Classification of nuclear morphology in endocytoscopy of colorectal neoplasms

Feasibility of new-generation endocytoscopy for the real-time diagnosis of ampullary lesions: A pilot study (with video)

BACKGROUND AND AIM

An early and accurate diagnosis of ampullary neoplasia is crucial; however, sampling bias is still a major concern. New-generation endocytoscopy enables real-time visualization of cellular structures and enables an accurate pathological prediction; however, its feasibility for small ampullary lesions has never been investigated.

METHODS

We developed a novel endocytoscopic (EC) classification system for ampullary lesions after an expert review and agreement from five experienced endoscopists and one pathologist. We then consecutively enrolled a total of 43 patients with an enlarged ampulla (< 3 cm), all of whom received an endocytoscopic examination. The feasibility of endocytoscopy was evaluated, and the performance of the EC classification system was then correlated with the final histopathology.

RESULTS

In five cases (11.6%), the endocytoscope could not approach the ampulla, and these cases were defined as technical failure. Among the remaining 38 patients, 8 had histopathology-confirmed adenocarcinoma, 15 had adenoma, and 15 had non-neoplastic lesions. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the EC classification system to diagnose ampullary neoplasias were 95.7%, 86.7%, 91.7%, 92.9%, and 92.1%, respectively. Moreover, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the EC classification to diagnose ampullary cancer were 62.5%, 100%, 100%, 90.9%, and 92.1%, respectively. One case with intra-ampullary papillary-tubular carcinoma was classified as having a non-neoplastic lesion by endocytoscopy.

CONCLUSIONS

Endocytoscopy and the novel EC classification system demonstrated good feasibility to discriminate ampullary neoplasias from non-neoplastic lesions and may be useful for optical biopsies of clinically suspicious ampullary lesions.

Diagnostic performance of endocytoscopy with normal pit-like structure sign for colorectal low-grade adenoma compared with conventional modalities

Objectives

A "resect-and-discard" strategy has been proposed for diminutive adenomas in the colorectum. However, this strategy is sometimes difficult to implement because of the lack of confidence in differentiating low-grade adenoma (LGA) from advanced lesions such as high-grade adenoma or carcinoma. To perform real-time precise diagnosis of LGA with high confidence, we assessed whether endocytoscopy (EC) diagnosis, considering normal pit-like structure (NP-sign), an excellent indicator of LGA, could have additional diagnostic potential compared with conventional modalities.

Methods

All the neoplastic lesions that were observed by non-magnifying narrow-band imaging (NBI), magnifying NBI (M-NBI), magnifying pit pattern, and EC prior to pathological examination between 2005 and 2018 were retrospectively investigated. The neoplastic lesions were classified into two categories: LGA and other neoplastic lesions. We assessed the differential diagnostic ability of EC with NP-sign between LGA and other neoplastic lesions compared with that of NBI, M-NBI, pit pattern, and conventional EC in terms of sensitivity, specificity, accuracy, and area under the receiver operating characteristic curve (AUC).

Results

A total of 1376 lesions from 1097 patients were eligible. The specificity (94.9%), accuracy (91.5%), and area under the receiver operating characteristic curve (0.95) of EC with NP-sign were significantly higher than those of NBI, M-NBI, pit pattern, and conventional EC.

Conclusions

EC diagnosis with NP-sign has significantly higher diagnostic performance for predicting colorectal LGA compared with the conventional modalities and enables stratification of neoplastic lesions for "resect-and-discard" with higher confidence.

The Role of Artificial Intelligence in Colorectal Cancer Screening: Lesion Detection and Lesion Characterization

Colorectal cancer remains a leading cause of cancer-related morbidity and mortality worldwide, despite the widespread uptake of population surveillance strategies. This is in part due to the persistent development of 'interval colorectal cancers', where patients develop colorectal cancer despite appropriate surveillance intervals, implying pre-malignant polyps were not resected at a prior colonoscopy. Multiple techniques have been developed to improve the sensitivity and accuracy of lesion detection and characterisation in an effort to improve the efficacy of colorectal cancer screening, thereby reducing the incidence of interval colorectal cancers. This article presents a comprehensive review of the transformative role of artificial intelligence (AI), which has recently emerged as one such solution for improving the quality of screening and surveillance colonoscopy. Firstly, AI-driven algorithms demonstrate remarkable potential in addressing the challenge of overlooked polyps, particularly polyp subtypes infamous for escaping human detection because of their inconspicuous appearance. Secondly, AI empowers gastroenterologists without exhaustive training in advanced mucosal imaging to characterise polyps with accuracy similar to that of expert interventionalists, reducing the dependence on pathologic evaluation and guiding appropriate resection techniques or referrals for more complex resections. AI in colonoscopy holds the potential to advance the detection and characterisation of polyps, addressing current limitations and improving patient outcomes. The integration of AI technologies into routine colonoscopy represents a promising step towards more effective colorectal cancer screening and prevention.

Mucosal imaging in colon polyps: New advances and what the future may hold

An expanding range of advanced mucosal imaging technologies have been developed with the goal of improving the detection and characterization of lesions in the gastrointestinal tract. Many technologies have targeted colorectal neoplasia given the potential for intervention prior to the development of invasive cancer in the setting of widespread surveillance programs. Improvement in adenoma detection reduces miss rates and prevents interval cancer development. Advanced imaging technologies aim to enhance detection without significantly increasing procedural time. Accurate polyp characterisation guides resection techniques for larger polyps, as well as providing the platform for the "resect and discard" and "do not resect" strategies for small and diminutive polyps. This review aims to collate and summarise the evidence regarding these technologies to guide colonoscopic practice in both interventional and non-interventional endoscopists.

New application of endocytoscope for histopathological diagnosis of colorectal lesions

BACKGROUND

The endocytoscope with ultra-high magnification (x 520) allows us to observe the cellular structure of the colon epithelium during colonoscopy, known as virtual histopathology. We hypothesized that the endocytoscope could directly observe colorectal histopathological specimens and store them as endocyto-pathological images by the endoscopists without a microscope, potentially saving the burden on histopathologists.

AIM

To assess the feasibility of endocyto-pathological images taken by an endoscopist as adequate materials for histopathological diagnosis.

METHODS

Three gastrointestinal pathologists were invited and asked to diagnose 40 cases of endocyto-pathological images of colorectal specimens. Each case contained seven endocyto-pathological images taken by an endoscopist, consisting of one loupe image, three low-magnification images, and three ultra-high magnification images. The participants chose hyperplastic polyp or low-grade adenoma for 20 cases of endocyto-pathological images (10 hyperplastic polyps, and 10 Low-grade adenomas in conventional histopathology) in study 1 and high-grade adenoma/ shallow invasive cancer or deep invasive cancer for 20 cases [10 tumor in situ/T1a and 10 T1b] in study 2. We investigated the agreement between the histopathological diagnosis using the endocyto-pathological images and conventional histopathological diagnosis.

RESULTS

Agreement between the endocyto-pathological and conventional histopathological diagnosis by the three gastrointestinal pathologists was 100% (95%CI: 94.0%–100%) in studies 1 and 2. The interobserver agreement among the three gastrointestinal pathologists was 100%, and the κ coefficient was 1.00 in both studies.

CONCLUSION

Endocyto-pathological images were adequate and reliable materials for histopathological diagnosis.

A new classification for the diagnosis of superficial non-ampullary duodenal epithelial tumors using endocytoscopy: A prospective study

BACKGROUND AND AIM

Although the frequency of endoscopic diagnosis of superficial non-ampullary duodenal epithelial tumors (SNADETs) has been increasing in recent years, no criteria for the endoscopic diagnosis of these tumors have been established yet. The aim of this study was to assess the usefulness of endocytoscopy for diagnosis SNADETs and to establish new criteria.

METHODS

This prospective study was conducted at the NTT Medical Center Tokyo from May 2019 to July 2020, and a total of 100 consecutive SNADETs were enrolled. All the endocytoscopic images of the lesions and surrounding normal mucosa were classified into three groups according to the degree of structural atypia and the nuclear morphology and size. The endocytoscopic diagnoses using endocytoscopic classification was compared with the final histopathological diagnoses.

RESULTS

Data of 93 patients with 98 lesions were included in the analysis. The preoperative diagnosis by endocytoscopy coincided with the final histopathological diagnosis in 85 (86.7%) of 98 SNADETs. In addition, the sensitivity and specificity for VCL 4/5 were 87.7% and 85.4%, respectively. In contrast, the accuracy, sensitivity, and specificity of preoperative diagnosis by biopsy were 64.3%, 50.9%, and 82.9%, respectively. Preoperative diagnosis by endocytoscopy showed significantly superior accuracy and sensitivity as compared with preoperative biopsy diagnosis (P < 0.001, respectively).

CONCLUSIONS

This new classification (endocytoscopic classification) allows prediction of the tumor histopathology in real time, during endocytoscopy without biopsy, and is expected to be of help in determining the appropriate therapeutic strategies for individual cases of SNADETs. (Clinical trial registration number: UMIN000038643.).

Advances in optical gastrointestinal endoscopy: a technical review

Optical endoscopy is the primary diagnostic and therapeutic tool for management of gastrointestinal (GI) malignancies. Most GI neoplasms arise from precancerous lesions; thus, technical innovations to improve detection and diagnosis of precancerous lesions and early cancers play a pivotal role in improving outcomes. Over the last few decades, the field of GI endoscopy has witnessed enormous and focused efforts to develop and translate accurate, user-friendly, and minimally invasive optical imaging modalities. From a technical point of view, a wide range of novel optical techniques is now available to probe different aspects of light-tissue interaction at macroscopic and microscopic scales, complementing white light endoscopy. Most of these new modalities have been successfully validated and translated to routine clinical practice. Herein, we provide a technical review of the current status of existing and promising new optical endoscopic imaging technologies for GI cancer screening and surveillance. We summarize the underlying principles of light-tissue interaction, the imaging performance at different scales, and highlight what is known about clinical applicability and effectiveness. Furthermore, we discuss recent discovery and translation of novel molecular probes that have shown promise to augment endoscopists' ability to diagnose GI lesions with high specificity. We also review and discuss the role and potential clinical integration of artificial intelligence-based algorithms to provide decision support in real time. Finally, we provide perspectives on future technology development and its potential to transform endoscopic GI cancer detection and diagnosis.

Clinical Efficacy of Endocytoscopy for Gastrointestinal Endoscopy

Endocytoscopy (EC) is a contact-type optical endoscope that allows in vivo cellular observation during gastrointestinal endoscopy and is now commercially available not only in Japan but also in Asian, European Union, and Middle Eastern countries. EC helps conduct a highly accurate pathological prediction without biopsy. Initially, EC was reported to be effective for esophageal diseases. Subsequently, its efficacy for stomach and colorectal diseases has been reported. In this narrative review, we searched for clinical studies that investigated the efficacy of EC. EC seems to accurately diagnose gastrointestinal diseases without biopsy. Most of the studies aimed to clarify the relationship between endocytoscopic findings of gastrointestinal neoplasia and pathological diagnosis. Some studies have investigated non-epithelial lesions or diseases, such as inflammatory bowel disease or infectious diseases. However, there are few high-level pieces of evidence, such as randomized trials; thus, further studies are needed.

Endocytoscopy: technology and clinical application in the lower GI tract

Endocytoscopy (EC) is now one of the valuable technologies in diagnosing colorectal tumors. Providing ultra-high-resolution white light images (520×), endocytoscopy attains the so called virtual histology or optical biopsy, making it a promising tool to diagnose colorectal lesions. Recent studies about artificial intelligence (AI) or computer aided diagnosis (CAD) are also increasingly reported. We investigate the current application of endocytoscopy, as well as the benefit of AI and CAD. Furthermore, we performed a meta-analysis comparing the diagnostic performance of endocytoscopy and magnified chromoendoscopy. In conclusion, this systematic review and meta-analysis supports the recent finding indicating the higher diagnostic performance of endocytoscope in the depth assessment of colorectal neoplasms.

Endocytoscopy for the differential diagnosis of colorectal low-grade adenoma: a novel possibility for the "resect and discard" strategy

BACKGROUND AND AIMS

Endocytoscopy, a next-generation endoscopic system, facilitates observation at a maximum magnification of ×520. To our knowledge, no study has reported high-precision diagnosis of colorectal low-grade adenoma, endoscopically. We aimed to reveal which endocytoscopic findings may be used as indicators of low-grade adenoma and to assess whether a "resect and discard" strategy using endocytoscopy is feasible.

METHODS

Lesions diagnosable with endocytoscopy were examined retrospectively between May 2005 and July 2017. A normal pit-like structure in endocytoscopic images was considered a normal pit (NP) sign and used as an indicator of low-grade adenoma. The primary outcome was the diagnostic accuracy of the NP sign for low-grade adenoma. We evaluated agreement rates between endocytoscopic and pathologic diagnosis for surveillance colonoscopy interval recommendation (SCIR) and performed a validation study to verify the agreement rates.

RESULTS

For 748 lesions in 573 cases diagnosed as colorectal adenoma using endocytoscopy, the results were as follows: sensitivity of the NP sign for low-grade adenoma, 85.0%; specificity, 90.7%; positive predictive value, 96.6%; negative predictive value, 66.1%; accuracy, 86.4%; and positive likelihood ratio, 9.2 (P < .001). The agreement rate between endocytoscopic and pathologic diagnosis for SCIR was 94.4% (95% confidence interval [CI], 92.2%-96.1%; P < .001) under United States guidelines and 96.3% (95% CI, 94.5%-97.7%; P < .001) under European Union guidelines. All inter- and intraobserver agreement rates for expert and nonexpert endoscopists had κ values ≥0.8 except one nonexpert pair.

CONCLUSIONS

Endocytoscopy is an effective modality in determining the differential diagnosis of colorectal low-grade adenoma. (University Hospital Medical Information Network Clinical Trials database registration number: UMIN000018623.).

Noncoding Centromeric RNA Expression Impairs Chromosome Stability in Human and Murine Stem Cells

We analyzed the effect of transcribed noncoding RNA centromeric satellites on chromosome segregation in normal human and murine stem and fibrosarcoma cells. The overexpression of different centromeric alphoid DNAs in all cell lines induced a marked increase in chromosome mis-segregation in anaphase. Overexpression of centromeric mouse minor satellite also increased chromosome instability in the murine stem but not in human cells. Analysis of chromosome segregation in vivo showed disturbances in the mitotic progression, which was frequently unresolved. Live cell imaging revealed that overexpression of centromeric satellites resulted in several different chromosomal morphological errors in the cell nuclei. Our findings correlated with other reports that several centromeric noncoding RNAs are detected in different carcinoma cells and their expression resulted in segregation errors. Our study furnishes further insights into a novel source of genomic instability in human and murine cells. It has recently been shown that noncoding centromeric RNAs are present in some form of cancer, and thus, overexpression of several types of centromeric noncoding RNAs may be useful as a specific maker for neoplastic cells.