Endoscopic imaging for the detection of esophageal dysplasia and carcinoma

Diagnostic tests for preoperative staging of esophagogastric junction tumors: performance and evidence-based recomendations

Preoperative clinical staging is critical to select those patients whose disease is localized and may benefit from surgery with curative intent. Ideally, such staging should predict tumor invasion, lymphatic involvement and distant metastases. With the cTNM, we are able to select patients who could benefit from endoscopic resection, radical surgery or less radical treatment in patients with distant metastasis. The initial diagnosis of adenocarcinomas of the esophagogastric junction requires endoscopy with biopsies. For clinical staging, thoracoabdominal-pelvic CT scan, endoscopic ultrasound and PET or PET/CT are used. Other useful explorations are: barium swallow, endoscopic mucosal resection or endoscopic submucosal dissection (for assessment in initial stages) and staging laparoscopy. Once the resectability of the tumor has been established, the operability of the tumor should be assessed according to the patient's condition.

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.

Characterization of eosinophilic esophagitis murine models using optical coherence tomography

Pre-clinical studies using murine models are critical for understanding the pathophysiological mechanisms underlying immune-mediated disorders such as Eosinophilic esophagitis (EoE). In this study, an optical coherence tomography (OCT) system capable of providing three-dimensional images with axial and transverse resolutions of 5 µm and 10 µm, respectively, was utilized to obtain esophageal images from a murine model of EoE-like disease ex vivo. Structural changes in the esophagus of wild-type (Tslpr(+/+) ) and mutant (Tslpr(-/-) ) mice with EoE-like disease were quantitatively evaluated and food impaction sites in the esophagus of diseased mice were monitored using OCT. Here, the capability of OCT as a label-free imaging tool devoid of tissue-processing artifacts to effectively characterize murine EoE-like disease models has been demonstrated.

Optical molecular imaging in the gastrointestinal tract

Recent developments in optical molecular imaging allow for real-time identification of morphologic and biochemical changes in tissue associated with gastrointestinal neoplasia. This review summarizes widefield and high-resolution imaging modalities in preclinical and clinical evaluation for the detection of colorectal cancer and esophageal cancer. Widefield techniques discussed include high-definition white light endoscopy, narrow band imaging, autofluoresence imaging, and chromoendoscopy; high-resolution techniques discussed include probe-based confocal laser endomicroscopy, high-resolution microendoscopy, and optical coherence tomography. New approaches to enhance image contrast using vital dyes and molecular-specific targeted contrast agents are evaluated.

Chromoendoscopy to detect early synchronous second primary esophageal carcinoma in patients with squamous cell carcinomas of the head and neck?

Objective. To evaluate the use of flexible esophagoscopy and chromoendoscopy with Lugol's solution in the detection of early esophageal carcinomas (second primary carcinomas) in patients with squamous cell carcinoma of the head and neck (HNSCC). Methods. All patients with newly diagnosed HNSCC underwent office-based Lugol's chromoendoscopy. After flexible esophagoscopy with white light, 3.0% Lugol's iodine solution was sprayed over the entire esophageal mucosa. Areas with less-intense staining (LVLs) were evaluated and biopsies taken. Results. 132 patients with HNSCC were enrolled in this study. The most frequent primary tumors were oropharyngeal (49/132), tumors of the oral cavity (36/132), and larynx (35/132). The majority of subjects (107/132 patients, 81.1%) had advanced HNSCC carcinomas (stages III and IV). Multiple LVLs were discovered in 24 subjects (18.2%) and no LVLs in 108 (81.8%) subjects. Fifty-five LVL biopsy specimens were obtained and assessed. Squamous cell carcinomas were detected in two patients, peptic esophagitis in 11 patients, gastric heterotopic mucosa in two patients, hyperplasia in two patients, and low- and high-grade dysplasia in three patients. Conclusion. Although only two patients with synchronous primary carcinomas were found among the patients, esophagoscopy should be recommended after detection of HNSCC to exclude secondary esophageal carcinoma or dysplasia.

Management strategies of Barrett's esophagus

Barrett’s esophagus is a condition resulting from chronic gastro-esophageal reflux disease with a documented risk of esophageal adenocarcinoma. Current strategies for improved survival in patients with Barrett's adenocarcinoma focus on detection of dysplasia. This can be obtained by screening programs in high-risk cohorts of patients and/or endoscopic biopsy surveillance of patients with known Barrett’s esophagus (BE). Several therapies have been developed in attempts to reverse BE and reduce cancer risk. Aggressive medical management of acid reflux, lifestyle modifications, antireflux surgery, and endoscopic treatments have been recommended for many patients with BE. Whether these interventions are cost-effective or reduce mortality from esophageal cancer remains controversial. Current treatment requires combinations of endoscopic mucosal resection techniques to eliminate visible lesions followed by ablation of residual metaplastic tissue. Esophagectomy is currently indicated in multifocal high-grade neoplasia or mucosal Barrett’s carcinoma which cannot be managed by endoscopic approach.

Current treatment options for the management of esophageal cancer

In recent years, esophageal cancer characteristics and management options have evolved significantly. There has been a sharp increase in the frequency of esophageal adenocarcinoma and a decline in the frequency of squamous cell carcinoma. A more comprehensive understanding of prognostic factors influencing outcome has also been developed. This has led to more management options for esophageal cancer at all stages than ever before. A multidisciplinary, team approach to management in a high volume center is the preferred approach. Each patient should be individually assessed based on type of cancer, local or regional involvement, and his or her own functional status to determine an appropriate treatment regimen. This review will discuss management of esophageal cancer relative to disease progression and patient functional status.

Affinity peptide developed by phage display selection for targeting gastric cancer

AIM: To develop an affinity peptide that binds to gastric cancer used for the detection of early gastric cancer.

METHODS: A peptide screen was performed by biopanning the PhD-12 phage display library, clearing non-specific binders against tumor-adjacent normal appearing gastric mucosa and obtaining selective binding against freshly harvested gastric cancer tissues. Tumor-targeted binding of selected peptides was confirmed by bound phage counts, enzyme-linked immunosorbent assay, competitive inhibition, fluorescence microscopy and semi-quantitative analysis on immunohistochemistry using different types of cancer tissues.

RESULTS: Approximately 92.8% of the non-specific phage clones were subtracted from the original phage library after two rounds of biopanning against normal- appearing gastric mucosa. After the third round of positive screening, the peptide sequence AADNAKTKSFPV (AAD) appeared in 25% (12/48) of the analyzed phages. For the control peptide, these values were 6.8 ± 2.3, 5.1 ± 1.7, 3.5 ± 2.1, 4.6 ± 1.9 and 1.1 ± 0.5, respectively. The values for AAD peptide were statistically significant (P < 0.01) for gastric cancer as compared with other histological classifications and control peptide.

CONCLUSION: A novel peptide is discovered to have a specific binding activity to gastric cancer, and can be used to distinguish neoplastic from normal gastric mucosa, demonstrating the potential for early cancer detection on endoscopy.

Comprehensive volumetric confocal microscopy with adaptive focusing

Comprehensive microscopy of distal esophagus could greatly improve the screening and surveillance of esophageal diseases such as Barrett's esophagus by providing histomorphologic information over the entire region at risk. Spectrally encoded confocal microscopy (SECM) is a high-speed reflectance confocal microscopy technology that can be configured to image the entire distal esophagus by helically scanning the beam using optics within a balloon-centering probe. It is challenging to image the human esophagus in vivo with balloon-based SECM, however, because patient motion and anatomic tissue surface irregularities decenter the optics, making it difficult to keep the focus at a predetermined location within the tissue as the beam is scanned. In this paper, we present a SECM probe equipped with an adaptive focusing mechanism that can compensate for tissue surface irregularity and dynamic focal variation. A tilted arrangement of the objective lens is employed in the SECM probe to provide feedback signals to an adaptive focusing mechanism. The tilted configuration also allows the probe to obtain reflectance confocal data from multiple depth levels, enabling the acquisition of three-dimensional volumetric data during a single scan of the probe. A tissue phantom with a surface area of 12.6 cm(2) was imaged using the new SECM probe, and 8 large-area reflectance confocal microscopy images were acquired over the depth range of 56 μm in 20 minutes. Large-area SECM images of excised swine small intestine tissue were also acquired, enabling the visualization of villous architecture, epithelium, and lamina propria. The adaptive focusing mechanism was demonstrated to enable acquisition of in-focus images even when the probe was not centered and the tissue surface was irregular.

Global epidemiology of Barrett's esophagus

Barrett's esophagus (BE) is defined as a metaplastic change of the distal esophageal epithelium from squamous to columnar type epithelium with the presence of intestinal metaplasia. There is a striking geographic variation in the prevalence rates of BE. Most epidemiological data on BE are derived from patients undergoing endoscopy and do not reflect prevalence rates in the general population. BE is much more common in the West when compared with Asia and Africa. Although BE is less common in Asia, the demographics are similar to the West, being predominantly found in older men with longer duration of reflux symptoms. Some studies from the West have suggested an increase in prevalence rates of BE. An increase in prevalence rates will have significant implications for health resource utilization and costs, due to the small but significant risk of developing esophageal adenocarcinoma. Endoscopic surveillance with the aim of detecting early lesions has been advocated. Compared with conventional white-light endoscopy with blind four-quadrant biopsies, the use of image-enhanced endoscopy, including chromoendoscopy, may improve detection of subtle mucosal irregularities and facilitate targeted biopsies. However, a truly cost-effective surveillance strategy remains to be determined.