length of BE, length of hiatal hernia, and presence of genetic mutations will be possible.

Comparison of methylene blue-directed biopsies and conventional biopsies in the detection of intestinal metaplasia and dysplasia in Barrett's esophagus: a preliminary study

BACKGROUND

The diagnostic advantage of methylene blue (MB) chromoendoscopy in Barrett's esophagus is unclear.

METHODS

Patients with columnar-lined esophagus (CLE) were enrolled into a prospective, randomized crossover trial of MB-directed biopsy versus conventional biopsy.

RESULTS

Forty-seven patients (19 long-segment CLE; 28 short-segment CLE) were enrolled and underwent MB-directed biopsy. Sensitivity and specificity of MB for specialized intestinal metaplasia were 53% and 51%, respectively. Sensitivity and specificity of MB for dysplasia were 51% and 48%, respectively. Thirty-five patients (15 long-segment CLE; 20 short-segment CLE) completed the crossover trial. Relative frequencies for specialized intestinal metaplasia were 73% and 71% from MB-directed and conventional biopsy specimens, respectively (p = 0.73). Relative frequencies for dysplasia were 20% and 18% from MB-directed and conventional biopsy specimens, respectively (p = 0.65). In patients with long-segment CLE, dysplasia was diagnosed in 10 patients with MB and 7 patients with conventional biopsy methods (p = 0.25). The number of biopsy specimens per EGD was greater with MB, which may have influenced the diagnosis. Histologically, the grade of dysplasia was indefinite/low in nearly all of the dysplastic specimens.

CONCLUSIONS

Results of MB-directed biopsy were similar to conventional biopsy in detecting specialized intestinal metaplasia and indefinite/low-grade dysplasia. MB was not useful in short-segment Barrett's esophagus.

Methylene blue chromoendoscopy for detection of short-segment Barrett's esophagus

BACKGROUND

The yield of intestinal metaplasia (IM) with randomly obtained biopsy specimens in patients with short lengths of columnar-appearing mucosa in the distal esophagus is low (30%-50%). Vital staining would be beneficial if it identified more patients with short-segment Barrett's esophagus (SSBE). Our aim was to compare the confirmation of IM in patients with suspected SSBE (columnar-appearing mucosa <3 cm in length) by using methylene blue (MB)-directed versus random biopsies.

METHODS

Consecutive patients undergoing EGD in whom columnar-appearing mucosa less than 3 cm in length was visualized underwent MB staining. Stained areas within suspected SSBE segments were targeted for biopsies. All biopsy specimens were stained with H & E with alcian blue at pH 2.5 and evaluated by a single pathologist. A historical control group (different from patients undergoing MB staining) consisted of patients with less than 3 cm of columnar-appearing mucosa in whom biopsy specimens were obtained randomly without MB staining.

RESULTS

The MB group included 75 patients (mean age 63.8 +/- 10.9 years) with a mean length of columnar-appearing mucosa of 1.2 cm (range 0.5-2.5 cm). The control group included 83 patients (mean age 60.5 +/- 12.9 years) with a mean length of columnar-appearing mucosa of 1.16 cm (range 0.5-2.5 cm). IM (i.e., confirmed SSBE) was detected in 61% of the MB group versus 42% of the control group (p = 0.0237). Patients in the MB group required significantly fewer biopsies (4.3 +/- 1.5 vs. 5.1 +/- 12.3, p = 0.0162). Confirmation of IM by length was as follows: less than 1 cm (irregular Z line), MB 17.4% versus control 25% (p = 0.73); 1 to less than 2 cm, MB 77% versus control 45% (p = 0.03); 2 to less than 3 cm, MB 90% versus control 58% (p = 0.02).

CONCLUSIONS

MB chromoendoscopy significantly increases the detection of IM and requires fewer biopsies in patients with suspected SSBE with greater than 1 cm of columnar-appearing mucosa. It does not appear to be beneficial in patients with irregular Z lines (<1 cm).

Barrett esophagus

There continues to be great interest in Barrett esophagus, the premalignant lesion for adenocarcinoma of the esophagus and the esophagogastric junction. There were several publications this past year related to the epidemiology, pathogenesis, new methods for detection, biomarkers for stratifying patients by risk, and the treatment of patients with Barrett esophagus. Patients with intestinal metaplasia in short lengths of columnar mucosa in the distal esophagus (ie, short-segment Barrett esophagus) appear to be distinct from those with intestinal metaplasia in the gastric cardia. The reported risk of cancer in patients with Barrett esophagus is probably subject to publication bias, with small series reporting a higher incidence of cancer. New methods for the diagnosis and detection of intestinal metaplasia and dysplasia are being evaluated and may, in future, help in obtaining more accurate screening and more focused surveillance of patients with Barrett esophagus. The validation of biomarkers may help us to risk stratify patients at high risk for cancer development. Endoscopic mucosal resection appears to be a safe and effective technique for the resection and accurate diagnosis of dysplastic or cancerous areas within Barrett esophagus.

Short segment Barrett esophagus and specialized columnar mucosa at the gastroesophageal junction

The rising incidence of adenocarcinoma of the esophagus and the gastric cardia has generated interest in the finding of intestinal metaplasia or specialized columnar mucosa in this location. Short segment Barrett esophagus is defined by the presence of columnar-appearing mucosa in the distal esophagus (<3 cm in length) with intestinal metaplasia on biopsy. In contrast, intestinal metaplasia may also be present if biopsy specimens are obtained from a normal-appearing squamocolumnar junction or from the gastric cardia (ie, immediately below the gastroesophageal junction) in the absence of columnar lining of the distal esophagus. This has been termed cardia intestinal metaplasia, gastroesophageal junction intestinal metaplasia, or specialized columnar mucosa at the gastroesophageal junction. This article reviews the currently available data on these rapidly evolving entities of short segment Barrett esophagus and specialized columnar mucosa at the gastroesophageal junction.

Dysplasia in Barrett's Esophagus

Dysplasia is the most important marker of progression to invasive cancer in Barrett's esophagus. Intensive endoscopic surveillance with biopsy may identify invasive cancer in a patient with high-grade dysplasia (HGD). Close relationship with an experienced gastrointestinal pathologist and thoracic surgeon will improve treatment decisions and patient outcomes. No intervention is required in patients with low-grade dysplasia (LGD); continued surveillance is recommended. Surgical resection is the currently accepted therapy for high-grade dysplasia. Endoscopic ablative therapy remains experimental.