Colorectal tumours and pit pattern

Akita Japan population-based colonoscopy screening trial: report of initial colonoscopy

OBJECTIVE

To assess the safety and quality of baseline screening colonoscopy in a randomised controlled trial (RCT).

METHODS

A population-based RCT with an explanatory design is ongoing to evaluate the efficacy of colonoscopy screening in 9751 men and women aged 40-74 years at average risk of colorectal cancer (CRC) in Japan. Screening colonoscopies for the intervention group were performed from June 2009 to June 2017.

RESULTS

Of the 4861 participants in the intervention group, 4495 (92.5%) underwent screening colonoscopy. The quality of bowel preparation was excellent (34.8%) or good (45.6%) in 80.4% of cases. The caecal intubation rate was 99.7% (4483/4495), and the mean (±SD) withdrawal time was 9.7 (±5.3) min. The adenoma detection rate (ADR) was 39.4% (1770/4495). A total of 27 participants (0.6%) were diagnosed with CRC, and 266 (5.9%) were diagnosed with advanced neoplasia (AN). In women, adenomas were more frequently detected in the proximal colon than in the distal colon (proximal: 18.9% vs distal: 16.4%, p=0.024), and a similar trend was observed for AN (proximal: 2.4% vs distal: 1.5%, p=0.045). No serious adverse events related to screening colonoscopy were reported, and minor adverse events were observed in two participants (0.04%).

CONCLUSIONS

Adequate performance in compliance, ADR, and safety was confirmed in the intervention arm of the RCT evaluating the efficacy of screening colonoscopy. The high quality of screening colonoscopy observed in the trial suggests its feasibility as a population-based screening approach.

TRIAL REGISTRATION NUMBER

UMIN000001980.

Will Rogers Paradox in Gastroenterology

The use of various classifications to grade and differentiate appearances of digestive diseases has enhanced precision and provided better means for their clinical evaluation and comparison. Staging systems abound to classify erosive esophagitis, gastro-esophageal varices, upper gastrointestinal hemorrhage, histopathology of celiac disease, various types of gastrointestinal neoplasia, and colitis associated with Crohn's disease or ulcerative colitis. The present review serves to highlight how potential bias may become introduced when comparing clinical outcomes based on varying and continuously evolving staging systems of digestive diseases.

Feasibility of a novel self-assembling submucosal injection peptide solution for endoscopic mucosal resection of colorectal lesions: A multicenter study

Objectives

Although a novel submucosal injection material consisting of a fully synthetic, self-assembling peptide solution, PuraLift, has recently become commercially available in Japan, there are a few reports regarding the usefulness of this solution. The aim of this study was to investigate the feasibility of PuraLift for conventional endoscopic mucosal resection (EMR) in clinical practice.

Methods

This multicenter retrospective study was conducted at the endoscopy units of five institutions from January 2023 to May 2023. Consecutive patients who underwent EMR with PuraLift for 5-20-mm colorectal lesions were included in the introduction of this solution at each institute. The primary endpoint was the "effective resection" rate, defined as pathological complete resection, with "effective injection" defined as requiring no more than one additional injection due to adequate maintenance of mucosal lifting during EMR.

Results

In total, 110 lesions in 70 patients were treated by conventional EMR using PuraLift. En-bloc resection was performed for 109 (99%) lesions, and complete resection was performed for 102 (93%) lesions. More than 95% of the lesions were neoplastic. Additional injections were required in only two lesions. Both were single additional injections, and the median overall injection volume was 1.5 mL. Therefore, the effective injection rate was 93% (95% confidence interval, 86%-96%). No adverse events occurred during the study period.

Conclusions

Although direct comparison with other materials is required, PuraLift seems feasible as an injection material for EMR.

The Efficacy of Texture and Color Enhancement Imaging Observation in the Detection of Colorectal Lesions: A Multicenter, Randomized Controlled Trial (deTXIon Study)

BACKGROUND & AIMS

Colonoscopy is the gold standard for detecting and resecting adenomas and early-stage cancers to reduce colorectal cancer (CRC) incidence and mortality rates. This study aimed to confirm the superiority of texture and color enhancement imaging (TXI) over white light imaging (WLI) in detecting colorectal lesions.

METHODS

This randomized controlled trial was conducted at 8 Japanese institutions between March 2023 and October 2023. Participants aged 40 to 80 years old scheduled for CRC screening and nonscreening purposes, such as postpolypectomy surveillance, positive fecal occult blood test results, and abdominal symptoms, were included. We used only the latest model colonoscopes and performed observations in each arm of the TXI model and WLI. The primary end point was the mean number of adenomas detected per procedure. Secondary end points included the adenoma detection rate, polyp detection rate, flat polyp detection rate, and adverse events.

RESULTS

A total of 956 patients were enrolled and randomized. After patients who did not meet the eligibility criteria were excluded, 451 and 445 patients were included in the TXI and WLI arms, respectively. The mean number of adenomas detected per procedure was 1.4 and 1.5 and the adenoma detection rate was 57.2% and 56.0% in TXI and WLI, respectively, and there were no statistically significant differences between 2 arms. The polyp detection rate and flat polyp detection rate were significantly higher in TXI than in WLI, which were 82.5% vs 74.4% (P = .003), and 76.5% vs 70.3% (P = .036), respectively.

CONCLUSIONS

This study did not demonstrate the superiority of TXI over WLI in detecting neoplastic lesions. However, TXI may be effective in detecting flat polyps.

CLINICAL TRIAL REGISTRATION

jRCT1032230089.

Artificial Intelligence Models May Aid in Predicting Lymph Node Metastasis in Patients with T1 Colorectal Cancer

Background/Aims

Inaccurate prediction of lymph node metastasis (LNM) may lead to unnecessary surgery following endoscopic resection of T1 colorectal cancer (CRC). We aimed to validate the usefulness of artificial intelligence (AI) models for predicting LNM in patients with T1 CRC.

Methods

We analyzed the clinical data, laboratory results, pathological reports, and endoscopic findings of patients who underwent radical surgery for T1 CRC. We developed AI models to predict LNM using four algorithms: regularized logistic regression classifier (RLRC), random forest classifier (RFC), CatBoost classifier (CBC), and the voting classifier (VC). Four histological factors and four endoscopic findings were included to develop AI models. Areas under the receiver operating characteristics curves (AUROCs) were measured to distinguish AI model performance in accordance with the Japanese Society for Cancer of the Colon and Rectum guidelines.

Results

Among 1,386 patients with T1 CRC, 173 patients (12.5%) had LNM. The AUROC values of the RLRC, RFC, CBC, and VC models for LNM prediction were significantly higher (0.673, 0.640, 0.679, and 0.677, respectively) than the 0.525 suggested in accordance with the Japanese Society for Cancer of the Colon and Rectum guidelines (vs RLRC, p<0.001; vs RFC, p=0.001; vs CBC, p<0.001; vs VC, p<0.001). The AUROC value was similar between T1 colon versus T1 rectal cancers (0.718 vs 0.615, p=0.700). The AUROC value was also similar between the initial endoscopic resection and initial surgery groups (0.581 vs 0.746, p=0.845).

Conclusions

AI models trained on the basis of endoscopic findings and pathological features performed well in predicting LNM in patients with T1 CRC regardless of tumor location and initial treatment method.

Advancing Colorectal Cancer Prevention in Inflammatory Bowel Disease (IBD): Challenges and Innovations in Endoscopic Surveillance

Patients with inflammatory bowel disease (IBD) face an elevated risk of developing colorectal cancer (CRC). Endoscopic surveillance is a cornerstone in CRC prevention, enabling early detection and intervention. However, despite recent advancements, challenges persist. Chromoendoscopy (CE), considered the gold standard for dysplasia detection, remains underutilized due to logistical constraints, prolonged procedural times, and the need for specialized training. New technologies, such as endomicroscopy, confocal laser endomicroscopy (CLE), and molecular endoscopy (ME), promise unprecedented precision in lesion characterization but are limited to specialized centers. Artificial intelligence (AI) can transform the field; however, barriers to widespread AI adoption include the need for robust datasets, real-time video integration, and seamless incorporation into existing workflows. Beyond technology, patient adherence to surveillance protocols, including bowel preparation and repeat procedures, remains a critical hurdle. This review aims to explore the advancements, ongoing challenges, and future prospects in CRC prevention for IBD patients, focusing on improving outcomes and expanding the implementation of advanced surveillance technologies.

Imaging colonic polyps in 2024

Screening colonoscopy and polypectomy are the cornerstone in decreasing the incidence and mortality of colorectal cancer. Despite the low incidence of colorectal cancer in India, there has been a rising trend in the incidence of colonic polyps and cancer over the last decade. It is, hence, imperative that we are well equipped in the management of colonic polyps. Adequate training in the detection and characterization of polyps to aid in their management is necessary. Detection of polyps can be increased by adhering to the standards of colonoscopy, including good bowel preparation, cecal intubation rate, adequate withdrawal time and use of distal attachment devices. A detected polyp needs optimal characterization to predict histology in real time and decide on the management strategies. Characterization of the polyps requires high-definition-white light endoscopy and/or image-enhanced endoscopy (dye based or digital). Various factors that help in predicting histology include size, location and morphology of the polyp and the pit pattern, vascular and surface pattern of the polyp. Polyps can be differentiated as neoplastic or non-neoplastic with reasonable accuracy with the above features. Prediction of advanced pathology including high-grade dysplasia and deep sub-mucosal invasion is essential, as it helps in deciding if the lesion is amenable to endotherapy and the technique of endoscopic resection. Adequate training in image-enhanced endoscopy is necessary to assess advanced pathology in polyps. Technology pertaining to image-enhanced endoscopy includes narrow banding imaging and blue laser imaging; newer variations are being introduced every few years making it necessary to be abreast with growing information. The recent advances in gastrointestinal (GI) endoscopy with the advent of endocytoscopy and artificial intelligence seem promising and are predicted to be the future of GI endoscopy.

Protocol for a prospective multicenter randomized controlled trial to evaluate the efficacy of texture and color enhancement imaging (TXI) observation in the detection of colorectal lesions (deTXIon study)

Colonoscopy is the gold standard for detecting and resecting adenomas or early stage cancers to reduce the incidence and mortality rates of colorectal cancer. In a recent observational study, texture and color enhancement imaging (TXI) was reported to improve polyp detection during colonoscopy. This randomized controlled trial involving six Japanese institutions aims to confirm the superiority of TXI over standard white-light imaging (WLI) in detecting colorectal lesions during colonoscopy. During the 1-year study period, 960 patients will be enrolled, with 480 patients in the TXI and WLI groups. The primary endpoint is the mean number of adenomas detected per procedure. The secondary endpoints include adenoma detection rate, advanced adenoma detection rate, polyp detection rate, flat polyp detection rate, depressed lesion detection rate, mean polyps detected per procedure, sessile serrated lesion (SSL) detection rate, mean SSLs detected per procedure and adverse events.

Local Excision for organ preservation in early REctal cancer with No Adjuvant treatment (LORENA Trial): prospective observational study protocol

INTRODUCTION

Local resection (LR) is an alternative to total mesorectal excision (TME) that avoids its associated morbidity to the detriment of oncological radicality in early stages of rectal cancer. There are several conditioning factors for the success of this strategy, such as poor prognosis histological factors (PPHF), involvement of resection margins, clinical under staging, or complications that may lead to the indication for radical surgery with TME.

PATIENTS AND METHOD

An international multicenter prospective observational open-label study has been designed. Consecutive patients diagnosed with early rectal cancer (cT1N0 on MRI +/- endorectal ultrasound) whose lower limit is a maximum of 2 cm proximal to the ano-rectal junction will be included. The primary objective of the study is to determine the overall prevalence of PPHF after LR and requiring TME or postoperative radio-chemotherapy.

DISCUSSION

The prevalence of PPHF conditioning the success of LR in early distal rectal cancer has been scarcely studied in the literature, and there are very few prospective data. Considering the increasing interest in the watch and wait strategy in rectal cancer and its possible application in early-stage tumors, it seems necessary to know this information. The results of this study will help guide clinical practice in patients with early distal rectal cancer. It will also provide quality information for the design of future comparative studies to improve organ preservation success in these patients.

TRIAL REGISTRATION NUMBER

NCT05927584.

Endoscopic Assessment of Colorectal Polyps

Colorectal cancer is the third most common cancer among men and the second among women. In the United States alone, there are 150,000 cases diagnosed each year. Colonoscopy remains the best method for identifying, evaluating, and intervening on patients with precancerous lesions. Multiple guidelines and techniques are available to assist the endoscopist with accurate diagnosis of these lesions. These include the Paris, Narrow-Band Imaging (NBI) International Colorectal Endoscopic (NICE), Japan NBI Expert Team (JNET), Kudo, Hiroshima, and Shudo classifications which utilize techniques such as chromoendoscopy, narrow-band imaging, and endocytoscopy to evaluate pit pattern and surface morphology. Utilization of these tools can help the endoscopist predict the cytology of a colonic lesion and select the most appropriate method for resection while maximizing organ preservation.

Endoscopic Resection of Neoplasia in the Lower GI Tract: A Clinical Algorithm

Background

Colorectal cancer is a highly prevalent malignancy and a significant driver of cancer mortality and health-related expenditure worldwide. Polyp removal reduces the incidence and mortality of colorectal cancer. In 2024, endoscopists have an array of resection modalities at their disposal. Each technique requires a unique skillset and has individual advantages and limitations. Consequently, resection in the colorectum requires an evidence-based algorithm approach that considers these factors.

Summary

A literature review of endoscopic resection for colonic neoplasia was conducted. Best supporting scientific evidence was summarized for the endoscopic resection of diminutive polyps, large ≥20 mm lesions and polyps containing invasive cancer. Factors including resection modality, complications and lesion selection were explored to inform an algorithm approach to colorectal resection.

Key Messages

Endoscopic resection in the colorectum is not a one-size-fits-all approach. Detailed understanding of polyp size, location, morphology and predicted histology are critical factors that inform appropriate endoscopic resection practice.

Diagnostic performance of the Japanese Narrow-band imaging expert team classification system using dual focus magnification in real-time Vietnamese setting

The JNET classification, combined with magnified narrowband imaging (NBI), is essential for predicting the histology of colorectal polyps and guiding personalized treatment strategies. Despite its recognized utility, the diagnostic efficacy of JNET classification using NBI with dual focus (DF) magnification requires exploration in the Vietnamese context. This study aimed to investigate the diagnostic performance of the JNET classification with the NBI-DF mode in predicting the histology of colorectal polyps in Vietnam. A cross-sectional study was conducted at the University Medical Center in Ho Chi Minh City, Vietnam. During real-time endoscopy, endoscopists evaluated the lesion characteristics and recorded optical diagnoses using the dual focus mode magnification according to the JNET classification. En bloc lesion resection (endoscopic or surgical) provided the final pathology, serving as the reference standard for optical diagnoses. A total of 739 patients with 1353 lesions were recruited between October 2021 and March 2023. The overall concordance with the JNET classification was 86.9%. Specificities and positive predictive values for JNET types were: type 1 (95.7%, 88.3%); type 2A (81.4%, 90%); type 2B (96.6%, 54.7%); and type 3 (99.9%, 93.3%). The sensitivity and negative predictive value for differentiating neoplastic from non-neoplastic lesions were 97.8% and 88.3%, respectively. However, the sensitivity for distinguishing malignant from benign neoplasia was lower at 64.1%, despite a specificity of 95.9%. Notably, the specificity and positive predictive value for identifying deep submucosal cancer were high at 99.8% and 93.3%. In Vietnam, applying the JNET classification with NBI-DF demonstrates significant value in predicting the histology of colorectal polyps. This classification guides treatment decisions and prevents unnecessary surgeries.

Accuracy of optical diagnosis with narrow band imaging in the surveillance of ulcerative colitis: a prospective study comparing Kudo, Kudo-IBD and NICE classifications

PURPOSE

The diagnostic accuracy of Narrow Band Imaging (NBI) in the endoscopic surveillance of ulcerative colitis (UC) has been disappointing in most trials which used the Kudo classification. We aim to compare the performance of NBI in the lesion characterization of UC, when applied according to three different classifications (NICE, Kudo, Kudo-IBD).

METHODS

In a prospective, real-life study, all visible lesions found during consecutive surveillance colonoscopies with NBI (Exera-II CV-180) for UC were classified as suspected or non-suspected for neoplasia according to the NICE, Kudo and Kudo-IBD criteria. The sensitivity (SE), specificity (SP), positive (+LR) and negative (-LR) likelihood ratios of the three classifications were calculated, using histology as the reference standard.

RESULTS

394 lesions (mean size 6 mm, range 2-40 mm) from 84 patients were analysed. Twenty-one neoplastic (5%), 49 hyperplastic (12%), and 324 inflammatory (82%) lesions were found. The diagnostic accuracy of the NICE, Kudo and Kudo-IBD classifications were, respectively: SE 76%-71%-86%; SP 55-69%-79% (p < 0.05 Kudo-IBD vs. both Kudo and NICE); +LR 1.69-2.34-4.15 (p < 0.05 Kudo-IBD vs. both Kudo and NICE); -LR 0.43-0.41-0.18.

CONCLUSION

The diagnostic accuracy of NBI in the differentiation of neoplastic and non-neoplastic lesions in UC is low if used with conventional classifications of the general population, but it is significantly better with the modified Kudo classification specific for UC.

Endoscopic submucosal dissection for colorectal neoplasms: Risk factors for local recurrence and long-term surveillance

Objectives

Endoscopic submucosal dissection (ESD) is an effective procedure for the en bloc resection of colorectal neoplasms. However, risk factors for local recurrence after ESD have not been identified. This study aimed to evaluate such risk factors after ESD for colorectal neoplasms.

Methods

This retrospective study included 1344 patients with 1539 consecutive colorectal lesions who underwent ESD between September 2003 and December 2019. We investigated various factors associated with local recurrence in these patients. The main outcomes were the incidence of local recurrence and its relationship with clinicopathological factors during long-term surveillance.

Results

The en bloc resection rate was 98.6%, the R0 resection rate was 97.2%, and the histologically complete resection rate was 92.7%. Local recurrence was observed in 7/1344 (0.5%) patients and the median follow-up period was 72 months (range 4-195 months). The incidence of local recurrence was significantly higher in lesions ≥40 mm in diameter (hazard ratio [HR] 15.68 [1.88-130.5]; p = 0.011), piecemeal resection (HR 48.42 [10.7-218.7]; p < 0.001), non-R0 resection (HR 41.05 [9.025-186.7]; p < 0.001), histologically incomplete resection (HR 16.23 [3.627-72.63]; p<0.001), and severe fibrosis (F2; HR 9.523 [1.14-79.3]; p = 0.037).

Conclusions

Five risk factors for local recurrence after ESD were identified. Patients with such factors should undergo careful surveillance colonoscopy.

Closing the Gap: A Critical Examination of Adherence, Inconsistency, and Improvements in Colonoscopy Reporting Practices

INTRODUCTION

Comprehensive and standardized colonoscopy reports are crucial in colorectal cancer prevention, monitoring, and research. This study investigates adherence to national and international guidelines by analyzing reporting practices among 21 endoscopists in 7 German centers, with a focus on polyp reporting.

METHODS

We identified and assessed German, European, American, and World Health Organization-provided statements to identify key elements in colonoscopy reporting. Board-certified gastroenterologists rated the relevance of each element and estimated their reporting frequency. Adherence to the identified report elements was evaluated for 874 polyps from 351 colonoscopy reports ranging from March 2021 to March 2022.

RESULTS

We identified numerous recommendations for colonoscopy reporting. We categorized the reasoning behind those recommendations into clinical relevance, justification, and quality control and research. Although all elements were considered relevant by the surveyed gastroenterologists, discrepancies were observed in the evaluated reports. Particularly diminutive polyps or attributes which are rarely abnormal (e.g., surface integrity) respectively rarely performed (e.g., injection) were sparsely documented. Furthermore, the white light morphology of polyps was inconsistently documented using either the Paris classification or free text. In summary, the analysis of 874 reported polyps revealed heterogeneous adherence to the recommendations, with reporting frequencies ranging from 3% to 89%.

CONCLUSION

The inhomogeneous report practices may result from implicit reporting practices and recommendations with varying clinical relevance. Future recommendations should clearly differentiate between clinical relevance and research and quality control or explanatory purposes. Additionally, the role of computer-assisted documentation should be further evaluated to increase report frequencies of non-pathological findings and diminutive polyps.

Characteristics and Prognosis of Sporadic Neoplasias Detected in Patients with Ulcerative Colitis

INTRODUCTION

Patients with ulcerative colitis (UC) develop not only UC-associated neoplasias but also sporadic neoplasias (SNs). However, few studies have described the characteristics of SNs in patients with UC. Therefore, this study aimed to evaluate the clinical features and prognosis of SNs in patients with UC.

METHODS

A total of 141 SNs in 59 patients with UC, detected by surveillance colonoscopy at Hiroshima University Hospital between January 1999 and December 2021, were included. SNs were diagnosed based on their location, endoscopic features, and histopathologic findings along with immunohistochemical staining for Ki67 and p53.

RESULTS

Of the SNs, 91.5% were diagnosed as adenoma and 8.5% were diagnosed as carcinoma (Tis carcinoma, 3.5%; T1 carcinoma, 5.0%). 61.0% of the SNs were located in the right colon, 31.2% were located in the left colon, and 7.8% were located in the rectum. When classified based on the site of the lesion, 70.9% of SNs occurred outside and 29.1% within the affected area. Of all SNs included, 95.7% were endoscopically resected and 4.3% were surgically resected. Among the 59 patients included, synchronous SNs occurred in 23.7% and metachronous multiple SNs occurred in 40.7% during surveillance. The 5-year cumulative incidence of metachronous multiple SNs was higher in patients with synchronous multiple SNs (54.2%) than in those without synchronous multiple SNs (46.4%).

CONCLUSION

Patients with UC with synchronous multiple SNs are at a higher risk of developing metachronous multiple SNs and may require a closer follow-up by total colonoscopy than patients without synchronous SNs.

A Novel Dual Layer Cascade Reliability Framework for an Informed and Intuitive Clinician-AI Interaction In Diagnosis of Colorectal Cancer Polyps

We present a novel Cascade Reliability Framework (CRF) that integrates two independent cascade layers of reliability (i.e., variational temperature scaling and conformal prediction) with a pre-trained Machine Learning (ML) model in order to provide clinicians with a more reliable and tunable tool for early-stage diagnosis of Colorectal Cancer (CRC) polyps. The conformal prediction layer generates predictive sets that are guaranteed to contain the true polyp type with an adjustable error rate tuned by clinicians, while the confidence calibration generates meaningful confidence estimates for each predicted label. These two layers provide additional information and an error-tuning-ability for clinicians to assist them in making informed and intuitive decisions considering the outputs of the pre-trained ML model. Utilizing a novel vision-based tactile sensor and unique 3D-printed CRC polyp phantoms, we evaluated the trustworthiness of the proposed architecture and particularly dual outputs of four different types of CRF models, integrated with two different pre-trained ML models (i.e., ResNet18 and Dilated Residual Network) to highlight the model-agnostic feature of the architecture. To thoroughly assess the performance of the proposed approach, we used reliability diagrams and metrics such as accuracy, coverage, and average set size, while also addressing inter-class performance. Results demonstrate that the calibrated CRF models are well capable of handling non-ideal inputs with noise and blur. Moreover, using the conformal prediction with a user-defined error rate and various experiments, we show how clinicians can intuitively interact with a pre-trained ML model to make informed decisions and minimize the risk of CRC polyps misdiagnoses.

Endoscopic Diagnosis of Superficial Gastrointestinal Cancer

White light image (WLI) findings are important for detection and characterization in the GI tract. However, magnified endoscopic examination with image enhanced endoscopy (IEE-NE) is becoming increasingly important for qualitative diagnosis of GI neoplastic lesions. IEE-ME is extremely useful for diagnosis of invasion depth in esophageal squamous cell cancer (ESCC) and colorectal cancer, whereas macroscopic findings of WLI are still useful in Barrett's adenocarcinoma (BAC) and gastric cancer. IEE-ME is also useful for diagnosis of tumor extent in BAC and gastric cancer, whereas chromoendoscopy with indigo carmine is useful in colorectal cancer and iodine staining is indispensable in ESCC.

Computer-aided polyp characterization in colonoscopy: sufficient performance or not?

Computer-assisted polyp characterization (computer-aided diagnosis, CADx) facilitates optical diagnosis during colonoscopy. Several studies have demonstrated high sensitivity and specificity of CADx tools in identifying neoplastic changes in colorectal polyps. To implement CADx tools in colonoscopy, there is a need to confirm whether these tools satisfy the threshold levels that are required to introduce optical diagnosis strategies such as "diagnose-and-leave," "resect-and-discard" or "DISCARD-lite." In this article, we review the available data from prospective trials regarding the effect of multiple CADx tools and discuss whether they meet these thresholds.

Methylation study of tumor suppressor genes in human aberrant crypt foci, colorectal carcinomas, and normal colon

BACKGROUND

Aberrant crypt foci (ACF) are the earliest preneoplastic lesions in human colon, identifiable on chromoendoscopic screening. Our objective was to evaluate the %methylation of APC, CDKN2A, MLH1, RASSF1, MGMT, and WIF1 tumor suppressor genes (TSG) in ACF, corresponding colorectal carcinomas (CRC), and normal colonic mucosal controls.

METHODS

In this study, macroscopically normal-appearing mucosal flaps were sampled 5-10 cm away from the tumor mass from 302 fresh colectomy specimens to identify ACF-like lesions. Thirty-five cases with multiple ACFs were selected (n 35) as the main study group, with corresponding sections from CRC (n 35) as disease controls, and mucosal tissue blocks from 20 colectomy specimens (normal controls), operated for non-neoplastic pathologies. Genomic DNA was extracted, and methylation-specific polymerase chain reaction (PCR) was performed on a customized methylation array model. %Methylation data were compared among the groups and with clinicopathological parameters. Selected target mRNA and protein expression studies were performed.

RESULTS

%Methylation of TSGs in ACF was intermediate between normal colon and CRC, although a statistically significant difference was observed only for the WIF1 gene (P < 0.01). Also, there was increased nuclear β-catenin expression and upregulation of CD44-positive cancer-stem cells in ACF and CRCs than in controls. Right-sided ACFs and dysplastic ACFs had a higher %methylation of CDKN2A (P < 0.01), whereas hyperplastic ACFs had a higher %methylation of RASSF1 (P 0.04). The topographic characteristics of ACFs did not correlate with TSG %methylation.

CONCLUSIONS

Early epigenetic methylation of WIF1 gene is one of the mechanisms for ACF development in human colon.

Advancements in Endoscopic Resection for Colitis-Associated Colorectal Neoplasia in Inflammatory Bowel Disease: Turning Visible into Resectable

Patients suffering from inflammatory bowel disease (IBD) face a two to three-fold higher risk of developing colorectal cancer (CRC) compared to the general population. In recent years, significant progress has been made in comprehending the natural history of IBD-associated CRC (IBD-CRC) and refining its treatment strategies. The decreased incidence of IBD-CRC can be attributed to improved therapeutic management of inflammation, advancements in endoscopy, and early detection of precancerous lesions via surveillance programs. Advanced imaging technologies have made previously undetectable dysplasia visible in most cases, allowing for a much more precise and detailed examination of the mucosa. Additionally, new tools have facilitated the endoscopic resection (ER) of visible lesions in IBD. Particularly, the key to effectively manage colitis-associated colorectal neoplasia (CAN) is to first identify it and subsequently guarantee a complete ER in order to avoid surgery and opt for continuing surveillance. Advanced ER techniques for CAN include endoscopic mucosal resection (EMR), endoscopic submucosal dissection (ESD), and hybrid ESD-EMR (h-ESD). This narrative review aims to consolidate the current literature on IBD-CRC, providing an overview of advanced techniques for ER of CAN in IBD, with a particular emphasis on the impact of ESD on the long-term outcomes of IBD patients.

Endoscopic characterization of neoplastic and non-neoplastic lesions in inflammatory bowel disease: systematic review in the era of advanced endoscopic imaging

Background

Current guidelines strongly recommend the use of validated classifications to support optical diagnosis of lesions with advanced endoscopic imaging in the lower gastrointestinal tract. However, the optimal strategy in inflammatory bowel disease (IBD) is still a matter of debate.

Objectives

To analyze the accuracy of endoscopic classifications or single predictors for in vivo lesion characterization during endoscopic surveillance of IBD with advanced endoscopic imaging.

Design

Systematic review.

Data sources and methods

Medline and PubMed were used to extract all studies which focused on lesion characterization of neoplastic and non-neoplastic lesions in IBD. The diagnostic accuracy of endoscopic classifications and single endoscopic predictors for lesion characterization were analyzed according to type of patients, lesions, and technology used. When available, the rates of true and false positives or negatives for neoplasia were pooled and the sensitivity (SE), specificity (SP), positive predictive value, and negative predictive value (NPV) were calculated.

Results

We included 35 studies (2789 patients; 5925 lesions - 1149 neoplastic). Advanced endoscopic imaging included dye-based chromoendoscopy, virtual chromoendoscopy (VCE), magnification and high-definition endoscopy, confocal laser endomicroscopy (CLE), endocytoscopy, and autofluorescence imaging. The Kudo classification of pit patterns was most frequently used, with pooled SE 83%, SP 83%, and NPV 95%. The endoscopic criteria with the highest accuracy, with minimum SE ⩾ 90%, SP ⩾ 80%, and NPV ⩾ 90% were: the Kudo-IBD classification used with VCE (Fuji Intelligent Color Enhancement and i-SCAN); combined irregular surface and vascular patterns used with narrow band imaging; the Mainz classification used with CLE. Multiple clinical and technical factors were found to influence the accuracy of optical diagnosis in IBD.

Conclusion

No single endoscopic factor has yet shown sufficient accuracy for lesion characterization in IBD surveillance. Conventional classifications developed in the non-IBD setting have lower accuracy in IBD. The use of new classifications adapted for IBD (Kudo-IBD), and new technologies based on in vivo microscopic analysis show promise.

Magnifying chromoendoscopy is a reliable method in the selection of rectal neoplasms for local excision

PURPOSE

Adequate staging of early rectal neoplasms is essential for organ-preserving treatments, but magnetic resonance imaging (MRI) frequently overestimates the stage of those lesions. We aimed to compare the ability of magnifying chromoendoscopy and MRI to select patients with early rectal neoplasms for local excision.

METHODS

This retrospective study in a tertiary Western cancer center included consecutive patients evaluated by magnifying chromoendoscopy and MRI who underwent en bloc resection of nonpedunculated sessile polyps larger than 20 mm, laterally spreading tumors (LSTs) [Formula: see text] 20 mm, or depressed-type lesions of any size (Paris 0-IIc). Sensitivity, specificity, accuracy, and positive and negative predictive values of magnifying chromoendoscopy and MRI to determine which lesions were amenable to local excision (i.e., [Formula: see text] T1sm1) were calculated.

RESULTS

Specificity of magnifying chromoendoscopy was 97.3% (95% CI 92.2-99.4), and accuracy was 92.7% (95% CI 86.7-96.6) for predicting invasion deeper than T1sm1 (not amenable to local excision). MRI had lower specificity (60.5%, 95% CI 43.4-76.0) and lower accuracy (58.3%, 95% CI 43.2-72.4). Magnifying chromoendoscopy incorrectly predicted invasion depth in 10.7% of the cases in which the MRI was correct, while magnifying chromoendoscopy provided a correct diagnosis in 90% of the cases in which the MRI was incorrect (p = 0.001). Overstaging occurred in 33.3% of the cases in which magnifying chromoendoscopy was incorrect and 75% of the cases in which MRI was incorrect.

CONCLUSION

Magnifying chromoendoscopy is reliable for predicting invasion depth in early rectal neoplasms and selecting patients for local excision.

Artificial Intelligence-Assisted Optical Diagnosis: A Comprehensive Review of Its Role in Leave-In-Situ and Resect-and-Discard Strategies in Colonoscopy

Colorectal cancer screening plays a vital role in early detection and removal of precancerous adenomas, contributing to decreased mortality rates. Most polyps found during colonoscopies are small and unlikely to harbor advanced neoplasia or invasive cancer, leading to the development of "leave-in-situ" and "resect-and-discard" approaches. These strategies could lead to significant cost savings and efficiencies, but their implementation has been hampered by concerns around financial incentives, medical-legal risks, and local rules for tissue handling. This article reviews the potential of artificial intelligence to enhance the accuracy of polyp diagnosis through computer-aided diagnosis (CADx). While the adoption of CADx in optical biopsy has shown mixed results, it has the potential to significantly improve the management of colorectal polyps. Several studies reviewed in this article highlight the varied results of CADx in optical biopsy for colorectal polyps. Although artificial intelligence does not consistently outperform expert endoscopists, it has the potential to serve as a beneficial secondary reader, aiding in accurate optical diagnosis and increasing the confidence of the endoscopist. These studies indicate that although CADx holds great potential, it is yet to fully meet the performance thresholds necessary for clinical implementation.

Update on Endoscopic Dysplasia Surveillance in Inflammatory Bowel Disease

As medical management of inflammatory bowel disease makes great advances, most patients with inflammatory bowel disease will have long life expectancies without need for total colectomy. With prolonged disease duration, however, there is increased risk of dysplasia leading to colorectal cancer. Multiple consensus and guideline documents have been published over the last decade with recommendations to optimize early detection and management of dysplastic lesions. Endoscopic technology has improved tremendously, even over the past few years. Previously invisible dysplasia has become visible in most cases with advanced imaging technologies that now allow for much clearer and more detailed mucosal inspection. New tools to facilitate endoscopic resection of visible lesions have also enabled patients to avoid colectomy, with resulting need to continue colon surveillance. There are limited or conflicting data leading to inconsistent recommendations regarding the need for random biopsies, the preferred endoscopic imaging technique, and surveillance intervals after resection of dysplasia. Similarly, there remains significant variability in the application of guidelines into daily practice and availability of and training with advanced imaging technologies. Here, we present a narrative review of which patients are at highest risk for dysplasia, the current guidelines on surveillance colonoscopy, factors affecting optimal mucosal visualization, enhanced imaging techniques, standardized reporting terminologies for surveillance colonoscopy, endoscopic management of dysplasia, indications for colectomy, and briefly on future potential technologies to assist in dysplasia detection.

Diagnostic Value of Adding Magnifying Chromoendoscopy to Magnifying Narrow-Band Imaging Endoscopy for Colorectal Polyps

BACKGROUND & AIMS

This study examined the additional value of magnifying chromoendoscopy (MCE) on magnifying narrow-band imaging endoscopy (M-NBI) in the optical diagnosis of colorectal polyps.

METHODS

A multicenter prospective study was conducted at 9 facilities in Japan and Germany. Patients with colorectal polyps scheduled for resection were included. Optical diagnosis was performed by M-NBI first, followed by MCE. Both diagnoses were made in real time. MCE was performed on all type 2B lesions classified according to the Japan NBI Expert Team classification and other lesions at the discretion of endoscopists. The diagnostic accuracy and confidence of M-NBI and MCE for colorectal cancer (CRC) with deep invasion (≥T1b) were compared on the basis of histologic findings after resection.

RESULTS

In total, 1173 lesions were included between February 2018 and December 2020, with 654 (5 hyperplastic polyp/sessile serrated lesion, 162 low-grade dysplasia, 403 high-grade dysplasia, 97 T1 CRCs, and 32 ≥T2 CRCs) examined using MCE after M-NBI. In the diagnostic accuracy for predicting CRC with deep invasion, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for M-NBI were 63.1%, 94.2%, 61.6%, 94.5%, and 90.2%, respectively, and for MCE they were 77.4%, 93.2%, 62.5%, 96.5%, and 91.1%, respectively. The sensitivity was significantly higher in MCE (P < .001). However, these additional values were limited to lesions with low confidence in M-NBI or the ones diagnosed as ≥T1b CRC by M-NBI.

CONCLUSIONS

In this multicenter prospective study, we demonstrated the additional value of MCE on M-NBI. We suggest that additional MCE be recommended for lesions with low confidence or the ones diagnosed as ≥T1b CRC. Trials registry number: UMIN000031129.

Impact of a Routine Colorectal Endoscopic Submucosal Dissection in the Surgical Management of Nonmalignant Colorectal Lesions Treated in a Referral Cancer Center

BACKGROUND

Recent data show an increasing number of abdominal surgeries being performed for the treatment of nonmalignant colorectal polyps in the West but in settings in which colorectal endoscopic submucosal dissection is not routinely performed. This study evaluated the number of nonmalignant colorectal lesions referred to surgical treatment in a tertiary cancer center that incorporated magnification chromoendoscopy and endoscopic submucosal dissection as part of the standard management of complex colorectal polyps.

OBJECTIVE

The study aimed to estimate the number of patients with nonmalignant colorectal lesions referred to surgical resection at our institution after the standardization of routine endoscopic submucosal dissection and to describe outcomes for patients undergoing colorectal endoscopic submucosal dissection.

DESIGN

Single-center retrospective study from a prospectively collected database of endoscopic submucosal dissections and colorectal surgeries performed between January 2016 and December 2019.

SETTING

Reference cancer center.

PATIENTS

Consecutive adult patients with complex nonmalignant colorectal polyps were included.

INTERVENTIONS

Patients with nonmalignant colorectal polyps were treated by endoscopic submucosal dissection or surgery (elective colectomy, rectosigmoidectomy, low anterior resection, or proctocolectomy).

MAIN OUTCOMES MEASURES

The primary outcome measure was the percentage of patients referred to colorectal surgery for nonmalignant lesions.

RESULTS

In the study period, 1.1% of 825 colorectal surgeries were performed for nonmalignant lesions, and 97 complex polyps were endoscopically removed by endoscopic submucosal dissection. The en bloc, R0, and curative resection rates of endoscopic submucosal dissection were 91.7%, 83.5%, and 81.4%, respectively. The mean tumor size was 59 (SD 37.8) mm. Perforations during endoscopic submucosal dissection occurred in 3 cases, all treated with clipping. One patient presented with a delayed perforation 2 days after the endoscopic resection and underwent surgery. The mean follow-up period was 3 years, with no tumor recurrence in this cohort.

LIMITATIONS

Single-center retrospective study.

CONCLUSIONS

A workflow that includes assessment of the lesions with magnification chromoendoscopy and resection through endoscopic submucosal dissection can lead to a very low rate of abdominal surgery for nonmalignant colorectal lesions. See Video Abstract at http://links.lww.com/DCR/C123 .

IMPACTO DE LA DISECCIN SUBMUCOSA ENDOSCPICA COLORRECTAL DE RUTINA EN EL MANEJO QUIRRGICO DE LESIONES COLORRECTALES NO MALIGNAS TRATADAS EN UN CENTRO ONCOLGICO DE REFERENCIA

ANTECEDENTES:Datos recientes muestran un número cada vez mayor de cirugías abdominales realizadas para el tratamiento de pólipos colorrectales no malignos en Occidente, pero no en los entornos donde la disección submucosa endoscópica colorrectal se realiza de forma rutinaria. El estudio evaluó el número de lesiones colorrectales no malignas referidas a tratamiento quirúrgico en un centro oncológico terciario, que incorporó cromoendoscopia de aumento y disección submucosa endoscópica como parte del manejo estándar de pólipos colorrectales complejos.OBJETIVO:Estimar el número de pacientes con lesiones colorrectales no malignas referidos para resección quirúrgica en nuestra institución, después de la estandarización de la disección submucosa endoscópica de rutina y describir los resultados para los pacientes sometidos a disección submucosa endoscópica colorrectal.DISEÑO:Estudio retrospectivo de un solo centro, a partir de una base de datos recolectada prospectivamente de disecciones submucosas endoscópicas y cirugías colorrectales realizadas entre enero de 2016 y diciembre de 2019.AJUSTE:Centro oncológico de referencia.PACIENTES:Pacientes adultos consecutivos con pólipos colorrectales no malignos complejos.INTERVENCIONES:Pacientes con pólipos colorrectales no malignos tratados mediante disección submucosa endoscópica o cirugía (colectomía electiva, rectosigmoidectomía, resección anterior baja o proctocolectomía).PRINCIPALES MEDIDAS DE RESULTADO:La medida de resultado primario fue el porcentaje de pacientes remitidos a cirugía colorrectal por lesiones no malignas.RESULTADOS:En el período, 1,1% de 825 cirugías colorrectales fueron realizadas por lesiones no malignas y 97 pólipos complejos fueron extirpados por. disección submucosa endoscópica. Las tasas de resección en bloque, R0 y curativa de disección submucosa endoscópica fueron 91,7%, 83,5% y 81,4%, respectivamente. El tamaño tumoral medio fue de 59 (DE 37,8) mm. Se produjeron perforaciones durante la disección submucosa endoscópica en 3 casos, todos tratados con clipaje. Un paciente presentó una perforación diferida 2 días después de la resección endoscópica y fue intervenido quirúrgicamente. El seguimiento medio fue de 3 años, sin recurrencia tumoral en esta cohorte.LIMITACIONES:Estudio retrospectivo de un solo centro.CONCLUSIONES:Un flujo de trabajo que incluye la evaluación de las lesiones con cromoendoscopia de aumento y resección a través de disección submucosa endoscópica, puede conducir a una tasa muy baja de cirugía abdominal para lesiones colorrectales no malignas. Consulte Video Resumen en http://links.lww.com/DCR/C123 . (Traducción-Dr. Fidel Ruiz Healy ).

Sessile serrated lesions with dysplasia: is it possible to nip them in the bud?

The serrated neoplasia pathway constitutes an "alternative route" to colorectal cancer (CRC), and sessile serrated lesions with dysplasia (SSLDs) are an intermediate step between sessile serrated lesions (SSLs) and invasive CRC in this pathway. While SSLs show indolent growth before becoming dysplastic (> 10-15 years), SSLDs are considered to rapidly progress to either immunogenic microsatellite instable-high (MSI-H) CRC (presumably 75% of cases) or mesenchymal microsatellite stable (MSS) CRC. Their flat shapes and the relatively short window of this intermediate state make it difficult to detect and diagnose SSLDs; thus, these lesions are potent precursors of post-colonoscopy/interval cancers. Confusing terminology and the lack of longitudinal observation data of serrated polyps have hampered the accumulation of knowledge about SSLDs; however, a growing body of evidence has started to clarify their characteristics and biology. Together with recent efforts to incorporate terminology, histological studies of SSLDs have identified distinct dysplastic patterns and revealed alterations in the tumor microenvironment (TME). Molecular studies at the single-cell level have identified distinct gene alterations in both the epithelium and the TME. Mouse serrated tumor models have demonstrated the importance of TME in disease progression. Advances in colonoscopy provide clues to distinguish pre-malignant from non-malignant-SSLs. Recent progress in all aspects of the field has enhanced our understanding of the biology of SSLDs. The aim of this review article was to assess the current knowledge of SSLDs and highlight their clinical implications.

Development and validation of an online calculator to predict the pathological nature of colorectal tumors

BACKGROUND

No single endoscopic feature can reliably predict the pathological nature of colorectal tumors (CRTs).

AIM

To establish and validate a simple online calculator to predict the pathological nature of CRTs based on white-light endoscopy.

METHODS

This was a single-center study. During the identification stage, 530 consecutive patients with CRTs were enrolled from January 2015 to December 2021 as the derivation group. Logistic regression analysis was performed. A novel online calculator to predict the pathological nature of CRTs based on white-light images was established and verified internally. During the validation stage, two series of 110 images obtained using white-light endoscopy were distributed to 10 endoscopists [five highly experienced endoscopists and five less experienced endoscopists (LEEs)] for external validation before and after systematic training.

RESULTS

A total of 750 patients were included, with an average age of 63.6 ± 10.4 years. Early colorectal cancer (ECRC) was detected in 351 (46.8%) patients. Tumor size, left semicolon site, rectal site, acanthosis, depression and an uneven surface were independent risk factors for ECRC. The C-index of the ECRC calculator prediction model was 0.906 (P = 0.225, Hosmer–Lemeshow test). For the LEEs, significant improvement was made in the sensitivity, specificity and accuracy (57.6% vs 75.5%; 72.3% vs 82.4%; 64.2% vs 80.2%; P < 0.05), respectively, after training with the ECRC online calculator prediction model.

CONCLUSION

A novel online calculator including tumor size, location, acanthosis, depression, and uneven surface can accurately predict the pathological nature of ECRC.

Curriculum for training in endoscopic mucosal resection in the colon: European Society of Gastrointestinal Endoscopy (ESGE) Position Statement

Endoscopic mucosal resection (EMR) is the standard of care for the complete removal of large (≥ 10 mm) nonpedunculated colorectal polyps (LNPCPs). Increased detection of LNPCPs owing to screening colonoscopy, plus high observed rates of incomplete resection and need for surgery call for a standardized approach to training in EMR. 1 : Trainees in EMR should have achieved basic competence in diagnostic colonoscopy, < 10-mm polypectomy, pedunculated polypectomy, and common methods of gastrointestinal endoscopic hemostasis. The role of formal training courses is emphasized. Training may then commence in vivo under the direct supervision of a trainer. 2 : Endoscopy units training endoscopists in EMR should have specific processes in place to support and facilitate training. 3: A trained EMR practitioner should have mastered theoretical knowledge including how to assess an LNPCP for risk of submucosal invasion, how to interpret the potential difficulty of a particular EMR procedure, how to decide whether to remove a particular LNPCP en bloc or piecemeal, whether the risks of electrosurgical energy can be avoided for a particular LNPCP, the different devices required for EMR, management of adverse events, and interpretation of reports provided by histopathologists. 4: Trained EMR practitioners should be familiar with the patient consent process for EMR. 5: The development of endoscopic non-technical skills (ENTS) and team interaction are important for trainees in EMR. 6: Differences in recommended technique exist between EMR performed with and without electrosurgical energy. Common to both is a standardized technique based upon dynamic injection, controlled and precise snare placement, safety checks prior to the application of tissue transection (cold snare) or electrosurgical energy (hot snare), and interpretation of the post-EMR resection defect. 7: A trained EMR practitioner must be able to manage adverse events associated with EMR including intraprocedural bleeding and perforation, and post-procedural bleeding. Delayed perforation should be avoided by correct interpretation of the post-EMR defect and treatment of deep mural injury. 8: A trained EMR practitioner must be able to communicate EMR procedural findings to patients and provide them with a plan in case of adverse events after discharge and a follow-up plan. 9: A trained EMR practitioner must be able to detect and interrogate a post-endoscopic resection scar for residual or recurrent adenoma and apply treatment if necessary. 10: Prior to independent practice, a minimum of 30 EMR procedures should be performed, culminating in a trainer-guided assessment of competency using a validated assessment tool, taking account of procedural difficulty (e. g. using the SMSA polyp score). 11: Trained practitioners should log their key performance indicators (KPIs) of polypectomy during independent practice. A guide for target KPIs is provided in this document.

Automated classification of polyps using deep learning architectures and few-shot learning

BACKGROUND

Colorectal cancer is a leading cause of cancer-related deaths worldwide. The best method to prevent CRC is a colonoscopy. However, not all colon polyps have the risk of becoming cancerous. Therefore, polyps are classified using different classification systems. After the classification, further treatment and procedures are based on the classification of the polyp. Nevertheless, classification is not easy. Therefore, we suggest two novel automated classifications system assisting gastroenterologists in classifying polyps based on the NICE and Paris classification.

METHODS

We build two classification systems. One is classifying polyps based on their shape (Paris). The other classifies polyps based on their texture and surface patterns (NICE). A two-step process for the Paris classification is introduced: First, detecting and cropping the polyp on the image, and secondly, classifying the polyp based on the cropped area with a transformer network. For the NICE classification, we design a few-shot learning algorithm based on the Deep Metric Learning approach. The algorithm creates an embedding space for polyps, which allows classification from a few examples to account for the data scarcity of NICE annotated images in our database.

RESULTS

For the Paris classification, we achieve an accuracy of 89.35 %, surpassing all papers in the literature and establishing a new state-of-the-art and baseline accuracy for other publications on a public data set. For the NICE classification, we achieve a competitive accuracy of 81.13 % and demonstrate thereby the viability of the few-shot learning paradigm in polyp classification in data-scarce environments. Additionally, we show different ablations of the algorithms. Finally, we further elaborate on the explainability of the system by showing heat maps of the neural network explaining neural activations.

CONCLUSION

Overall we introduce two polyp classification systems to assist gastroenterologists. We achieve state-of-the-art performance in the Paris classification and demonstrate the viability of the few-shot learning paradigm in the NICE classification, addressing the prevalent data scarcity issues faced in medical machine learning.

Complete endoscopic removal rate of detected colorectal polyps in a real world out-patient practical setting

OBJECTIVES

Colonoscopy with adenomatous polypectomy reduces the incidence and mortality of colorectal cancer. We introduced a strategy of removing all neoplastic polyps in single-session out-patient colonoscopy using cold polypectomy. We aimed to investigate the achievement of single-session complete removal rate of detected colorectal polyps in clinical practice.

MATERIALS AND METHODS

This retrospective study included colonoscopy-scheduled 40-79-year-old outpatients, with at least one colorectal neoplasm, between January 2015 and December 2016. Exclusion criteria were: colorectal neoplasms 21 mm or larger in size; pre-examination for colorectal surgery or endoscopic submucosal dissection; colonoscopy performed by health check program; ongoing antithrombotic treatment; inflammatory bowel disease; familial adenomatous polyposis. We defined 'clean colon' as the removal of all detected neoplastic polyps in a single-session colonoscopy. We evaluated clean colon rate, factors relating to clean colon failure and complications.

RESULTS

We evaluated 2527 patients (mean age 68 years; 799 women) with 8203 colorectal polyps (7675 adenomas, 423 serrated lesions, 105 Tis and T1 cancers). In 1-4 mm polyps, cold snare polypectomy (CSP; 51.8%) and cold forceps polypectomy (CFP; 45.8%) were applied. Clean colon rates were 95.1% per patient and 97.1% per lesion. The significant factors denoting clean colon failure were inadequate bowel preparation, ≥5 lesions, and the most advanced estimated histology of adenocarcinoma, on multivariate analyses. Post-polypectomy bleeding requiring endoscopic hemostasis occurred in five patients (0.2%) who had undergone endoscopic mucosal resection (EMR) or hot snare polypectomy (HSP). Perforation occurred in one patient (0.04%) with EMR.

CONCLUSIONS

The clean colon rates were satisfactory in single-session out-patient colonoscopy using cold polypectomy.

A narrative review: narrow-band imaging endoscopic classifications

Background and Objective

With the development of endoscopic techniques, narrow-band imaging (NBI) has been widely used in the diagnosis of various types of diseases. NBI can detect mucosal lesions at an early stage and different classification strategies have been established to help clinicians in disease diagnosis. However, there is currently no consensus for the classification criteria. This report summarizes the current classifications of diseases using NBI, so as to provide a comprehensive understanding of the various manifestations of mucosal lesions under NBI, and to promote the development of more practical NBI classifications.

Methods

The PubMed database was searched for English language articles published between January 1994 and November 2021 using the keywords 'narrow band imaging', 'NBI', and 'classification'.

Key Content and Findings

We systematically summarized the NBI classifications and manifestations of different diseases. The morphology of the mucosa and vessels was used as the basis of most classifications. These classifications are mainly helpful to distinguish benign and malignant tumors and to detect early neoplastic lesions.

Conclusions

This review summarized existing NBI classifications for different systems. These classifications will be updated as the understanding of diseases increases and new optical techniques become available to better assist doctors in making clinical decisions.

NBI International Colorectal Endoscopic-derived high-confidence optical diagnosis of small polyps compared with histology: understanding errors to improve diagnostic accuracy

BACKGROUND AND AIMS

Developments in image-enhancing endoscopy and polyp classification systems have led to a number of gastroenterology societies endorsing an optical diagnosis (OD) approach for small polyps at colonoscopy. In this study we performed a root-cause analysis of ODs to determine the most likely causes of OD error.

METHODS

As part of a prospective feasibility study, DISCARD3 (Detect InSpect ChAracterise Resect and Discard 3), evaluating implementation and quality assurance of a "resect and discard" strategy for consecutive small polyps <10 mm, a root-cause analysis of 184 cases of high-confidence OD error was performed. In all cases, histopathology underwent a second blinded review and, where discrepancy persisted, further review with deeper levels.

RESULTS

After a root-cause analysis, 133 of 184 true OD errors were identified and classified into 4 types: A (OD, adenoma; histology, serrated), 45/133 (33.8%); B (OD, serrated; histology, adenoma), 55/133 (41.4%); C (OD, adenoma; histology, normal), 19/133 (14.3%); and D (OD, serrated; histology, normal), 14/133 (10.5%). The remaining 51 of 184 errors were because of a pathology error requiring deeper levels (43/184), pathology observer or laboratory error (7/184), or other error (1/184).

CONCLUSIONS

OD errors can be related to endoscopist-related factors such as poor photodocumentation, failures of current classification systems, and incomplete histology. We identified a subset of serrated polyps frequently misdiagnosed as adenomas ("pseudoadenomas") using the NBI International Colorectal Endoscopic (NICE) classification. An enhanced algorithm for OD is proposed based on the NICE classification including morphologic and adjunct polyp features.

Updates in narrow-band imaging for colorectal polyps: Narrow-band imaging generations, detection, diagnosis, and artificial intelligence

Narrow-band imaging (NBI) is an optical digital enhancement method that allows the observation of vascular and surface structures of colorectal lesions. Its usefulness in the detection and diagnosis of colorectal polyps has been demonstrated in several clinical trials and the diagnostic algorithms have been simplified after the establishment of endoscopic classifications such as the Japan NBI Expert Team classification. However, there were issues including lack of brightness in the earlier models, poor visibility under insufficient bowel preparation, and the incompatibility of magnifying endoscopes in certain endoscopic platforms, which had impeded NBI from becoming standardized globally. Nonetheless, NBI continued its evolution and the newest endoscopic platform launched in 2020 offers significantly brighter and detailed images. Enhanced visualization is expected to improve the detection of polyps while universal compatibility across all scopes including magnifying endoscopy will promote the global standardization of magnifying diagnosis. Therefore, knowledge related to magnifying colonoscopy will become essential as magnification becomes standardly equipped in future models, although the advent of computer-aided diagnosis and detection may greatly assist endoscopists to ensure quality of practice. Given that most endoscopic departments will be using both old and new models, it is important to understand how each generation of endoscopic platforms differ from each other. We reviewed the advances in the endoscopic platforms, artificial intelligence, and evidence related to NBI essential for the next generation of endoscopic practice.

Sessile serrated lesions: Clinicopathological characteristics, endoscopic diagnosis, and management

The 2019 World Health Organization (WHO) Classification of Tumours of the Digestive System (5th edition) introduced the term "sessile serrated lesion" (SSL) to replace the term "sessile serrated adenoma/polyp" (SSA/P). SSLs are early precursor lesions in the serrated neoplasia pathway that result in colorectal carcinomas with BRAF mutations, methylation for DNA repair genes, a CpG island methylator phenotype, and high levels of microsatellite instability. Some of these lesions can rapidly become dysplastic or invasive carcinomas that exhibit high lymphatic invasion and lymph node metastasis potential. The 2019 WHO classification noted that dysplasia arising in an SSL most likely is an advanced polyp, regardless of the morphologic grade of the dysplasia. Detecting SSLs with or without dysplasia is critical; however, detection of SSLs is challenging, and their identification by endoscopists and pathologists is inconsistent. Furthermore, indications for their endoscopic treatment have not been established. Moreover, SSLs are considered to contribute to the development of post-colonoscopy colorectal cancers. Herein, the clinicopathological and endoscopic characteristics of SSLs, including features determined using white light and image-enhanced endoscopy, therapeutic indications, therapeutic methods, and surveillance are reviewed based on the literature. This information may lead to more intensive research to improve detection, diagnosis, and rates of complete resection of these lesions and reduce post-colonoscopy colorectal cancer rates.

Risk factors for vertical incomplete resection in endoscopic submucosal dissection of deep invasive submucosal colorectal cancer

INTRODUCTION

It has been recently reported that deep invasive submucosal (T1b) colorectal cancer (CRC) without other pathological risk factors for lymph node metastasis has a low rate of lymph node metastasis, increasing the possibility of endoscopic submucosal dissection (ESD) in the future. However, ESD for T1b CRC is technically difficult, and some lesions cannot be resected en bloc. This study aimed to identify the risk factors associated with vertical incomplete ESD in T1b CRC.

METHODS

We retrospectively studied 140 pathological T1b CRC lesions that underwent initial ESD at our institution between January 2011 and October 2020, and categorized them into positive vertical margin (PVM) and negative vertical margin (NVM) groups. The risk factors for PVM were examined using univariate and multivariate analyses, and a subgroup analysis for T1b CRC with an obvious depressed surface was performed.

RESULTS

Multivariate analysis revealed obvious depression (hazard ratio [HR]: 7.4; 95% confidence interval [CI]: 2.47-22.5) and severe fibrosis (HR: 11.4; 95% CI: 3.95-33.0) as significant risk factors for PVM. Length of depressed surface ≥12 mm (HR: 6.19; 95% CI: 1.56 -24.6) was identified as an independent predictor of PVM for T1b CRC with an obvious depression.

CONCLUSION

Pathological T1b CRC cases with an obvious depression and severe fibrosis are at a high risk of vertical incomplete ESD.

Comparison of postpolypectomy bleeding events between cold snare polypectomy and hot snare polypectomy for small colorectal lesions: a large-scale propensity score-matched analysis

BACKGROUND AND AIMS

Cold snare polypectomy (CSP), a safe procedure for removing colon polyps, has a low prevalence of postpolypectomy bleeding (PPB). Previous studies have failed to demonstrate differences in PPB rates between CSP and hot snare polypectomy (HSP), possibly because of their small sample sizes. This study analyzed PPB rates after CSP and HSP.

METHODS

This was a retrospective analysis of colorectal lesions (diameter <10 mm) treated using endoscopic resection at our institution between January 2015 and December 2019. Resections were performed using CSP or HSP, depending on the endoscopist's preference. Endoscopic and histologic findings were recorded in the endoscopic database at our institution. Propensity score (PS) matching was performed to match patient age, lesion size, macroscopic features, location of the lesions, clipping after resection, and antithrombotic agent use. The CSP and HSP groups were compared to determine the adverse event (PPB) rates.

RESULTS

The CSP and HSP groups included 12,928 and 2408 lesions (total of 5371 patients), respectively. Univariate analysis revealed that the overall prevalence of PPB after HSP was higher than that after CSP (odds ratio [OR], 5.39; 95% confidence interval [CI], 2.50-11.60). After PS matching (2135 lesions per group), the prevalence of PPB after HSP remained higher than that after CSP (OR, 6.0; 95% CI, 1.34-26.8).

CONCLUSIONS

For colorectal lesions <10 mm in diameter, the risk of PPB after CSP is significantly lower than that after HSP, after PS matching. CSP for lesions <10 mm could be safely performed compared with HSP.

Endoscopic Surveillance in Inflammatory Bowel Diseases: Selecting a Suitable Technology

In the treat-to-target era, endoscopy has become the backbone of the assessment of remission, defined as mucosal healing, in inflammatory bowel disease (IBD) patients. Current recommendations indicate that endoscopic procedures should be performed with high-definition white-light endoscopy (HD-WLE), as it guarantees the best possible visualization of the mucosa. With respect to endoscopic surveillance, the preventive strategy for dysplasia and colorectal cancer (CRC) in long-standing IBD, is the use of dye-chromoendoscopy (DCE), which enhances the mucosal pattern of the colonic walls. DCE has been established as the gold standard for dysplasia detection and is at present incorporated in all international guidelines. Over the past years, novel technologies, such as high-definition endoscopic imaging, and optical and digital enhancement tools have revolutionized the quality and level of fine details of vascular and mucosal patterns. These endoscopic images have the ambition to reflect histological changes for suspected neoplastic lesions and inflammation or healing and are emerging as potential alternatives to DCE. Indeed, the comparison of DCE with high-definition imaging is an open issue that deserves further investigation. We aimed to examine and summarize the technical aspects and the current evidence on endoscopic technologies with a specific focus on the surveillance in IBD patients.

Endoscopic submucosal dissection using traction by a spring-and-loop with clip for a laterally spreading tumor in the inferior aspect of the cecum: a nonreferral center experience

Video 1Endoscopic submucosal dissection using traction by a spring-and-loop with clip for a laterally spreading tumor in the inferior aspect of the cecum: a nonreferral center experience.

Differential diagnosis of superficial duodenal epithelial tumor and non-neoplastic lesion in duodenum by magnified endoscopic examination with image-enhanced endoscopy

BACKGROUND

Differential diagnosis of superficial duodenal epithelial tumors (SDETs) and non-neoplastic lesions (NNLs) in duodenum by endoscopy is difficult. Here, we attempted to distinguish them by magnified endoscopic examination with image-enhanced endoscopy (IEE-ME).

METHODS

Various IEE-ME findings of 95 SDETs who underwent endoscopic resection and 58 NNLs who underwent biopsy were retrospectively reviewed.

RESULTS

When we compared the IEE-ME findings of SDETs and NNLs, the presence of demarcation line (DL) (97.9% vs. 79.3%, P = 0.0002), white opaque substance (WOS) (84.2% vs. 1.7%, P < 0.0001) and light blue crest (LBC) (93.7% vs. 32.8%, P < 0.0001) and the absence of enlarged marginal epithelium (EME) (98.9% vs. 62.1%, P < 0.0001) were significantly more frequent in SDETs than NNLs. When divided into each superficial structure, it was the most effective to evaluate the combination of WOS and LBC as SDET with open-loop structure (OLS), and the combination of DL and EME as SDET with closed-loop structure (CLS). However, LBC was excluded because of low inter- and intra-observer agreements. Finally, the sensitivity, specificity and accuracy for the diagnosis of SDETs were 88.4%, 98.3% and 92.2%, respectively, and we developed an algorithm for the differential diagnosis of duodenal lesions.

CONCLUSION

We could distinguish SDET from NNL, diagnosed SDET as presence of WOS indicated OLS of superficial structure, and presence of DL and absence of EME indicated CLS of superficial structure.

Minimally Invasive Endoscopic and Surgical Management of Rectal Neoplasia

Rectal cancer demonstrates a characteristic natural history in which benign rectal neoplasia precedes malignancy. The worldwide burden of rectal cancer is significant, with rectal cancer accounting for one-third of colorectal cancer cases annually. The importance of early detection and successful management is essential in decreasing its clinical burden. Minimally invasive treatment of rectal neoplasia has evolved over the past several decades, which has led to reduced local recurrence rates and improved survival outcomes. The approach to diagnosis, staging, and selection of appropriate treatment modalities is a multidisciplinary effort combining interventional endoscopy, surgery, and radiology tools. This review examines the currently available minimally invasive endoscopic and surgical management options of rectal neoplasia.

Current Approaches in Managing Colonic Serrated Polyps and Serrated Polyposis

For decades, conventional adenomas were the only known precursor lesions of colorectal cancer (CRC). Accordingly, education and research regarding CRC prevention were mainly focused on adenomas. The groundbreaking discovery that serrated polyps (SPs) also have the potential to develop into CRCs, and seem to account for a considerable proportion of sporadic CRCs, has led to a paradigm shift in the prevention, diagnosis, and treatment of CRC. Studies in recent years have led to our current understanding of SPs and associated CRC, but a lot of work is still to be done to further improve knowledge about this serrated neoplasia pathway and the clinical management of SPs and serrated polyposis syndrome (SPS). In this review, we reflect on the current understanding of SPs with respect to terminology, detection, resection, and surveillance and reflect on the management of SPS.

Three-dimensional morphological characterization of colorectal pits from label-free microscopy images

The prognosis of colorectal cancer (CRC), one of the most prevalent pathologies worldwide, is linked to early detection. Kudo's pit pattern classification states morphological pit patterns of the Lieberkühn crypts by analyzing the superficial mucosa, predicting the histology of colorectal lesions. Its use as a highly accurate two-dimensional diagnostic criterion has increased, mostly involving expert endoscopists' judgment. The processing of autofluorescence images could allow the diagnostic, bypassing staining techniques and decreasing the biopsies, resources and times involved in the inspection. That criterion could be extended by data of the pit three-dimensional (3D) morphology. Thus, this work was aimed at obtaining 3D morphological information by quantifying geometrical and shape descriptors through software processing and analysis of widefield autofluorescence microscopy image stacks acquired by fresh colon tissue samples from a murine model of CRC. Statistical analyses included pits from control mice and from the second (2nd), fourth (4th), and eighth (8th) weeks of treatment. Statistically significant differences were found for almost all parameters between the pits from control and from the 4th treated week, stating that the major morphological changes begin after the 2nd week. In particular, pits from control or initial treatment time points were more tubular, straighter and less rough than the ones from later treatment points. Therefore, they may be more associated to normal or non-neoplastic crypt lumens than linked to adenomas or even cancer crypts. These preliminary outcomes could be considered an advance in 3D pit morphology characterization.

The "diagnose and leave in" strategy for diminutive rectosigmoid polyps in Lynch syndrome: a post hoc analysis from a randomized controlled trial

BACKGROUND

The "diagnose-and-leave-in" policy has been established to reduce the risks and costs related to unnecessary polypectomies in the average-risk population. In individuals with Lynch syndrome, owing to accelerated carcinogenesis, the general recommendation is to remove all polyps, irrespective of size, location, and appearance. We evaluated the feasibility and safety of the diagnose-and-leave-in strategy in individuals with Lynch syndrome. METHODS : We performed a post hoc analysis based on per-polyp data from a randomized, clinical trial conducted by 24 dedicated colonoscopists at 14 academic centers, in which 256 patients with confirmed Lynch syndrome underwent surveillance colonoscopy from July 2016 to January 2018. In vivo optical diagnosis with confidence level for all detected lesions was obtained before polypectomy using virtual chromoendoscopy alone or with dye-based chromoendoscopy. Primary outcome was the negative predictive value (NPV) for neoplasia of high-confidence optical diagnosis among diminutive (≤ 5 mm) rectosigmoid lesions. Histology was the reference standard.

RESULTS

Of 147 rectosigmoid lesions, 128 were diminutive. In 103 of the 128 lesions (81 %), the optical diagnostic confidence was high and showed an NPV of 96.0 % (95 % confidence interval [CI] 88.9 %-98.6 %) and accuracy of 89.3 % (95 %CI 81.9 %-93.9 %). By following the diagnose-and-leave-in policy, we would have avoided 59 % (75/128) of polypectomies at the expense of two diminutive low grade dysplastic adenomas and one diminutive sessile serrated lesion that would have been left in situ.

CONCLUSION

In patients with Lynch syndrome, the diagnose-and-leave-in strategy for diminutive rectosigmoid polyps would be feasible and safe.

Depth diagnosis of early colorectal cancer: Magnifying chromoendoscopy or image enhanced endoscopy with magnification?

Depth diagnosis is extremely crucial in making a treatment choice between endoscopic resection and surgery in the early stages of cancers. Among several imaging modalities, we use magnifying endoscopy to diagnose lesions by close observation of the findings at mucosal surface layer. In combination with topical staining, magnifying endoscopy enables us to assess the definite pit structure, which referred to as magnifying chromoendoscopy (MCE). The pit pattern classification by MCE was proposed and is now widely accepted as the standard diagnostic criteria for colorectal lesions. Meanwhile, image enhanced endoscopy (IEE) represented by narrow-band imaging was developed to improve the visibility of surface and vascular findings without dyeing. Recent collaborative work performed by endoscopic experts in Japan yielded the unified diagnostic criteria, the Japan NBI Expert Team (JNET) classification, based on the findings of IEE with magnification. In this review, focusing on MCE and IEE with magnification, we aimed to give an outline of the pit pattern classification and the JNET classification, and further discuss their accuracy rate of depth diagnosis of early colorectal lesions by performing a review of the related literature. Both modalities have a high accuracy rate of nearly 90% for depth diagnosis. IEE with magnification is an ideal modality because it helps observe lesions without dye spraying; however, lesions with JNET type 2B have an inadequate diagnostic ability, which should be complemented by MCE. We conclude that accurate diagnosis is possible by examining lesions using both modalities properly to overcome the limitations of each modality.

[One thousand endoscopic submucosal dissections. Experience of the national center]

BACKGROUND

Endoscopic submucosal dissection (ESD) is a perspective method of organ-sparing treatment of benign colon tumors.

MATERIAL AND METHODS

The study included 1.000 patients with colon neoplasms who underwent ESD between October 2016 and October 2021. All surgeries were performed under intravenous sedation.

RESULTS

Mean dimension of tumors was 3.4 cm, median of surgery time - 51 (31; 101) minutes. Conversion of endoscopic approach occurred in 7.6% of cases. The main cause of conversion was unsatisfactory lifting in submucosal injection process. Incidence of en bloc and R0 resections was 84.1% and 68.3%, respectively. Postoperative morbidity was 2.9% that correlates with the world literature data.

CONCLUSION

Endoscopic submucosal dissection is an effective and safe method for benign colon neoplasms. Considering high incidence of en bloc resection and low rate of local recurrence in benign neoplasms, further research of efficacy and safety of ESD in early colon cancer is needed.