Chromoendoscopy: role in modern endoscopic imaging

Global progress and future prospects of early gastric cancer screening

Gastric cancer is a prevalent malignancy that poses a serious threat to global health. Despite advances in medical technologies, screening methods, and public awareness, gastric cancer remains a significant cause of morbidity and mortality worldwide. Early gastric cancer frequently does not present with characteristic symptoms, while advanced stage disease is characterized by a dismal prognosis. As such, early screening in gastric cancer is of great importance. In recent years, advances have been made globally in both clinical and basic research for the screening of early gastric cancer. The current predominant screening methods for early gastric cancer include imaging screening, endoscopic screening and serum biomarker screening. Imaging screening encompasses upper gastrointestinal barium meal, multidimensional spiral computed tomography (MDCT), Magnetic resonance imaging (MRI), and ultrasonography. Endoscopic screening methods include white light endoscopy, chromoendoscopy, computed virtual chromoendoscopy, and other endoscopic techniques like endocytoscopy, confocal laser endomicroscopy, optical coherence tomography and so on. Biomarkers screening involves the assessment of conventional biomarkers such as CEA, CA19-9 and CA72-4 as well as more emerging biomarkers such as peptides (PG, G-17, GCAA, TAAs and others), DNA (cfDNA, DNA methylation, MSI), noncoding RNA (miRNA, lncRNA, circRNA, and tsRNA) and others. Each screening method has its strengths and limitations. This article systematically summarizes worldwide progress and future development of early gastric cancer screening methods to provide new perspectives and approaches for early diagnostic and treatment advancements in gastric cancer worldwide.

Precision in detecting colon lesions: A key to effective screening policy but will it improve overall outcomes?

Colonoscopy is the gold standard for the screening and diagnosis of colorectal cancer, resulting in a decrease in the incidence and mortality of colon cancer. However, it has a 21% rate of missed polyps. Several strategies have been devised to increase polyp detection rates and improve their characterization and delimitation. These include chromoendoscopy (CE), the use of other devices such as Endo cuffs, and major advances in endoscopic equipment [high definition, magnification, narrow band imaging, i-scan, flexible spectral imaging color enhancement, texture and color enhancement imaging (TXI), etc.]. In the retrospective study by Hiramatsu et al, they compared white-light imaging with CE, TXI, and CE + TXI to determine which of these strategies allows for better definition and delimitation of polyps. They concluded that employing CE associated with TXI stands out as the most effective method to utilize. It remains to be demonstrated whether these results are extrapolatable to other types of virtual CE. Additionally, further investigation is needed in order to ascertain whether this strategy could lead to a reduction in the recurrence of excised lesions and potentially lower the occurrence of interval cancer.

Improved visibility of colorectal tumor by texture and color enhancement imaging with indigo carmine

BACKGROUND

Accurate diagnosis and early resection of colorectal polyps are important to prevent the occurrence of colorectal cancer. However, technical factors and morphological factors of polyps itself can lead to missed diagnoses. Image-enhanced endoscopy and chromoendoscopy (CE) have been developed to facilitate an accurate diagnosis. There have been no reports on visibility using a combination of texture and color enhancement imaging (TXI) and CE for colorectal tumors.

AIM

To investigate the visibility of margins and surfaces with the combination of TXI and CE for colorectal lesions.

METHODS

This retrospective study included patients who underwent lower gastrointestinal endoscopy at the Toyoshima Endoscopy Clinic. We extracted polyps that were resected and diagnosed as adenomas or serrated polyps (hyperplastic polyps and sessile serrated lesions) from our endoscopic database. An expert endoscopist performed the lower gastrointestinal endoscopies and observed the lesion using white light imaging (WLI), TXI, CE, and TXI + CE modalities. Indigo carmine dye was used for CE. Three expert endoscopists rated the visibility of the margin and surface patterns in four ranks, from 1 to 4. The primary outcomes were the average visibility scores for the margin and surface patterns based on the WLI, TXI, CE, and TXI + CE observations. Visibility scores between the four modalities were compared by the Kruskal-Wallis and Dunn tests.

RESULTS

A total of 48 patients with 81 polyps were assessed. The histological subtypes included 50 tubular adenomas, 16 hyperplastic polyps, and 15 sessile serrated lesions. The visibility scores for the margins based on WLI, TXI, CE, and TXI + CE were 2.44 ± 0.93, 2.90 ± 0.93, 3.37 ± 0.74, and 3.75 ± 0.49, respectively. The visibility scores for the surface based on WLI, TXI, CE, and TXI + CE were 2.25 ± 0.80, 2.84 ± 0.84, 3.12 ± 0.72, and 3.51 ± 0.60, respectively. The visibility scores for the detection and surface on TXI were significantly lower than that on CE but higher than that on WLI (P < 0.001). The visibility scores for the margin and surface on TXI + CE were significantly higher than those on CE (P < 0.001). In the sub-analysis of adenomas, the visibility for the margin and surface on TXI + CE was significantly better than that on WLI, TXI, and CE (P < 0.001). In the sub-analysis of serrated polyps, the visibility for the margin and surface on TXI + CE was also significantly better than that on WLI, TXI, and CE (P < 0.001).

CONCLUSION

TXI + CE enhanced the visibility of the margin and surface compared to WLI, TXI, and CE for colorectal lesions.

Exploratory Study of a New Technique of Pixelated Chromoendoscopy in the Diagnosis of Early Esophageal Cancer

BACKGROUND

Chromoendoscopy is an effective method for early screening of esophageal cancer, but diagnosis can depend on subjective judgment. The study aimed to explore a new technique of pixelated chromoendoscopy in the diagnosis of early esophageal cancer.

PATIENTS AND METHODS

The study included patients with symptoms of esophageal cancer who attended Jiangyin People's Hospital between January 2015 and July 2021. Chromoendoscopy was performed on each patient. The images then underwent digital analysis; the lesion area (the sensitive region) was pixelated by dividing it into the smallest image unit and the red, green, and blue color components. The diagnostic performance of pixelated chromoendoscopy was evaluated by calculating the area under the receiver operating characteristic.

RESULTS

The study finally enrolled 86 patients (aged 51.34 ± 5.82 y), including 54 males and 32 females. Pathologic diagnosis identified 54 cases in the cancer group and 32 cases in the non-cancer group. Traditional judgment had a diagnostic sensitivity of 70.73% and specificity was 75.00%. Pixelated chromoendoscopy sensitivity was 80.49%, and specificity was 83.33%. The area under the receiver operating characteristic was 0.814, at a cutoff value of 0.625, indicating a good prediction effect.

CONCLUSIONS

These results showed that pixelated chromoendoscopy might improve the rate of esophageal cancer diagnoses from early screening.

Image enhanced colonoscopy: updates and prospects-a review

Colonoscopy has been proven to be a successful approach in both identifying and preventing colorectal cancer. The incorporation of advanced imaging technologies, such as image-enhanced endoscopy (IEE), plays a vital role in real-time diagnosis. The advancements in endoscopic imaging technology have been continuous, from replacing fiber optics with charge-coupled devices to the introduction of chromoendoscopy in the 1970s. Recent technological advancements include "push-button" technologies like autofluorescence imaging (AFI), narrowed-spectrum endoscopy, and confocal laser endomicroscopy (CLE). Dye-based chromoendoscopy (DCE) is falling out of favor due to the longer time required for application and removal of the dye and the difficulty of identifying lesions in certain situations. Narrow band imaging (NBI) is a technology that filters the light used for illumination leading to improved contrast and better visibility of structures on the mucosal surface and has shown a consistently higher adenoma detection rate (ADR) compared to white light endoscopy. CLE has high sensitivity and specificity for polyp detection and characterization, and several classifications have been developed for accurate identification of normal, regenerative, and dysplastic epithelium. Other IEE technologies, such as blue laser imaging (BLI), linked-color imaging (LCI), i-SCAN, and AFI, have also shown promise in improving ADR and characterizing polyps. New technologies, such as Optivista, red dichromatic imaging (RDI), texture and color enhancement imaging (TXI), and computer-aided detection (CAD) using artificial intelligence (AI), are being developed to improve polyp detection and pathology prediction prior to widespread use in clinical practice.

Phthalocyanine-Blue Nanoparticles for the Direct Visualization of Tumors with White Light Illumination

The current standard of care for colon cancer surveillance relies heavily on white light endoscopy (WLE). However, dysplastic lesions that are not visible to the naked eye are often missed when conventional WLE equipment is used. Although dye-based chromoendoscopy shows promise, current dyes cannot delineate tumor tissues from surrounding healthy tissues accurately. The goal of the present study was to screen various phthalocyanine (PC) dye-loaded micelles for their ability to improve the direct visualization of tumor tissues under white light following intravenous administration. Zinc PC (tetra-tert-butyl)-loaded micelles were identified as the optimal formulation. Their accumulation within syngeneic breast tumors led the tumors to turn dark blue in color, making them clearly visible to the naked eye. These micelles were similarly able to turn spontaneous colorectal adenomas in Apc+/Min mice a dark blue color for easy identification and could enable clinicians to more effectively detect and remove colonic polyps.

Non-contact optical in-vivo sensing of cilia motion by analyzing speckle patterns

Cilia motion is an indicator of pathological-ciliary function, however current diagnosis relies on biopsies. In this paper, we propose an innovative approach for sensing cilia motility. We present an endoscopic configuration for measuring the motion frequency of cilia in the nasal cavity. The technique is based on temporal tracking of the reflected spatial distribution of defocused speckle patterns while illuminating the cilia with a laser. The setup splits the optical signal into two channels; One imaging channel is for the visualization of the physician and another is, defocusing channel, to capture the speckles. We present in-vivo measurements from healthy subjects undergoing endoscopic examination. We found an average motion frequency of around 7.3 Hz and 9.8 Hz in the antero-posterior nasal mucus (an area rich in cilia), which matches the normal cilia range of 7–16 Hz. Quantitative and precise measurements of cilia vibration will optimize the diagnosis and treatment of pathological-ciliary function. This method is simple, minimally invasive, inexpensive, and promising to distinguish between normal and ciliary dysfunction.

20-Year Trends in Detection Rates of Cardia Cancer via Endoscopic Surveillance in Tianjin, China: A Hospital-Based Study

Background

To analyze the time trends in cardia cancer detection rates using endoscopic surveillance from 1999 to 2019 in a high-volume Chinese hospital.

Methods

In this retrospective, single-center study, data were collected from the Endoscopy Center of the Department of Gastroenterology, Tianjin Medical University General Hospital, from 1999 to 2019. Cases of cardia cancer (n = 1567) were extracted from a database of patients who underwent endoscopy. Clinical and epidemiological characteristics of patients with cardia cancer were analyzed, including sex, age, and proportion of early gastric cancer and degree of tumor differentiation. The joinpoint regression method was used to identify change points in incidence trends. Annual percent change (APC) values, with 95% confidence intervals (CI), were calculated for time periods before and after change points.

Results

Of the 343942 patients who underwent endoscopy during 1999–2009, 1567 (4.6%) were identified with cardia cancer. The overall cardia adenocarcinoma detection rate decreased significantly from 1999 to 2004 (APC = −37.3, 95% CI: -20.9, -6.4), followed by a relatively slower decline rate from 2004 to 2019 (APC = −7.7, 95% CI: -4.4, -7.6). The crude rate of detection of early cardia cancer could not be determined by joinpoint analysis. Rates of detection reduced significantly in patients aged 60–69 and 70-79 years (APC = −8.3, 95% CI: -9.8, -6.8 and APC = −7.3, 95% CI: -8.8, -5.8, respectively). The detection rate in males decreased rapidly from 1999 to 2004 (APC = −35.9, 95% CI: -18.2, 5.6, P < 0.05), while the decline rate was relatively slow from 2005 to 2019 (APC = −6.9, 95% CI: -3.4, -6.1, P < 0.05). Among females, the detection rates also decreased from 1999 to 2004 (APC = −21.2, 95% CI: -28.1, -13.7), but remained stable from 2007 to 2019 (APC = −3.8, 95% CI: -7.9, -0.5). Detection of poorly differentiated cardia cancer also declined from 2009 to 2019 (APC = −12.8, 95% CI: -15.3, -10.0).

Conclusions

The detection rate of cardia cancer among gastric cancers has been stable from 2008 to 2019. The trend of detection rate of early cardia cancer showed no significant statistical meaning; hence, it remains necessary to carefully observe the cardia area during endoscopy examination.

Are we Missing Barrett's Esophagus in Our Busy Endoscopy Practice? Improving Detection

Barrett's esophagus (BE) denotes the replacement of stratified squamous epithelium of esophagus by columnar epithelium. It is associated with a significantly increased risk of esophageal adenocarcinoma and hence patients with BE are advised endoscopic surveillance for early detection of dysplastic and neoplastic lesions. Esophageal cancer is the sixth most common cancer in terms of incidence and mortality in India. Around 15 to 25% of esophageal cancers are adenocarcinoma. BE is likely to be an important precursor of esophageal adenocarcinoma and we may be missing patients with BE in our busy endoscopy practice. The detection of BE may be improved by identifying high-risk groups, performing thorough endoscopic examination, and applying newer imaging techniques. The high-risk group includes patients with chronic gastroesophageal reflux disease, obesity, smoking, etc. During endoscopic examination, a careful assessment of the gastroesophageal junction and identification of important landmarks such as gastroesophageal junction and Z line are essential to detect BE. Management of BE depends on the detection of dysplasia and for this four quadrant mucosal biopsy is recommended every 1 to 2 cm. However, random biopsy samples only a small area of mucosa and advanced technologies for real-time detection of dysplasia and neoplasia may overcome this limitation. In this review, we discuss the current scenario of BE in India and ways to improve the detection of BE including dysplastic lesions.

Advances in the Aetiology & Endoscopic Detection and Management of Early Gastric Cancer

Simple Summary

Gastric adenocarcinoma has remained a highly lethal disease. Awareness and recognition of preneoplastic conditions (including gastric atrophy and intestinal metaplasia) using high-resolution white-light endoscopy as well as chromoendoscopy is therefore essential. Helicobacter pylori, a class I carcinogen, remains the main contributor to the development of sporadic distal gastric neoplasia. Management of early gastric neoplasia with endoscopic resections should be in line with standard indications. A multidisciplinary approach to any case of an early gastric neoplasia is imperative. Hereditary forms of gastric cancer require a tailored approach and individua-lized surveillance.

Abstract

The mortality rates of gastric carcinoma remain high, despite the progress in research and development in disease mechanisms and treatment. Therefore, recognition of gastric precancerous lesions and early neoplasia is crucial. Two subtypes of sporadic gastric cancer have been recognized: cardia subtype and non-cardia (distal) subtype, the latter being more frequent and largely associated with infection of Helicobacter pylori, a class I carcinogen. Helicobacter pylori initiates the widely accepted Correa cascade, describing a stepwise progression through precursor lesions from chronic inflammation to gastric atrophy, gastric intestinal metaplasia and neoplasia. Our knowledge on He-licobacter pylori is still limited, and multiple questions in the context of its contribution to the pathogenesis of gastric neoplasia are yet to be answered. Awareness and recognition of gastric atrophy and intestinal metaplasia on high-definition white-light endoscopy, image-enhanced endoscopy and magnification endoscopy, in combination with histology from the biopsies taken accurately according to the protocol, are crucial to guiding the management. Standard indications for endoscopic resections (endoscopic mucosal resection and endoscopic submucosal dissection) of gastric dysplasia and intestinal type of gastric carcinoma have been recommended by multiple societies. Endoscopic evaluation and surveillance should be offered to individuals with an inherited predisposition to gastric carcinoma.

Artificial intelligence for the early detection of colorectal cancer: A comprehensive review of its advantages and misconceptions

Colorectal cancer (CRC) was the second-ranked worldwide type of cancer during 2020 due to the crude mortality rate of 12.0 per 100000 inhabitants. It can be prevented if glandular tissue (adenomatous polyps) is detected early. Colonoscopy has been strongly recommended as a screening test for both early cancer and adenomatous polyps. However, it has some limitations that include the high polyp miss rate for smaller (< 10 mm) or flat polyps, which are easily missed during visual inspection. Due to the rapid advancement of technology, artificial intelligence (AI) has been a thriving area in different fields, including medicine. Particularly, in gastroenterology AI software has been included in computer-aided systems for diagnosis and to improve the assertiveness of automatic polyp detection and its classification as a preventive method for CRC. This article provides an overview of recent research focusing on AI tools and their applications in the early detection of CRC and adenomatous polyps, as well as an insightful analysis of the main advantages and misconceptions in the field.

Association between mucin phenotype and lesion border detection using acetic acid-indigo carmine chromoendoscopy in early gastric cancers

BACKGROUND

For successful treatment of early gastric cancers (EGCs), it is crucial to define the horizontal border of the lesion with high accuracy. Acetic acid-indigo carmine (AI) chromoendoscopy has been used to determine the horizontal border in EGCs, but this technique is less potent in certain situations. Mucin phenotype in gastric cancers refers to biological differences in precursor lesions and differences in histopathologic findings, and it might affect AI chromoendoscopy findings. We aimed to investigate the association between mucin phenotype and AI chromoendoscopy findings in EGCs.

METHODS

We prospectively evaluated 126 lesions in 126 patients with endoscopically diagnosed EGCs. Conventional endoscopy and AI chromoendoscopy findings of these lesions before treatment were prospectively analyzed. The border distinction between the lesion and surrounding mucosa was classified as distinct or indistinct on conventional endoscopy and AI chromoendoscopy, respectively. Mucin phenotypes were classified as gastric, intestinal, gastrointestinal, or null type by immunohistochemistry.

RESULTS

The lesion borders were distinct in 46.8% (59/126) of the lesions assessed using conventional endoscopy and in 73.0% (92/126) of those assessed with AI chromoendoscopy (p < 0.001). The border distinction rate of differentiated-type cancers on AI chromoendoscopy was significantly higher than that on conventional endoscopy (66/71 [93.0%] vs. 34/71 [47.9%], p < 0.001), but the border distinction rate of undifferentiated-type cancers on AI chromoendoscopy was not different from that on conventional endoscopy (26/55 [47.3%] vs. 25/55 [45.5%], p = 0.848). Compared with conventional endoscopy, AI chromoendoscopy identified borders in a significantly higher percentage of gastric, intestinal, and gastrointestinal mucin types; however, there was no difference in AI chromoendoscopy findings according to the mucin phenotype (p = 0.271).

CONCLUSION

AI chromoendoscopy was effective in horizontal border delineation in differentiated-type EGCs, but not in undifferentiated-type EGCs. Mucin phenotype had no effect on border distinction using AI chromoendoscopy.