Risk factors for local recurrence and appropriate surveillance interval after endoscopic resection

Construction and validation of machine learning-based predictive model for colorectal polyp recurrence one year after endoscopic mucosal resection

BACKGROUND

Colorectal polyps are precancerous diseases of colorectal cancer. Early detection and resection of colorectal polyps can effectively reduce the mortality of colorectal cancer. Endoscopic mucosal resection (EMR) is a common polypectomy procedure in clinical practice, but it has a high postoperative recurrence rate. Currently, there is no predictive model for the recurrence of colorectal polyps after EMR.

AIM

To construct and validate a machine learning (ML) model for predicting the risk of colorectal polyp recurrence one year after EMR.

METHODS

This study retrospectively collected data from 1694 patients at three medical centers in Xuzhou. Additionally, a total of 166 patients were collected to form a prospective validation set. Feature variable screening was conducted using univariate and multivariate logistic regression analyses, and five ML algorithms were used to construct the predictive models. The optimal models were evaluated based on different performance metrics. Decision curve analysis (DCA) and SHapley Additive exPlanation (SHAP) analysis were performed to assess clinical applicability and predictor importance.

RESULTS

Multivariate logistic regression analysis identified 8 independent risk factors for colorectal polyp recurrence one year after EMR (P < 0.05). Among the models, eXtreme Gradient Boosting (XGBoost) demonstrated the highest area under the curve (AUC) in the training set, internal validation set, and prospective validation set, with AUCs of 0.909 (95%CI: 0.89-0.92), 0.921 (95%CI: 0.90-0.94), and 0.963 (95%CI: 0.94-0.99), respectively. DCA indicated favorable clinical utility for the XGBoost model. SHAP analysis identified smoking history, family history, and age as the top three most important predictors in the model.

CONCLUSION

The XGBoost model has the best predictive performance and can assist clinicians in providing individualized colonoscopy follow-up recommendations.

Approaches and considerations in the endoscopic treatment of T1 colorectal cancer

The detection of early colorectal cancer (CRC) is increasing through the implementation of screening programs. This increased detection enhances the likelihood of minimally invasive surgery and significantly lowers the risk of recurrence, thereby improving patient survival and reducing mortality rates. T1 CRC, the earliest stage, is treated endoscopically in cases with a low risk of lymph node metastasis (LNM). The advantages of endoscopic treatment compared with surgery include minimal invasiveness and limited tissue disruption, which reduce morbidity and mortality, preserve bowel function to avoid colectomy, accelerate recovery, and improve cost-effectiveness. However, T1 CRC has a risk of LNM. Thus, selection of the appropriate treatment between endoscopic treatment and surgery, while avoiding overtreatment, is challenging considering the potential for complete resection, LNM, and recurrence risk.

Colorectal polypectomy and endoscopic mucosal resection: European Society of Gastrointestinal Endoscopy (ESGE) Guideline - Update 2024

1:  ESGE recommends cold snare polypectomy (CSP), to include a clear margin of normal tissue (1-2 mm) surrounding the polyp, for the removal of diminutive polyps (≤ 5 mm).Strong recommendation, high quality of evidence. 2:  ESGE recommends against the use of cold biopsy forceps excision because of its high rate of incomplete resection.Strong recommendation, moderate quality of evidence. 3:  ESGE recommends CSP, to include a clear margin of normal tissue (1-2 mm) surrounding the polyp, for the removal of small polyps (6-9 mm).Strong recommendation, high quality of evidence. 4:  ESGE recommends hot snare polypectomy for the removal of nonpedunculated adenomatous polyps of 10-19 mm in size.Strong recommendation, high quality of evidence. 5:  ESGE recommends conventional (diathermy-based) endoscopic mucosal resection (EMR) for large (≥ 20 mm) nonpedunculated adenomatous polyps (LNPCPs).Strong recommendation, high quality of evidence. 6:  ESGE suggests that underwater EMR can be considered an alternative to conventional hot EMR for the treatment of adenomatous LNPCPs.Weak recommendation, moderate quality of evidence. 7:  Endoscopic submucosal dissection (ESD) may also be suggested as an alternative for removal of LNPCPs of ≥ 20 mm in selected cases and in high-volume centers.Weak recommendation, low quality evidence. 8:  ESGE recommends that, after piecemeal EMR of LNPCPs by hot snare, the resection margins should be treated by thermal ablation using snare-tip soft coagulation to prevent adenoma recurrence.Strong recommendation, high quality of evidence. 9:  ESGE recommends (piecemeal) cold snare polypectomy or cold EMR for SSLs of all sizes without suspected dysplasia.Strong recommendation, moderate quality of evidence. 10:  ESGE recommends prophylactic endoscopic clip closure of the mucosal defect after EMR of LNPCPs in the right colon to reduce to reduce the risk of delayed bleeding.Strong recommendation, high quality of evidence. 11:  ESGE recommends that en bloc resection techniques, such as en bloc EMR, ESD, endoscopic intermuscular dissection, endoscopic full-thickness resection, or surgery should be the techniques of choice in cases with suspected superficial invasive carcinoma, which otherwise cannot be removed en bloc by standard polypectomy or EMR.Strong recommendation, moderate quality of evidence.

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.

Recurrence rate after piecemeal endoscopic mucosal resection of <20 mm non-pedunculated colorectal lesions: should we worry about the risk?

INTRODUCTION

There is scarce data focused on recurrence neoplasia rate (RR) after piecemeal endoscopic mucosal resection (pEMR) of 10-19 mm non-pedunculated colorectal lesions (NPL). We aimed to analyze the RR after pEMR of 10-19 mm NPL, identify risk factors for its development and compare it with RR after pEMR of ≥ 20 mm NPL.

METHODS

Retrospective cohort-study including all ≥10 mm NPL resected by pEMR in our center between 2018-2022 with an early repeat colonoscopy (ERC). RR was defined as recurrence neoplasia identified in the ERC EMR scar with virtual chromoendoscopy or histological confirmation.

RESULTS

A total of 444 NPL were assessed, 124 (27.9%) with 10-19 mm. In the ERC, performed a median of 6 months after pEMR, RR was significantly lower for 10-19 mm NPL compared to ≥ 20 mm NPL (13/124 vs 68/320, p = 0.005). In subgroup analysis, RR after pEMR of 15-19 mm NPL was significantly higher compared to 10-14 mm NPL (13/98 vs 0, p = 0.041) but not significantly different compared to ≥ 20 mm NPL (13/98 vs 68/320, p = 0.073). In multivariable analysis, size of NPL (HR 1.501, 95% CI 1.012-2.227, p = 0.044) was the only independent risk factor identified for RR for 10-19 mm NPL.

CONCLUSION

Although the early RR after pEMR of 10-19 mm NPL is significantly lower compared to ≥ 20 mm NPL, it is non-negligible (10.5%) and appears to be the highest among 15-19 mm NPL. The size of the lesion was the only independent risk factor for RR. Our findings should be accounted in the selection of the most appropriate post-polypectomy endoscopic surveillance.

The feasibility of endoscopic resection for colorectal laterally spreading tumors

The present study aimed to investigate the feasibility and safety of endoscopic resection for colorectal laterally spreading tumors (LSTs) in different size groups. This retrospective study included 2699 patients with LSTs who underwent endoscopic treatment at the Second Xiangya Hospital of Central South University from May 2012 to February 2022. The patient baseline and procedure outcomes were compared between the < 5 cm group, 5-10 cm group, and ≥ 10 cm group. Meanwhile, lesions larger than 5 cm in diameter were longitudinally compared for endoscopic safety using ESD with surgical operation outcomes. There were 2105 patients in the < 5 cm group, 547 patients in the 5-10 cm group, and 47 patients in the ≥ 10 cm group. En bloc resection and R0 resection rates, the incidence of adverse events, length of stay (LOS), and medical costs significantly differed between the groups (P < 0.01). Comorbidity of diabetes or hypertension, history of antithrombotic drug use, lesion size, location, gross type, endoscopic procedures selection, and circumferential extent of the mucosal defect were independent risk factors for delayed bleeding (P < 0.05). En bloc resection, R0 resection, and lesion canceration were associated with local recurrence. For lesions larger than 5 cm in diameter, ESD had similar R0 resection and local recurrence rates compared with a surgical operation but a lower en bloc rate, LOS, and medical costs. Expert endoscopists can significantly increase en bloc and R0 resection rates and reduce the incidence of adverse events. Endoscopic resection results distinguish in different size groups of colorectal LSTs, yet its safety and feasibility are not inferior to a surgical operation.

Tip-in Versus Conventional Endoscopic Mucosal Resection for Colorectal Neoplasia: A Systematic Review and Meta-analysis

BACKGROUND

Early-stage gastrointestinal neoplasms are frequently treated with conventional endoscopic mucosal resection (C-EMR). However, C-EMR frequently leads to incomplete resection of large colorectal lesions. Tip-in endoscopic mucosal resection (EMR), which was recently introduced for en bloc resection of colorectal neoplasms, minimizes slippage during the procedure.

METHODS

We conducted a systematic review and meta-analysis of published studies that compared Tip-in EMR with conventional EMR. We searched several electronic databases and included studies that reported on the primary outcomes of en bloc resection rate and complete resection rate, as well as secondary outcomes such as procedure time and procedure-related complications (including perforation and delayed bleeding rate). We used a random effects model to calculate odds ratios (ORs) with 95% CIs for dichotomous data and weighted mean differences with 95% CIs for continuous data. We also conducted several sensitivity analyses to assess the robustness of our findings.

RESULTS

A total of 11 studies involving 1244 lesions (684 in the Tip-in EMR group and 560 in C-EMR group) were included in the meta-analysis. Our meta-analysis showed that compared with conventional EMR, Tip-in EMR significantly increased the en bloc resection rate in patients with colorectal neoplasia (OR=3.61; 95% CI, 2.09-6.23; P <0.00001; I2 =0%) and had a higher complete resection rate (OR=2.49; 95% CI, 1.65-3.76; P <0.0001; I2 =0%). However, the procedure time and rates of procedure-related complications did not differ significantly between the 2 groups.

CONCLUSIONS

Tip-in EMR outperformed C-EMR for both the en bloc and complete resection of colorectal lesions with similar rates of procedural complications.

Recurrence and survival in dogs with excised colorectal polyps: A retrospective study of 58 cases

BACKGROUND

Compared to humans, colorectal polyps are relatively rare in dogs. Epidemiological and prognostic data remain accordingly sparse, although they could help veterinary clinicians in the management of these cases.

OBJECTIVES

To report the epidemiological data of dogs with colorectal polyps and identify factors associated with recurrence and survival.

ANIMALS

Fifty-eight client-owned dogs with colorectal polyps admitted to 7 veterinary hospitals (53 dogs from France, 5 dogs from Spain, and 4 dogs from Portugal) were included.

METHODS

Retrospective multicentric cohort study. Medical records and long-term outcome of the dogs were reviewed. When available, histological samples were reassessed by 2 board-certified pathologists according to the revised Vienna classification (RVC).

RESULTS

The West Highland White Terrier (WHWT) breed was significantly associated with the presence of colorectal polyps (OR: 20; 95% CI: 7.5-52; P < .001). The overall median time to recurrence was not reached after 2000 days. The overall estimated median survival time was 1640 days. WHWT breed and larger polyps were significantly associated with a shorter time of polyp recurrence after surgical removal (respectively, P = .05 and P = .01).

CONCLUSIONS AND CLINICAL IMPORTANCE

The probability of recurrence of colorectal polyps in dogs is low, but increased in WHWTs and larger polyps, which might benefit from routine screening after removal. No effective predictors of polyp recurrence and survival were identified using the RVC.

pT1 colorectal cancer: A treatment dilemma

The implementation of population screening programs for colorectal cancer (CRC) has led to a considerable increase in the prevalence pT1-CRC originating on polyps amenable by local treatments. However, a high proportion of patients are referred for unnecessary oncological surgeries without a clear benefit in terms of survival. Selecting the appropriate endoscopic resection technique in the moment of diagnosis becomes crucial to provide the best treatment alternative to each individual polyp and patient. For this, it is imperative to increase the optical diagnostic skill for differentiating pT1-CRCs and decide the appropriate initial therapy. En bloc resection is crucial to obtain an adequate histological specimen that might allow organ preserving therapeutic management. In this review, we address key challenges in T1 CRC management, explore the efficacy and safety of the available diagnostic and therapeutic approaches, and shed light on upcoming advances in the field.

Comparative efficacy and safety of resection techniques for treating 6 to 20mm, nonpedunculated colorectal polyps: A systematic review and network meta-analysis

INTRODUCTION

Various endoscopic resection techniques have been proposed for the treatment of nonpedunculated colorectal polyps sized 6-20 mm, however the optimal technique still remains unclear.

METHODS

A comprehensive literature review was conducted for randomized controlled trials (RCTs), investigating the efficacy of endoscopic treatments for the management of 6-20 mm nonpedunculated colorectal polyps. Primary outcomes were complete and en bloc resection rates and adverse event rate was the secondary. Effect size on outcomes is presented as risk ratio (RR; 95% confidence interval [CI]).

RESULTS

Fourteen RCTs (5219 polypectomies) were included. Endoscopic mucosal resection(EMR) significantly outperformed cold snare polypectomy(CSP) in terms of complete [(RR 95%CI): 1.04(1.00-1.07)] and en bloc resection rate [RR:1.12(1.04-1.21)]. EMR was superior to hot snare polypectomy (HSP) [RR:1.04(1.00-1.08)] regarding complete resection, while underwater EMR (U-EMR) achieved significantly higher rate of en bloc resection compared to CSP [RR:1.15(1.01-1.30)]. EMR yielded the highest ranking for complete resection(SUCRA-score 0.81), followed by cold-snare EMR(CS-EMR,SUCRA-score 0.76). None of the modalities was different regarding adverse event rate compared to CSP, however EMR and CS-EMR resulted in fewer adverse events compared to HSP [RR:0.44(0.26-0.77) and 0.43(0.21-0.87),respectively].

CONCLUSION

EMR achieved the highest performance in resecting 6-20 mm nonpedunculated colorectal polyps, with this effect being consistent for polyps 6-9 and ≥10 mm; findings supported by very low quality of evidence.

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.

Korean Guidelines for Postpolypectomy Colonoscopic Surveillance: 2022 revised edition

Colonoscopic polypectomy is effective in decreasing the incidence and mortality of colorectal cancer (CRC). Premalignant polyps discovered during colonoscopy are associated with the risk of metachronous advanced neoplasia. Postpolypectomy surveillance is the most important method for managing advanced metachronous neoplasia. A more efficient and evidence-based guideline for postpolypectomy surveillance is required because of the limited medical resources and concerns regarding colonoscopy complications. In these consensus guidelines, an analytic approach was used to address all reliable evidence to interpret the predictors of CRC or advanced neoplasia during surveillance colonoscopy. The key recommendations state that the high-risk findings for metachronous CRC following polypectomy are as follows: adenoma ≥10 mm in size; 3 to 5 (or more) adenomas; tubulovillous or villous adenoma; adenoma containing high-grade dysplasia; traditional serrated adenoma; sessile serrated lesion containing any grade of dysplasia; serrated polyp of at least 10 mm in size; and 3 to 5 (or more) sessile serrated lesions. More studies are needed to fully comprehend the patients who are most likely to benefit from surveillance colonoscopy and the ideal surveillance interval to prevent metachronous CRC.

Endoscopic mucosal resection-precutting vs conventional endoscopic mucosal resection for sessile colorectal polyps sized 10-20 mm

BACKGROUND

The optimal method to remove sessile colorectal lesions sized 10-20 mm remains uncertain. Piecemeal and incomplete resection are major limitations in current practice, such as endoscopic mucosal resection (EMR) and cold or hot snare polypectomy. Recently, EMR with circumferential precutting (EMR-P) has emerged as an effective technique, but the quality of current evidence in comparative studies of conventional EMR (CEMR) and EMR-P is limited.

AIM

To investigate whether EMR-P is superior to CEMR in removing sessile colorectal polyps.

METHODS

This multicenter randomized controlled trial involved seven medical institutions in China. Patients with colorectal polyps sized 10-20 mm were enrolled and randomly assigned to undergo EMR-P or CEMR. EMR-P was performed following submucosal injection, and a circumferential mucosa incision (precutting) was conducted using a snare tip. Primary outcomes included a comparison of the rates of en bloc and R0 resection, defined as one-piece resection and one-piece resection with histologically assessed clear margins, respectively.

RESULTS

A total of 110 patients in the EMR-P group and 110 patients in the CEMR group were finally evaluated. In the per-protocol analysis, the proportion of en bloc resections was 94.3% [95% confidence interval (CI): 88.2%-97.4%] in the EMR-P group and 86% (95%CI: 78.2%-91.3%) in the CEMR group (P = 0.041), while subgroup analysis showed that for lesions > 15 mm, EMR-P also resulted in a higher en bloc resection rate (92.0% vs 58.8% P = 0.029). The proportion of R0 resections was 81.1% (95%CI: 72.6%-87.4%) in the EMR-P group and 76.6% (95%CI: 68.8%-84.4%) in the CEMR group (P = 0.521). The EMR-P group showed a longer median procedure time (6.4 vs 3.0 min; P < 0.001). No significant difference was found in the proportion of patients with adverse events (EMR-P: 9.1%; CEMR: 6.4%; P = 0.449).

CONCLUSION

In this study, EMR-P served as an alternative to CEMR for removing nonpedunculated colorectal polyps sized 10-20 mm, particularly polyps > 15 mm in diameter, with higher R0 and en bloc resection rates and without increasing adverse events. However, EMR-P required a relatively longer procedure time than CEMR. Considering its potential benefits for en bloc and R0 resection, EMR-P may be a promising technique in colorectal polyp resection.

Risk of recurrence after endoscopic resection of nonpedunculated T1 colorectal cancer

BACKGROUND

The long-term outcome after local excision of T1 colorectal cancer (CRC) remains unknown. The aim of this study was to examine clinical and histopathological risk factors for recurrence in patients with T1 CRC undergoing endoscopic resection.

METHODS

This was a retrospective registry-based population study on prospectively collected data of all patients with nonpedunculated T1 CRC undergoing only local excision (no salvage surgery) in Sweden between 2009 and 2018. Potential risk factors for recurrence, including age, sex, tumor location, resection margins, lymphovascular, perineural, and submucosal invasion, grade of differentiation, and mucinous subtype, were analyzed using univariate and multivariate cox regression.

RESULTS

Median follow-up time was 60 months, and 28 /602 patients (4.7 %) had a recurrence (13 local and 18 distant). Recurrence rate stratified by submucosal invasion was: Sm1 3.5 % (14 /397), Sm2 6.0 % (8 /133), and Sm3 8.3 % (6 /72), with no significant differences. Resection margins, lymphovascular and perineural invasion, grade of differentiation, mucinous subtype, and age were not significant risk factors for recurrence. In contrast, rectal location was found to be a significant risk factor for tumor recurrence in multivariate analysis (hazard ratio 3.08, P = 0.006). The 3- and 5-year disease-free survival was 96.2 % and 91.1 %, respectively, in T1 CRC patients undergoing endoscopic resection.

CONCLUSION

Tumor recurrence was rare (4.7 %) in this large population-based study on recurrence after local excision of nonpedunculated T1 CRC. Rectal location was an independent risk factor for recurrence, suggesting the need for strict surveillance after endoscopic resection of early rectal cancer.

Clinical outcomes of endoscopic submucosal dissection for colorectal neoplasms: A single-center experience in Southern Taiwan

Background and aims

Endoscopic submucosal dissection (ESD) as an advanced endoscopic procedure can be considered for the removal of colorectal lesions with high suspicion of limited submucosal invasion or cannot be optimally removed by snare-based techniques. We aimed to analyze the clinical outcomes of ESD for colorectal neoplasms in our hospital.

Methods

We retrospectively enrolled 230 patients with 244 colorectal neoplasms who received ESD procedures from April 2012 to October 2020 at Kaohsiung Chang Gung Memorial Hospital. Clinicopathological data were collected by chart review. We also recorded ESD-related complications and clinical outcomes.

Results

The average age was 64 years old, with a mean follow-up time of 22.59 months. There was a loss of follow-up in 34 lesions. Most lesions were lateral spreading tumors of the non-granular type. The average ESD time was 51.9 minutes. Nine cases (3.7%) had procedure-related complications, including two intra-procedure perforations (0.8%) and seven delayed bleeding (2.9%) without procedure-related mortality. 241 lesions (98.8%) achieved en-bloc resection, while 207 lesions (84.8%) achieved R0 resection. Most lesions were tubulo-(villous) adenoma. Malignancy included 35 adenocarcinomas and 5 neuroendocrine tumors. No local recurrence was developed during follow-up. Multivariate analysis for long ESD time revealed significance in size ≥ 10 cm² and endoscopist’s experience < 3 years. Pre-ESD endoscopic ultrasound revealed good prediction in discrimination of mucosal (sensitivity: 0.90) and submucosal lesion (specificity: 0.67).

Conclusions

ESD for colorectal neoplasms is an effective and safe technique. Size ≥ 10 cm² and endoscopist’s experience < 3 years were significantly associated with long procedure time. Pre-ESD EUS provided a good prediction for colorectal neoplasms in invasion depth.

[Korean Guidelines for Postpolypectomy Colonoscopic Surveillance: 2022 Revised Edition]

Colonoscopic polypectomy is effective in decreasing the incidence and mortality of colorectal cancer (CRC). Premalignant polyps discovered during colonoscopy are associated with the risk of metachronous advanced neoplasia. Postpolypectomy surveillance is the most important method for managing advanced metachronous neoplasia. A more efficient and evidence-based guideline for postpolypectomy surveillance is required because of the limited medical resources and concerns regarding colonoscopy complications. In these consensus guidelines, an analytic approach was used to address all reliable evidence to interpret the predictors of CRC or advanced neoplasia during surveillance colonoscopy. The key recommendations state that the high-risk findings for metachronous CRC following polypectomy are as follows: 1) adenoma ≥10 mm in size; 2) 3-5 (or more) adenomas; 3) tubulovillous or villous adenoma; 4) adenoma containing high-grade dysplasia; 5) traditional serrated adenoma; 6) sessile serrated lesion (SSL) containing any grade of dysplasia; 7) serrated polyp of at least 10 mm in size; and 8) 3-5 (or more) SSLs. More studies are needed to fully comprehend the patients who are most likely to benefit from surveillance colonoscopy and the ideal surveillance interval to prevent metachronous CRC.

[Korean Guidelines for Postpolypectomy Colonoscopic Surveillance: 2022 Revised Edition]

Colonoscopic polypectomy is effective in decreasing the incidence and mortality of colorectal cancer (CRC). Premalignant polyps discovered during colonoscopy are associated with the risk of metachronous advanced neoplasia. Postpolypectomy surveillance is the most important method for managing advanced metachronous neoplasia. A more efficient and evidence-based guideline for postpolypectomy surveillance is required because of the limited medical resources and concerns regarding colonoscopy complications. In these consensus guidelines, an analytic approach was used to address all reliable evidence to interpret the predictors of CRC or advanced neoplasia during surveillance colonoscopy. The key recommendations state that the high-risk findings for metachronous CRC following polypectomy are as follows: 1) adenoma ≥10 mm in size; 2) 3-5 (or more) adenomas; 3) tubulovillous or villous adenoma; 4) adenoma containing high-grade dysplasia; 5) traditional serrated adenoma; 6) sessile serrated lesion (SSL) containing any grade of dysplasia; 7) serrated polyp of at least 10 mm in size; and 8) 3-5 (or more) SSLs. More studies are needed to fully comprehend the patients who are most likely to benefit from surveillance colonoscopy and the ideal surveillance interval to prevent metachronous CRC.

Artificial Intelligence Assisted Topographic Mapping System for Endoscopic Submucosal Dissection Specimens

Background

Endoscopic submucosal dissection (ESD), a minimally invasive surgery used to treat early gastrointestinal malignancies, has been widely embraced around the world. The gross reconstruction of ESD specimens can facilitate a more precise pathological diagnosis and allow endoscopists to explore lesions thoroughly. The traditional method of mapping is time-consuming and inaccurate. We aim to design a topographic mapping system via artificial intelligence to perform the job automatically.

Methods

The topographic mapping system was built using computer vision techniques. We enrolled 23 ESD cases at the Peking Union Medical College Hospital from September to November 2019. The reconstruction maps were created for each case using both the traditional approach and the system.

Results

Using the system, the time saved per case ranges from 34 to 3,336 s. Two approaches revealed no significant variations in the shape, size, or tumor area.

Conclusion

We developed an AI-assisted system that would help pathologists complete the ESD topographic mapping process rapidly and accurately.

Outcomes of cold snare piecemeal EMR for nonampullary small-bowel adenomas larger than 1 cm: a retrospective study

BACKGROUND AND AIMS

Nonampullary small-bowel adenomas ≥10 mm are typically resected using cautery-based polypectomy, which is associated with significant adverse events. Studies have demonstrated the safety and efficacy of piecemeal cold snare EMR for removing large colon polyps. Our aim was to assess the safety and efficacy of cold snare EMR for removal of large adenomas in the small bowel.

METHODS

A retrospective study of patients who underwent lift and piecemeal cold snare EMR of small-bowel adenomas ≥1 cm between January 2014 and March 2019 was conducted at a tertiary care medical center. Polyp characteristics at the time of index and surveillance endoscopy were collected. Primary outcomes were residual or recurrent adenoma (RRA) seen on surveillance endoscopy, polyp eradication rate, and number of endoscopic procedures required for eradication. Adverse events including immediate and delayed bleeding, perforation, stricture, pancreatitis, and postpolypectomy syndrome were assessed.

RESULTS

Of 43 patients who underwent piecemeal cold snare EMR, 39 had follow-up endoscopy. Polyps ranged in size from 10 to 70 mm (mean, 26.5 mm). RRA was found in 18 patients (46%), with increased polyp size correlating with higher recurrence (P < .001). Polyp eradication was observed in 35 patients (89%), requiring a median of 2 (range, 1-6) endoscopic procedures. Only 1 patient (2.3%) had immediate postprocedural bleeding. No cases of perforation or postpolypectomy syndrome were seen.

CONCLUSIONS

Piecemeal cold snare EMR may be a feasible, safe, and efficacious technique for small-bowel polyps >10 mm. Prospective, randomized studies are needed to assess how outcomes compare with traditional cautery-based polypectomy.

Training program using a traction device improves trainees' learning curve of colorectal endoscopic submucosal dissection

BACKGROUND

Colorectal endoscopic submucosal dissection (ESD) requires advanced endoscopic skill. For safer and more reliable ESD implementation, various traction devices have been developed in recent years. The purpose of this research was to evaluate whether an ESD training program using a traction device (TD) would contribute to the improvement of trainees' skill acquisition.

METHODS

The differences in treatment outcomes and learning curves by the training program were compared before and after the introduction of TD (control group: January 2014 to March 2016; TD group: April 2016 to June 2018).

RESULTS

A total of 316 patients were included in the analysis (TD group: 202 cases; control group: 114 cases). The number of cases required to achieve proficiency in ESD techniques was 10 in the TD group and 21 in the control group. Compared to the control group, the TD group had a significant advantage in ESD self-completion rate (73.8% vs. 58.8%), dissection speed (19.5 mm²/min vs. 15.9 mm²/min), en bloc resection rate (100% vs. 90%), and R0 resection rate (96% vs. 83%).

CONCLUSIONS

The rate of colorectal ESD self-completion by trainees improved immediately after the start of the training program using a traction device compared to the conventional method, and the dissection speed tended to increase linearly with ESD experience. We believe that ESD training using a traction device will help ESD techniques to be performed safely and reliably among trainees.

Patient Selection, Risks, and Long-Term Outcomes Associated with Colorectal Polyp Resection

The 2 most significant complications of colonoscopy with polypectomy are bleeding and perforation. Although the incidence rates are generally low (<1%), these can be avoided by recognizing pertinent risk factors, which can be patient, polyp, and technique/device related. Endoscopists should be equipped to manage bleeding and perforation. Currently available devices and techniques to achieve hemostasis and manage colon perforations are reviewed.

In vitro analysis of exfoliated tumor cells in intraluminal lavage samples after colorectal endoscopic submucosal dissection

PURPOSE

Colorectal endoscopic submucosal dissection (ESD) produces exfoliated tumor cells that occasionally cause local recurrence. However, the biological characteristics of these tumor cells have not been clarified. The aim of this study was to clarify the genetic background and viability of exfoliated tumor cells in colorectal ESDs, as well as possible method for their elimination.

METHODS

Post-ESD intraluminal lavage samples from 19 patients who underwent colorectal ESDs were collected. In four patients with adenocarcinoma, gene mutations in the primary tumors and exfoliated cells in lavage samples were analyzed using a next-generation sequencer (NGS). In 15 patients with adenoma or adenocarcinoma, the viability of exfoliated cells and the cell-killing effect of povidone-iodine on exfoliated cells were evaluated.

RESULTS

The analysis using a NGS demonstrated that tumors targeted for ESD had already acquired mutations in many genes involved in cell proliferation, angiogenesis, and invasions. Furthermore, gene mutations between the exfoliated tumor cells and tumors resected by ESDs showed a 92 to 100% concordance. The median viable cell counts and the median viability of exfoliated cells in intraluminal lavage samples after ESDs were 4.9 × 10⁵ cells/mL and 24%, respectively. The viability of the exfoliated cells did not decrease even 12 h after ESD. However, contact with 2.0% povidone-iodine solution reduced both viable cell counts and viability, significantly.

CONCLUSION

A large number of tumor cells exfoliated during colorectal ESDs had acquired survival-favorable gene mutations and could survive for some time. Therefore, a lavage using a solution of 2.0% povidone-iodine may be effective against such cells.

TRIAL REGISTRATION

The prospective study registered 1317, and the retrospective study registered 2729. The prospective study approved on June 20, 2016, and the retrospective study approved on October 6, 2020.

Endoscopic resection for gastrointestinal tumors (esophageal, gastric, colorectal tumors): Japanese standard and future prospects

Endoscopic resection (ER) techniques such as polypectomy, endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are widely accepted as a less invasive treatment for gastrointestinal (GI) tumors. Since there is a limit to the size that can be resected by EMR and it is often divided, it is not possible to accurately evaluate the degree of cancer progression, and the cancer remains or causes recurrence. ESD is a technology that overcomes these weaknesses. ER techniques are considered for tumors that have a very low possibility of lymph node metastasis and are suitable for en-bloc resection. As ESD became more widespread, the difficulty of treating ESD was gradually resolved by the development of technology and equipment, the curative resection rate increased, and the complication rate decreased. ER techniques have become the standard treatment for early cancer and precancerous lesions in Japan, and the therapeutic indications are expanding day by day. The indications for whether endoscopic treatment can be performed are defined by the guidelines for each organ such as the esophagus, stomach, and colorectum. In the coming aging society, it is also necessary to evaluate the indications for endoscopic treatment and invasive treatment. In addition, recent advances in endoscopic technology are making it possible to remove submucosal tumors that previously required surgery. In this review, we summarize the recent Japanese standard indications of ER for each GI location and future prospects of ER.

Modified endoscopic mucosal resection techniques for treating precancerous colorectal lesions

Endoscopic mucosal resection (EMR) is a technique allowing efficacious and minimally invasive resection of precancerous lesions across the entire gastrointestinal tract. However, conventional EMR, involving injection of fluid into the submucosal space, is imperfect, given the high rate of recurrence of post-endoscopic resection adenoma, especially after piecemeal resection. In light of these observations, modifications of the technique have been proposed to overcome the weakness of conventional EMR. Some of them were designed to maximize the chance of en bloc resection-cap-assisted EMR, underwater EMR, tip-in EMR, precutting, assisted by ligation device-while others were designed to minimize the complications (cold EMR). In this review, we present their modes of action and summarize the evidence regarding their efficacy and safety.

Does precutting prior to endoscopic piecemeal resection of large colorectal neoplasias reduce local recurrence? A KASID multicenter study

BACKGROUND

It would be expected that local recurrence could be reduced by performing precutting (with sufficient margins) prior to endoscopic piecemeal mucosal resection (EPMR). We explored the clinical outcomes and local recurrence after precutting EPMR of large colorectal neoplasias.

METHODS

Between January 2005 and December 2015, in total, 223 patients with colorectal neoplasias ≥ 2 cm in diameter removed via EPMR in four tertiary hospitals were enrolled. The patients were divided into a precut EPMR group (n = 62) and a non-precut EPMR group (n = 161). We retrospectively evaluated clinical outcomes and factors associated with local recurrence.

RESULTS

The mean total procedure time was significantly shorter in the non-precut EPMR group than in the precut EPMR group. However, the number of pieces, and the complete resection and recurrence rates, did not differ significantly [for the latter, precut 8.1% vs. non-precut 9.9%, P = 0.668]. The complete resection rate, number of pieces, and use of argon plasma coagulation (APC) were significantly associated with the local recurrence rate on univariate analysis. In the Cox's proportional hazards model, prophylactic APC [hazard ratio 0.307, 95% confidence interval (CI) 0.114-0.823; P = 0.019] and complete resection rate (odds ratio 0.083, 95% CI 0.011-0.655; P = 0.018) were significantly associated with the local recurrence rate.

CONCLUSION

Precutting prior to EPMR did not significantly reduce the local recurrence rate or the number of resected pieces. Histologically complete resection, reducing the number of pieces, and prophylactic APC seem to be important in terms of reducing local recurrence.

The Application of Core Needle Biopsy Through the Trocar Hole in the Surgical Operation of Endoscopically Unresectable Giant Colon Polyps: A Systematic Review Study

INTRODUCTION

The study aimed to investigate the application of core needle biopsy through the trocar hole during surgery on endoscopically unresectable giant colon polyps.

METHODS

The clinical data of 51 patients with endoscopically unresectable giant colon polyps from May 2016 to May 2020 were retrospectively analyzed. The primary observational outcomes were two comparative analyses of pathologic results, using the kappa index: comparison of the pathologic results from the preoperative colonoscopy and the postoperative pathologic results and comparison of the intraoperative pathologic results from core needle biopsy of the intestinal wall and the postoperative pathologic results. The secondary observational outcomes were duration of needle biopsy, operation duration, volume of intraoperative hemorrhage, rate of postoperative wound infection, rate of abdominal cavity infection, length of stay, and number and positivity of lymph node dissections after laparoscopic radical resection of colon cancer.

RESULTS

Poor consistency was found between the preoperative (colonoscopy) and postoperative pathologic results, with kappa = 0.222 (i.e., kappa < 0.4), P < 0.05. However, good consistency was found between the intraoperative (core needle biopsy) and postoperative pathologic results, with kappa = 0.923 (i.e., kappa ≥ 0.75), P < 0.05. The postoperative pathologic results were as follows: 7 cases of adenomatous polyps of the colon, 12 cases of low-grade intraepithelial neoplasia, 12 cases of high-grade intraepithelial neoplasia, and 25 cases of invasive colon cancer. There was no incision infection, no abdominal cavity infection or formation of an abdominal abscess, no anastomotic leakage, and no death for any of the 51 patients. Postoperative complications occurred in two cases (3.92%).

CONCLUSION

Biopsy through the trocar hole during laparoscopic surgery produced highly accurate pathologic results and was a fast, safe, and effective diagnostic method. Pathologic results from intraoperative biopsy could accurately determine the nature of colon polyps and provide a basis for choosing an appropriate surgical scheme.

Does Additional Laparoscopic-Assisted Surgery after Endoscopic Submucosal Dissection Affect Short Outcomes in Patients with Stage T1 Colorectal Cancer? A Propensity Score-Based Analysis

BACKGROUND

Additional surgery is necessary in cases with non-curative endoscopic submucosal dissection. It is still unknown whether preceding endoscopic submucosal dissection (ESD) for T1 colorectal carcinoma affects the short outcomes of patients who underwent additional surgery or not as compared with surgery alone without ESD.

METHODS

Patients (101 pairs) with T1 colorectal cancer who underwent additional laparoscopic-assisted surgery after endoscopic submucosal dissection (additional surgery group, n = 101) or laparoscopic-assisted surgery alone (surgery alone group, n = 101) were matched (1:1). Short-term morbidity, operation outcomes, and lymph node metastasis of the resected specimen were compared.

RESULTS

There were no significant differences between the additional laparoscopic-assisted surgery and laparoscopic-assisted surgery alone groups in lymph node metastasis (9.9 vs. 5.9%, respectively, p = 0.297), operative time (147.76 ± 52.00 min vs. 156.50 ± 54.28 min, p = 0.205), first flatus time (3.56 ± 1.10 days vs. 3.63 ± 1.05 days, p = 0.282), first stool time (4.30 ± 1.04 days vs. 4.39 ± 1.22 days, p = 0.293), time to intake (5.00 ± 1.18 days vs. 5.25 ± 1.39 days, p = 0.079), blood loss (44.75 ± 45.40 mL vs. 60.40 ± 78.98 mL, p = 0.603), harvest lymph nodes (18.74 ± 7.22 vs. 20.32 ± 9.69, p = 0.438), postoperative surgical complications (p = 0.733), and postoperative length of hospital stay (8.68 ± 4.00 days vs. 8.39 ± 1.94 days, p = 0.401).

CONCLUSION

ESD did not increase the difficulty of additional laparoscopic-assisted surgery, hospital stay, or the incidence of postoperative complications. Additional laparoscopic-assisted surgery is safe and recommended for patients with T1 cancer at high risk of lymph node metastasis and residual cancer after non-curative ESD.

Role of Endoscopic Resection Versus Surgical Resection in Management of Malignant Colon Polyps: a National Cancer Database Analysis

BACKGROUND

Endoscopic resection (polypectomy) or surgery, are the main approaches in management of malignant colon polyps. There are very few large population-based studies comparing outcomes between the two.

METHODS

Using the National Cancer Database, we identified patients ≥ 18 years with the first diagnosis of T1N0M0 malignant polyp from 2004 to 2015. Patients with a positive resection margin were excluded. Outcomes were compared between those who had surgery versus those who had polypectomy. Overall survival was compared using Kaplan-Meier curves. Multivariate Cox proportional hazards analysis was performed to generate hazard ratios, adjusted for patient, demographic, and tumor factors.

RESULTS

A total of 31,062 patients met the inclusion criteria, out of which 2593 (8.3%) underwent polypectomy alone and 28,469 (91.7%) had surgery. Overall survival was significantly better in the surgical group compared with the polypectomy group. One-year and 5-year survival for surgery were 95.8% and 86.1% respectively compared with 94.2% and 80.6% for polypectomy (p < .0001). Hazard ratio for surgery after adjusting for various clinical-, demographic-, and tumor-level factors was 0.53 (p < .0001).

CONCLUSION

Our study is the largest population-based analysis of patients with T1N0M0 malignant colon polyps. Overall survival was higher in patients who underwent surgery compared with polypectomy. This remained consistent even after adjusting for multiple patient and tumor factors between the two groups.

Is Additional Surgery Necessary After Non-Curative Endoscopic Submucosal Dissection for Early Colorectal Cancer?

BACKGROUND

Although endoscopic submucosal dissection (ESD) is considered to be a curative treatment for early colorectal cancer, additional surgery with lymph node dissection is routinely recommended for patients treated in non-curative ESD, owing to the risk of residual cancer and lymph node metastasis (LNM). However, in clinical practice, few patients are found to have either residual cancer or LNM after additional surgery. Therefore, we conducted this study to determine the risk factors associated with residual cancer and LNM.

METHODS

Patients with early colorectal cancer after non-curative ESD and additional surgery from January 2015 to May 2019 were retrospectively identified. Clinicopathological characteristics were collected to determine the predictors of residual cancer and LNM.

RESULTS

A total of 62 patients were enrolled for analysis in this study. After additional surgery, residual cancer and LNM was detected in 12 patients (19.35%). Clinicopathological comparison of patients with the presence or absence of residual cancer and LNM demonstrated that piecemeal resection (80% vs. 14.04%, P < 0.001), submucosal invasion greater than 2000 μm (26.09% vs. 0%, P = 0.026), lymphovascular infiltration (37.5% vs. 13.04%, P = 0.033), and perineuronal invasion (75% vs. 15.52%, P = 0.004) were more frequent in residual cancer and LNM cases. Multivariate analysis identified lymphovascular infiltration (P = 0.031) as the only significantly independent risk factor associated with residual cancer and LNM.

CONCLUSIONS

Additional surgery with lymphadenectomy should be performed after non-curative ESD owing to the high risk of residual cancer and LNM, especially in cases with lymphovascular infiltration.