Endoscopic submucosal dissection for colorectal neoplasia during the clinical learning curve

Multidisciplinary Treatment Strategy for Early Colon Cancer: A Review-An English Version

Treatment for early colon cancer has progressed rapidly, with endoscopic resection and minimally invasive surgery. It is important to select patients without risk of lymph node metastasis before deciding on endoscopic resection for early colon cancer treatment. Pathological risk factors include histologic grade of cancer cell differentiation, lymphovascular invasion, perineural invasion, tumor budding, and deep submucosal invasion. These risk factors for predicting lymph node metastasis are crucial for determining the treatment strategy of endoscopic excision and radical resection for early colon cancer. A multidisciplinary approach is emphasized to establish a treatment strategy for early colon cancer to minimize the risk of complications and obtain excellent oncologic outcomes by selecting an appropriate treatment optimized for the patient's stage and condition. Therefore, we aimed to review the optimal multidisciplinary treatment strategies, including endoscopy and surgery, for early colon cancer.

Transanal endoscopic microsurgical submucosal dissection: Are there advantages over conventional ESD?

INTRODUCTION

Transanal endoscopic microsurgical submucosal dissection (TEM-ESD) is a technique that has been recently described for the treatment of large rectal adenomas and early rectal cancer. The purpose of our study is to compare TEM-ESD with flexible endoscopic submucosal dissection (ESD) in an experimental, ex vivo porcine model.

MATERIAL AND METHODS

We used TEM-ESD and flexible ESD to resect a total of 100 standardized 4 × 4cm lesions in an ex vivo porcine stomach model, performing 50 resections with each technique. Total procedure time, en bloc resection rate, injuries of the muscularis propria, perforation rate and learning curve were analysed.

RESULTS

TEM-ESD was associated with a significantly shorter total procedure time in comparison to ESD (19 min vs. 33 min, p < .001). The rates of en bloc resection, injury of the muscularis propria layer, and perforation were the same in both groups. The learning curve of TEM-ESD was shallower than that of ESD.

CONCLUSION

TEM-ESD showed an advantage over ESD in terms of procedure time and learning curve, with similar en bloc resection rates and safety profile in our experimental model.

[Clinical Practice Guideline for Endoscopic Resection of Early Gastrointestinal Cancer]

Although surgery was the standard treatment for early gastrointestinal cancers, endoscopic resection is now a standard treatment for early gastrointestinal cancers without regional lymph node metastasis. High-definition white light endoscopy, chromoendoscopy, and image-enhanced endoscopy such as narrow band imaging are performed to assess the edge and depth of early gastrointestinal cancers for delineation of resection boundaries and prediction of the possibility of lymph node metastasis before the decision of endoscopic resection. Endoscopic mucosal resection and/or endoscopic submucosal dissection can be performed to remove early gastrointestinal cancers completely by en bloc fashion. Histopathological evaluation should be carefully made to investigate the presence of risk factors for lymph node metastasis such as depth of cancer invasion and lymphovascular invasion. Additional treatment such as radical surgery with regional lymphadenectomy should be considered if the endoscopically resected specimen shows risk factors for lymph node metastasis. This is the first Korean clinical practice guideline for endoscopic resection of early gastrointestinal cancer. This guideline was developed by using mainly de novo methods and encompasses endoscopic management of superficial esophageal squamous cell carcinoma, early gastric cancer, and early colorectal cancer. This guideline will be revised as new data on early gastrointestinal cancer are collected.

Factors Associated with Fibrosis during Colorectal Endoscopic Submucosal Dissection: Does Pretreatment Biopsy Potentially Elicit Submucosal Fibrosis and Affect Endoscopic Submucosal Dissection Outcomes?

BACKGROUND

Submucosal fibrosis observed during colorectal endoscopic submucosal dissection (ESD) is an important factor related to incomplete resection. Biopsy is generally accepted as having the potential to elicit submucosal fibrosis, but few reports have presented definitive proof. This study investigated the relation between submucosal fibrosis and colorectal ESD outcomes and assessed factors related to fibrosis, including pretreatment biopsy.

METHODS

After reviewing 369 records of colorectal ESD performed between January 2011 and December 2016, we assessed the relation between fibrosis and ESD outcomes. Multiple logistic regression analysis revealed fibrosis risk factors.

RESULTS

Severe fibrosis was related significantly to ESD outcomes such as the mean procedure time (p < 0.001), en bloc resection rate (p < 0.001), and R0 resection rate (p = 0.011). Multivariate analyses indicated residual lesions (ORs 175.4, p < 0.001), pretreatment biopsy (ORs 8.30, p = 0.002), nongranular-type laterally spreading tumors (LST-NG; ORs 5.86, p = 0.025), and invasive carcinoma (ORs 5.83, p = 0.03) as independent risk factors of severe fibrosis. In each macroscopic type, LST-NG was more strongly related to fibrosis induced by pretreatment than granular-type laterally spreading tumors with adjust ORs of 50.8 and 4.69.

CONCLUSIONS

Pretreatment biopsy causes submucosal fibrosis resulting in prolonged procedure times and incomplete resection. These findings suggest important benefits of avoiding biopsy before ESD.

Clinical practice guideline for endoscopic resection of early gastrointestinal cancer

Although surgery was the standard treatment for early gastrointestinal cancers, endoscopic resection is now a standard treatment for early gastrointestinal cancers without regional lymph node metastasis. High-definition white light endoscopy, chromoendoscopy, and image-enhanced endoscopy such as narrow band imaging are performed to assess the edge and depth of early gastrointestinal cancers for delineation of resection boundaries and prediction of the possibility of lymph node metastasis before the decision of endoscopic resection. Endoscopic mucosal resection and/or endoscopic submucosal dissection can be performed to remove early gastrointestinal cancers completely by en bloc fashion. Histopathological evaluation should be carefully made to investigate the presence of risk factors for lymph node metastasis such as depth of cancer invasion and lymphovascular invasion. Additional treatment such as radical surgery with regional lymphadenectomy should be considered if the endoscopically resected specimen shows risk factors for lymph node metastasis. This is the first Korean clinical practice guideline for endoscopic resection of early gastrointestinal cancer. This guideline was developed by using mainly de novo methods and encompasses endoscopic management of superficial esophageal squamous cell carcinoma, early gastric cancer, and early colorectal cancer. This guideline will be revised as new data on early gastrointestinal cancer are collected.

Learning curve for endoscopic submucosal dissection of early colorectal neoplasms with a monopolar scissor-type knife: use of the cumulative sum method

OBJECTIVE

Although scissor-type knives such as the Stag-Beetle (SB) Knife Jr are expected to result in a safe and easy colorectal endoscopic submucosal dissection (CR-ESD), information regarding the learning curve is lacking. Therefore, this study evaluated the learning curve with using SB Knife Jr.

MATERIALS AND METHODS

We retrospectively reviewed 507 CR-ESD procedures performed in 464 patients using SB Knife Jr. The primary endpoint was a learning curve to achieve a satisfactory complete resection rate. The secondary endpoints were learning curves to achieve a satisfactory en bloc resection rate, curative resection rate, and resection speed.

RESULTS

The complete, en bloc, and curative resection rates were 91.9%, 95.9%, and 84.0%, respectively. Moving average analysis showed that 39 cases were required for a complete resection rate of >80%, 41 for an en bloc resection rate of >90%, and 50 for a curative resection rate of >75%. We divided the procedure into three phases using the cumulative sum method: I, II, and III (cases 1-36, 37-119, and 120-507, respectively). Although we found no significant between-phase differences, the complete resection rate showed an increasing trend in Phase III (83.3 vs. 89.2 vs. 93.3%; p = .099). The en bloc resection rate (91.7 vs. 91.6 vs. 97.2%; p = .047) and resection speed (20.5 vs. 7.2 vs. 6.8 min/cm²; p < .001) were greater in Phase III. Despite the larger specimen size (27.3 vs. 38.2 vs. 40.4 mm; p < .001) and more severe fibrosis (p < .001) in Phase III, the procedure time was shorter (73.8 vs. 57.8 vs. 54.2 min; p = .041). The curative resection rate was not significantly different between phases.

CONCLUSIONS

SB Knife Jr enables safe and easy CR-ESD during the introductory period compared to the conventional tip-type knife and has an acceptable learning curve. Therefore, using this knife will encourage the widespread adoption of CR-ESD in Asian general hospitals and non-Asian countries.

Predicting and managing complications following colonoscopy: risk factors and management of advanced interventional endoscopy with a focus on colorectal ESD

INTRODUCTION

Colorectal endoscopic submucosal dissection (ESD) has been introduced widely in Western and Asian countries. The management of the perforation during ESD is crucial.

AREAS COVERED

The rate of intraprocedural perforation, risk factors, prevention, and management of perforation during ESD and EMR were discussed in this review. The perforation rate in ESD and EMR depending on the lesion size is also discussed.

EXPERT OPINION

The knowledge regarding the risk factor and techniques to manage perforation is important during colorectal ESD and EMR. The development of novel suturing techniques devices is key for colorectal ESD in the future.

Systematic literature review of learning curves for colorectal polyp resection techniques in lower gastrointestinal endoscopy

AIM

The performance of therapeutic procedures in lower gastrointestinal endoscopy (LGI) can be challenging and carries an increased risk of adverse events. There is increasing demand for the training of endoscopists in these procedures, but limited guidelines exist concerning procedural competency. The aim of this study was to assess the learning curves for LGI polypectomy, colorectal endoscopic mucosal resection (EMR) and colorectal endoscopic submucosal dissection (ESD).

METHOD

A systematic review of electronic databases between 1946 and September 2019 was performed. Citations were included if they reported learning curve data. Outcome measures that defined the success of procedural competency were also recorded.

RESULTS

A total of 34 out of 598 studies met the inclusion criteria of which 28 were related to ESD, three to polypectomy and three to EMR. Outcome measures for polypectomy competency (en bloc resection, delayed bleeding and independent polypectomy rate) were achieved after completion of between 250 and 400 polypectomies and after 300 colonoscopies. EMR outcome measures, including complete resection and recurrence, were achieved variably between 50 and 300 procedures. Outcome measures for ESD included efficiency (resection rates and procedural speed) and safety (adverse events). En bloc resection rates of over 80% and R0 resection rates of over 70% were achieved at 20-40 cases and procedural speed increased after 30 ESD cases. Competency in safety metrics was variably achieved at 20-200 cases.

CONCLUSION

There is a paucity of data on learning curves in LGI polypectomy, EMR and ESD. Despite limited evidence, we have identified relevant outcome measures and threshold numbers for the most common LGI polyp resection techniques for potential inclusion in training programmes/credentialing guidelines.

Bipolar-current needle-knife with a water jet function (Jet B-knife) shortens the procedure time of endoscopic submucosal dissection for colorectal tumors

BACKGROUND

Endoscopic submucosal dissection (ESD) is a technically difficult and time-consuming procedure for the treatment of large colorectal tumors. In Japan, the ball-tip bipolar-current needle-knife (BB-knife) has been used in ESD as a safe device that minimizes the damage to deeper tissues of colorectal neoplasms. In May 2012, a BB-knife combined with a water jet function (Jet B-knife) was newly developed.

METHODS

This retrospective study was aimed at examining the effectiveness and safety of the Jet B-knife. The BB-knife was used in 276 lesions (BB-knife group), while the Jet B-knife was used in 245 lesions (Jet B-knife group). We evaluated tumor characteristics and the results of the ESD procedures, including the size of the resected tumor, histological diagnosis, time required for resection, frequency of using other electrical devices, en bloc resection rate, and incidence rate of associated complications. Then, the data obtained were compared between the two groups.

RESULTS

The histological evaluation of the resected tumors revealed that the incidence of cancer was not significantly different between the two groups. The median time required for resection was 103 min (45-255) in the BB-knife group and 51 min (28-210) in the Jet B-knife group. The difference was statistically significant (p < 0.05). Furthermore, the median tumor diameters were 23.1 mm (18-50) and 26.2 mm (20-60) in the BB-knife and Jet B-knife groups, respectively, demonstrating a statistically significant difference (p < 0.05). Multivariate logistic regression analysis revealed that short resection time (p < 0.001) and reduced use of hemostatic devices (p < 0.01) were independent favorable features of Jet B-knife. The en bloc resection rate and the perforation rate were not statistically significant between the two groups.

CONCLUSIONS

Use of the Jet B-knife may contribute to the development of a time-saving, cost-effective, and safe procedure for ESD of colorectal tumors.

Clinical Practice Guideline for Endoscopic Resection of Early Gastrointestinal Cancer

Although surgery was the standard treatment for early gastrointestinal cancers, endoscopic resection is now a standard treatment for early gastrointestinal cancers without regional lymph node metastasis. High-definition white light endoscopy, chromoendoscopy, and image-enhanced endoscopy such as narrow band imaging are performed to assess the edge and depth of early gastrointestinal cancers for delineation of resection boundaries and prediction of the possibility of lymph node metastasis before the decision of endoscopic resection. Endoscopic mucosal resection and/or endoscopic submucosal dissection can be performed to remove early gastrointestinal cancers completely by en bloc fashion. Histopathological evaluation should be carefully made to investigate the presence of risk factors for lymph node metastasis such as depth of cancer invasion and lymphovascular invasion. Additional treatment such as radical surgery with regional lymphadenectomy should be considered if the endoscopically resected specimen shows risk factors for lymph node metastasis. This is the first Korean clinical practice guideline for endoscopic resection of early gastrointestinal cancer. This guideline was developed by using mainly de novo methods and encompasses endoscopic management of superficial esophageal squamous cell carcinoma, early gastric cancer, and early colorectal cancer. This guideline will be revised as new data on early gastrointestinal cancer are collected.

Review on colorectal endoscopic submucosal dissection focusing on the technical aspect

BACKGROUND

Endoscopic submucosal dissection (ESD) enables removal of broad-based colorectal polyps or lateral spreading tumors with a higher rate of en bloc resection and a lower risk of local recurrence. However, it is technically demanding. Over the past 20 years, various equipment and innovative techniques have been developed to reduce the difficulty of ESD. The information in the literature is scattered. Our aim is to provide a comprehensive review on the setup and technical aspects of colorectal ESD.

METHODS

We searched the PubMed database and systemically reviewed all original and review articles related to colorectal ESD. Further manual search according to reference lists of identified articles were done. The selected articles were categorized and reviewed. Original figures were created to help readers understand some of the ESD techniques.

RESULTS

A total of 216 articles were identified, in which 25 of them were review articles and 191 of them were original articles. They were categorized and reviewed. An in-depth appraisal of the setting, equipment, and technical aspects of colorectal ESD was performed.

CONCLUSIONS

Although ESD is a technically demanding procedure that requires expert endoscopic skills, it can be mastered. With good peri-procedural preparation, sufficient knowledge of the equipment, and thorough understanding of the useful endoscopic tricks and maneuvers, colorectal ESD can be performed smoothly and safely.

Clinical Practice Guideline for Endoscopic Resection of Early Gastrointestinal Cancer

Although surgery was the standard treatment for early gastrointestinal cancers, endoscopic resection is now a standard treatment for early gastrointestinal cancers without regional lymph node metastasis. High-definition white light endoscopy, chromoendoscopy, and image-enhanced endoscopy such as narrow band imaging are performed to assess the edge and depth of early gastrointestinal cancers for delineation of resection boundaries and prediction of the possibility of lymph node metastasis before the decision of endoscopic resection. Endoscopic mucosal resection and/or endoscopic submucosal dissection can be performed to remove early gastrointestinal cancers completely by <i>en bloc</i> fashion. Histopathological evaluation should be carefully made to investigate the presence of risk factors for lymph node metastasis such as depth of cancer invasion and lymphovascular invasion. Additional treatment such as radical surgery with regional lymphadenectomy should be considered if the endoscopically resected specimen shows risk factors for lymph node metastasis. This is the first Korean clinical practice guideline for endoscopic resection of early gastrointestinal cancer. This guideline was developed by using mainly de novo methods and encompasses endoscopic management of superficial esophageal squamous cell carcinoma, early gastric cancer, and early colorectal cancer. This guideline will be revised as new data on early gastrointestinal cancer are collected.

Comparing outcomes for endoscopic submucosal dissection between Eastern and Western countries: A systematic review and meta-analysis

AIM

To compare endoscopic submucosal dissection (ESD) outcomes between Eastern and Western countries.

METHODS

A systematic review and meta-analysis was performed using PubMed, MEDLINE, Web of Science, CINAHL and EBM reviews to identify studies published between 1990 and February 2016. The primary outcome was the efficacy of ESD based on information about either curative resection, en bloc or R0 resection rates. Secondary outcomes were complication rates, local recurrence rates and procedure times.

RESULTS

Overall, 238 publications including 84318 patients and 89512 gastrointestinal lesions resected using ESD were identified. 90% of the identified studies reporting ESD on 87296 lesions were conducted in Eastern countries and 10% of the identified studies reporting ESD outcomes in 2216 lesions were from Western countries. Meta-analyses showed higher pooled percentage of curative, en bloc, and R0 resection in the Eastern studies; 82% (CI: 81%-84%), 95% (CI: 94%-96%) and 89% (CI: 88%-91%) compared to Western studies; 71% (CI: 61%-81%), 85% (CI: 81%-89%) and 74% (CI: 67%-81%) respectively. The percentage of perforation requiring surgery was significantly greater in the Western countries (0.53%; CI: 0.10-1.16) compared to Eastern countries (0.01%; CI: 0%-0.05%). ESD procedure times were longer in Western countries (110 min vs 77 min).

CONCLUSION

Eastern countries show better ESD outcomes compared to Western countries. Availability of local ESD expertise and regional outcomes should be considered for decision making to treat gastrointestinal lesions with ESD.

Endoscopic submucosal dissection in the West: Current status and future directions

Endoscopic submucosal dissection (ESD) was first conceptually described almost 30 years ago in Japan and is now widely practiced throughout East Asia. ESD expands the boundaries of endoscopic resection (ER) by allowing en bloc resection of large early neoplastic lesions within the gastrointestinal tract (GIT). This offers advantages over other ER techniques by facilitating definitive histological staging and curative treatment of early cancer in selected cases. Indeed, the experience of ESD in Eastern countries is significant, and excellent outcomes from high-volume centers are reported. The potential benefits of ESD are recognized by Western endoscopists, but its adoption has been limited. A number of factors contribute to this, including epidemiological differences in GIT neoplasia between Western and Eastern populations and limitations in training opportunities. In this review, we discuss the role of ESD, its current status and the future in Western endoscopic practice.

Clinical outcomes of endoscopic submucosal dissection for colorectal tumors: a large multicenter retrospective study from the Hiroshima GI Endoscopy Research Group

BACKGROUND AND AIMS

Although advanced high-volume centers have reported good outcomes of colorectal endoscopic submucosal dissection (ESD), a limited number of highly skilled experts in specialized institutions performed these procedures. We undertook a retrospective multicenter survey, which included nonspecialized hospitals, to investigate the clinical outcomes of colorectal ESD.

METHODS

We recruited 1233 consecutive patients with 1259 colorectal tumors resected by ESD at 12 institutions. We evaluated the en bloc resection rate, histologic complete resection rate, curative (R0) resection rate, adverse events, and the long-term prognoses, including local recurrence, metachronous tumor development, and survival rate.

RESULTS

The en bloc, histologic complete, and R0 resection rates were 92.6%, 87.4%, and 83.7%, respectively. The delayed bleeding, intraoperative perforation, and delayed perforation rates were 3.7%, 3.4%, and .4%, respectively. The long-term outcomes analysis included 1091 patients (88.4%). Local recurrences occurred in 1.7%, and metachronous tumors (>5 mm) developed in 11.0% of the patients. The 3- and 5-year overall survival rates were 95.1% and 92.3%, respectively. The number of colonic tumors, severe submucosal fibrosis, and en bloc resection rates were significantly higher in the high-volume centers (Group H) than those in the low-volume centers (Group L). The average tumor size in Group H was significantly larger than that in Group L.

CONCLUSIONS

Colorectal ESDs are feasible, have acceptable adverse event risks, and favorable long-term prognoses. (Clinical trial registration number: UMIN000016197.).

The influence of procedural volume and proficiency gain on mortality from upper GI endoscopic mucosal resection

OBJECTIVE

Endoscopic mucosal resection (EMR) is established for the management of benign and early malignant upper GI disease. The aim of this observational study was to establish the effect of endoscopist procedural volume on mortality.

DESIGN

Patients undergoing upper GI EMR between 1997 and 2012 were identified from the Hospital Episode Statistics database. The primary outcome was 30-day mortality and secondary outcomes were 90-day mortality, requirement for emergency intervention and elective cancer re-intervention. Risk-adjusted cumulative sum (RA-CUSUM) analysis was used to assess patient mortality risk during initial stage of endoscopist proficiency gain and the effect of endoscopist and hospital volume. Mortality was compared before and after the change point or threshold in the RA-CUSUM curve.

RESULTS

11 051 patients underwent upper GI EMR. Endoscopist procedure volume was an independent predictor of 30-day mortality. Fifty-eight per cent of EMR procedures were performed by endoscopists with annual volume of 2 cases or less, and had a higher 30-day and 90-day mortality rate for patients with cancer, 6.1% vs 0.4% (p<0.001) and 12% vs 2.1% (p<0.001), respectively. The requirement for emergency intervention after EMR for cancer was also greater with low volume endoscopists (1.8% vs 0.1%, p=0.002). In patients with cancer, the RA-CUSUM curve change points for 30-day mortality and elective re-intervention were 4 cases and 43 cases, respectively.

CONCLUSIONS

EMR performed by high volume endoscopists is associated with reduced adverse outcomes. In order to reach proficiency, appropriate training and procedural volume accreditation training programmes are needed nationally.

Colorectal endoscopic submucosal dissection: predictors and neoplasm-related gradients of difficulty

BACKGROUND AND STUDY AIM

 The role of colorectal endoscopic submucosal dissection (ESD) is standardized in Japan and East Asia, but technical difficulties hinder its diffusion. The aim was to identify predictors of difficulty for each neoplasm type.

METHODS

 A competent operator performed all procedures. ESD difficulty was defined as: en bloc with a slow speed (< 0.07 cm ² /min; 30 × 30 mm neoplasm in > 90 min), conversion to endoscopic mucosal resection, or resection abandonment. Pre- and intraoperative difficulty variables were defined according to standard criteria, and evaluated separately for the rectum and colon. Difficulty predictors and gradients were evaluated by the multivariate logistic regression model.

RESULTS

 A total of 140 ESDs were included: 110 in the colon and 30 in the rectum. Neoplasms were laterally spreading tumors - granular type (LST-G) in 85 cases (61 %); the median longer axis was 30 mm (range 15 - 180 mm); a scar was present in 15 cases (11 %). ESD en bloc resection and difficulty rates were 85 % (n = 94) and 35 % (n = 39) in the colon, and 73 % (n = 22) and 50 % (n = 15) in the rectum ( P  = 0.17 and 0.28, respectively). The scar was the only preoperative predictor of difficulty in the rectum (odds ratio [OR] 12.3, 95 % confidence interval [CI] 1.27 - 118.36), whereas predictors in the colon were: scar (OR 12.7, 95 %CI 1.15 - 139.24), LST - nongranular type (NG) (OR 10.5, 95 %CI 1.20 - 55.14), and sessile polyp morphology (OR 3.1, 95 %CI 1.18 - 10.39). Size > 7 - ≤ 12 cm ² (OR 0.20, 95 %CI 0.06 - 0.74) and operator experience > 120 procedures (OR 0.19, 95 %CI 0.04 - 0.81) were predictors for a easy procedure. No intraoperative predictors of difficulty were identified in the rectum, whereas predictors in the colon were: severe submucosal fibrosis (OR 21.9, 95 %CI 2.11 - 225.64), ineffective submucosal exposure by gravity countertraction (OR 12.3, 95 %CI 2.43 - 62.08), and perpendicular submucosal dissection approach (OR 5.2, 95 %CI 1.07 - 25.03). When experience was /= 90, preoperative gradient of colonic ESD difficulty was the highest for LST-NGs (scar positive and negative up to 47 % and 20 %, respectively), intermediate for sessile polyps with scar (up to 23 %), and the lowest for LST-Gs (< 8 %). Different difficulty gradients between neoplasm types persisted with increasing experience: LST-NG rate up to 14 % after 120 procedures.

CONCLUSIONS

 Colonic and rectal ESD difficulty has qualitative differences. Preoperative predictors should be considered to identify the difficulty gradient of each neoplasm type and the appropriate setting for ESD.

Feasibility of colorectal endoscopic submucosal dissection (ESD) carried out by endoscopists with no or little experience in gastric ESD

BACKGROUND AND AIM

Colorectal endoscopic submucosal dissection (ESD) is recommended to be carried out only by endoscopists with sufficient experience in gastric ESD. However, early gastric carcinoma is less common in Western countries than in Japan, and endoscopic maneuverability differs between the stomach and colorectum. We assessed the feasibility of colorectal ESD carried out by endoscopists with no or little experience in gastric ESD.

METHODS

We analyzed en bloc resection, R0 resection and perforation rates in 180 consecutive colorectal ESD carried out by three endoscopists who had no or <5 cases of experience in gastric ESD. We also identified factors associated with R0 resection failure.

RESULTS

Overall en bloc and R0 resection rates were 93.3% (168/180) and 82.2% (148/180), respectively. All 11 cases with perforation were treated endoscopically. Dividing 180 cases into three learning phases (early, middle, or late phases), the en bloc and R0 resection rates increased from 88.3% and 75.0% in the early phase to 98.3% and 88.3% in the late phase, respectively. Perforation rate also improved from 10.0% to 3.3%. Factors associated with R0 resection failure were location at junctions (odds ratio: 6.8, 95% CI: 1.9-27.5), preoperative factors reflecting fibrosis (5.8, 1.9-19.0), and late phase (0.2, 0.1-0.7).

CONCLUSION

Endoscopists without experience in gastric ESD carried out colorectal ESD safely. In the early and middle phases (≤40 cases), they should treat mainly rectal lesions but may also resect lesions in the colon avoiding flexures. Lesions located at junctions and those with preoperative factors reflecting fibrosis should be resected after completing 40 procedures.

Standardization of endoscopic resection for colorectal tumors larger than 10 mm in diameter

Currently, several endoscopic resection (ER) methods for colorectal tumors are available, including polypectomy, conventional endoscopic mucosal resection (EMR), endoscopic submucosal dissection (ESD), and modified ER. In the present review, we mainly focus on the current status of ER for colorectal tumors as well as the report from the Endoscopic Forum Japan (EFJ) 2016, which was held in Tokyo in August 2016. The proposed ER methods for colorectal tumors larger than 10 mm in diameter are as follows. (i) Pedunculated-type tumor is an indication for polypectomy, regardless of size. (ii) Non-pedunculated-type tumor larger than 20 mm in diameter is an indication for ESD in which en bloc resection using conventional EMR is difficult or impossible. (iii) Non-pedunculated-type tumor from 10 mm to 20 mm in diameter is an indication for conventional EMR. However, ESD or modified ER methods are acceptable according to the procedure and the condition of the tumor.

Colorectal endoscopic submucosal dissection: a systematic review and meta-analysis

Background and study aims: Endoscopic submucosal dissection (ESD) is an advanced endoscopic technique that allows en-bloc resection of gastrointestinal tumor. We systematically review the medical literature in order to evaluate the safety and efficacy of colorectal ESD. Patients and methods: We performed a comprehensive literature search of MEDLINE, EMBASE, Ovid, CINAHL, and Cochrane for studies reporting on the clinical efficacy and safety profile of colorectal ESD. Results: Included in this study were 13833 tumors in 13603 patients (42 % female) who underwent colorectal ESD between 1998 and 2014. The R0 resection rate was 83 % (95 % CI, 80 - 86 %) with significant between-study heterogeneity (P < 0.001) which was partly explained by difference in continent (P = 0.004), study design (P = 0.04), duration of the procedure (P = 0.009), and, marginally, by average tumor size (P = 0.09). Endoscopic en bloc and curative resection rates were 92 % (95 % CI, 90 - 94 %) and 86 % (95 % CI, 80 - 90 %), respectively. The rates of immediate and delayed perforation were 4.2 % (95 % CI, 3.5 - 5.0 %) and 0.22 % (95 % CI, 0.11 - 0.46 %), respectively, while rates of immediate and delayed major bleeding were 0.75 % (95 % CI, 0.31 - 1.8 %) and 2.1 % (95 % CI, 1.6 - 2.6 %). After an average postoperative follow up of 19 months, the rate of tumor recurrence was 0.04 % (95 % CI, 0.01 - 0.31) among those with R0 resection and 3.6 % (95 % CI, 1.4 - 8.8 %) among those without R0 resection. Overall, irrespective of the resection status, recurrence rate was 1.0 % (95 % CI, 0.42 - 2.1 %). Conclusions: Our meta-analysis, the largest and most comprehensive assessment of colorectal ESD to date, showed that colorectal ESD is safe and effective for colorectal tumors and warrants consideration as first-line therapy when an expert operator is available.

Update on Difficult Polypectomy Techniques

Endoscopists often encounter colon polyps that are technically difficult to resect. These lesions traditionally were managed surgically, with significant potential morbidity and mortality. Recent advances in endoscopic techniques and instruments have allowed endoscopists to safely and effectively remove colorectal lesions with high technical and clinical success and potentially avoid invasive surgery. Endoscopic mucosal resection (EMR) has gained acceptance as the first-line therapy for large colorectal lesions. Endoscopic submucosal dissection (ESD) has been reported to be associated with higher rate of en bloc resection and less risk of short-time recurrence, but with an increased risk of adverse events. Therefore, the role of colorectal ESD should be restricted to lesions with high-risk morphologic features of submucosal invasion. In this article, we review the recent literature on the endoscopic management of difficult colorectal neoplasms.

Usefulness of training using animal models for colorectal endoscopic submucosal dissection: is experience performing gastric ESD really needed?

BACKGROUND AND STUDY AIMS

Despite the clinical advantages of colorectal endoscopic submucosal dissection (ESD), an effective training system, especially for Western endoscopists, has been challenging to establish. Herein, we propose a novel training program using ex vivo animal models and evaluate the learning curve of colorectal ESD trainees without gastric ESD experience.

PATIENTS AND METHODS

A total of 80 colorectal lesions were prospectively collected and removed by two novice operators. Before human ESD procedures, they received ESD training using an ex vivo porcine "proximal colon" model, which simulates a lumen with many folds and flexions. To assess the validity of our training system, the self-completion and en bloc R0 resection rates, the operation time, and prevalence of complications were compared between the first and latter period. Moreover the factors associated with prolonged operation time were evaluated.

RESULTS

The overall rates of self-completion and en bloc R0 resection were 98 % (78/80) and 100 % (80/80), respectively. The operation time during the first period was significantly longer than that during the latter period (86 ± 50 minutes vs. 60 ± 36 minutes, P = 0.01). Regarding complications, only two cases of perforations and delayed hemorrhage were observed during the first period; however, all of the complications were successfully managed endoscopically. The presence of fibrosis was identified as a significant independent predictor of a prolonged operation time during the first period (coefficient, 5.90; 95 %CI, 2.36 - 9.44, P = 0.002).

CONCLUSIONS

Our trainees achieved high rates of self-completion and R0 resection without severe complications even during the first 20 cases, suggesting that our training programs using ex vivo animal models are useful for trainees without gastric ESD experience.

STUDY REGISTRATION

UMIN000013566.

Endoscopic submucosal dissection

ESD is an established effective treatment modality for premalignant and early-stage malignant lesions of the stomach, esophagus, and colorectum. Compared with EMR, ESD is generally associated with higher rates of en bloc, R0, and curative resections and a lower rate of local recurrence. Oncologic outcomes with ESD compare favorably with competing surgical interventions, and ESD also serves as an excellent T-staging tool to identify noncurative resections that will require further treatment. ESD is technically demanding and has a higher rate of adverse events than most endoscopic procedures including EMR. As such,sufficient training is critical to ensure safe conduct and high-quality resections. A standardized training model for Western endoscopists has not been clearly established,but will be self-directed and include courses, animal model training, and optimally an observership at an expert center.Numerous dedicated ESD devices are now available in the United States from different manufacturers. Although the use of ESD in the United States is increasing, issues related to technical difficulty, limited training opportunities and mentors, risk of adverse events, long procedure duration,and suboptimal reimbursement may limit ESD adoption in the United States to a modest number of academic referral centers for the foreseeable future.

Colorectal endoscopic submucosal dissection from a Western perspective: Today’s promises and future challenges

Over the last few years, endoscopic submucosal dissection (ESD) has shown to be effective in the management of early colorectal neoplasms, particularly in Asian countries where the technique was born. In the Western world, its implementation has been slow and laborious. In this paper, the indications for ESD, its learning model, the available methods to predict the presence of deep submucosal invasion before the procedure and the published outcomes from Asia and Europe will be reviewed. Since ESD has several limitations in terms of learning achievement in the West, and completion of the procedure for the first cases is difficult in our part of the world, a short review on colorectal assisted ESD has been included. Finally, other endoscopic and surgical treatment modalities that are in competition with colorectal ESD will be summarized.

Colorectal endoscopic submucosal dissection (ESD) performed by experienced endoscopists with limited experience in gastric ESD

PURPOSE

Since colorectal endoscopic submucosal dissection (ESD) requires higher-level skills than endoscopic mucosal resection (EMR), it is recommended to acquire sufficient experience in gastric ESD prior to attempting colorectal ESD. We evaluated the ability of experienced endoscopists with limited experience in gastric ESD to perform colorectal ESD.

METHODS

We retrospectively reviewed 120 colorectal ESDs performed by two endoscopists who had expertise in colonoscopy and colorectal EMR but experience of fewer than five gastric ESDs. Main outcomes were the en bloc resection rate with tumor-free margins (R0 resection rate) and adverse events rate. Using only clinical characteristics prior to ESD, we also identified factors affecting outcomes.

RESULTS

A total of 113 patients (94.2 %) received en bloc resection, and the R0 resection rate was 80.0 % (96/120). Perforation and postoperative hemorrhage occurred in eight (6.7 %) and two (1.7 %) patients, respectively. Dividing the 120 cases into three learning phases, R0 resection and perforation rates improved from 77.5 % (31/40) and 12.5 % (5/40) in phase 1 to 85.0 % (34/40) and 2.5 % (1/40) in phase 3, respectively. Multivariate analysis revealed that lesions at junctions (dentate line, sigmoid-descending junction, splenic flexure, hepatic flexure, ileocecal valve) and lesions with factors reflecting fibrosis in the submucosal layer (based on endoscopic findings before ESD) were significantly correlated with R0 resection failure, with adjusted odds ratios of 10.5 (95 % CI 2.1-67.6) and 10.4 (2.7-48.6), respectively.

CONCLUSIONS

Colorectal ESD is feasible for experienced endoscopists with limited experience in gastric ESD. Novices should avoid lesions at junctions or those with factors reflecting fibrosis.

Coagulation syndrome: Delayed perforation after colorectal endoscopic treatments

Various procedure-related adverse events related to colonoscopic treatment have been reported. Previous studies on the complications of colonoscopic treatment have focused primarily on perforation or bleeding. Coagulation syndrome (CS), which is synonymous with transmural burn syndrome following endoscopic treatment, is another typical adverse event. CS is the result of electrocoagulation injury to the bowel wall that induces a transmural burn and localized peritonitis resulting in serosal inflammation. CS occurs after polypectomy, endoscopic mucosal resection (EMR), and even endoscopic submucosal dissection (ESD). The occurrence of CS after polypectomy or EMR varies according previous reports; most report an occurrence rate around 1%. However, artificial ulcers after ESD are largely theoretical, and CS following ESD was reported in about 9% of cases, which is higher than that for CS after polypectomy or EMR. Most cases of post-polypectomy syndrome (PPS) have an excellent prognosis, and they are managed conservatively with medical therapy. PPS rarely develops into delayed perforation. Delayed perforation is a severe adverse event that often requires emergency surgery. Since few studies have reported on CS and delayed perforation associated with CS, we focused on CS after colonoscopic treatments in this review. Clinicians should consider delayed perforation in CS patients.

Current status of local treatment for early rectal cancer in Japan: a questionnaire survey by the 81st Congress of the Japanese Society for Cancer of the Colon and Rectum (JSCCR) in 2014

PURPOSE

The aim of this questionnaire survey was to assess the change in treatment modality over time and the current status of clinical outcomes of local treatment in Japanese patients with pathological T1 (pT1) rectal tumors.

METHODS

A questionnaire survey was conducted by the 81st Congress of the Japan Society for Cancer of the Colon and Rectum. Clinical and pathological outcomes of all eligible patients undergoing local treatment were retrospectively collected from the medical records of each participating hospital.

RESULTS

A total of 1371 pT1 patients from January 2006 to December 2008 (Period A), and 659 patients in 2013 (Period B) were registered. Approximately 70 % of patients underwent radical surgery in both periods. The rate of patients undergoing laparoscopic surgery increased from 46.5 % in Period A to 84.7 % in Period B. The indications for local excision were comparable with those for endoscopic intervention in 78 % of institutions. The rate of endoscopic submucosal dissection (ESD) increased from 20.1 % in Period A to 37.9 % in Period B, whereas local excision decreased from 36.9 to 24.1 %. Few patients received adjuvant therapy, and approximately 40 % of patients underwent additional surgery in both periods. Local recurrence was observed in 9.2 % of patients in Period A, with the median follow-up period being 59 months. Eighty-two percent of patients with local recurrence underwent salvage surgery.

CONCLUSIONS

Local treatment with various modalities was properly performed for early rectal cancer. The number of less invasive modalities, such as laparoscopic surgery and ESD, increased between study periods.