Chromoendoscopy

Early Rectal Cancer and Local Excision: A Narrative Review

A rise in the incidence of early rectal cancer consequent to bowel-screening programs around the world and an increase in the incidence in young adults has led to a growing interest in organ-sparing treatment options. The rectum, being the most distal portion of the large intestine, is a fertile ground for local excision techniques performed with endoscopic or surgical techniques. Moreover, the advancement in endoscopic optical evaluation and the better definition of imaging techniques allow for a more precise local staging of early rectal cancer. Although the local treatment of early rectal cancer seems promising, in clinical practice, a significant number of patients who could benefit from local excision techniques undergo total mesorectal excision (TME) as the first approach. All relevant prospective clinical trials were identified through a computer-assisted search of the PubMed, EMBASE, and Medline databases until January 2024. This review is dedicated to endoscopic and surgical local excision in the treatment of early rectal cancer and highlights its possible role in current and future clinical practice, taking into account surgical completion techniques and chemoradiotherapy.

Squamous Cell Carcinoma of the Esophagus

Esophageal squamous cell carcinoma (ESCC) is common in the developing world with decreasing incidence in developed countries and carries significant morbidity and mortality. Major risk factors for ESCC development include significant use of alcohol and tobacco. Screening for ESCC can be recommended in high-risk populations living in highly endemic regions. The treatment of ESCC ranges from endoscopic resection therapy or surgery in localized disease to chemoradiotherapy in metastatic disease, and prognosis is directly related to the stage at diagnosis. New immunotherapies and molecular targeted therapies may improve the dismal survival outcomes in patients with metastatic ESCC.

Artificial Intelligence and Its Role in Identifying Esophageal Neoplasia

Randomized trials have demonstrated that ablation of dysplastic Barrett's esophagus can reduce the risk of progression to cancer. Endoscopic resection for early stage esophageal adenocarcinoma and squamous cell carcinoma can significantly reduce postoperative morbidity compared to esophagectomy. Unfortunately, current endoscopic surveillance technologies (e.g., high-definition white light, electronic, and dye-based chromoendoscopy) lack sensitivity at identifying subtle areas of dysplasia and cancer. Random biopsies sample only approximately 5% of the esophageal mucosa at risk, and there is poor agreement among pathologists in identifying low-grade dysplasia. Machine-based deep learning medical image and video assessment technologies have progressed significantly in recent years, enabled in large part by advances in computer processing capabilities. In deep learning, sequential layers allow models to transform input data (e.g., pixels for imaging data) into a composite representation that allows for classification and feature identification. Several publications have attempted to use this technology to help identify dysplasia and early esophageal cancer. The aims of this reviews are as follows: (a) discussing limitations in our current strategies to identify esophageal dysplasia and cancer, (b) explaining the concepts behind deep learning and convolutional neural networks using language appropriate for clinicians without an engineering background, (c) systematically reviewing the literature for studies that have used deep learning to identify esophageal neoplasia, and (d) based on the systemic review, outlining strategies on further work necessary before these technologies are ready for "prime-time," i.e., use in routine clinical care.

Endoscopic management of mucosal lesions in the gastrointestinal tract

With the increasing role of endoscopy in patient evaluation, more mucosal lesions, including gastric, duodenal and colonic polyps, are encountered during routine examinations. It is imperative for gastroenterologists to become familiar with the endoscopic management of these various gastrointestinal lesions. In this article, various resection techniques will be discussed, including hot/cold forceps polypectomy, hot/cold snare polypectomy, endoscopic mucosal resection, and endoscopic submucosal dissection. The article will also discuss the evidence regarding the efficacy and safety of these techniques and the future direction of endoscopic management of mucosal lesions in the gastrointestinal tract.

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.

Endoscopic surveillance of patients with hereditary diffuse gastric cancer: biopsy recommendations after topographic distribution of cancer foci in a series of 10 CDH1-mutated gastrectomies

The management of hereditary diffuse-type gastric cancer revolves around surveillance biopsies and the timing of prophylactic gastrectomy. In the absence of a validated surveillance biopsy protocol, we modeled bioptic diagnostic yield on the basis of the topographic distribution of cancer foci in a series of 10 gastrectomies in CDH1-mutation carriers. Complete histologic examination was performed in all cases, and 1817 slides were evaluated for the presence of in situ, intramucosal, or submucosal diffuse-type carcinoma. Detailed maps determined the density of cancer foci. On the basis of the number of sampled glands per biopsy in routine surveillance preoperative endoscopy, we estimated the theoretical number of biopsies necessary for a 90% rate of detection of neoplastic foci, and we evaluated this number, taking into account the regional distribution of these foci. A total of 96 m of gastric mucosa with ≈ 1,193,453 gastric glands yielded 302 cancer foci [in situ (n=89), intramucosal (n=209), and submucosal (n=4)] spanning the width of a total of 1820 glands (8 to 1205 per case; average 182 ± 115). On the basis of the number of glands per stomach and the average number of glands sampled during surveillance biopsy (28.7 ± 1.7; range, 0 to 79; n=112), the theoretical number of biopsies necessary to capture at least 1 cancer focus was estimated to be 1768 (range, 50 to 5832) to assure a 90% detection rate. Mapping of cancer foci showed the highest density in the anterior proximal fundus (37%) and cardia/proximal fundus (27%). Our results argue for the incorporation of cancer focus distribution into any biopsy protocol, although detection is likely to remain extremely low, and they call into question the validity of endoscopic surveillance.

Application of optical imaging and spectroscopy to radiation biology

Optical imaging and spectroscopy is a diverse field that has been of critical importance in a wide range of areas in radiation research. It is capable of spanning a wide range of spatial and temporal scales, and has the sensitivity and specificity needed for molecular and functional imaging. This review will describe the basic principles of optical imaging and spectroscopy, highlighting a few relevant applications to radiation research.

Endomicroscopy imaging of epithelial structures using tissue autofluorescence

We explore autofluorescence endomicroscopy as a potential tool for real-time visualization of epithelial tissue microstructure and organization in a clinical setting. The design parameters are explored using two experimental systems--an Olympus Medical Systems Corp. stand-alone clinical prototype probe, and a custom built bench-top rigid fiber conduit prototype. Both systems entail ultraviolet excitation at 266 nm and/or 325 nm using compact laser sources. Preliminary results using ex vivo animal and human tissue specimens suggest that this technology can be translated toward in vivo application to address the need for real-time histology.

Endoscopic colorectal imaging and therapy

PURPOSE OF REVIEW

Colorectal cancer screening and prevention is a pivotal element in every gastroenterologist practice. Recent advances in imaging technology and treatment opened the field for endoscopic management of large flat colorectal polyps and early cancer.

RECENT FINDINGS

High-definition white light colonoscopy allowed for better characterization of colon polyps, particularly flat lesions. Chromoendoscopy facilitated the identification of colon polyps as well as better endoscopic polyp characterization, with strong correlation with final pathological diagnosis, opening the field of 'virtual' biopsy. One particular technology, confocal endomicroscopy can magnify an image approximately 1000 times resembling optical microscopy with very good correlation with histology. Endoscopic mucosal resection has gained great acceptance to manage flat colorectal polyps with the two major complications being bleeding and perforation, both now under 5% in experienced hands. Endoscopic submucosal resection was developed to increase en-bloc resection (less residual disease) of a flat colorectal lesion but one has to accept a higher perforation rate around 10%.

SUMMARY

Current technology allows for better polyp identification and characterization, which can be managed endoscopically.

High-definition and filter-aided colonoscopy

New high-resolution colonoscopes and filter technologies are allowing us to visualize more lesions and better characterize lesions within the gastrointestinal tract. In light of recent findings that flat and serrated lesions are more likely to contain invasive cancer and that even small lesions (5-10 mm) may contain advanced histology, detecting these lesions earlier with improved optical technologies may help decrease the rate of interval cancers after colonoscopy. With the limited accuracy of white-light colonoscopy (59%-84%) in distinguishing non-neoplastic lesions from neoplastic lesions, these new technologies can help us improve our abilities to risk stratify patients and determine more precise surveillance intervals.

Endoscopic mucosal resection and endoscopic submucosal dissection in esophageal and gastric cancers

PURPOSE OF REVIEW

To summarize the literature to date on endoscopic mucosal removal techniques as applied to the upper gastrointestinal tract, predominantly the stomach and esophagus. This is an area that has rapidly advanced in terms of new procedures and techniques with a large body of outcomes that support their use.

RECENT FINDINGS

The resection techniques can be divided into two forms, mucosal resection and submucosal dissection. Mucosal resection is typically done with cap techniques and is more suitable for removable of neoplastic lesions that are less than 1.5 cm in size. Submucosal dissection techniques are more difficult, associated with increased complications, and typically reserved for lesions greater than 1.5 cm and less than 3 cm in size. Ideal lesions for mucosal resection are generally flat and are located in areas easily accessible by the endoscope.

SUMMARY

Endoscopic tissue removal methods are capable of removing neoplastic lesions en bloc in the upper gastrointestinal tract. These techniques fulfill cancer treatment guidelines by having histological confirmation of total removal of neoplastic lesions with assessment of the margins of resections. Long-term clinical outcomes of these techniques are emerging and seem promising in terms of disease-free and overall survival.

Endoscopic techniques for recognizing neoplasia in Barrett's esophagus: which should the clinician use?

PURPOSE OF REVIEW

The key to prevention and cure of esophageal adenocarcinoma is the detection and eradication of neoplasia in patients with Barrett's esophagus. Multiple tools and technologies are emerging for this purpose.

RECENT FINDINGS

A detailed white light examination with high-resolution endoscopy and recognition of lesions is paramount. A variety of imaging modalities are being studied for the detection of neoplasia in Barrett's esophagus. Chromoendoscopy, narrow band imaging, and autofluorescence provide a way to target suspicious areas. Confocal endomicroscopy and optical coherence tomography are means to pinpoint imaging to obtain information about the tissue microarchitecture.

SUMMARY

The key to detection of neoplasia is a careful white light examination with high-resolution endoscopy and recognition of lesion characteristics. Additional imaging modalities may enhance targeting of lesions or provide more information at a focused level. Many of these modalities have yet to be validated in prospective randomized, multicenter trials.