Comparison of endoscopic therapies for rectal carcinoid tumors: Endoscopic mucosal resection with circumferential incision versus endoscopic submucosal dissection

Endoscopic treatments for rectal neuroendocrine tumors: a systematic review and network meta-analysis

BACKGROUND

Conventional endoscopic mucosal resection (cEMR), EMR with a transparent cap, EMR using a ligation device (EMR-L), EMR after circumferential precutting (EMR-P), and endoscopic submucosal dissection (ESD) have been used for resecting rectal neuroendocrine tumors (r-NETs). However, there is no consensus regarding which is the best treatment. This study aimed to compare the outcomes of the aforementioned 5 techniques for resecting r-NETs by network meta-analysis.

METHODS

Electronic databases (PubMed, Cochrane Library, Embase, Ovid Medline, and Web of Science) were systematically searched to include relevant studies published from inception to September 1, 2023. The en bloc resection rate, histologic complete resection rate, positive lateral margin rate, positive vertical margin rate, adverse events rate, and procedure time were compared.

RESULTS

A total of 27 studies with a total of 2112 r-NETs were included, and the mean diameter of tumors was 6.24 mm. Pairwise meta-analysis showed that EMR-L and ESD had higher en bloc resection and histologic complete resection rates and lower positive vertical margin rate than those of cEMR in resecting r-NETs. Compared with ESD, EMR-L and EMR-P achieved similar resection rates and significantly shortened the procedure time without increasing adverse events. The network meta-analysis evaluated the surface under the cumulative ranking curves and revealed that EMR-L was the best modality for treating r-NETs considering the comprehensive results of the en bloc resection rate, histologic complete resection rate, positive lateral margin rate, positive vertical margin rate, adverse events rate, and procedure time.

CONCLUSION

EMR-L should be recommended as the first-line endoscopic treatment for small r-NETs.

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.

Efficacy of Endoscopic Resection for Rectal Neuroendocrine Tumors Smaller than 15 mm

BACKGROUND

Local resection, including endoscopic resection, is recommended for rectal neuroendocrine tumors (NETs) < 15 mm in patients without risk factors for metastasis, though the short- and long-term outcomes are unclear.

AIMS

This study investigates the efficacy of endoscopic resection for rectal NETs < 15 mm.

METHODS

The short- and long-term outcomes of patients with rectal NETs < 15 mm who underwent endoscopic resection and the outcomes of each endoscopic technique were analyzed. The tumors were stratified as < 10 mm (small-size group, SSG) and 10-14 mm (intermediate-size group, IMG).

RESULTS

Overall, 139 lesions (SSG, n = 118; IMG, n = 21) were analyzed. All tumors were classified as G1 (n = 135) or G2 (n = 4) according to the 2019 World Health Organization grading criteria. The complete resection rate was not different between the groups (P = 0.151). Endoscopic submucosal dissection (ESD) and endoscopic submucosal resection with a ligation device (ESMR-L) achieved complete resection rates > 90% in the SSG. The ESMR-L procedure time (P < 0.001) and hospitalized period (P < 0.001) were significantly shorter than those of ESD. ESD achieved a complete resection rate of 80.0% in the IMG. The tumor size did not affect the overall survival or rate of lymph node/distant metastases.

CONCLUSIONS

Endoscopic resection is a feasible and effective treatment for patients with rectal NETs < 15 mm without the risk factors of metastasis. ESMR-L and ESD are optimal techniques for resecting tumors smaller than 10 mm and 10-14 mm, respectively.

Comparison of endoscopic submucosal resection with ligation and endoscopic submucosal dissection for small rectal neuroendocrine tumors: A multicenter retrospective study

Objectives

Endoscopic submucosal resection with band ligation (ESMR‐L) and endoscopic submucosal dissection (ESD) are both standard endoscopic resection methods for rectal neuroendocrine tumors (NETs) <10 mm in size. However, there is no definitive consensus on which is better. Here, we compared the efficacy of ESMR‐L and ESD for small rectal NETs.

Methods

This was a multicenter retrospective cohort study including 205 patients with rectal NETs who underwent ESMR‐L or ESD. Treatment outcomes were compared by univariate analysis, multivariate analysis, and inverse probability treatment weighting (IPTW) using propensity scores. Subgroup analysis evaluated the impact of the endoscopist's experience on the technical outcome.

Results

Eighty‐nine patients were treated by ESMR‐L and 116 by ESD. The R0 resection rate was not significantly different between the two (90% vs. 92%, p = 0.73). The procedure time of ESMR‐L was significantly shorter than for ESD (17 min vs. 52 min, p < 0.01) and the hospitalization period was also significantly shorter (3 days vs. 5 days, p < 0.01). These results were confirmed by multivariate analysis and also after IPTW adjustment. The procedure time of ESD was significantly prolonged by a less‐experienced endoscopist (49 min vs. 70 min, p = 0.02), but that of ESMR‐L was not affected (17 min vs. 17 min, p = 0.27).

Conclusions

For small rectal NETs, both ESMR‐L and ESD showed similar high complete resection rates. However, considering the shorter procedure time and shorter hospitalization period, ESMR‐L is the more efficient treatment method, especially for less‐experienced endoscopists.

Multiple ligation-assisted endoscopic submucosal resection combined with endoscopic ultrasonography: a novel method to treat rectal neuroendocrine tumors

OBJECTIVE

The first choice of treatment for rectal neuroendocrine tumors (R-NETs) 10 mm in size is endoscopic resection, there is still controversy concerning the optimal endoscopic treatment for resecting R-NETs. This study evaluated the efficacy and safety of multiple ligation-assisted endoscopic submucosal resection combined with endoscopic ultrasonography (EMR-MLUS) for R-NETs.

METHODS

We retrospectively analyzed the data of 62 patients with R-NETs ≤10 mm in size who underwent EMR-MLUS or ligation-assisted endoscopic submucosal resection combined with endoscopic ultrasonography (EMR-LUS) between May 2019 and April 2022, including tumor characteristics, endoscopic complete resection, pathological complete resection, the procedure time, adverse events, and follow-up were compared between the two groups of patients.

RESULTS

Of the 62 patients, 19 underwent EMR-MLUS and 43 underwent EMR-LUS. The endoscopic morphology of lesions was statistically different between group EMR-MLUS and group EMR-LUS ( P = 0.015), and most of them were flat and slightly raised lesions in group EMR-MLUS. Although the pathological complete resection rate was slightly higher in the EMR-MLUS group than in the EMR-LUS group (94.74% vs. 90.70%; P = 0.290), the endoscopic complete resection rate was high in both groups. Involvement of the lateral resection margin was found four cases in the ESMR-LUS group; one case of deep resection margin involvement in the EMR-MLUS group. The mean procedure time was longer in the EMR-MLUS group than in the EMR-LUS group (12.79 ± 1.01 min vs. 11.08 ± 1.89 min; P = 0.041). In group EMR-LUS, there were two cases of immediate bleeding; in group EMR-MLUS, one case of perforation, all of them were successfully treated by endoscopy. No recurrence, progression, or metastasis was found in all patients.

CONCLUSION

EMR-MLUS is a safe and effective technique that could be considered when removing small rectal NETs, especially flat and slightly raised lesions.

ACG Clinical Guideline: Diagnosis and Management of Gastrointestinal Subepithelial Lesions

Subepithelial lesions (SEL) of the GI tract represent a mix of benign and potentially malignant entities including tumors, cysts, or extraluminal structures causing extrinsic compression of the gastrointestinal wall. SEL can occur anywhere along the GI tract and are frequently incidental findings encountered during endoscopy or cross-sectional imaging. This clinical guideline of the American College of Gastroenterology was developed using the Grading of Recommendations Assessment, Development, and Evaluation process and is intended to suggest preferable approaches to a typical patient with a SEL based on the currently available published literature. Among the recommendations, we suggest endoscopic ultrasound (EUS) with tissue acquisition to improve diagnostic accuracy in the identification of solid nonlipomatous SEL and EUS fine-needle biopsy alone or EUS fine-needle aspiration with rapid on-site evaluation sampling of solid SEL. There is insufficient evidence to recommend surveillance vs resection of gastric gastrointestinal stromal tumors (GIST) <2 cm in size. Owing to their malignant potential, we suggest resection of gastric GIST >2 cm and all nongastric GIST. When exercising clinical judgment, particularly when statements are conditional suggestions and/or treatments pose significant risks, health-care providers should incorporate this guideline with patient-specific preferences, medical comorbidities, and overall health status to arrive at a patient-centered approach.

Efficacy and safety of ligation-assisted endoscopic submucosal resection combined with endoscopic ultrasonography for treatment of rectal neuroendocrine tumors

OBJECTIVE

Rectal neuroendocrine tumors (R-NETs) usually invade the submucosa, and so complete resection is difficult. The treatment of choice for R-NETs ≤10 mm in size is endoscopic resection, but there is still controversy concerning the best endoscopic method. This study evaluated the efficacy and safety of ligation-assisted endoscopic submucosal resection combined with endoscopic ultrasonography (ESMR-LUS) for treatment of R-NETs.

METHODS

We retrospectively analyzed the data of 101 patients with R-NETs ≤10 mm in size who underwent ESMR-LUS (n = 48) or conventional ligation-assisted endoscopic submucosal resection (ESMR-L; n = 53) between May 2019 and September 2021 at the 900th Hospital of Joint Logistics Support Force. Complete resection rate, pathological complete resection rate, procedure time, and adverse events were compared between the two groups of patients.

RESULTS

The endoscopic complete resection rate was slightly higher in the ESMR-LUS group than in the ESMR-L group (100 vs. 96.2%, p = .496). The pathological complete resection rate was also slightly higher in the ESMR-LUS group (97.9 vs. 88.7%, p = .152), these findings, though statistically non-significant, have practical clinical significance. Margin involvement was less common in ESMR-LUS patients than in ESMR-L patients (1 vs. 6). Involvement of the lateral resection margin was found one patient in the ESMR-LUS group versus two patients in the ESMR-L group, and deep resection margin involvement in no patient in the ESMR-LUS group versus four patients in the ESMR-L group. Mean procedure time was longer in the ESMR-LUS group than in the ESMR-L group (11.08 ± 1.89 min vs. 9.38 ± 2.09 min, p = .061). Immediate bleeding occurred in two patients in the ESMR-LUS group vs. seven patients in the ESMR-L group. Two patients in the ESMR-L group also suffered perforation; both patients were successfully treated by endoscopy.

CONCLUSIONS

ESMR-LUS appears to be a safe and effective technique for removal of small rectal NETs confined to the submucosal layer without metastasis. Further studies are warranted to compare the efficacy and safety of different methods.

Clinical Outcomes of Endoscopic Treatment for Type 1 Gastric Neuroendocrine Tumor

BACKGROUND

Although the rate of early detection and endoscopic treatment of gastric neuroendocrine tumors (NETs) is steadily increasing, there are insufficient studies on the long-term outcomes of endoscopic treatment. Therefore, we aimed to investigate the clinical features and long-term outcomes of endoscopic treatment for type 1 gastric NETs.

METHODS

Subjects who underwent endoscopic treatment for gastric NETs between March 1997 and December 2015 were included. Clinical features and endoscopic treatment outcomes were retrospectively investigated by reviewing medical records.

RESULTS

In total, 125 subjects underwent endoscopic treatment including forceps biopsy (n = 21), argon plasma coagulation (n = 1), endoscopic mucosal resection (EMR, n = 62), and endoscopic submucosal dissection (ESD, n = 41). In total, 103 patients with 114 lesions, who underwent EMR or ESD, were analyzed to evaluate endoscopic and oncologic outcomes. The rates of en bloc resection in the EMR and ESD groups were 91.5% and 97.7%, respectively. Complete resection rates were significantly higher in the ESD group than in the EMR group; it was also higher in < 1-cm small-sized lesions than in 1-2-cm large-sized lesions. Adverse events were similar between the two groups. During a median follow-up period of 63 months, local recurrence rates were 6.5% and 2.4% in the EMR and ESD groups, respectively, and the disease-free survival rate did not differ significantly between the groups.

CONCLUSION

Endoscopic treatment for type 1 gastric NETs less than 2 cm in diameter and confined to mucosal and submucosal layers could be an effective and safe treatment strategy based on the favorable long-term outcome.

Endoscopic submucosal dissection versus endoscopic mucosal resection for rectal carcinoid tumor. A meta-analysis and meta-regression with single-arm analysis

OBJECTIVE

As there has been so far no consensus on the best endoscopic resection technique, a meta-analysis was conducted to compare the efficacy and safety of endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR) for treating rectal carcinoid tumors.

METHODS

MEDLINE and EMBASE databases were searched for articles on the treatment of rectal carcinoid tumors using ESD vs EMR published up to October 2020 for outcomes including en bloc and complete resection, margin involvement, procedure time, requirement for additional surgery, bleeding, perforation and recurrence. Risk ratio and weighted mean differences were used for a DerSimonian and Laird random effects pairwise meta-analysis. Single-arm meta-analyses of proportions and random effects meta-regression analysis were also conducted.

RESULTS

Twenty-two studies involving 1360 rectal carcinoid tumors were included, in which 655 and 705 rectal carcinoid tumors were resected with ESD and EMR, respectively. The resection efficacy of ESD was comparable to that of EMR for tumors <10 mm. However, there were a significantly higher complete resection rate, and lower rates of vertical margin involvement and requirement for additional surgery using ESD than using EMR for tumors ≤20 mm. ESD had a longer procedure time and an increased likelihood of bleeding than EMR.

CONCLUSIONS

ESD is more effective in providing a curative treatment for rectal carcinoid tumors ≤20 mm in size as ESD can achieve a higher complete resection rate with lower vertical margin involvement than EMR. While they are suitable for treating rectal carcinoid tumors <10 mm as both techniques provide similar efficacy.

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.

Endoscopic full thickness resection vs. transanal endoscopic microsurgery for local treatment of rectal neuroendocrine tumors - a retrospective analysis

PURPOSE

Local treatment of small well-differentiated rectal neuroendocrine tumors (NETs) is recommended by current guidelines. However, although several endoscopic methods have been established, the highest R0 rate is achieved by transanal endoscopic microsurgery (TEM). Since a recently published study about endoscopic full thickness resection (eFTR) showed a R0 resection rate of 100%, the aim of this study was to evaluate both methods (eFTR vs. TEM).

METHODS

We retrospectively analyzed all patients with rectal NET treated either by TEM (1999-2018) or eFTR (2016-2019) in two tertiary centers (University Hospital Wuerzburg and Ulm). We analyzed clinical, procedural, and histopathological outcomes in both groups.

RESULTS

Twenty-eight patients with rectal NET received local treatment (TEM: 13; eFTR: 15). Most tumors were at stage T1a and grade G1 or G2 (in the TEM group two G3 NETs were staged T2 after neoadjuvant chemotherapy). In both groups, similar outcomes for en bloc resection rate, R0 resection rate, tumor size, or specimen size were found. No procedural adverse events were noted. Mean procedure time in the TEM group was 48.9 min and 19.2 min in the eFTR group.

CONCLUSION

eFTR is a convincing method for local treatment of small rectal NETs combining high safety and efficacy with short interventional time.

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.