Endoscopic submucosal resection of rectal carcinoid tumors with a ligation device

Comparison of endoscopic resection therapies for rectal neuroendocrine tumors

AIMS

This study was to evaluate and compare the efficacy and safety of endoscopic mucosal resection (EMR), clip-and-snare assisted endoscopic mucosal resection (CS-EMR), and endoscopic submucosal dissection (ESD) for the endoscopic resection of rectal NETs.

MATERIAL AND METHODS

A retrospective analysis was performed on 47 patients with rectal NETs who underwent endoscopic treatment in The Second Affiliated Hospital of Soochow University. Manifestations of clinic pathological characteristics, complications, procedure time and hospitalization costs were studied.

RESULTS

The complete resection rates with CS-EMR and ESD were significantly higher than those with EMR (CS-EMR vs. EMR, p = 0.038; ESD vs. EMR, p = 0.04), but no significant difference was found between the CS-EMR and ESD groups (p = 0.383). The lateral margin was less distant in the CS-EMR group than in the ESD group and there was no difference with regard to vertical margin (lateral margin distance, 1500 ± 3125 vs.3000 ± 3000 μm; vertical margin distance, 400 ± 275 vs.500 ± 500 μm). Compared to ESD, CS-EMR required less operation time (p < 0.01) and money (p < 0.01) and reduced the length of hospital stays (p < 0.01).

CONCLUSIONS

The CS-EMR technique is more effective and efficient than EMR for small rectal NETs. In addition, CS-EMR reduces procedure time, duration of post-procedure hospitalization and decreases patients' cost compared to ESD while ensuring sufficient vertical margin distances.

Short-term outcomes of endoscopic resection for colorectal neuroendocrine tumors: Japanese multicenter prospective C-NET STUDY

OBJECTIVES

The incidence of colorectal neuroendocrine tumors (NETs) has increased with colorectal cancer screening programs and increased colonoscopies. The management of colorectal NETs has recently shifted from radical surgery to endoscopic resection. We aimed to evaluate the short-term outcomes of various methods of endoscopic resection for colorectal NETs.

METHODS

Among those registered in the C-NET STUDY, patients with colorectal NETs who underwent endoscopic treatment as the initial therapy were included. Short-term outcomes, such as the en bloc resection rate and R0 resection (en bloc resection with tumor-free margin) rate, were analyzed based on treatment modalities.

RESULTS

A total of 472 patients with 477 colorectal NETs received endoscopic treatment. Of these, 418 patients with 421 lesions who met the eligibility criteria were included in the analysis. The median age of the patients was 55 years, and 56.9% of them were men. The lower rectum was the most commonly affected site (88.6%), and lesions <10 mm accounted for 87% of the cases. Endoscopic submucosal resection with a ligation device (ESMR-L, 56.5%) was the most common method, followed by endoscopic submucosal dissection (ESD, 31.4%) and endoscopic mucosal resection using a cap (EMR-C, 8.5%). R0 resection rates <10 mm were 95.5%, 94.8%, and 94.3% for ESMR-L, ESD, and EMR-C, respectively. All 16 (3.8%) patients who developed treatment-related complications could be treated conservatively. Overall, 23 (5.5%) patients had incomplete resection without independent clinicopathological risk factors.

CONCLUSION

ESMR-L, ESD, and EMR-C were equally effective and safe for colorectal NETs with a diameter <10 mm.

Treatment strategy and post-treatment management of colorectal neuroendocrine tumor

Following the increase in colorectal neuroendocrine tumors (NETs), there is a consequent increase in the importance of their appropriate treatment and post-treatment management. It is widely accepted that colorectal NETs sized ≥20 mm and those with muscularis propria invasion are indicated for radical surgery, and those sized <10 mm without the invasion are indicated for local resection. No consensus has been reached regarding the treatment strategy for those sized 10-19 mm without the invasion. Endoscopic resection has become a primary option for the local resection of colorectal NETs. For rectal NETs sized <10 mm, modified endoscopic mucosal resection, such as endoscopic submucosal resection with ligation device and endoscopic mucosal resection with a cap-fitted panendoscope, seems favorable because of its ability to achieve a high R0 resection rate, safety, and convenience. Endoscopic submucosal dissection can also be helpful for these lesions; however, this procedure may be more effective for large lesions or those in the colon. Management following local resection of colorectal NETs is based on the pathological evaluation of factors associated with metastasis, including tumor size, invasion depth, tumor cell proliferative activity (NET grading), presence of lymphovascular invasion, and resection margins. There remain unclear issues in managing cases with NET grading ≥2, positive lymphovascular invasion, and positive resection margins following local resection. In particular, there is confusion regarding managing positive lymphovascular invasion because positivity has become remarkably high with the increased use of the immunohistochemical/special staining. Further evidence based on long-term clinical outcomes is required to address these issues.

Benign Lymphoid Polyp of the Rectum Diagnosed and Treated With Endoscopic Submucosal Resection With a Ligation Device

Benign lymphoid polyps of the rectum, also termed "Rectal tonsil" or "Pseudolymphoma," are submucosal tumor-like growths with localized hyperplasia of the lymphoid follicles and are often discovered incidentally during colonoscopy. Its diagnosis and differentiation from other submucosal tumors pose challenges owing to their similar endoscopic features. A 72-year-old woman presented with a positive fecal occult blood test, which led to the discovery of a 10-mm lower rectal tumor resembling a neuroendocrine tumor during colonoscopy. Upon closer examination, the lesion had a yellow submucosal appearance with dilated capillaries. Endoscopic submucosal resection with a ligation device (ESMR-L) was performed because the patient preferred immediate removal. Histopathological examination revealed lymphocytic infiltration with germinal center-containing lymphoid follicles, confirming the diagnosis of benign lymphoid polyp. Benign lymphoid polyps are often difficult to differentiate from carcinoid tumors and malignant lymphomas because the endoscopic findings are similar. Although preoperative endoscopic ultrasonography aids localization and characterization, definitive differentiation remains elusive and necessitates complete lesion resection. ESMR-L is a viable approach for diagnostic accuracy and therapeutic intervention, offering advantages in terms of procedural efficiency and patient care, particularly in cases involving submucosal rectal lesions.

Endoscopic mucosal resection using anchored snare Tip-in versus precut technique for small rectal neuroendocrine tumors

BACKGROUND/AIMS

Small rectal neuroendocrine tumors (NETs) can be treated with modified endoscopic mucosal resection (EMR). However, an optimal EMR method remains to be established. We aimed to assess the non-inferiority of Tip-in EMR versus precut EMR (EMR-P) for treating rectal NETs.

METHODS

This prospective, multicenter, randomized controlled trial enrolled patients with rectal NETs of < 10 mm in diameter. The patients were randomly assigned to EMR-P and Tip-in EMR groups in a 1:1 ratio. Primary outcome was margin-negative (R0) resection rate between the two methods, with a noninferiority margin of 10%.

RESULTS

Seventy-five NETs in 73 patients, including 64 eligible lesions (32 lesions in each, EMR-P and Tip-in EMR groups), were evaluated. In a modified intention-to-treat analysis, R0 resection rates of the EMR-P and Tip-in EMR groups were 96.9% and 90.6%, respectively, which did not demonstrate non-inferiority (risk difference, -6.3 [95% confidence interval: -18.0 to 5.5]). Resection time in the EMR-P group was longer than that in the Tip-in EMR group (p < 0.001). One case of intraprocedural bleeding was reported in each group.

CONCLUSION

We did not demonstrate the non-inferiority of Tip-in EMR compared to EMR-P for treating small rectal NETs. However, the R0 resection rates for both techniques were high enough for clinical application.

Efficacy of endoscopic submucosal resection with a ligation device for small rectal neuroendocrine tumor: study protocol of a multicenter open-label randomized control trial (BANDIT trial)

BACKGROUND

Endoscopic resection is widely accepted as a local treatment for rectal neuroendocrine tumors sized ≤ 10 mm. However, there is no consensus on the best method for the endoscopic resection of rectal neuroendocrine tumors. As a simplified endoscopic procedure, endoscopic submucosal resection with a ligation device (ESMR-L) indicates a histologically complete resection rate comparable to that of endoscopic submucosal dissection (ESD). We hypothesized that ESMR-L than ESD would be preferred for rectal neuroendocrine tumors. Hence, this trial aimed to verify whether ESMR-L is non-inferior to ESD in terms of histologically complete resection rate.

METHODS

This is a prospective, open-label, multicenter, non-inferiority, randomized controlled trial of two parallel groups, conducted at the Shizuoka Cancer Center and 31 other institutions in Japan. Patients with a lesion endoscopically diagnosed as a rectal neuroendocrine tumor ≤ 10 mm are eligible for inclusion. A total of 266 patients will be recruited and randomized to undergo either ESD or ESMR-L. The primary endpoint is the rate of en bloc resection with histologically tumor-free margins (R0 resection). Secondary endpoints include en bloc resection rate, procedure time, adverse events, hospitalization days, total devices and agents cost, adverse event rate between groups with and without resection site closure, outcomes between expert and non-expert endoscopists, and factors associated with R0 resection failure. The sample size is determined based on the assumption that the R0 resection rate will be 95.2% in the ESD group and 95.3% in the ESMR-L group, with a non-inferiority margin of 8%. With a one-sided significance level of 0.05 and a power of 80%, 226 participants are required. Assuming a dropout rate of 15%, 266 patients will be included in this study.

DISCUSSION

This is the first multicenter randomized controlled trial comparing ESD and ESMR-L for the R0 resection of rectal neuroendocrine tumors ≤ 10 mm. This will provide valuable information for standardizing endoscopic resection methods for rectal neuroendocrine tumors.

TRIAL REGISTRATION

Japan Registry of Clinical Trials, jRCTs042210124. Registered on Jan 6, 2022.

A deep learning-based system to identify originating mural layer of upper gastrointestinal submucosal tumors under EUS

Background and Objective

EUS is the most accurate procedure to determine the originating mural layer and subsequently select the treatment of submucosal tumors (SMTs). However, it requires superb technical and cognitive skills. In this study, we propose a system named SMT Master to determine the originating mural layer of SMTs under EUS.

Materials and Methods

We developed 3 models: deep convolutional neural network (DCNN) 1 for lesion segmentation, DCNN2 for mural layer segmentation, and DCNN3 for the originating mural layer classification. A total of 2721 EUS images from 201 patients were used to train the 3 models. We validated our model internally and externally using 283 images from 26 patients and 172 images from 26 patients, respectively. We applied 368 images from 30 patients for the man-machine contest and used 30 video clips to test the originating mural layer classification.

Results

In the originating mural layer classification task, DCNN3 achieved a classification accuracy of 84.43% and 80.68% at internal and external validations, respectively. In the video test, the accuracy was 80.00%. DCNN1 achieved Dice coefficients of 0.956 and 0.776 for lesion segmentation at internal and external validations, respectively, whereas DCNN2 achieved Dice coefficients of 0.820 and 0.740 at internal and external validations, respectively. The system achieved 90.00% accuracy in classification, which is comparable with that of EUS experts.

Conclusions

Our proposed system has the potential to solve difficulties in determining the originating mural layer of SMTs in EUS procedures, which relieves the EUS learning pressure of physicians.

Modified Cap-Assisted Endoscopic Mucosal Resection Versus Endoscopic Submucosal Dissection for the Treatment of Rectal Neuroendocrine Tumors ≤10 mm: A Randomized Noninferiority Trial

INTRODUCTION

Although recent guidelines recommend endoscopic resection of rectal neuroendocrine tumors (NET) ≤10 mm, there is no consensus on which endoscopic modality should be performed. We aimed to compare the safety and efficacy of modified cap-assisted endoscopic mucosal resection (mEMR-C) and endoscopic submucosal dissection (ESD) methods for the treatment of rectal NET ≤10 mm.

METHODS

A randomized noninferiority trial comparing mEMR-C and ESD was conducted. The primary outcome was the histological complete resection rate; the secondary outcomes included en bloc resection rate, operation time, complications, and so on. Subgroup analyses and follow-up were also performed.

RESULTS

Ninety patients were enrolled, and 79 patients with pathologically confirmed rectal NET were finally analyzed, including 38 cases of mEMR-C and 41 cases of ESD. Histological complete resection rate was 97.4% in the mEMR-C group and 92.7% in the ESD group. The noninferiority of mEMR-C compared with that of ESD was confirmed because the absolute difference was 4.7% (2-sided 90% confidence interval, -3.3% to 12.2%; P = 0.616). En bloc resection and successful removal of rectal NET were achieved in all patients. Advantages of mEMR-C over ESD included shorter operation time (8.89 ± 4.58 vs 24.8 ± 9.14 minutes, P < 0.05) and lower hospitalization cost ($2,233.76 ± $717.70 vs $2,987.27 ± $871.81, P < 0.05). Postoperative complications were recorded in 4 patients who received mEMR-C and 2 patients in the ESD group (11.5% vs 4.9%, P = 0.509), which were all well managed using endoscopy. Similar findings were observed when subgroup analysis was performed.

DISCUSSION

mEMR-C is noninferior to ESD with a similar complete resection rate. In addition, mEMR-C had shorter procedure duration time and lower hospitalization costs.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03982264.

Research trends on endoscopic mucosal resection: A bibliometric analysis from 1991 to 2021

BACKGROUND

In recent years, the rapid development of digestive endoscopy technology has brought revolutionary changes to endoscopic therapy. A growing number of articles have been published annually. We aimed to explore global scientific outputs and hotspots of endoscopic mucosal resection (EMR) published by different countries, organizations, and authors.

METHODS

We extracted relevant publications from the Web of Science Core Collection (WOSCC) on June 23, 2022. We examined the retrieved data by bibliometric analysis (e.g., cocited and cluster analysis, keyword co-occurrence) using the software CiteSpace and VOSviewer to analyze and predict the trends and hot spots in this field.

RESULTS

A total of 2,695 papers were finally identified. The results showed that the number of articles fluctuated with the year and reached its peak in 2021. NATIONAL CANCER CENTER JAPAN was the most influential institution. MICHAEL J BOURKE and YUTAKA SAITO are two of the most prolific scholars. ENDOSCOPY and GASTROINTESTINAL ENDOSCOPY were the most productive journals. "Early gastric cancer" and "Barrett's esophagus" were the focus of EMR research. "Adverse events", "cold snare polypectomy" and "outcomes" have become increasingly popular in recent years and could become hot spots in the future.

CONCLUSION

In this study, we summarized the characteristics of the publications; identified the most influential countries, institutions, and journals; and identified the leading topics in the EMR field.

Underwater endoscopic mucosal resection of upper gastrointestinal subepithelial tumors: A case series pilot study (with video)

INTRODUCTION

Underwater endoscopic mucosal resection (UW-EMR) has been recently introduced as an effective technique for rectal third layer subepithelial tumors. Therefore, we aimed to assess the safety, efficacy, and procedure time of UW-EMR for upper gastrointestinal subepithelial tumors (SETs) originating from the deep mucosal and/or submucosal layers.

METHODS

Between August 2018 to July 2022, a total of 17 SETs (7 duodenal SETs, 6 gastric SETs, and 4 esophageal SETs) were included in this study. On endoscopic ultrasound examinations, the tumors were found to be embedded in the submucosa without muscularis propria invasion. All SETs were resected successfully using UW-EMR. The characteristics of the tumors and their R0 resection rate, adverse event rate, and recurrence rate were evaluated retrospectively.

RESULTS

The mean tumor size was 0.9 cm (range, 0.3-1.5 cm). En bloc resection and complete resection rates were 100%, respectively. The patients showed no complications such as perforation or bleeding. Histologic assessments of the resected tumors revealed 9 neuroendocrine tumors (7 on the duodenum, 2 on the stomach), 2 gastric cystica profunda, 1 gastric follicular lymphoma, 1 gastric fibromyxoma, 3 esophageal granular cell tumors, and 1 esophageal adenoid cystic carcinoma. The mean procedural time was 3.2 min (range, 1.3-8.7 minutes). The overall en bloc and complete resection rates were 100%, respectively. No recurrence was observed during the follow-up period.

CONCLUSION

UW-EMR is a safe and effective treatment for upper gastrointestinal SETs embedded in the submucosal layer. Further studies are needed to compare other endoscopic resection techniques.

Endoscopic treatment for rectal neuroendocrine tumor: which method is better?

Recently, research on rectal neuroendocrine tumors (NETs) has increased during the last few decades. Rectal NETs measuring <10 mm without atypical features and confined to the submucosal layer have only 1% risk of metastasis, and the long-term survival probability of patients without metastasis at the time of diagnosis is approximately 100%. Therefore, the current guidelines suggest endoscopic resection of rectal NETs of <10 mm is regarded as a safe therapeutic option. However, there are currently no clear recommendations for technique selection for endoscopic resection. The choice of treatment modality for rectal NETs should be based on the lesion size, endoscopic characteristics, grade of differentiation, depth of vertical involvement, lymphovascular invasion, and risk of metastasis. Moreover, the complete resection rate, complications, and experience at the center should be considered. Modified endoscopic mucosal resection is the most suitable resection method for rectal NETs of <10 mm, because it is an effective and safe technique that is relatively simple and less time-consuming compared with endoscopic submucosal dissection. Endoscopic submucosal dissection should be considered when the tumor size is >10 mm, suctioning is not possible due to fibrosis in the lesion, or when the snaring for modified endoscopic mucosal resection does not work well.

Clinical outcomes of endoscopic resection for rectal neuroendocrine tumors: Advantages of endoscopic submucosal resection with a ligation device compared to conventional EMR and ESD

Objectives

Methods

Results

Conclusions

Ligation-assisted endoscopic mucosal resection has high complete resection rate in rectal carcinoid tumor

AIM

We aimed to compare the outcomes of different therapeutic modalities in rectal carcinoid tumors.

METHOD

We retrospectively collected 145 patients with rectal carcinoid tumors which were pathologically diagnosed from 2005/01/01 to 2016/12/31. We compared tumor size, complete resection rate and recurrent rate between different therapeutic modalities. Then, prospectively compared the treatment outcomes of 28 patients treated with ligation assisted endoscopic mucosal resection (LEMR) and 25 patients treated with endoscopic mucosal resection with cap (EMRC).

RESULT

The mean size of tumors was 6.5 mm (1-25 mm), and the mean follow-up duration was 26 months (6-118 months). The therapeutic modalities included ligation-assisted endoscopic mucosal resection (LEMR) (25 tumors, 17%), endoscopic mucosal resection (EMR) (31 tumors, 21%), snare polypectomy (30 tumors, 21%), biopsy forceps removal (46 tumors, 32%) and surgical resection (13 tumors, 11%), including 6 tumors treated with transanal endoscopic microsurgery (TEM) method. In view of pathologically complete resection rate, LEMR was highest (100%), followed by surgical resection (85%). However, EMR only had 42% pathologically complete resection rate. Besides, LEMR and surgical resection had no local recurrence and significantly higher clinically complete resection rate, compared to other treatments. For the further prospective study, complete resection was noted in 28 (100%) patients in LEMR group and 13 (52%) patients in EMRC group.

CONCLUSION

In the treatment of rectal carcinoid tumors, LEMR is safe and effective compared with traditional endoscopic treatments.

Favorable long-term outcomes of endoscopic resection for nonampullary duodenal neuroendocrine tumor

BACKGROUND AND AIM

The long-term outcomes of endoscopic resection for nonampullary duodenal neuroendocrine tumors are limited. We aimed to clarify it.

METHODS

Consecutive patients with nonampullary duodenal neuroendocrine tumors endoscopically treated at our institute between January 2005 and June 2020 were included in this retrospective study. En bloc and R0 resection rates and adverse events were evaluated as short-term outcomes of endoscopic resection. The 5-year overall and recurrence-free survival rates of patients after endoscopic resection were calculated as long-term outcomes.

RESULTS

Of 34 patients with 34 lesions, 33 patients (97%) underwent endoscopic mucosal resection, and one (3%) underwent endoscopic submucosal dissection. En bloc resection was achieved in 33 lesions (97%). R0 resection was achieved in 20 lesions (59%). The median tumor size was 6 mm (range: 3-13). Thirty-one lesions (91%) and three lesions (9%) were classified as G1 and G2, respectively. Lymphovascular invasion was observed in six lesions (18%). Intraprocedural perforation occurred in four patients (12%) who were conservatively treated with endoscopic closure. All 34 patients were followed up without additional treatment after endoscopic resection, and no recurrence or metastasis developed during the median follow-up period of 47.9 months (range: 9.0-187.1). The 5-year overall survival and recurrence-free survival rates were 87.1% and 100%, respectively.

CONCLUSIONS

Endoscopic resection provided a favorable long-term prognosis for patients with nonampullary duodenal neuroendocrine tumors without lymph node metastasis.

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.

Current Endoscopic Resection Techniques for Gastrointestinal Lesions: Endoscopic Mucosal Resection, Submucosal Dissection, and Full-Thickness Resection

BACKGROUND

Endoscopic resection of dysplastic lesions in early stages of cancer reduces mortality rates and is recommended by many national guidelines throughout the world. Snare polypectomy and endoscopic mucosal resection (EMR) are established techniques of polyp removal. The advantages of these methods are their relatively short procedure times and acceptable complication rates. The latter include delayed bleeding in 0.9% and a perforation risk of 0.4-1.3%, depending on the size and location of the resected lesion. EMR is a recent modification of endoscopic resection. A limited number of studies suggest that larger lesions can be removed en bloc with low complication rates and short procedure times. Novel techniques such as endoscopic submucosal dissection (ESD) are used to enhance en bloc resection rates for larger, flat, or sessile lesions. Endoscopic full-thickness resection (EFTR) is employed for non-lifting lesions or those not easily amenable to resection. Procedures such as ESD or EFTR are emerging standards for lesions inaccessible to EMR techniques.

SUMMARY

Endoscopic treatment is now regarded as first-line therapy for benign lesions.

KEY MESSAGE

Endoscopic resection of dysplastic lesions or early stages of cancer is recommended. A plethora of different techniques can be used dependent on the lesions.

Risk of lymph node metastasis after endoscopic treatment for rectal NETs 10 mm or less

PURPOSE

For rectal neuroendocrine tumors (NETs) ≤ 10 mm, endoscopic resection is a standard treatment. However, there is no consensus whether additional surgery should be performed for patients at risk of lymph node metastasis (LNM) after endoscopic resection. The purpose of this study was to analyze the results of endoscopic resection and additional surgery of rectal NETs, thereby clarify the characteristics of cases with LNM.

METHODS

This study was a multicenter retrospective cohort study conducted at 12 Japanese institutions. A total of 132 NETs ≤ 10 mm were analyzed regarding various therapeutic results. A comparative analysis was performed by dividing the cases into two groups that underwent additional surgery or not. Furthermore, the relationship between tumor size and LNM was examined.

RESULTS

The endoscopic treatments were 12 endoscopic mucosal resections (EMR), 58 endoscopic submucosal resections with ligation (ESMR-L), 29 precutting EMRs, and 33 endoscopic submucosal dissections (ESD). The R0 resection rates of EMR were 41.7%, and compared to this rate, other three treatments were 86.2% (p < 0.001), 86.2% (p = 0.005), and 97.0% (p < 0.001), respectively. There were 41 non-curative cases (31.1%), and 13 had undergone additional surgery. Then, LNM was observed in 4 of the 13 patients, with an overall rate of LNM of 3.0% (4/132). The rate of positive lymphatic invasion and the rate of LNM by tumor size ≤ 6 mm and 7-10 mm were 9.7 vs. 15.4% (p = 0.375) and 0 vs. 10.3% (p = 0.007).

CONCLUSIONS

A multicenter study revealed the priority of each endoscopic resection and the low rate of LNM for rectal NETs ≤ 6 mm.

Comparison of conventional and modified endoscopic mucosal resection methods for the treatment of rectal neuroendocrine tumors

BACKGROUND/AIM

Small rectal neuroendocrine tumors (NETs) confined to the submucosa are endoscopically resectable. Because most rectal NETs are submucosal tumors, conventional endoscopic mucosal resection (cEMR) may not result in a complete resection. This study investigated whether modified EMRs, namely endoscopic submucosal resection with ligation (ESMR-L), EMR with precutting (EMR-P), and strip biopsy are superior to cEMR for achieving histologically complete resection (HCR) of rectal NETs.

METHODS

Medical records of 215 patients who were treated with endoscopic resections for rectal NETs between January 2011 and July 2019 were retrospectively enrolled. Of the patients, 110, 33, 29, and 43 underwent cEMR, ESMR-L, EMR-P, and strip biopsy, respectively. For each method, HCR and en bloc resection rates, procedure times, and complication rates were measured.

RESULTS

HCR was achieved with cEMR, EMR-P, ESMR-L, and strip biopsies for 74.5%, 90.9%, 93.1%, and 90.7% of cases, respectively. The HCR rate for cEMR was inferior to those of the modified EMRs (p = 0.045 for cEMR vs. EMR-P; p = 0.031 for cEMR vs. ESMR-L; p = 0.027 for cEMR vs. strip biopsy). Among the three modified EMRs, there was no significant difference in achieving HCR (p = 1.000). En bloc resection (p = 0.096) and complication rates (p = 0.071) were not significantly different among the four EMR methods, although EMR-P required the longest procedure time (p = 0.000).

CONCLUSIONS

All three modified EMRs are superior to cEMR and are equally effective for achieving HCR of rectal NETs.

The outcomes of modified endoscopic mucosal resection and endoscopic submucosal dissection for the treatment of rectal neuroendocrine tumors and the value of endoscopic morphology classification in endoscopic resection

BACKGROUND

To compare the outcomes of modified endoscopic mucosal resection (m-EMR) and endoscopic submucosal dissection (ESD) for rectal neuroendocrine tumors (NETs) and evaluate the value of endoscopic morphology classification in endoscopic resection (ER).

METHODS

Patients with rectal NET diameters less than 2 cm who were treated between April 2007 and January 2019 were enrolled. The endoscopic morphology of rectal NETs was classified based on the endoscopic views. Patients who underwent ESD and m-EMR were compared. Baseline characteristics as well as en bloc resection, complete resection, the procedure time, adverse events and the risk factors associated with incomplete resection were analyzed.

RESULTS

A total of 429 patients with 449 rectal NETs were enrolled for the classification of endoscopic morphology and were classified into four types (Ia, IIb, II, and III). There were 79 patients in the m-EMR group and 259 patients in the ESD group before matching. Propensity score matching created 77 pairs between the two groups that were well balanced. The mean procedure time was significantly shorter for m-EMR than for ESD (9.1 ± 4.4 min vs 16.0 ± 7.9 min, P = 0.000). The rates of en bloc resection (98.7% vs 100%; P = 1.000), complete resection (90.9% vs 93.5%, P = 0.548) and adverse events (2.6% vs 2.6%, P = 1.000) were similar between the two groups. Univariate and multivariate analyses showed that histopathological grade and endoscopic morphology were associated with incomplete resection.

CONCLUSION

Both ESD and m-EMR are effective and safe for the treatment of rectal NETs. Endoscopic morphology should be considered along with histopathological grade for ER.

Relevant risk factors and the prognostic impact of positive resection margins after endoscopic resection of gastrointestinal neuroendocrine tumors

Introduction

Endoscopic resection for the treatment of gastrointestinal neuroendocrine tumors has a risk of resection margin residues. The related risk factors and prognosis of post-endoscopic resection margin residues have not been fully evaluated.

Aim

To investigate the associated risk factors and prognostic impact of resection margin residues after endoscopic resection of gastrointestinal neuroendocrine tumors.

Material and methods

We conducted a retrospective analysis of 129 patients who underwent endoscopic resection for the treatment of gastrointestinal neuroendocrine tumors. Sex, age, location, diameter of tumor, depth of invasion, endoscopic treatment methods, endoscopic ultrasonography (EUS) evaluation, and the work experience of endoscopists were evaluated as potential risk factors. In addition, the prognoses of patients with positive resection margins were analyzed.

Results

A total of 18 (18/129, 14.0%) patients exhibited positive resection margins after endoscopic resection. Among 16 successfully followed-up patients, 1 died due to rupture of pulmonary artery aneurysms, 2 underwent supplementary surgical operations, and 2 underwent additional endoscopic submucosal dissection. The remaining 11 patients were periodically followed up, and no recurrences were found. The results of univariate analysis suggested that endoscopic treatment method, the depth of invasion, and EUS evaluation correlated with positive resection margin. Multivariate regression analysis suggested that the depth of invasion and EUS evaluation were risk factors for resection margin residues.

Conclusions

The depth of invasion and EUS evaluation are independent risk factors for positive resection margins after endoscopic resection. This finding suggests that a greater depth of invasion increases the risk for positive resection margins, while EUS evaluation before resection decreases this risk.

Ligation-assisted endoscopic mucosal resection for esophageal granular cell tumors is safe and effective

Given their malignant potential, resection of esophageal granular cell tumors (GCTs) is often undertaken, yet the optimal technique is unknown. We present a large series of dedicated endoscopic resection using band ligation (EMR-B) of esophageal GCTs. Patients diagnosed with esophageal GCTs between 2002 and 2019 were identified using a prospectively collected pathology database. Endoscopic reports were reviewed, and patients who underwent dedicated EMR-B of esophageal GCTs were included. Medical records were queried for demographics, findings, adverse events, and follow-up. We identified 21 patients who underwent dedicated EMR-B for previously identified esophageal GCT. Median age was 39 years; 16 (76%) were female. Eight (38%) had preceding signs or symptoms, potentially attributable to the GCT. Upon endoscopic evaluation, 12 (57%) were found in the distal esophagus. Endoscopic ultrasound was used in 15 cases (71%). Median lesion size was 7 mm, interquartile range 4 mm-8 mm. The largest lesion was 12 mm. A total of 20 (95%) had en bloc resection confirmed with pathologic examination. The only patient with tumor extending to the resection margin underwent surveillance endoscopy that showed no residual tumor. No patients experienced bleeding, perforation, or stricturing in our series. No patients have had known recurrence of their esophageal GCT. EMR-B of esophageal GCT achieves complete histopathologic resection with minimal adverse events. EMR-B is safe and effective and seems prudent compared with observation for what could be an aggressive and malignant tumor. EMR-B should be considered first-line therapy when resecting esophageal GCT up to 12 mm in diameter.

Comparison of underwater endoscopic mucosal resection and endoscopic submucosal dissection of rectal neuroendocrine tumors (with videos)

BACKGROUND AND AIMS

The first choice of treatment for rectal neuroendocrine tumors (NETs) ≤10 mm in size is endoscopic resection. However, because rectal NETs usually invade the submucosal layer, achieving R0 resection is difficult. Endoscopic submucosal dissection (ESD) has a high R0 resection rate, and underwater endoscopic mucosal resection (UEMR) was recently introduced to ensure a negative resection margin easily and safely. The aim of this study was to evaluate the efficacy and safety of UEMR versus ESD for rectal NETs ≤10 mm in size.

METHODS

This retrospective observational study enrolled 115 patients with rectal NETs ≤10 mm in size who underwent ESD or UEMR between January 2015 and July 2019 at the National Cancer Center, Korea. The differences in R0 resection rate, adverse event rate, and procedure time between the ESD and UEMR groups were evaluated.

RESULTS

Of the 115 patients, 36 underwent UEMR and 79 underwent ESD. The R0 resection rate was not different between the UEMR and ESD groups (UEMR vs ESD, 86.1% vs 86.1%, P = .996). The procedure time was significantly shorter with UEMR (UEMR vs ESD, 5.8 ± 2.9 vs 26.6 ±13.4 minutes, P < .001). Two patients (2.5%, 2/79) experienced adverse events in the ESD group and but there were no adverse events in the UEMR group; however, this difference was not statistically significant.

CONCLUSION

UEMR is a safe and effective technique that should be considered when removing small rectal NETs. Further studies are warranted to define its role compared with ESD.

Resectability of Rectal Neuroendocrine Tumors Using Endoscopic Mucosal Resection with a Ligation Band Device and Endoscopic Submucosal Dissection

BACKGROUND

Rectal neuroendocrine tumors (NETs) < 10 mm in diameter, limited to the submucosa without local or distant metastasis, can be treated endoscopically. Endoscopic mucosal resection with a ligation band device (EMR-L) and endoscopic submucosal dissection (ESD) have been employed to resect rectal NETs. We evaluated and compared the clinical outcomes of EMR-L and ESD for endoscopic resection of rectal NETs G1 < 10 mm in diameter.

METHODS

We conducted a retrospective study of 82 rectal NETs in 82 patients who underwent either EMR-L or ESD. Therapeutic outcomes (en bloc resection and complete resection rates), procedure time, and procedure-related adverse events were evaluated. Additionally, we measured the distance of the lateral and vertical margins from the border of the tumor in pathologic specimens and compared the resectability between EMR-L and ESD.

RESULTS

Sixty-six lesions were treated using EMR-L and 16 using ESD. En bloc resection was achieved in all patients. The complete resection rate with EMR-L was significantly higher than that with ESD (95.5% vs.75.0%, p = 0.025). The prevalence of vertical margin involvement was significantly higher in the ESD group than in the EMR-L group (12.5% vs. 0%, p = 0.036), and ESD was more time consuming than EMR-L (24.21 ± 12.18 vs. 7.05 ± 4.53 min, p < 0.001). The lateral and vertical margins were more distant in the EMR-L group than in the ESD group (lateral margin distance, 1661 ± 849 vs. 1514 ± 948 μm; vertical margin distance, 277 ± 308 vs. 202 ± 171 μm).

CONCLUSIONS

EMR-L is more favorable for small rectal NETs with respect to therapeutic outcomes, procedure time, and technical difficulties. Additionally, EMR-L enables achievement of sufficient vertical margin distances.

Endoloop ligation after endoscopic mucosal resection using a transparent cap: A novel method to treat small rectal carcinoid tumors

BACKGROUND

Local endoscopic resection is an effective method for the treatment of small rectal carcinoid tumors, but remnant tumor at the margin after resection remains to be an issue.

AIM

To evaluate the efficacy and safety of resection of small rectal carcinoid tumors by endoloop ligation after cap-endoscopic mucosal resection (LC-EMR) using a transparent cap.

METHODS

Thirty-four patients with rectal carcinoid tumors of less than 10 mm in diameter were treated by LC-EMR (n = 22) or endoscopic submucosal dissection (ESD) (n = 12) between January 2016 and December 2017. Demographic data, complete resection rates, pathologically complete resection rates, operation duration, and postoperative complications were collected. All cases were followed for 6 to 30 mo.

RESULTS

A total of 22 LC-EMR cases and 12 ESD cases were enrolled. The average age was 48.18 ± 12.31 and 46.17 ± 12.57 years old, and the tumor size was 7.23 ± 1.63 mm and 7.50 ± 1.38 mm, respectively, for the LC-EMR and ESD groups. Resection time in the ESD group was longer than that in the LC-EMR group (15.67 ± 2.15 min vs 5.91 ± 0.87 min; P < 0.001). All lesions were completely resected at one time. No perforation or delayed bleeding was observed in either group. Pathologically complete resection (P-CR) rate was 86.36% (19/22) and 91.67% (11/12) in the LC-EMR and ESD groups (P = 0.646), respectively. Two of the three cases with a positive margin in the LC-EMR group received transanal endoscopic microsurgery (TEM) and tumor cells were not identified in the postoperative specimens. The other case with a positive margin chose follow-up without further operation. One case with remnant tumor after ESD received further local ligation treatment. Neither local recurrence nor lymph node metastasis was found during the follow-up period.

CONCLUSION

LC-EMR appears to be an efficient and simple method for the treatment of small rectal carcinoid tumors, which can effectively avoid margin remnant tumors.

[Endoscopic Treatment Outcome of Rectal Neuroendocrine Tumors Removed by Ligation-assisted Endoscopic Submucosal Resection]

BACKGROUND/AIMS

Ligation-assisted endoscopic submucosal resection (ESMR-L) is preferred for the treatment of rectal neuroendocrine tumors because its results are better than those for endoscopic mucosal resection (EMR), and the procedure time is shorter and the incidence of complications is lower than endoscopic submucosal dissection. The aim of this study was to evaluate the clinical usefulness of ESMR-L compared with EMR for rectal neuroendocrine tumors.

METHODS

From March 2007 to May 2017, 148 patients diagnosed with rectal neuroendocrine tumors were divided into ESMR-L and EMR groups and analyzed retrospectively.

RESULTS

Of 148 patients with rectal neuroendocrine tumor, 120 had ESMR-L and 28 had EMR. The ESMR-L group had a significantly higher rate of complete resection and curative resection than the EMR group (93.3% vs. 75.0% and 92.5% vs. 71.4%, p=0.009 and p=0.003, respectively).

CONCLUSIONS

ESMR-L for the treatment of small rectal neuroendocrine is a significantly superior modality to EMR.

Endoscopic mucosal resection with suction vs. endoscopic submucosal dissection for small rectal neuroendocrine tumors: a meta-analysis

OBJECTIVE

There are no guidelines or consensus on the optimal treatment measures for small rectal neuroendocrine tumors (NETs) at present. This meta-analysis was conducted to compare the efficacy and safety of endoscopic mucosal resection (EMR) with suction and endoscopic submucosal dissection (ESD) for the small rectal NETs.

METHODS

The literature searches were conducted using Pubmed and Embase databases, and then a meta-analysis was performed. The primary outcome was complete resection rate, and the secondary outcomes were complication rate, procedure time, and recurrence rate.

RESULTS

Fourteen studies with 823 patients were included in our meta-analysis. The overall complete resection rates in EMR with suction and ESD procedure were 93.65% (472/504) and 84.08% (243/289), respectively. The pooled analysis showed that EMR with suction could achieve a higher complete resection rate than ESD with significance (OR: 4.08, 95% CI: 2.42-6.88, p < .00001) when the outlier study was excluded, and procedure time was significantly shorter in the EMR with suction group than in the ESD group (SMD: -1.59, 95% CI: -2.27 to -0.90, p < .00001). Moreover, there was no significant difference in overall complication rate (OR: 0.56, 95% CI: 0.28-1.14, p = .11) and overall recurrence rate (OR: 0.76, 95% CI: 0.11-5.07, I²=48%) between EMR with suction and ESD group.

CONCLUSIONS

The present meta-analysis mostly based on retrospective studies show that EMR with suction is superior to ESD for small rectal NETs (≤10 mm) with higher complete resection rate, shorter procedure time, and similar overall complication rate and recurrence.

Pocket Creation Method of Endoscopic Submucosal Dissection to Ensure Curative Resection of Rectal Neuroendocrine Tumors

Purpose

Pancreatic/gastrointestinal tract neuroendocrine neoplasm (NEN) is divided into neuroendocrine tumor (NET) and neuroendocrine carcinoma (NEC) according to the grade of malignancy, and differences are seen in clinical prognosis. NET, and rectal NET in particular, is often treated endoscopically. Endoscopic mucosal resection (EMR) was previously the main intervention for rectal NET, but EMR with a ligation device (EMR-L) and endoscopic submucosal dissection (ESD) are now also used. However, complete resection with these therapies is not always achieved. The pocket creation method (PCM) is a safe ESD method for colon tumors that offers a high en bloc resection rate compared with conventional colonic ESD. We performed ESD using the PCM for rectal NET and evaluated the complete resection rate.

Methods

We performed ESD using the PCM in 4 patients. This procedure was technically feasible in all patients.

Results

Endoscopically, all cases were resected en bloc, and pathological complete resection was achieved in all cases. No complications such as perforation or delayed postoperative bleeding were encountered.

Conclusions

PCM should be considered when treating NET of appropriate size.

How should incidental NEN of the pancreas and gastrointestinal tract be followed?

Neuroendocrine gastro-entero-pancreatic neoplasms (GEP-NENs) constitute a heterogeneous group of tumors, whose incidence has increased over the years. The most frequent site for primary disease is the stomach followed by small and large intestine, and pancreas. In the last decade, a dramatic growing in the incidence of small, incidental GEP-NENs has been recorded. In parallel, an increasing attitude toward more conservative approaches instead of surgical management has being widely spreading. This is particularly true for small, asymptomatic, pancreatic NEN as for these tumor forms an active surveillance has proven to be safe and feasible. Primary site and biological features of the neoplasms lead to different strategies and indications for surveillance and follow-up. This review focuses on the current evidence on modality and timing of surveillance and conservative treatment of incidentally discovered lesions.

Endocytoscopic findings of colorectal neuroendocrine tumors (with video)

Background and study aims  Gastrointestinal neuroendocrine tumors (NET) are generally submucosal in location. Because these tumors are covered with normal mucosa, biopsy is necessary to confirm histological diagnosis before treatment. We explored the diagnostic capabilities of the endocytoscope, which can perform ultra-high magnification in vivo, for staining and diagnosing submucosal tumors in situ.

Diagnosis and Management of Rectal Neuroendocrine Tumors

The incidence of rectal neuroendocrine tumors (NETs) has increased by almost ten-fold over the past 30 years. There has been a heightened awareness of the malignant potential of rectal NETs. Fortunately, many rectal NETs are discovered at earlier stages due to colon cancer screening programs. Endoscopic ultrasound is useful in assessing both residual tumor burden after retrospective diagnosis and tumor characteristics to help guide subsequent management. Current guidelines suggest endoscopic resection of rectal NETs ≤10 mm as a safe therapeutic option given their low risk of metastasis. Although a number of endoscopic interventions exist, the best technique for resection has not been identified. Endoscopic submucosal dissection (ESD) has high complete and en-bloc resection rates, but also an increased risk of complications including perforation. In addition, ESD is only performed at tertiary centers by experienced advanced endoscopists. Endoscopic mucosal resection has been shown to have variable complete resection rates, but modifications to the technique such as the addition of band ligation have improved outcomes. Prospective studies are needed to further compare the available endoscopic interventions, and to elucidate the most appropriate course of management of rectal NETs.

Endoscopic resection of rectal granular-cell tumor using elastic band ligation

Granular cell tumor (GCT) is a rare neoplasm that develops in the gut's submucosal layer. We report the case of a male with a history of surgically excised colon neoplasm where a rectal polyp was identified during a follow-up endoscopy. The lesion, eventually identified as a GCT, was endoscopically removed by band ligation-assisted mucosectomy. This may be the second report of a colorectal GCT successfully managed using band ligation, and the first one on a rectal GCT excised with this technique.

The clinical outcomes and risk factors associated with incomplete endoscopic resection of rectal carcinoid tumor

BACKGROUND AND AIM

The risk of lymph node metastasis of a small rectal carcinoid tumor (<10 mm) is known to be lower than that of tumors at other gastrointestinal sites. Although rectal carcinoid tumors can be treated by endoscopic resection, the resected specimen may be incomplete. The consequences of an incomplete resection are not well known.

METHOD

From December 2008 to November 2015, cases of rectal carcinoid tumors resected by endoscopic resection techniques such as endoscopic submucosal dissection (ESD), or endoscopic mucosal resection using band ligation device (EMR-L), or cap aspiration (EMR-C) were enrolled. The factors associated with incomplete endoscopic resection and clinical outcomes were retrospectively analyzed.

RESULTS

During the study period, a total of 134 rectal carcinoid tumors were resected by endoscopic techniques; ESD (n = 53), EMR-C (n = 65), and EMR-L (n = 16). The mean tumor size was 5.5 ± 2.4 mm. The mean follow-up period was 835 ± 501 days. The en bloc resection and complete resection rates were 100 and 85.8%, respectively. Procedure time was longer and the size of the resected tumor was larger in the ESD group than in the EMR-C or EMR-L (p < 0.001) group by the univariate analysis. A factor related to incomplete resection was central depression on the surface (OR 11.529, 95% CI 2.377-55.922, p = 0.002), as revealed by the multivariate analysis. Nineteen patients had an incomplete resection status and did not undergo additional resection treatment; none of these patients had recurrence during the study period.

CONCLUSIONS

A rectal carcinoid tumor with a central depression on the surface was associated with a higher incomplete resection rate. After an incomplete resection of small rectal carcinoid tumors, without evidence of lymphovascular invasion, a periodic follow-up examination without additional resection may be recommended.

Endoscopic resection for small esophageal submucosa tumor: Band ligation versus conventional endoscopic mucosal resection

Because an esophageal submucosa tumor (SMT) may be malignant despite its small size, a safe endoscopic resection method is needed in some small SMTs. Conventional endoscopic mucosal resection (EMR) may be simple, but incomplete pathologic resection margin status is common. We aimed to investigate the clinical outcomes of 2 kinds of EMR techniques (conventional EMR and EMR with band ligation device) and to evaluate the factors associated with incomplete pathologic resection.We evaluated the medical records of 36 patients. All lesions were esophageal SMTs located in the submucosa or muscularis mucosa less than 10 mm in size by endoscopic ultrasound (EUS). The clinical outcomes based on the endoscopic procedures and factors associated with incomplete pathologic resection were evaluated.The mean tumor size was 6.6 ± 4.1 mm. The overall en bloc and complete resection rates were 100% and 80.6%, respectively. No procedure-related complications, such as perforation and bleeding, were found. Univariate analysis showed that complete resection rates were higher in granular cell tumors than in leiomyomas (82.8% vs 17.2%, P = .029), tumors located in the submucosa layer than in the muscularis mucosa (96.6% vs 3.4%, P = .003), and in EMR with band ligation device than in conventional EMR (82.8% vs 17.2%, P < .001). Multivariate analysis showed that conventional EMR was the only significant factor associated with incomplete resection (OR, 35.594; 95% CI, 2.042-520.329; P = .014)EMR with a band ligation device is an effective and safe treatment method for small esophageal SMT.

Evolving role of the endoscopist in management of gastrointestinal neuroendocrine tumors

Neuroendocrine tumors (NETs) are uncommon gastrointestinal neoplasms but have been increasingly recognized over the past few decades. Luminal NETs originate from the submucosa of the gastrointestinal tract and careful endoscopic exam is a key for accurate diagnosis. Despite their reputation as indolent tumors with a good prognosis, some NETs may have aggressive features with associated poor long-term survival. Management of NETs requires full understanding of tumor size, depth of invasion, local lymphadenopathy status, and location within the gastrointestinal tract. Staging with endoscopic ultrasound or cross-sectional imaging is important for determining whether endoscopic treatment is feasible. In general, small superficial NETs can be managed by endoscopic mucosal resection and endoscopic submucosal dissection (ESD). In contrast, NETs larger than 2 cm are almost universally treated with surgical resection with lymphadenectomy. For those tumors between 11-20 mm in size, careful evaluation can identify which NETs may be managed with endoscopic resection. The increasing adoption of ESD may improve the results of endoscopic resection for luminal NETs. However, enthusiasm for endoscopic resection must be tempered with respect for the more definitive curative results afforded by surgical treatment with more advanced lesions.

Two Cases of Rectal Neuroendocrine Tumor Resection Combined with Dissection of the Circular Muscle Layer Using the Endoscopic Submucosal Dissection Technique

Generally, lesions of rectal neuroendocrine tumors (NETs) 10 mm or smaller are less malignant and are indicated for endoscopic therapy. However, the vertical margin may remain positive after conventional endoscopic mucosal resection (EMR) because NETs develop in a way similar to submucosal tumors (SMTs). The usefulness of EMR with a ligation device, which is modified EMR, and endoscopic submucosal dissection (ESD) was reported, but no standard treatment has been established. We encountered 2 patients in whom rectal NETs were completely resected by combined dissection and resection of the circular muscle layer using the ESD technique. Case 1 was an 8-mm NET of the lower rectum. Case 2 was NET of the lower rectum treated with additional resection for a positive vertical margin after EMR. In both cases, the circular muscle layer was dissected applying the conventional ESD technique, followed by en bloc resection while conserving the longitudinal muscle layer. No problems occurred in the postoperative course in either case. Rectal NETs are observed in the lower rectum in many cases, and it is less likely that intestinal perforation by endoscopic therapy causes peritonitis. The method employed in these cases, namely combined dissection and resection of the circular muscle layer using the ESD technique, can be performed relatively safely, and it is possible to ensure negativity of the vertical margin. In addition, it may also be useful for additional treatment of cases with a positive vertical margin after EMR.

Treatment outcomes of endoscopic resection for rectal carcinoid tumors: an analysis of the resectability and long-term results from 46 consecutive cases

AIM

In Japan, most of colorectal carcinoid tumors developed in rectum. The choice of treatment is important because surgical treatment may need to construct artificial anus. Although curative endoscopic resection (ER) is desirable from the point of quality of life, sufficient evidence of endoscopic treatment for rectal carcinoid tumors is not fully obtained.

METHODS

Between April 2001 and August 2013, 46 rectal carcinoid tumors in 46 patients who underwent either with endoscopic mucosal resection with a ligation device (EMR-L) or endoscopic submucosal dissection (ESD) were analyzed retrospectively. The rates of en bloc resection, positive for lateral and/or vertical margin, curative resection, local recurrence, additional treatments, overall and disease-specific survival rate after ER were evaluated during follow-up (median observation period 61.6 months).

RESULTS

Twenty-two lesions were treated by EMR-L and 24 lesions were treated by ESD. Both groups had similar mean tumor size (EMR-L: 6.2 mm, ESD: 6.0 mm). The rate of en bloc resection, negative for both lateral and vertical margins, and curative resection were, respectively, 73%, 63%, and 50% for EMR-L, 100%, 100%, and 83% for ESD. These results suggested that the rate of resectability and curability for ESD was significantly higher than EMR-L (p < 0.05). Complications such as perforation and bleeding did not occur in both groups. Fifteen patients were judged as non-curative and 3 patients underwent additional surgery and lymph node metastasis was evident in 1 patient. Remained 11 patients were carefully followed-up, and so far no obvious recurrence was found. Thirty-two patients (84%) were eligible for long-term follow-up and 5-year overall and disease-specific survival rates were 100% and 100%, respectively.

CONCLUSION

The long-term outcomes of ER for rectal carcinoid tumors were excellent. ESD has advantage for resectability and curability compared with EMR-L; therefore, ESD is more favorable procedure as treatment for rectal carcinoid tumors.

Evaluation and long-term outcomes of the different modalities used in colonic endoscopic mucosal resection

Endoscopic mucosal resection (EMR) has been used in western countries to remove colonic polyps for at least the last two decades. Significant experience has been accumulated and the efficacy of the method has recently been evaluated in a large meta-analysis. A number of variations to modify the technique, including knife-assisted, cap-assisted, ligation devices, and underwater EMR, have been developed in an attempt to improve outcomes. However, to date there are only limited data comparing these techniques or demonstrating the superiority of any one of them. This article reviews the current evidence on the efficacy of each of these modified techniques.

Short- and long-term outcomes of endoscopic resection of rectal neuroendocrine tumours: analyses according to the WHO 2010 classification

OBJECTIVE

Although the World Health Organisation (WHO) defined a novel classification of gastroenteropancreatic neuroendocrine tumours (NETs) in 2010, indications for endoscopic resection of rectal NETs in the guidelines were based on evidence accumulated for carcinoid tumours defined by a previous classification. This study was designed to clarify indications for endoscopic resection of rectal NETs corresponding to the new WHO classifications.

MATERIAL AND METHODS

One hundred-seventy rectal NETs resected endoscopically from April 2001 to March 2012 were histologically re-classified according to the WHO 2010 criteria. The clinicopathological features of these lesions were analysed, and the short- and long-term outcomes of endoscopic resection were evaluated.

RESULTS

Of the 170 rectal NETs, 166 were histopathologically diagnosed as NET G1 and four as NET G2. Thirty-eight tumours (22.4%) were positive for lymphovascular invasion, a percentage higher than expected. Although the curative resection rate was low (65.3%), en bloc (98.8%) and complete (85.9%) resection rates were high. Modified endoscopic mucosal resection (88.0%) and endoscopic submucosal dissection (92.2%) resulted in significantly higher complete resection rates than conventional endoscopic mucosal resection (36.4%). No patient experienced tumour recurrence, despite the low curative resection rate.

CONCLUSION

Despite the low curative resection rate, prognosis after endoscopic resection of rectal NETs was excellent. Prospective large-scale, long-term studies are required to determine whether NET G2 and tumours >1 cm should be included in the indication for endoscopic resection and whether tumours with lymphovascular invasion can be followed up without additional surgery.

Endoscopic treatments for rectal neuroendocrine tumors smaller than 16 mm: a meta-analysis

OBJECTIVE

Endoscopic mucosal resection (EMR), including conventional EMR (c-EMR) and modified EMR (m-EMR), was applied to remove small rectal neuroendocrine tumors (NETs). We aim to evaluate treatment outcomes of endoscopic submucosal dissection (ESD), m-EMR and c-EMR for rectal NETs <16 mm.

METHODS

The PubMed, Cochrane Library and Elsevier Science Direct were searched to identify eligible articles. After quality assessment and data extraction, meta-analysis was performed. The main outcomes were complete resection rate, overall complication rate, procedure time and local recurrence rate.

RESULTS

Compared with c-EMR, ESD could achieve higher complete resection rate (OR = 4.38, 95%CI: 2.43-7.91, p < 0.00001) without increasing overall complication rates (OR = 2.21, 95%CI: 0.56-8.70, p = 0.25). However, ESD was more time-consuming than c-EMR (MD = 6.72, 95%CI: 5.84-7.60, p < 0.00001). Compared with m-EMR, ESD did not differ from m-EMR in complete resection and overall complication rates (OR = 0.80, 95%CI: 0.51-1.27, p = 0.34; OR = 1.91, 95%CI: 0.75-4.86, p = 0.18, respectively). However, ESD was more time-consuming than m-EMR (MD = 12.21, 95%CI: 7.78-16.64, p < 0.00001). Compared with c-EMR, m-EMR could achieve higher complete resection rate (OR = 4.23, 95%CI: 2.39-7.50, p < 0.00001) without increasing overall complication rate (OR = 1.07, 95%CI: 0.35-3.32, p = 0.90). Moreover, m-EMR was not time-consuming than c-EMR (MD = 2.01, 95%CI: -0.37-4.40, p= 0.10). The local recurrence rate was 0.84% (9/1067) during follow-up.

CONCLUSIONS

Both ESD and m-EMR have great advantages over c-EMR in complete resection rate without increasing safety concern while m-EMR shares similar outcomes with ESD for rectal NETs <16 mm. The results should be confirmed by well-designed, multicenter, randomized controlled trials with large samples and long-term follow-ups from more countries.

Endoscopic submucosal resection with a ligation device for the treatment of duodenal neuroendocrine tumors

BACKGROUND

Endoscopic submucosal resection with a ligation device (ESMR-L) is effective for rectal neuroendocrine tumors (NETs); however, its effectiveness for duodenal NETs is unclear. This study evaluated the efficacy and safety of ESMR-L for duodenal NETs.

METHODS

A total of 32 consecutive patients with duodenal NETs were treated in our hospital between December 2010 and August 2015. Among these 32 patients, we retrospectively analyzed the data of all patients who underwent ESMR-L for the treatment of duodenal NETs. ESMR-L was considered for patients in whom (1) the lesion size was ≤10 mm in diameter, (2) the lesion was located within the submucosal layer, and (3) no lymph node metastasis or distant metastasis was detected.

RESULTS

Five patients underwent ESMR-L for the treatment of duodenal NETs. The en bloc complete resection rate was 100 %. The median procedure time for ESMR-L was 15 min (range 10-30 min). In all patients, perforation during and after the operation, and intraoperative bleeding were not observed; however, one patient experienced postoperative bleeding. During follow-up, no local recurrence or distant metastasis was noted in any of the patients.

CONCLUSION

ESMR-L is feasible, effective, and safe for duodenal NETs measuring ≤10 mm in diameter that are confined to the submucosal layer without metastasis.

Endoscopic Resection for Small Rectal Neuroendocrine Tumors: Comparison of Endoscopic Submucosal Resection with Band Ligation and Endoscopic Submucosal Dissection

Background and Aims. There is no consensus so far regarding the optimal endoscopic method for treatment of small rectal neuroendocrine tumor (NET). The aim of this study was to compare treatment efficacy, safety, and procedure time between endoscopic submucosal resection with band ligation (ESMR-L) and endoscopic submucosal dissection (ESD). Methods. We conducted a prospective study of patients who visited Inha University Hospital for endoscopic resection of rectal NET (≦10 mm). Pathological complete resection rate, procedure time, and complications were evaluated. Results. A total of 77 patients were treated by ESMR-L (n = 53) or ESD (n = 24). En bloc resection was achieved in all patients. A significantly higher pathological complete resection rate was observed in the ESMR-L group (53/53, 100%) than in the ESD group (13/24, 54.2%) (P = 0.000). The procedure time of ESD (17.9 ± 9.1 min) was significantly longer compared to that of ESMR-L (5.3 ± 2.8 min) (P = 0.000). Conclusions. Considering the clinical efficacy, technical difficulty, and procedure time, the ESMR-L method should be considered as the first-line therapy for the small rectal NET (≤10 mm). ESD should be left as a second-line treatment for the fibrotic lesion which could not be removed using the ESMR-L method.

Endoscopic submucosal dissection versus transanal local excision for rectal carcinoid: a comparative study

Aim

The aim of this study is to compare the short-term clinical outcomes between endoscopic submucosal dissection and transanal local excision for rectal carcinoid tumors.

Methods

Between 2007 and 2012, 31 patients with rectal carcinoid underwent endoscopic submucosal dissection at our hospital. They were compared with a matched cohort of 23 patients who underwent transanal local excision for rectal carcinoid between 2007 and 2012. Short-term clinical outcomes including surgical parameters, postoperative recovery, and oncologic outcomes were compared between the two groups.

Results

The mean size of tumors was significantly bigger in the transanal local excision group (0.8 ± 0.2 versus 1.1 ± 0.5 cm; P = 0.018). En bloc resection was achieved for 30 patients (97 %) in the endoscopic submucosal dissection group and all the patients in the transanal local excision group. The operation time was longer in the transanal local excision than that in the endoscopic submucosal dissection group (40.0 ± 22.7 min versus 12.2 ± 5.3 min; P < 0.001). Complications in the transanal local excision group were five cases of acute retention of urine. There was no local recurrence or distant metastasis in either group during the follow-up period.

Conclusion

For the treatment of rectal carcinoid tumors with diameter <1 cm, endoscopic submucosal dissection has better short-term clinical outcomes than transanal local excision in terms of faster recovery and possibly a lower morbidity rate. Transanal local excision may be the first therapeutic choice of scar-embedded rectal carcinoid tumors.

Usefulness of endoscopic resection using the band ligation method for rectal neuroendocrine tumors

Background/Aims

Rectal neuroendocrine tumors (NETs) are among the most common of gastrointestinal NETs. Due to recent advances in endoscopy, various methods of complete endoscopic resection have been introduced for small (≤10 mm) rectal NETs. However, there is a debate about the optimal treatment for rectal NETs. In our study, we aimed to evaluate the efficacy and feasibility of endoscopic resection using pneumoband and elastic band (ER-BL) for rectal NETs smaller than 10 mm in diameter.

Methods

A total of 55 patients who were diagnosed with rectal NET from January 2004 to December 2011 at Gil Medical Center were analyzed retrospectively. Sixteen patients underwent ER-BL. For comparison, 39 patients underwent conventional endoscopic mucosal resection (EMR).

Results

There was a markedly lower deep margin positive rate for ER-BL than for conventional EMR (6% [1/16] vs. 46% [18/39], P=0.029). Four patients who underwent conventional EMR experienced perforation or bleeding. However, they recovered within a few days. On the other hand, patients whounderwent endoscopic resection using a pneumoband did not experience any complications. In multivariate analysis, ER-BL (P=0.021) was independently associated with complete resection.

Conclusions

ER-BL is an effective endoscopic treatment with regards to deep margin resection for rectal NET smaller than 10 mm.

Effectiveness of Endoscopic Treatment for Gastrointestinal Neuroendocrine Tumors: A Retrospective Study

Several recent studies have explored efficacy and safety of different endoscopic treatments for gastrointestinal neuroendocrine tumors (GI-NETs). However, there is no definitive consensus regarding the best endoscopic approach for GI-NETs treatment. Therefore, the present study was conducted to investigate the application of various endoscopic techniques for the treatment of GI-NETs according to the previous conclusions and to summarize the optimal endoscopic modalities for GI-NETs. Ninety-eight patients with 100 GI-NETs removed by endoscopic therapies were reviewed. The pathological complete resection rate (PCRR), complication, local recurrence, and factors possibly associated with the pathological complete resection were analyzed. Twenty-two patients were treated by conventional polypectomy (including 6 cold biopsy forceps polypectomy and 16 snare polypectomy with electrocauterization), 41 by endoscopic mucosal resection (EMR), and 35 by endoscopic submucosal dissection (ESD). The PCRRs of conventional polypectomy, EMR, and ESD were 86.4%, 75.6%, and 85.7%, respectively. Sixteen GI-NETs that had a polypoid appearance, with a mean tumor size of 5.2 mm, were removed by snare polypectomy (PCRR 93.8%). The complication rates of conventional polypectomy, EMR, and ESD were 0.0% (0/22), 2.4% (1/41), and 2.9% (1/35), respectively. There were 2 local recurrences after cold biopsy forceps polypectomy treatment and no local recurrences in the EMR and ESD groups (P = 0.049). The results showed that PCRR was only associated with the depth of invasion (P = 0.038). Endoscopic resection of GI-NETs is safe and effective in properly selected patients. For submucosal GI-NETs, ESD was a feasible modality, with a higher PCRR compared with EMR. For ≤5 mm polypoid-like NETs, snare polypectomy with electrocauterization was a simple procedure with a high PCRR.

Excellent prognosis following endoscopic resection of patients with rectal neuroendocrine tumors despite the frequent presence of lymphovascular invasion

BACKGROUND

Endoscopic resection (ER) has been increasingly used for the treatment of rectal neuroendocrine tumors (NETs); however, only limited data are available on its long-term outcomes. This study analyzed the long-term outcomes of rectal NETs treated by ER and characterized potential risk factors for metastasis in these cases, with emphasis on lymphovascular invasion.

METHODS

We retrospectively analyzed the clinicopathological features and outcomes of 86 patients with 90 rectal NETs who had been treated by ER. Lymphovascular invasion was reevaluated using elastic-staining and double-staining immunohistochemistry.

RESULTS

En bloc resection with tumor-free margins was achieved in 87 lesions (96.7%). The median tumor size was 5 mm (range 2-13), and all the lesions were confined to the submucosal layer. The Ki-67 index was less than 3% in all the lesions, which were therefore classified as NET G1. Elastic-staining and double-staining immunohistochemistry revealed the presence of lymphatic and venous invasion in 23 (25.6%) and 35 lesions (36.7%), respectively. Collectively, lymphatic and/or vascular invasion was identified in 42 lesions (46.7%). All cases were followed up without additional surgery, and no metastasis or recurrence was detected during the median follow-up period of 67.5 months.

CONCLUSIONS

This study showed an excellent long-term prognosis following ER of patients with rectal NETs, confirming that ER is a valid treatment option for small rectal NETs. The present study also revealed highly prevalent lymphovascular invasion even in minute rectal NETs; this observation raises a question regarding its significance as a risk factor for metastasis.

Hwang JH, Konda V, Abu Dayyeh BK, Chauhan SS, Enestvedt BK, Fujii-Lau LL, Komanduri S, Maple JT, Murad FM, Pannala R, Thosani NC, Banerjee S. Endoscopic mucosal resection

EMR has become an established therapeutic option for premalignant and early-stage GI malignancies, particularly in the esophagus and colon. EMR can also aid in the diagnosis and therapy of subepithelial lesions localized to the muscularis mucosa or submucosa. Several dedicated EMR devices are available to facilitate these procedures. Adverse event rates, particularly bleeding and perforation, are higher after EMR relative to other basic endoscopic interventions but lower than adverse event rates for ESD. Endoscopists performing EMR should be knowledgeable and skilled in managing potential adverse events resulting from EMR.