Endoscopic Recognition and Management Strategies for Malignant Colorectal Polyps: Recommendations of the US Multi-Society Task Force on Colorectal Cancer

Surveillance and Management of Pouch Neoplasia in Familial Adenomatous Polyposis: A Systematic Review

BACKGROUND

Patients with familial adenomatous polyposis often require prophylactic colectomy with IPAA to treat or reduce the risk of colorectal neoplasia. However, after surgery, patients are still at some risk of developing pouch polyps and even cancer in both handsewn and stapled anastomoses. Management relies mainly on endoscopic or surgical interventions, whereas chemopreventive agents have a limited role in the management and prevention of pouch neoplasia. Novel endoscopic techniques are evolving and may gradually overtake surgical intervention in selected cases. Because familial adenomatous polyposis is relatively rare, there is a scarcity of data regarding the natural history of pouch polyps and cancer in this population.

OBJECTIVE

This systematic literature review aims to describe the evolution, characteristics, various treatment modalities and their outcomes, and recommended surveillance strategies of pouch neoplasia.

DATA SOURCES

PubMed and Cochrane databases and the International Ileal Pouch Consortium (for expert opinion).

STUDY SELECTION

Studies published between 1990 and 2023 in English were included. Studies reporting neoplastic outcomes of only patients with IBD-related pouch neoplasia were excluded.

MAIN OUTCOME MEASURES

Incidence of pouch neoplasia and its outcomes (successful resections, surgical complications, and mortality).

RESULTS

Thirty-five studies were included.

LIMITATIONS

Most studies focused on patients with IBD-related pouch neoplasia; there were scarce data regarding polyposis patients only. Most cohorts were small and retrospective. Data on interventions were mainly descriptive, and no randomized controlled trials were available.

CONCLUSIONS

Pouch adenomas are common and well managed by endoscopic resections because advanced endoscopic techniques are becoming more available. Additional data are required for defining updated recommendations for either endoscopic or surgical intervention. Pouch cancer is a very rare event and may arise despite surveillance. Continued endoscopic surveillance is key in cancer prevention and early detection. The outcome of cancer cases is poor, and management in a referral center should be advised with tumor board discussions. See video from symposium .

Development and validation of a novel colonoscopy withdrawal time indicator based on YOLOv5

BACKGROUND AND AIM

The study aims to introduce a novel indicator, effective withdrawal time (WTS), which measures the time spent actively searching for suspicious lesions during colonoscopy and to compare WTS and the conventional withdrawal time (WT).

METHODS

Colonoscopy video data from 472 patients across two hospitals were retrospectively analyzed. WTS was computed through a combination of artificial intelligence (AI) and manual verification. The results obtained through WTS were compared with those generated by the AI system. Patients were categorized into four groups based on the presence of polyps and whether resections or biopsies were performed. Bland Altman plots were utilized to compare AI-computed WTS with manually verified WTS. Scatterplots were used to illustrate WTS within the four groups, among different hospitals, and across various physicians. A parallel box plot was employed to depict the proportions of WTS relative to WT within each of the four groups.

RESULTS

The study included 472 patients, with a median age of 55 years, and 57.8% were male. A significant correlation with manually verified WTS (r = 0.918) was observed in AI-computed WTS. Significant differences in WTS/WT among the four groups were revealed by the parallel box plot (P < 0.001). The group with no detected polyps had the highest WTS/WT, with a median of 0.69 (interquartile range: 0.40, 0.97). WTS patterns were found to be varied between the two hospitals and among senior and junior physicians.

CONCLUSIONS

A promising alternative to traditional WT for quality control and training assessment in colonoscopy is offered by AI-assisted computation of WTS.

Mitochondria-Modulating Liposomes Reverse Radio-Resistance for Colorectal Cancer

Complete remission of colorectal cancer (CRC) is still unachievable in the majority of patients by common fractionated radiotherapy, leaving risks of tumor metastasis and recurrence. Herein, clinical CRC samples demonstrated a difference in the phosphorylation of translation initiation factor eIF2α (p-eIF2α) and the activating transcription factor 4 (ATF4), whose increased expression by initial X-ray irradiation led to the resistance to subsequent radiotherapy. The underlying mechanism is studied in radio-resistant CT26 cells, revealing that the incomplete mitochondrial outer membrane permeabilization (iMOMP) triggered by X-ray irradiation is key for the elevated expression of p-eIF2α and ATF4, and therefore radio-resistance. This finding guided to discover that metformin and 2-DG are synergistic in reversing radio resistance by inhibiting p-eIF2α and ATF4. Liposomes loaded with metformin and 2-DG (M/D-Lipo) are thus prepared for enhancing fractionated radiotherapy of CRC, which achieved satisfactory therapeutic efficacy in both local and metastatic CRC tumors by reversing radio-resistance and preventing T lymphocyte exhaustion.

A population-based analysis on the incidence of metachronous colon cancer after endoscopic resection of advanced adenomas with high-grade dysplasia: does location matter?

BACKGROUND

Advanced adenomas (AAs) with high-grade dysplasia (HGD) represent a risk factor for metachronous neoplasia, with guidelines recommending short-interval surveillance. Although the worse prognosis of proximal (vs distal) colon cancers (CCs) is established, there is paucity of evidence on the impact of laterality on the risk of subsequent neoplasia for these AAs.

METHODS

Adults with HGD adenomas undergoing polypectomy were identified in the Surveillance, Epidemiology, and End Results database (2000-2019). Cumulative incidence of malignancy was estimated using the Kaplan-Meier method. Fine-Gray models assessed the effect of patient and disease characteristics on CC incidence.

RESULTS

Of 3199 patients, 26% had proximal AAs. A total of 65 cases of metachronous adenocarcinoma were identified after polypectomy of 35 proximal and 30 distal adenomas with HGD. The 10-year cumulative incidence of CC was 2.3%; when stratified by location, it was 4.8% for proximal vs 1.4% for distal adenomas. Proximal location was significantly associated with increased incidence of metachronous cancer (adjusted hazard ratio, 3.32; 95% CI, 2.05-5.38).

CONCLUSION

Proximal location of AAs with HGD was associated with >3-fold increased incidence of metachronous CC and shorter time to diagnosis. These data suggest laterality should be considered in the treatment and follow-up of these patients.

Detailed Superiority of the CAD EYE Artificial Intelligence System over Endoscopists for Lesion Detection and Characterization Using Unique Movie Sets

Objectives

Detailed superiority of CAD EYE (Fujifilm, Tokyo, Japan), an artificial intelligence for polyp detection/diagnosis, compared to endoscopists is not well examined. We examined endoscopist's ability using movie sets of colorectal lesions which were detected and diagnosed by CAD EYE accurately.

Methods

Consecutive lesions of ≤10 mm were examined live by CAD EYE from March-June 2022 in our institution. Short unique movie sets of each lesion with and without CAD EYE were recorded simultaneously using two recorders for detection under white light imaging (WLI) and linked color imaging (LCI) and diagnosis under blue laser/light imaging (BLI). Excluding inappropriate movies, 100 lesions detected and diagnosed with CAD EYE accurately were evaluated. Movies without CAD EYE were evaluated first by three trainees and three experts. Subsequently, movies with CAD EYE were examined. The rates of accurate detection and diagnosis were evaluated for both movie sets.

Results

Among 100 lesions (mean size: 4.7±2.6 mm; 67 neoplastic/33 hyperplastic), mean accurate detection rates of movies without or with CAD EYE were 78.7%/96.7% under WLI (p<0.01) and 91.3%/97.3% under LCI (p<0.01) for trainees and 85.3%/99.0% under WLI (p<0.01) and 92.6%/99.3% under LCI (p<0.01) for experts. Mean accurate diagnosis rates of movies without or with CAD EYE for BLI were 85.3%/100% for trainees (p<0.01) and 92.3%/100% for experts (p<0.01), respectively. The significant risk factors of not-detected lesions for trainees were right-sided, hyperplastic, not-reddish, in the corner, halation, and inadequate bowel preparation.

Conclusions

Unique movie sets with and without CAD EYE could suggest it's efficacy for lesion detection/diagnosis.

Prevalence of diverse colorectal polyps and risk factors for colorectal carcinoma in situ and neoplastic polyps

BACKGROUND

Most colorectal cancers originate from precancerous polyps. This study aimed to determine the prevalence of colorectal polyps with diverse pathological morphologies and to explore the risk factors for colorectal carcinoma in situ (CCS) and neoplastic polyps.

METHODS

Inpatients admitted from January 2018 to May 2023 were screened through the hospital information system. Polyps were classified according to pathological morphology. The prevalence of polyps was described by frequency and 95% confidence interval. Univariate and multivariate logistic regression analyses were used to explore the risk factors for CCS and neoplastic polyps.

RESULTS

In total, 2329 individuals with 3550 polyps were recruited. Among all patients, 76.99% had neoplastic polyps and 44.31% had advanced adenomas. Tubular adenoma had the highest prevalence at 60.15%, and the prevalence of CCS was 3.86%. Patients with a colorectal polyp diameter ≥ 1.0 cm or number ≥ 3 were 8.07 times or 1.98 times more likely to develop CCS than were those with a diameter < 1.0 cm or number < 3, respectively (OR 8.07, 95%CI 4.48-14.55, p < 0.0001; and OR 1.98, 95%CI 1.27-3.09, p = 0.002). The risk of CCS with schistosome egg deposition was also significantly increased (OR 2.70, 95%CI 1.05-6.98). The higher the levels of carbohydrate antigen (CA) 724 (OR 1.01, 95%CI 1.00-1.02) and CA211 (OR 1.16, 95%CI 1.03-1.32) in patients with colorectal polyps were, the greater the risk of CCS. When colorectal neoplastic polyps were analyzed, we discovered that for each 1-year increase in age, the risk of neoplastic polyps increased by 3% (OR 1.03, 95%CI 1.02-1.04), p < 0.0001. Patients with a polyp diameter ≥ 1.0 cm had a 2.11-fold greater risk of neoplastic polyps compared to diameter < 1.0 cm patients (OR 3.11, 95%CI 2.48-3.92), p < 0.0001. In addition, multiple polyps and CA199 levels are risk factors for neoplastic polyps.

CONCLUSION

More than 3/4 of colorectal polyp patients have neoplastic polyps. Patients are more inclined to develop CCS and neoplastic polyps if they have large polyps (> 1.0 cm) or multifocal polyps. The levels of the tumor markers CA724 and CA211 show some potential usefulness for predicting CCS and may be exploited for early identification of high-risk populations.

Long-term outcomes after endoscopic removal of malignant colorectal polyps: Results from a 10-year cohort

BACKGROUND

Choosing an optimal post-polypectomy management strategy of malignant colorectal polyps is challenging, and evidence regarding a surveillance-only strategy is limited.

AIM

To evaluate long-term outcomes after endoscopic removal of malignant colorectal polyps.

METHODS

A single-center retrospective cohort study was conducted to evaluate outcomes after endoscopic removal of malignant colorectal polyps between 2010 and 2020. Residual disease rate and nodal metastases after secondary surgery and local and distant recurrence rate for those with at least 1 year of follow-up were investigated. Event rates for categorical variables and means for continuous variables with 95% confidence intervals were calculated, and Fisher's exact test and Mann-Whitney test were performed. Potential risk factors of adverse outcomes were determined with univariate and multivariate logistic regression models.

RESULTS

In total, 135 lesions (mean size: 22.1 mm; location: 42% rectal) from 129 patients (mean age: 67.7 years; 56% male) were enrolled. The proportion of pedunculated and non-pedunculated lesions was similar, with en bloc resection in 82% and 47% of lesions, respectively. Tumor differentiation, distance from resection margins, depth of submucosal invasion, lymphovascular invasion, and budding were reported at 89.6%, 45.2%, 58.5%, 31.9%, and 25.2%, respectively. Residual tumor was found in 10 patients, and nodal metastasis was found in 4 of 41 patients who underwent secondary surgical resection. Univariate analysis identified piecemeal resection as a risk factor for residual malignancy (odds ratio: 1.74; P = 0.042). At least 1 year of follow-up was available for 117 lesions from 111 patients (mean follow-up period: 5.59 years). Overall, 54%, 30%, 30%, 11%, and 16% of patients presented at the 1-year, 3-year, 5-year, 7-year, and 9-10-year surveillance examinations. Adverse outcomes occurred in 9.0% (local recurrence and dissemination in 4 patients and 9 patients, respectively), with no difference between patients undergoing secondary surgery and surveillance only.

CONCLUSION

Reporting of histological features and adherence to surveillance colonoscopy needs improvement. Long-term adverse outcome rates might be higher than previously reported, irrespective of whether secondary surgery was performed.

Should we perform sigmoidoscopy for colorectal cancer screening in people under 45 years?

BACKGROUND

The strategy for preventing colorectal cancer is screening by colonoscopy, which offers a direct way for detection and removal of adenomatous polyps (APs). American College of Gastroenterology guidelines recommend that people aged ≥ 45 years should undergo colonoscopy; however, how to deal with people aged ≤ 45 years is still unknown.

AIM

To compare the prevalence of APs and high-grade neoplasia between the left and right colon in patients ≤ 45 years.

METHODS

A retrospective observational study was conducted at a single tertiary III hospital in China. This study included patients aged 18-45 years with undergoing initial colonoscopy dissection and pathological diagnosis AP or high-grade neoplasia between February 2014 and January 2021. The number of APs in the entire colon while screening and post-polypectomy surveillance in following 1-3 years were evaluated.

RESULTS

A total of 3053 cases were included. The prevalence of APs in the left and right colon was 55.0% and 41.6%, respectively (OR 1.7, 95%CI 1.6-2.4; P < 0.05). For APs with high-grade neoplasia, the prevalence was 2.7% and 0.9%, respectively (OR 3.0, 95%CI 2.0-4.6; P < 0.05). Therefore, the prevalence of APs and high-grade neoplasia in the left colon was significantly higher than in the right colon in patients aged ≤ 45 years. There were 327 patients who voluntarily participated in post-polypectomy surveillance in following 1-3 years, and APs were found in 216 cases (66.1%); 170 cases had 1-3 polyps (52.0%) and 46 cases had > 3 polyps (14.1%; OR 0.3, 95%CI 0.1-0.6; P < 0.05).

CONCLUSION

This study suggests that flexible sigmoidoscopy would be an optimal approach for initial screening in people aged ≤ 45 years and would be a more cost-effective and safe strategy.

Sporadic Polyps of the Colorectum

Colorectal polyps are common, and their diagnosis and classification represent a major component of gastrointestinal pathology practice. The majority of colorectal polyps represent precursors of either the chromosomal instability or serrated neoplasia pathways to colorectal carcinoma. Accurate reporting of these polyps has major implications for surveillance and thus for cancer prevention. In this review, we discuss the key histologic features of the major colorectal polyps with a particular emphasis on diagnostic pitfalls and areas of contention.

Management after non-curative endoscopic resection of T1 rectal cancer

Since the introduction of population-based screening, increasing numbers of T1 rectal cancers are detected and removed by local endoscopic resection. Patients can be cured with endoscopic resection alone, but there is a possibility of residual tumor cells remaining after the initial resection. These can be located intraluminally at the resection site or extraluminally in the form of (lymph node) metastases. To decrease the risk of residual cells progressing towards more advanced disease, additional treatment is usually needed. However, with the currently available risk stratification models, it remains challenging to determine who should and should not be further treated after non-curative endoscopic resection. In this review, the different management strategies for patients with non-curatively treated T1 rectal cancers are discussed, along with the available evidence for each strategy and relevant considerations for clinical decision making. Furthermore, we provide practical guidance on the management and surveillance following non-curative endoscopic resection of T1 rectal cancer.

Potential Molecular Markers Related to Lymph Node Metastasis and Stalk Resection Margins in Pedunculated T1 Colorectal Cancers Using Digital Spatial Profiling: A Pilot Study with a Small Case Series

There is a debate regarding the prediction of lymph node metastasis (LNM) in pedunculated T1 colorectal cancer (CRC). In this study with four cases of pedunculated T1 CRCs, we aimed to investigate gene expression variations based on the distance from the Haggitt line (HL) and identify potential molecular risk factors for LNM. By leveraging the Cancer Transcriptome Atlas and digital spatial profiling technology, we meticulously analyzed discrete regions, including the head, HL, proximal stalk region (300-1000 μm from HL), and distal stalk region (1500-2000 μm from HL) to identify spatially sequential molecular changes. Our findings showed significant overall gene expression variations among the head, proximal stalk, and distal stalk regions of pedunculated T1 CRCs compared to the control adenoma. Compared to LNM-negative T1 CRCs, LNM-positive T1 CRC showed that the expression of genes involved in immune-related pathways such as B2M, HLA-B, and HLA-E were significantly downregulated in the distal stalk region compared to the proximal stalk region. In summary, our results may tentatively suggest considering endoscopic resection of the stalk with a minimum 2000 μm margin from the HL, taking into account the gene expression alterations related to immune-related pathways. However, we acknowledge the limitations of this pilot study, notably the small case series, which may restrict the depth of interpretation. Further validation is imperative to substantiate these findings.

Colonoscopy plays an important role in detecting colorectal neoplasms in patients with gastric neoplasms

BACKGROUND

Gastric cancer (GC) and colorectal cancer (CRC) are the fifth and third most common cancer worldwide, respectively. Nowadays, GC is reported to have a potential predictive value for CRC, especially for advanced CRC.

AIM

To evaluate the necessity of colonoscopy for gastric neoplasm (GN) patients.

METHODS

Four databases, including PubMed, EMBASE, the Cochrane Library, and Ovid, were used to perform the search strategy on May 2, 2023. The prevalence of colorectal neoplasms (CRN) and baseline characteristics were compared between the neoplasm group and the control group. Continuous variables are expressed as the mean difference and standard deviation. Relationships of categorical variables in the two groups are expressed as odds ratios (OR) and 95% confidence intervals (95%CIs). Subgroup analysis according to different kinds of GNs was conducted for more in-depth analysis. The results of this study are represented by forest plots. Publication bias was evaluated by a funnel plot. All data analyses were performed by STATA SE 16.0 software.

RESULTS

A total of 3018 patients with GNs and 3905 healthy controls (age and sex matched) were enrolled for analysis. After comparing the prevalence of CRNs between the two groups, CRNs were detected significantly more frequently in GN patients than in controls (OR = 1.69, 95%CI = 1.28 to 2.23, I2 = 85.12%, P = 0.00), especially in patients with GC (OR =1.80, 95%CI = 1.49 to 2.18, I2 = 25.55%, P < 0.1). Moreover, other risk factors including age (OR = 1.08, 95%CI = 1.00 to 1.17, I2 = 90.13%, P = 0.00) and male sex (OR = 2.31, 95%CI = 1.26 to 4.22, I2 = 87.35%, P = 0.00), were related to the prevalence of CRNs. For patients in the GN group, body mass index (BMI, OR = 0.88, 95%CI = 0.80 to 0.98, I2 = 0.00%, P = 0.92) and smoking (OR = 1.03, 95%CI = 1.01 to 1.05, I2 = 0.00%, P = 0.57) were protective and risk factors for CRNs, respectively.

CONCLUSION

Patients are recommended to undergo colonoscopy when diagnosed with GNs, especially GC patients with a low BMI and a history of smoking.

Whole slide image-based prediction of lymph node metastasis in T1 colorectal cancer using unsupervised artificial intelligence

OBJECTIVES

Lymph node metastasis (LNM) prediction for T1 colorectal cancer (CRC) is critical for determining the need for surgery after endoscopic resection because LNM occurs in 10%. We aimed to develop a novel artificial intelligence (AI) system using whole slide images (WSIs) to predict LNM.

METHODS

We conducted a retrospective single center study. To train and test the AI model, we included LNM status-confirmed T1 and T2 CRC between April 2001 and October 2021. These lesions were divided into two cohorts: training (T1 and T2) and testing (T1). WSIs were cropped into small patches and clustered by unsupervised K-means. The percentage of patches belonging to each cluster was calculated from each WSI. Each cluster's percentage, sex, and tumor location were extracted and learned using the random forest algorithm. We calculated the areas under the receiver operating characteristic curves (AUCs) to identify the LNM and the rate of over-surgery of the AI model and the guidelines.

RESULTS

The training cohort contained 217 T1 and 268 T2 CRCs, while 100 T1 cases (LNM-positivity 15%) were the test cohort. The AUC of the AI system for the test cohort was 0.74 (95% confidence interval [CI] 0.58-0.86), and 0.52 (95% CI 0.50-0.55) using the guidelines criteria (P = 0.0028). This AI model could reduce the 21% of over-surgery compared to the guidelines.

CONCLUSION

We developed a pathologist-independent predictive model for LNM in T1 CRC using WSI for determination of the need for surgery after endoscopic resection.

TRIAL REGISTRATION

UMIN Clinical Trials Registry (UMIN000046992, https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000053590).

Impact of the SARS-CoV-2 on the journey of high-risk colon cancer patients within the scope of the Unified Health System in Brazil

BACKGROUND

Colon cancer is an important cause of mortality related to cancer. During the COVID-19 pandemic, an important reallotment of assistance resources was necessary to tackle the crisis, directly impacting medical practice all over the globe.

OBJECTIVE

To assess the impact of the Sars-Cov-2 pandemic on the time between diagnosis and the beginning of systemic treatment in patients diagnosed with high-risk colon neoplasia.

METHODS

This is a retrospective study based on the analysis of medical records of patients diagnosed with colon neoplasia who required systemic treatment and were treated between March 2019 and March 2022, in a reference Oncology unit of the Brazilian Unified Health System. The study's population was divided into two groups: (I) Pre-COVID-19: diagnoses made between March 2019 and February 2020, (II) COVID-19: diagnoses made between March 2020 and March 2022.

RESULTS

The sample consisted of 228 patients, 108 (47.97%) of whom were diagnosed during pre-COVID-19 and 118 (52.21%) diagnosed during the two years-period of COVID-19. Regarding the time between colonoscopy and surgery, the time between surgery and first consultation in clinical oncology, and the time between requesting and beginning of systemic treatment, a statistically significant reduction was observed during the COVID-19 period.

CONCLUSION

A decrease in time between diagnosis and systemic treatment of patients with colorectal cancer during the COVID-19 pandemic was observed. Yet, even with this improvement, the time to begin treatment remains greater than the recommended by the current guidelines, regardless of the time of diagnosis (before or after the pandemic), which negatively impacts the disease outcome.

Superficial non-ampullary duodenal epithelial tumors now: endoscopic diagnosis and therapy

With the recent increase in the frequency of duodenal tumor detection, significant progress has been made in endoscopic diagnosis and treatment. Although the first guidelines were issued in Japan, patient treatment varies widely among institutions. There is a need for improving the quality of endoscopic diagnosis and more curative and safer treatments. Biopsy is the standard diagnostic method; however, the diagnostic accuracy of endoscopic biopsy is not so high. Therefore, the differentiation of superficial non-ampullary duodenal epithelial tumors from non-neoplastic lesions is being developed. The incidence of lymph node and distant metastases of duodenal epithelial tumors is extremely rare in intramucosal carcinomas, and they are considered good candidates for endoscopic treatment if the technical difficulties can be resolved. Adverse events associated with endoscopic treatment are greatly reduced at advanced facilities through novel resection and closure methods, and further improvements are expected in the future. Clarifying the risk of metastatic recurrence may lead to the development of more appropriate treatments and curative resection criteria.

Cap-assisted endoscopic mucosal resection as a salvage technique for challenging colorectal laterally spreading tumors

BACKGROUND

Cap-assisted endoscopic mucosal resection (EMR-c) has emerged as a potential alternative to standard piecemeal wide-field EMR (WF-EMR) for the resection of laterally spreading tumors (LSTs). However, clear indications for this technique are still lacking. Our objective was to investigate the performance of salvage EMR-c after WF-EMR failure in the resection of large colorectal LSTs.

METHODS

The data of consecutive patients undergoing WF-EMR for large colorectal LSTs (2015-2021) were analyzed in this single-center, retrospective, observational study. In the event of a WF-EMR failure, the procedure was switched to EMR-c in the same session. The efficacy of the two techniques was evaluated in terms of complete endoscopic resection, R0 resection, and recurrence rate. Safety was also assessed.

RESULTS

Overall, the data from 81 WF-EMRs were collected. Eighteen cases of WF-EMR failure were switched to EMR-c in the same session and complete endoscopic resection was achieved in 17/18 patients (94.4%). No statistically significant difference was observed between WF-EMR and salvage EMR-c in terms of macroscopic radicality (P = 0.40) and R0 resection (P = 0.12). However, recurrence was more common with EMR-c (44.4% vs. 23.5%; P = 0.05), as were adverse events, particularly intraprocedural bleeding (27.8% vs. 7.9%; P = 0.04).

CONCLUSION

EMR-c is an effective salvage technique for challenging colorectal LSTs following WF-EMR failure. Due to the elevated risk of adverse events associated with this procedure, careful patient selection, endoscopic expertise, and close follow-up are strongly recommended.

Evaluation of a new method, "non-injection resection using bipolar soft coagulation mode (NIRBS)", for colonic adenomatous lesions

BACKGROUND/AIMS

Endoscopic resection of all colorectal adenomatous lesions with a low complication rate, simplicity, and negative residuals is challenging. Hence, we developed a new method called "non-injection resection using bipolar soft coagulation mode (NIRBS)" method, adapted for colorectal lesions. In addition, we evaluated the effectiveness of this method.

METHODS

We performed NIRBS throughout a 12-month period for all colorectal lesions which snare resection was acceptable without cancerous lesions infiltrating deeper than the submucosal layer.

RESULTS

A total of 746 resected lesions were included in the study, with a 4.5 mm mean size (range, 1-35 mm). The major pathological breakdowns were as follows: 64.3% (480/746) were adenomas, and 5.0% (37/746) were intraepithelial adenocarcinomas (Tis lesions). No residuals were observed in any of the 37 Tis lesions (mean size, 15.3 mm). Adverse events included bleeding (0.4%) but no perforation.

CONCLUSIONS

NIRBS allowed the resection of multiple lesions with simplicity because of the non-injection and without perforating due to the minimal burn effect of the bipolar snare set in the soft coagulation mode. Therefore, NIRBS can be used to resect adenomatous lesions easily, including Tis lesions, from small to large lesions without leaving residuals.

Dilemmas in the Clinical Management of pT1 Colorectal Cancer

Implementation of population-based colorectal cancer screening programs has led to increases in the incidence of pT1 colorectal cancer. These incipient invasive cancers have a very good prognosis and can be treated locally, but more than half of these cases are treated with surgery due to the presence of histological high-risk criteria. These high-risk criteria are suboptimal, with no consensus among clinical guidelines, heterogeneity in definitions and assessment, and poor concordance in evaluation, and recent evidence suggests that some of these criteria considered high risk might not necessarily affect individual prognosis. Current criteria classify most patients as high risk with an indication for additional surgery, but only 2-10.5% have lymph node metastasis, and the residual tumor is present in less than 20%, leading to overtreatment. Patients with pT1 colorectal cancer have excellent disease-free survival, and recent evidence indicates that the type of treatment, whether endoscopic or surgical, does not significantly impact prognosis. As a result, the protective role of surgery is questionable. Moreover, surgery is a more aggressive treatment option, with the potential for higher morbidity and mortality rates. This article presents a comprehensive review of recent evidence on the clinical management of pT1 colorectal cancer. The review analyzes the limitations of histological evaluation, the prognostic implications of histological risk status and the treatment performed, the adverse effects associated with both endoscopic and surgical treatments, and new advances in endoscopic treatment.

Cold resection for colorectal polyps: where we are and where we are going?

INTRODUCTION

Endoscopic resection of colonic precancerous lesions has been demonstrated to significantly decrease colorectal cancer (CRC) incidence and mortality. Among resection techniques, cold snare polypectomy (CSP) has been shown as a highly feasible, effective and safe option and is widely used in clinical practice, being regarded as the first-line technique for removal of small and diminutive colorectal polyps. On the other hand, conventional hot snare polypectomy (HSP) and endoscopic mucosal resection (EMR), namely the gold standard treatments for larger polyps, may be occasionally associated to complications due to electrocautery injury.

AREAS COVERED

To overcome these shortcomings of electrocautery-based resection techniques, in the last few years CSP has been increasingly assessed as a treatment option for additional indications, with a focus on nonpedunculated colorectal polyps ≥10 mm.

EXPERT OPINION

This review aims to present current and widened indications of CSP discussing the latest findings from the most remarkable studies, with an insight into technical issues, novelties and potential advances in the near future.

Limited wedge resection for T1 colon cancer (LIMERIC-II trial) - rationale and study protocol of a prospective multicenter clinical trial

BACKGROUND

The sole presence of deep submucosal invasion is shown to be associated with a limited risk of lymph node metastasis. This justifies a local excision of suspected deep submucosal invasive colon carcinomas (T1 CCs) as a first step treatment strategy. Recently Colonoscopy-Assisted Laparoscopic Wedge Resection (CAL-WR) has been shown to be able to resect pT1 CRCs with a high R0 resection rate, but the long term outcomes are lacking. The aim of this study is to evaluate the safety, effectiveness and long-term oncological outcomes of CAL-WR as primary treatment for patients with suspected superficial and also deeply-invasive T1 CCs.

METHODS

In this prospective multicenter clinical trial, patients with a macroscopic and/or histologically suspected T1 CCs will receive CAL-WR as primary treatment in order to prevent unnecessary major surgery for low-risk T1 CCs. To make a CAL-WR technically feasible, the tumor may not include > 50% of the circumference and has to be localized at least 25 cm proximal from the anus. Also, there should be sufficient distance to the ileocecal valve to place a linear stapler. Before inclusion, all eligible patients will be assessed by an expert panel to confirm suspicion of T1 CC, estimate invasion depth and subsequent advise which local resection techniques are possible for removal of the lesion. The primary outcome of this study is the proportion of patients with pT1 CC that is curatively treated with CAL-WR only and in whom thus organ-preservation could be achieved. Secondary outcomes are 1) CAL-WR's technical success and R0 resection rate for T1 CC, 2) procedure-related morbidity and mortality, 3) 5-year overall and disease free survival, 4) 3-year metastasis free survival, 5) procedure-related costs and 6) impact on quality of life. A sample size of 143 patients was calculated.

DISCUSSION

CAL-WR is a full-thickness local resection technique that could also be effective in removing pT1 colon cancer. With the lack of current endoscopic local resection techniques for > 15 mm pT1 CCs with deep submucosal invasion, CAL-WR could fill the gap between endoscopy and major oncologic surgery. The present study is the first to provide insight in the long-term oncological outcomes of CAL-WR.

TRIAL REGISTRATION

CCMO register (ToetsingOnline), NL81497.075.22, protocol version 2.3 (October 2022).

Chicken skin mucosa surrounding small colorectal cancer could be an endoscopic predictive marker of submucosal invasion

BACKGROUND

Chicken skin mucosa (CSM) surrounding colon polyps is a common endoscopic finding with pale yellow-speckled mucosa during a colonoscopy screening. Although reports about CSM surrounding small colorectal cancer are scarce, and its clinical significance in intramucosal and submucosal cancers is unclear, previous studies have suggested it could be an endoscopic predictive marker for colonic neoplastic and advanced polyps. Currently, because of the inaccurate preoperative evaluation by endoscopists, many small colorectal cancers, particularly lesions with a diameter < 2 cm, are improperly treated. Therefore, more effective methods are required to better assess the depth of the lesion before treatment.

AIM

To explore potential markers of small colorectal cancer early invasion under white light endoscopy, providing patients with better treatment alternatives.

METHODS

This retrospective cross-sectional study included 198 consecutive patients [233 early colorectal cancers (ECCs)] who underwent endoscopy or surgical procedures at the Digestive Endoscopy Center of Chengdu Second People’s Hospital between January 2021 and August 2022. The participants had pathologically confirmed colorectal cancer with a lesion diameter < 2 cm and received endoscopic or surgical treatment, including endoscopic mucosal resection and submucosal dissection. Clinical pathology and endoscopy parameters, including tumor size, invasion depth, anatomical position, and morphology, were reviewed. Fisher’s exact test, the χ² test, and Student’s t-test were used to analyze the patient’s basic characteristics. Logistic regression analysis was used to examine the relationship between morphological characteristics, size, CSM prevalence, and ECC invasion depth under white light endoscopy. Statistical significance was set at P < 0.05.

RESULTS

The submucosal carcinoma (SM stage) was larger than the mucosal carcinoma (M stage) with a significant difference (17.2 ± 4.1 vs 13.4 ± 4.6 mm, P < 0.01). M- and SM-stage cancers were common in the left colon; however, no significant differences were found between them (151/196, 77% and 32/37, 86.5%, respectively, P = 0.199). The endoscopic features of colorectal cancer revealed that CSM, depressed areas with clear boundaries, and erosion or ulcer bleeding were more common in the SM-stage cancer group than in the M-stage cancer group (59.5% vs 26.2%, 46% vs 8.7%, and 27.3% vs 4.1%, respectively, P < 0.05). CSM prevalence in this study was 31.3% (73/233). The positive rates of CSM in flat, protruded, and sessile lesions were 18% (11/61), 30.6% (30/98), and 43.2% (32/74), respectively, with significant differences (P = 0.007).

CONCLUSION

CSM-related small colorectal cancer was primarily located in the left colon and could be a predictive marker of submucosal invasion in the left colon.

Identification and Reporting of Anal Pathology during Routine Colonoscopies

The gold-standard procedure for anal canal examination is anoscopy. Nonetheless, patients are referred for a colonoscopy for many reasons, and a routine exam might provide an opportunity to diagnose anal pathologies, such as hemorrhoids, anal fissures, anal polyps, condylomas, and anal squamous cell carcinoma. It is important to know the main features of these conditions and relevant information to report in order to help guide patient treatment and follow-up.

Endoscopic management of colorectal polyps

Colorectal polyps are premalignant lesions in the lower gastrointestinal tract. Endoscopic polypectomy is an effective strategy to prevent colorectal cancer morbidity and more invasive procedures. Techniques for the endoscopic resection of polyps keep evolving, and endoscopists are required to perform the most appropriate technique for each polyp. In this review, we outline the evaluation and classification of polyps, update the recommendations for optimal treatment, describe the polypectomy procedures and their strengths/weaknesses, and discuss the promising innovative methods or concepts.

Extended delay in endoscopic mucosal resection is not associated with adverse outcomes: Findings from the COVID-19 pandemic

Background and study aims The aim of this study was to investigate the impact of delayed endoscopic mucosal resection (EMR) of colorectal polyps on health outcomes.

Patients and methods A bidirectional cohort study was completed. A baseline group consisting of all EMRs performed within a 15-month period before a province-wide, government-mandated cessation of EMR procedures due to the global pandemic was compared to EMRs impacted by the shutdown, defined as the COVID-19-delayed group. The primary outcome was the incidence of malignant polyps. Secondary outcomes included technical success, polyp recurrence at follow-up colonoscopy, advanced polyp histology, probability of meeting endoscopic criteria for adequate resection for malignant polyps, metastatic colorectal cancer, and complications.

Results A total of 268 EMR procedures were included in the study cohort, of which 208 formed the baseline group and 60 were in the COVID-19-delayed group. The median (IQR) patient age was 72 (13.0) and 113 (41.2 %) were females. The median (IQR) wait time was 92 days (87.8) in the baseline group and 191 days (127.8) in the COVID-19-delayed group (P < 0.001). Overall, there were no significant differences in the incidence of malignant polyps, technical success, polyp recurrence on follow-up colonoscopy, advanced polyp histology, adequate endoscopic resection for malignant polyps, metastatic colorectal cancer, or complications between the two groups (P > 0.05 for all outcomes).

Conclusions A longer wait time for EMR of colorectal polyps, increasing from a median of 92 to 191 days, was not associated with worse outcomes.

Analysis of the relationship between the gut microbiota enterotypes and colorectal adenoma

Introduction

The essence of enterotypes is to stratify the entire human gut microbiota, and dysregulation of gut microbiota is closely related to the development of colorectal adenoma. Enterotypes may therefore be a useful target for the prevention of colorectal adenoma. However, the relationship between gut microbiota and colorectal adenoma has not been fully elucidated. In this study, we aimed to analyze the differences in gut microbiome composition between adenoma and control populations.

Methods

We recruited 31 patients with colorectal adenoma and 71 non-adenoma controls. Patient demographics, risk factors, fecal samples from each subject were collected and metagenomic sequencing was performed. LEfSe analysis was used to reveal differences in intestinal microbiome composition. Multiple logistic regression analysis was used to determine the association between enterotypes and colorectal adenoma.

Results

The results showed that Prevotella enterotype (enterotype 4) is only present in adenoma group. Logistic regression analysis showed that Prevotella enterotype was an independent risk factor for colorectal adenoma.

Discussion

The Prevotella enterotype may increase the occurrence of colorectal adenoma through inflammatory association and interference with glucose and lipid metabolism in human body. In conclusion, the differences we observed between different enterotypes add a new potential factor to the development of colorectal adenoma.

Interobserver agreement of the modified Paris classification and histology prediction of colorectal lesions in patients with inflammatory bowel disease

BACKGROUND AND AIMS

SCENIC (International Consensus Statement on Surveillance and Management of Dysplasia in IBD) guidelines recommend that visible dysplasia in patients with longstanding inflammatory bowel disease (IBD) should be endoscopically characterized using a modified Paris classification. This study aimed to determine the interobserver agreement (IOA) of the modified Paris classification and endoscopists' accuracy for pathology prediction of IBD visible lesions.

METHODS

One hundred deidentified endoscopic still images and 30 videos of IBD visible colorectal lesions were graded by 10 senior and 4 trainee endoscopists from 5 tertiary care centers. Endoscopists were asked to assign 4 classifications for each image: the standard Paris classification, modified Paris classification, pathology prediction, and lesion border. Agreement was measured using Light's kappa coefficient. Consensus of ratings was assessed according to strict majority.

RESULTS

The overall Light's kappa for all study endpoints was between .32 and .49. In a subgroup analysis between junior and senior endoscopists, Light's kappa continued to be less than .6 with a slightly higher agreement among juniors. Lesions with the lowest agreement and no consensus were mostly classified as Is, IIa, and mixed Paris classification and sessile and superficial elevated for modified Paris classification. Endoscopist accuracy for prediction of dysplastic, nondysplastic, and serrated pathology was 77%, 56%, and 30%, respectively. There was a strong association (P < .001) between the given morphology classification and the predicted pathology with Ip lesions carrying a much lower expectation of dysplasia than Is/IIc/III and mixed lesions. The agreement for border prediction was .5 for junior and .3 for senior endoscopists.

CONCLUSIONS

This study demonstrates very low IOA for Paris and modified Paris classifications and low accuracy and IOA for lesion histopathology prediction. Revisions of these classifications are required to create a clinically useful risk stratification tool and enable eventual application of augmented intelligence tools.

Colonoscopy-Assisted Laparoscopic Wedge Resection for the Treatment of Suspected T1 Colon Cancer

BACKGROUND

Local en bloc resection of pT1 colon cancer has been gaining acceptance during the last few years. In the absence of histological risk factors, the risk of lymph-node metastases (LNM) is negligible and does not outweigh the morbidity and mortality of an oncologic resection. Colonoscopy-assisted laparoscopic wedge resection (CAL-WR) has proved to be an effective and safe technique for removing complex benign polyps. The role of CAL-WR for the primary resection of suspected T1 colon cancer has to be established.

METHODS

This retrospective study aimed to determine the radicality and safety of CAL-WR as a local en bloc resection technique for a suspected T1 colon cancer. Therefore, the study identified patients in whom high-grade dysplasia or a T1 colon carcinoma was suspected based on histology and/or macroscopic assessment, requiring an en bloc resection.

RESULTS

The study analyzed 57 patients who underwent CAL-WR for a suspected macroscopic polyp or polyps with biopsy-proven high-grade dysplasia or T1 colon carcinoma. For 27 of these 57 patients, a pT1 colon carcinoma was diagnosed at pathologic examination after CAL-WR. Histological risk factors for LNM were present in three cases, and 70% showed deep submucosal invasion (Sm2/Sm3). For patients with pT1 colon carcinoma, an overall R0-resection rate of 88.9% was achieved. A minor complication was noted in one patient (1.8%).

CONCLUSIONS

The CAL-WR procedure is an effective and safe technique for suspected high-grade dysplasia or T1-colon carcinoma. It may fill the gap for tumors that are macroscopic suspected for deep submucosal invasion, providing more patients an organ-preserving treatment option.

Resection margin involvement after endoscopic excision of malignant colorectal polyps: definition of margin involvement and its impact upon tumour recurrence

AIMS

Malignant polyps are examined to assess histological features which predict residual tumour in the unresected bowel and guide surgical decision-making. One of the most important of these features is resection margin involvement, although the best definition of margin involvement is unknown. In this study we aimed to investigate three different definitions and determine their impact on clinical outcomes.

METHODS AND RESULTS

One hundred and sixty-five malignant polyps removed endoscopically were identified and histological features correlated with either residual tumour in subsequent surgical resections or tumour recurrence following a period of clinical follow-up. Involvement of the polyp margin by cancer was defined in three different ways and outcomes compared. Tumour recurrence was associated with tumour grade, mucinous histology and resection margin involvement. All three definitions of margin involvement separated polyps into clinically significant categories; however, a margin ≤ 1 mm identified 73% of polyps as 'high-risk' compared with 59.1% when involvement was defined as tumour within the zone of coagulation artefact at the polyp base or 50% when tumour was present at the margin. All three 'low-risk' groups had a locoregional recurrence rate < 6.5%.

CONCLUSIONS

Definitions of margin involvement for endoscopically removed malignant polyps in the colon and rectum vary between health-care systems, but a 1-mm clearance is widely used in Europe and North America. Our results suggest that a 1-mm margin is unnecessary and should be replaced by a definition based on tumour at the margin or within coagulation artefact at the polyp base.

Standard Endoscopic Mucosal Resection vs Precutting Endoscopic Mucosal Resection Using Novel Disk-Tip Snare for Colorectal Lesions

INTRODUCTION

SOUTEN (KANEKA Co., Tokyo, Japan) is a unique snare with a disk tip. We analyzed the efficacy of precutting endoscopic mucosal resection with SOUTEN (PEMR-S) for colorectal lesions.

METHODS

We retrospectively reviewed 57 lesions of 10-30 mm treated with PEMR-S at our institution from 2017 to 2022. The indications were lesions that were difficult for standard EMR due to size, morphology, and poor elevation by injection. Various therapeutic results of PEMR-S such as en bloc resection, procedure time, and perioperative hemorrhage were analyzed, and the results of 20 lesions of 20-30 mm with PEMR-S were compared to those of lesions with standard EMR (2012-2014) using propensity score matching. Additionally, the stability of the SOUTEN disk tip was analyzed in a laboratory experiment.

RESULTS

The polyp size was 16.5 ± 4.2 mm and the non-polypoid morphology rate was 80.7%. Histopathological diagnosis included 10 sessile-serrated lesions, 43 low-grade and high-grade dysplasias, and 4 T1 cancers. After matching, the en bloc resection and histopathological complete resection rates of lesions of 20-30 mm between PEMR-S and standard EMR (90.0% vs. 58.1%, p = 0.03 and 70.0% vs. 45.0%, p = 0.11). The procedure time (min) was 14.8 ± 9.7 and 9.7 ± 8.3 (p < 0.01). The en bloc resection (%) and procedure time of expert/non-expert were 89.7/85.7 (p = 0.96) and 6.1 ± 2.2/18.5 ± 7.2 (p < 0.01). The perioperative bleeding and hemostasis success rates with SOUTEN were 43.9% and 96.0%. In the experiment, the SOUTEN disk tip was fixed stably compared to other EMR snares.

CONCLUSIONS

PEMR-S achieved high en bloc resection of colorectal lesions of 20-30 mm though it leaded to long procedure time.

Endoscopic polypectomy for malignant polyps: Should tumor location (right versus left side) guide clinical decisions?

BACKGROUND

Current guidelines consider endoscopic resection appropriate treatment for malignant colon polyps with negative margins, low-grade histology, and no lymphovascular invasion. While increasing literature demonstrates a worse prognosis for advanced stage right- versus left-sided colon cancers after curative treatment, there is paucity of data regarding prognostic effect of location in patients undergoing endoscopic resection of T1 polyps. We hypothesized the more aggressive biologic behavior observed in advanced right-sided cancers would be similarly represented in malignant polyps, and this location would be associated with lower overall survival.

METHODS

The National Cancer Database was queried for adults with T1NxMx tumors who underwent endoscopic polypectomy (2004-2017). Patients with positive margins or without follow-up information were excluded.

RESULTS

A total of 2,337 patients met inclusion criteria; 22% had right-sided polyps. Endoscopically excised proximal tumors were more common in elderly, and those with public insurance and more comorbidities (all P < .01). Among patients with complete pathologic data, there were no statistical differences between right- and left-sided polyps with 1 cm median size, >92% without lymphovascular invasion, and 100% without tumor deposits. Univariate analysis showed 73% vs 86% 5-year overall survival for right versus left polyps (P < .01). After adjustment for available confounders, right-sided location remained significantly associated with worse overall survival (hazard ratio 1.49, 95% confidence interval 1.21-1.83).

CONCLUSION

In this national cohort of patients with endoscopically excised malignant polyps, we identified right colon location as an independent prognostic factor associated with increased risk of mortality. Our data suggest polyp location should be taken into consideration when making clinical decisions regarding treatment and/or surveillance.

Advanced endoscopic resections in the treatment of malignant colorectal lesions: Are early oncological outcomes impacted?

BACKGROUND

Limited data exists on the impact of advanced endoscopic resections on early oncological outcomes of malignant colorectal lesions, especially in the presence of perforation.

METHODS

Retrospective chart review of patients who underwent advanced endoscopic resections and had adenocarcinoma was performed. The primary endpoint was cancer recurrence.

RESULTS

63 patients were included. Mean age was 64.6 years with 58.7% of the patients being male. Mean BMI was 30.2 kg/m² 12 patients underwent advanced endoscopic resections followed by surveillance, 5 patients had conversion to surgery due to intra-procedural perforation, and 5 patients due to incomplete resection. 41 patients underwent salvage surgery following a median of 5.4 weeks of initial endoscopic resection. Neither local nor distant recurrence was observed within a median follow-up of 21.2 months.

CONCLUSION

Advanced endoscopic procedures do not have negative impact on the early oncological outcomes of patients with malignant colorectal lesions, even in the presence of perforation.

Long-term outcomes after endoscopic versus surgical resection of T1 colorectal carcinoma

BACKGROUND

The long-term outcomes of patients with T1 colorectal cancer (CRC) who undergo endoscopic and/or surgical treatment are not well understood. Invasive CRC confined to the colonic submucosa (T1 CRC) is challenging in terms of clinical decision-making. We compared the long-term outcomes of T1 CRC by treatment method.

METHODS

We examined 370 patients with pathological T1 CRC treated between 2000 and 2015 at Seoul St. Mary's Hospital. In total, 93 patients underwent endoscopic resection (ER) only, 82 underwent additional surgery after ER, and 175 underwent surgical resection only. Patients who did not meet the curative criteria were defined as "high-risk." High-risk patients were classified into three groups according to the treatment modalities: ER only (Group A: 35 patients), additional surgery after ER (Group B: 72 patients), and surgical resection only (Group C: 133 patients). The recurrence-free and overall survival (OS) rates, and factors associated with recurrence and mortality, were analyzed. Factors associated with lymph node metastasis (LNM) were subjected to multivariate analysis.

RESULTS

Of the 370 patients, 7 experienced recurrence and 7 died. All recurrences occurred in the high-risk group and two deaths were in the low-risk group. In high-risk groups, there was no significant group difference in recurrence-free survival (P = 0.511) or OS (P =0.657). Poor histology (P =0.042) was associated with recurrence, and vascular invasion (P =0.044) with mortality. LNMs were observed in 30 of 277 patients who underwent surgery either initially or secondarily. Lymphatic invasion was significantly associated with the incidence of LNM (P < 0.001).

CONCLUSIONS

ER prior to surgery did not affect the prognosis of high-risk T1 CRC patients, and did not worsen the clinical outcomes of patients who required additional surgery. Lymphatic invasion was the most important predictor of LNM.

Development and validation of an artificial intelligence-based system for predicting colorectal cancer invasion depth using multi-modal data

OBJECTIVES

Accurate endoscopic optical prediction of the depth of cancer invasion is critical for guiding an optimal treatment approach of large sessile colorectal polyps but was hindered by insufficient endoscopists expertise and inter-observer variability. We aimed to construct a clinically applicable artificial intelligence (AI) system for the identification of presence of cancer invasion in large sessile colorectal polyps.

METHODS

A deep learning-based colorectal cancer invasion calculation (CCIC) system was constructed. Multi-modal data including clinical information, white light (WL) and image-enhanced endoscopy (IEE) were included for training. The system was trained using 339 lesions and tested on 198 lesions across three hospitals. Man-machine contest, reader study and video validation were further conducted to evaluate the performance of CCIC.

RESULTS

The overall accuracy of CCIC system using image and video validation was 90.4% and 89.7%, respectively. In comparison with 14 endoscopists, the accuracy of CCIC was comparable with expert endoscopists but superior to all the participating senior and junior endoscopists in both image and video validation set. With CCIC augmentation, the average accuracy of junior endoscopists improved significantly from 75.4% to 85.3% (P = 0.002).

CONCLUSIONS

This deep learning-based CCIC system may play an important role in predicting the depth of cancer invasion in colorectal polyps, thus determining treatment strategies for these large sessile colorectal polyps.

Relevance of polyp size for primary endoscopic full-thickness resection of suspected T1 colorectal cancers

BACKGROUND

En bloc local excision of suspected T1 colorectal cancer (CRC) provides optimal tumor risk assessment with curative intent. Endoscopic full-thickness resection (eFTR) with an over-the-scope device has emerged as a local excision technique for T1 CRCs, but data on the upper size limit for achieving a histological complete (R0) resection are lacking. We aimed to determine the influence of polyp size on the R0 rate.

METHODS

eFTR procedures for suspected T1 CRCs performed between 2015 and 2021 were selected from the endoscopy databases of three tertiary centers. The main outcome was R0 resection, defined as tumor- and dysplasia-free margins (≥ 0.1 mm) for both the deep and lateral resection margins. Regression analysis was performed to identify risk factors for R1/Rx resection, mainly focusing on endoscopically estimated polyp size.

RESULTS

136 patients underwent eFTR for suspected T1 CRC (median size 15 mm [IQR 13-18 mm]; 83.1 % cancer). The rates of technical success and R0 resection were 87.5 % (119/136; 95 %CI 80.9 %-92.1 %) and 79.7 % (106/136; 95 %CI 72.1 %-85.7 %), respectively. Increasing polyp size was significantly associated with R1/Rx resection (risk ratio 2.35 per 5-mm increase, 95 %CI 1.80-3.07; P < 0.001). The R0 rate was 89.9 % (80/89) for polyps ≤ 15 mm, 71.4 % (25/35) for 16-20 mm, and 11.1 % (1/9) for those > 20 mm.

CONCLUSIONS

eFTR is associated with a 90 % R0 rate for T1 CRCs of ≤ 15 mm. Performing eFTR for polyps 16-20 mm should depend on access, their mobility, and the availability of alternative resection techniques. eFTR for > 20-mm polyps results in a high R1 rate and should not be recommended.

Mechanisms of chemotherapeutic resistance and the application of targeted nanoparticles for enhanced chemotherapy in colorectal cancer

Colorectal cancer is considered one of the major malignancies that threaten the lives and health of people around the world. Patients with CRC are prone to post-operative local recurrence or metastasis, and some patients are advanced at the time of diagnosis and have no chance for complete surgical resection. These factors make chemotherapy an indispensable and important tool in treating CRC. However, the complex composition of the tumor microenvironment and the interaction of cellular and interstitial components constitute a tumor tissue with high cell density, dense extracellular matrix, and high osmotic pressure, inevitably preventing chemotherapeutic drugs from entering and acting on tumor cells. As a result, a novel drug carrier system with targeted nanoparticles has been applied to tumor therapy. It can change the physicochemical properties of drugs, facilitate the crossing of drug molecules through physiological and pathological tissue barriers, and increase the local concentration of nanomedicines at lesion sites. In addition to improving drug efficacy, targeted nanoparticles also reduce side effects, enabling safer and more effective disease diagnosis and treatment and improving bioavailability. In this review, we discuss the mechanisms by which infiltrating cells and other stromal components of the tumor microenvironment comprise barriers to chemotherapy in colorectal cancer. The research and application of targeted nanoparticles in CRC treatment are also classified.

Endoscopic diagnosis and treatment of early colorectal cancer

Early colorectal cancer refers to cancer in the colorectum that is confined to the mucosa or submucosa and does not invade the muscularis propria, irrespective of lymph node or distant metastasis. As the number of persons undergoing screening colonoscopy increases, the proportion of patients diagnosed with precancerous colorectal lesions and early colorectal cancer also increases. In the last decade, innovative optical technologies for endoscopic diagnosis have been introduced and endoscopic treatment techniques such as endoscopic submucosal dissection have provided major breakthroughs in the management of early colorectal cancer. With these remarkable developments, endoscopic treatment has established itself as an alternative to surgical resection in the treatment of early colorectal cancer. This review will discuss the endoscopic diagnosis and treatment of early colorectal cancer. Furthermore, the unmet needs in this field and the latest research addressing those issues will be summarized.

Advanced Endoscopic Resection Techniques: Endoscopic Submucosal Dissection and Endoscopic Full-Thickness Resection

Endoscopic resection is first-line therapy in the management of superficial neoplasms throughout the gastrointestinal tract, as well as an increasingly viable therapeutic alternative in the resection of selected small deep lesions throughout the upper and lower gastrointestinal tract. The mainstay of therapy has traditionally been endoscopic snare polypectomy and endoscopic mucosal resection. However, recent innovative advancements in therapeutic endoscopy have provided for the ability to resect large superficial lesions and selected subepithelial lesions in en bloc and margin-negative fashion. In this review, we discuss the current state of the art in advanced endoscopic resection techniques including endoscopic submucosal dissection and endoscopic full-thickness resection.

Guidelines for Colorectal Cold Polypectomy (supplement to "Guidelines for Colorectal Endoscopic Submucosal Dissection/Endoscopic Mucosal Resection")

The Japan Gastroenterological Endoscopy Society published the second edition of the "Guidelines for Colorectal Endoscopic Submucosal Dissection/Endoscopic Mucosal Resection" in 2019 to clarify the indications for colorectal endoscopic mucosal resection (EMR) and endoscopic submucosal dissection and to ensure appropriate preoperative diagnoses as well as effective and safe endoscopic treatment in front-line clinical settings. Endoscopic resection with electrocautery, including polypectomy and EMR, is indicated for colorectal polyps. Recently, the number of facilities introducing and implementing cold polypectomy without electrocautery has increased. Herein, we establish supplementary guidelines for cold polypectomy. Considering that the level of evidence for each statement is limited, these supplementary guidelines must be verified in clinical practice.

Safety and efficacy of common endoscopic treatments in patients with decompensated liver cirrhosis

INTRODUCTION

The safety and efficacy have always been a concern, when patients with decompensated liver cirrhosis (DLC) receive endoscopic treatments.

METHODS

To evaluate the safety and efficacy of common endoscopic treatments including endoscopic resection (ER) and endoscopic retrograde cholangiopancreatography (ERCP) applying to patients with DLC, we performed a retrospective study finally including 81 patients receiving ER (43 endoscopic mucosal resection (EMR) and 38 endoscopic submucosal dissection (ESD)) and 131 patients treated by ERCP.

RESULTS

There were no significant differences in the rate of degeneration and invariability of Child-Pugh (CP) class and the overall rate of adverse events between two groups (93.8%/8.6% ER vs. 96.2%/15.3% ERCP). Both the degeneration rate of CP class (35.4%) and the rate of adverse events (27.1%) in subgroup CP class C of ERCP group were significantly higher (P=0). The rate of poor outcomes was higher in ERCP group (12.2%) than that in ER group (2.5%) (P=0.02). And subgroup CP class C of ERCP group had a higher poor outcome rate (27.1%) (P=0).

CONCLUSION

ER and ERCP could remove focal lesions or relieve symptoms induced by targeted diseases without significant changes of CP class. Significant benefits and risks coexisted in CP class C patients with DLC when receiving ERCP.

Machine Learning Model to Stratify the Risk of Lymph Node Metastasis for Early Gastric Cancer: A Single-Center Cohort Study

Stratification of the risk of lymph node metastasis (LNM) in patients with non-curative resection after endoscopic resection (ER) for early gastric cancer (EGC) is crucial in determining additional treatment strategies and preventing unnecessary surgery. Hence, we developed a machine learning (ML) model and validated its performance for the stratification of LNM risk in patients with EGC. We enrolled patients who underwent primary surgery or additional surgery after ER for EGC between May 2005 and March 2021. Additionally, patients who underwent ER alone for EGC between May 2005 and March 2016 and were followed up for at least 5 years were included. The ML model was built based on a development set (70%) using logistic regression, random forest (RF), and support vector machine (SVM) analyses and assessed in a validation set (30%). In the validation set, LNM was found in 337 of 4428 patients (7.6%). Among the total patients, the area under the receiver operating characteristic (AUROC) for predicting LNM risk was 0.86 in the logistic regression, 0.85 in RF, and 0.86 in SVM analyses; in patients with initial ER, AUROC for predicting LNM risk was 0.90 in the logistic regression, 0.88 in RF, and 0.89 in SVM analyses. The ML model could stratify the LNM risk into very low (<1%), low (<3%), intermediate (<7%), and high (≥7%) risk categories, which was comparable with actual LNM rates. We demonstrate that the ML model can be used to identify LNM risk. However, this tool requires further validation in EGC patients with non-curative resection after ER for actual application.

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.

Is underwater endoscopic mucosal resection of colon polyps superior to conventional techniques? A network analysis of endoscopic mucosal resection and submucosal dissection

Background and study aims  Evidence from recent trials comparing conventional endoscopic mucosal resection (EMR) to underwater EMR (UEMR) have matured. However, studies comparing UEMR to endoscopic submucosal dissection (ESD) are lacking. Hence, we sought to conduct a comprehensive network meta-analysis to compare the efficacy of UEMR, ESD, and EMR. Methods  Embase and Medline databases were searched from inception to December 2020 for articles comparing UEMR with EMR and ESD. Outcomes of interest included rates of en bloc and complete polyp resection, risk of perforation and bleeding, and local recurrence. A network meta-analysis comparing all three approaches was conducted. In addition, a conventional comparative meta-analysis comparing UEMR to EMR was performed. Analysis was stratified according to polyp sizes (< 10 mm, ≥ 10 mm, and ≥ 20 mm). Results  Twenty-two articles were included in this study. For polyps ≥ 10 mm, UEMR was inferior to ESD in achieving en bloc resection ( P  = 0.02). However, UEMR had shorter operating time for polyps ≥ 10 mm ( P  < 0.001), and ≥20 mm ( P  = 0.019) with reduced perforation risk for polyps ≥ 10 mm ( P  = 0.05) compared to ESD. In addition, en bloc resection rates were similar between UEMR and EMR, although UEMR had reduced recurrence for polyps ≥ 10 mm ( P  = 0.013) and ≥ 20 mm ( P  = 0.014). UEMR also had shorter mean operating than EMR for polyps ≥ 10 mm ( P  < 0.001) and ≥ 20 mm ( P  < 0.001). Risk of bleeding and perforation with UEMR and EMR were similar for polyp of all sizes. Conclusions  UEMR has demonstrated technical and oncological outcomes comparable to ESD and EMR, along with a desirable safety profile. UEMR appears to be a safe and effective alternative to conventional methods for resection of polyps ≥ 10 mm.

Colorectal malignant polyps: a modern approach

Colorectal malignant polyps (MP) are polyps with invasive cancer into the submucosa harboring a variable risk of lymph node involvement, which can be estimated through evaluation of morphological, endoscopic, and histologic features. The recent advances in imaging endoscopic techniques have led to the possibility of performing an optical diagnosis of T1 colorectal cancer, allowing the selection of the best therapeutic modality to optimize outcomes for the patient. When MP are diagnosed after endoscopic removal, their management can be challenging. Differentiating low- and high-risk histologic features that influence the possibility of residual tumor, the risk of recurrence and the risk of lymph node metastasis, is crucial to further optimize treatment and surveillance plans. While the presence of high-risk features indicates a need for surgery in the majority of cases, location, comorbidities and the patient’s preference should be taken in account when making the final decision. This is a particularly important issue in the management of low rectal MP presenting with high-risk features, where chemoradiotherapy followed by a watch-and-wait strategy has demonstrated promising results. In this review we discuss the important prognostic features of MP and the most modern approaches regarding their management.

Value of combined detection of serum tumor markers and M2-PK in colorectal cancer screening

BACKGROUND

Colorectal cancer (CRC) is a highly malignant tumor with a significant increase in incidence and fatality rate year by year. Great attention has been paid to early screening for colorectal cancer. However, due to the non-specific clinical symptoms and complicated mechanisms of CRC, its early screening is not easy.

AIM

To explore the value of serum carbohydrate antigen 19-9 (CA19-9) and carcinoembryonic antigen (CEA) combined with tumor M2 pyruvate kinase (M2-PK) in the screening of CRC.

METHODS

Eighty patients with CRC and 75 patients with benign colorectal diseases treated at our hospital from January 1, 2018 to October 10, 2020 were selected. In addition, 90 healthy controls were also included. All subjects were tested for serum CA19-9, CEA, and M2-PK. The differences in serum CA19-9, CEA, and M2-PK levels between the three groups were compared, and the receiver operating characteristic (ROC) curve was used to assess the performance of serum CA19-9, CEA, and M2-PK levels, either alone or in combination, in CRC screening.

RESULTS

The results of one-way variance showed that the differences in serum CEA, CA19-9, and TuM2-PK were statistically significant among the three groups (P < 0.05); the levels of serum CEA, CA19-9, and TuM2-PK in the CRC group were significantly higher than those of the other two groups (P < 0.05). ROC curve analysis showed that the area under the ROC curve (AUC) values of serum CEA, CA19-9, and TuM2-PK for the diagnosis of CRC were 0.72, 0.69, and 0.85, respectively. The sensitivity of combined detection of CEA + CA19-9 + TuM2-PK was 90%, which was significantly higher than that of other combinations (P < 0.05).

CONCLUSION

The detection of serum tumor markers combined with M2-PK can effectively improve the sensitivity of the diagnosis of CRC, and may play an important role in the early screening of this malignancy.

Artificial intelligence-assisted colonoscopy: A review of current state of practice and research

Colonoscopy is an effective screening procedure in colorectal cancer prevention programs; however, colonoscopy practice can vary in terms of lesion detection, classification, and removal. Artificial intelligence (AI)-assisted decision support systems for endoscopy is an area of rapid research and development. The systems promise improved detection, classification, screening, and surveillance for colorectal polyps and cancer. Several recently developed applications for AI-assisted colonoscopy have shown promising results for the detection and classification of colorectal polyps and adenomas. However, their value for real-time application in clinical practice has yet to be determined owing to limitations in the design, validation, and testing of AI models under real-life clinical conditions. Despite these current limitations, ambitious attempts to expand the technology further by developing more complex systems capable of assisting and supporting the endoscopist throughout the entire colonoscopy examination, including polypectomy procedures, are at the concept stage. However, further work is required to address the barriers and challenges of AI integration into broader colonoscopy practice, to navigate the approval process from regulatory organizations and societies, and to support physicians and patients on their journey to accepting the technology by providing strong evidence of its accuracy and safety. This article takes a closer look at the current state of AI integration into the field of colonoscopy and offers suggestions for future research.

Cold snare polypectomy for superficial non-ampullary duodenal epithelial tumor: a prospective clinical trial (pilot study)

BACKGOUND

Cold snare polypectomy (CSP) can minimize the risk of adverse events and has become a standard treatment for small colorectal polyps. CSP might also be suitable for small superficial non-ampullary duodenal epithelial tumors (SNADETs). This study aimed to evaluate the safety of CSP for SNADETs.

METHODS

The major indication criteria were as follows: (1) endoscopically diagnosed SNADET, (2) ≤ 10 mm, and (3) a single primary lesion. CSP was performed using an electrosurgical snare without electrocautery. Follow-up endoscopy and scar biopsy were performed 3 months after CSP. The primary endpoint was the delayed adverse events rate.

RESULTS

In total, 21 patients were enrolled. Two and 19 lesions were located in the duodenal bulb and 2nd portion, respectively; the median lesion size was 8 mm. CSP was attempted for all lesions; three lesions could not be resected without electrocautery and were removed by conventional endoscopic mucosal resection (EMR). The rate of spurting bleeding after CSP was 0%. The median procedure time was 12 min, the median resected specimen size was 12 mm, and the rate of en bloc resection was 81% (17/21). No adverse events were observed intraoperatively, with no delayed adverse events after CSP. Histopathology revealed 15 adenomas, 4 cancers (intramucosal), and 2 non-neoplastic lesions. The horizontal margins were negative/positive/undetermined in 9, 1, and 11 cases, respectively. All vertical margins were negative. Only one recurrence was detected by follow-up endoscopy 3 months after CSP.

CONCLUSIONS

CSP can be performed safely for small SNADETs.

CLINICAL TRIAL REGISTRATION

This trial was registered with the University Hospital Medical Information Network Clinical Trials Registry ( http://www.umin.ac.jp/ctr/index.htm ), and the registration number is UMIN000019157.

Management of large polyps in a colorectal cancer screening program with fecal immunochemical test: a community- and population-based observational study

Background and study aims  The aim of this study was to analyze presentation, management, and outcomes of large polyps (LPs; ≥ 20 mm) detected in a colorectal cancer (CRC) screening program using a quantitative fecal immunochemical test (FIT). Patients and methods  This was a retrospective community- and population-based observational study of all LPs detected in patients aged 50 to 74 years between 2015 and 2019 during FIT-positive colonoscopies within the screening program organized in Alsace (France). Results  Among 13,633 FIT-positive colonoscopies, 1256 LPs (8.5 % malignant and 51.8 % nonpedunculated) were detected by 102 community gastroenterologists in 1164 patients (one in 12 colonoscopies). The sensitivity of optical diagnosis of malignancy was 54 % for nonpedunculated and 27 % for pedunculated T1 CRCs. The endoscopic resection rate was 82.7 % (95 % confidence interval [CI] 80.3-84.9) for benign LPs (70.2 % [95 % CI 66.4-74.1]) nonpedunculated, 95.2 % [95 % CI 93.4-97.1] pedunculated), varying from 0 to 100 % depending on the endoscopist. It was correlated with cecal intubation (Pearson r  = 0.49, P  < 0.01) and adenoma detection rates ( r  = 0.25, P  = 0.01). Most endoscopists did not refer patients to more experienced endoscopists, and as a result, 60 % to 90 % of 183 surgeries for benign LPs were unwarranted. Endoscopic resection was curative for 4.3 % (95 % CI 0.9-12.0) of nonpedunculated and 37.8 % (95 % CI 22.5-55.2) of pedunculated T1 CRCs. Overall, 22 endoscopic submucosal dissections had to be performed to avoid one surgery. Conclusions  Compared with current recommendations, there is tremendous room for improvement in community endoscopy practices in the diagnosis and management of LPs. Detection and polypectomy competencies are correlated and highly variable among endoscopists. Endoscopic resection is curative for 83 % of benign LPs and 16 % of T1 CRCs.

An analysis about the function of a new artificial intelligence, CAD EYE with the lesion recognition and diagnosis for colorectal polyps in clinical practice

OBJECTIVES

Recently, CAD EYE (Fujifilm, Tokyo, Japan), an artificial intelligence for the lesion recognition (CADe) and the optical diagnosis (CADx) of colorectal polyps, was released. We evaluated the function of CADe and CADx of CAD EYE.

METHODS

In this single-center retrospective study, we examined consecutive polyps ≤ 10 mm detected from March to April 2021 to determine whether CAD EYE could recognize them live with both normal- and high-speed observation using white-light imaging (WLI) and linked-color imaging (LCI). We then examined whether the polyps were neoplastic or hyperplastic live with magnified or non-magnified blue-laser imaging (BLI-LASER) or blue-light imaging (BLI-LED) under CAD EYE, comparing the retrospective evaluations with 5 experts and 5 trainees using still images. All polyps were histopathologically examined.

RESULTS

We analyzed 100 polyps (mean size 3.9 ± 2.6 mm; 55 neoplastic and 45 hyperplastic lesions) in 25 patients. Regarding CADe, the respective detection rates of CAD EYE with normal- and high-speed observation were 85.0% and 67.0% for WLI (p = 0.002) and 89.0% and 75.0% for LCI (p = 0.009). Regarding CADx for differentiating neoplastic and hyperplastic lesions, the diagnostic accuracy values of CAD EYE with non-magnified and magnified BLI-LASER/LED were 88.8% and 87.8%. Regarding magnified BLI-LASER/LED, the diagnostic accuracy value of CAD EYE was not significantly different from that of experts (92.0%, p = 0.17), but that of trainees (79.0%, p = 0.04). We also found no significant differences in CADe or CADx between LED (53 lesions) and LASER (47 lesions).

CONCLUSIONS

CAD EYE was a helpful tool for CADe and CADx in clinical practice.