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

Efficacy analysis of modified double band ligation-assisted endoscopic submucosal resection and endoscopic mucosal dissection in the treatment of gastric gastrointestinal stromal tumors (≤ 1.5 cm)

BACKGROUND

Recently, the application of double band ligation-assisted endoscopic submucosal resection (ESMR-DL) in the resection of rectal endocrine tumors ≤ 10 mm has shown promising prospects. However, the use of ESMR-DL has not been reported for gastric gastrointestinal stromal tumors (gGISTs). In this study, we aimed to compare the application of modified ESMR-DL with ESD in gGISTs (≤ 1.5 cm).

METHODS

Data were retrospectively collected from 472 patients who underwent modified ESMR-DL or endoscopic submucosal dissection (ESD) for resection of gGISTs (≤ 1.5 cm). To overcome selection bias, a propensity score matching method was applied using four covariates for 1:1 matching: sex, age, tumor size, and tumor location. Clinical data, surgical status, and postoperative outcomes were compared between the two groups.

RESULTS

Of the 472 patients, 78 (16.5%) received modified ESMR-DL and 394 (83.5%) received ESD; after matching, there were 78 patients in each group. There was no statistical difference in the baseline characteristics between the two groups after matching (p > 0.05). Compared to ESD, modified ESMR-DL resulted in shorter operation time, time to a liquid diet and postoperative hospitalization time, but had a higher incidence of intraoperative perforation (p < 0.05). There was no significant difference in the R0 resection rate of tumors, incidence of postoperative complications, and average hospitalization costs between the two groups after matching (p > 0.05). Univariate and multivariate analyses showed that the maximum dimension of the lesion (7 mm increments) and the surgical method were factors affecting procedure time, and the maximum dimension of the lesion (7 mm increments) and operator (novice vs instructor) were factors affecting intraoperative perforation in modified ESMR-DL (P < 0.05). During the follow-up, there were no recurrences or metastases of gGISTs in either group.

CONCLUSIONS

Modified ESMR-DL is noninferior to ESD with a similar complete resection rate. In addition, modified ESMR-DL had shorter procedure time and hospitalization time.

Comparison of endoscopic submucosal dissection and modified endoscopic mucosal resection for rectal neuroendocrine tumors

Although some studies have compared the treatment outcomes between modified endoscopic mucosal resection (m-EMR) and endoscopic submucosal dissection (ESD) for rectal neuroendocrine tumors (NETs), the results are based on the experience of experts from a single high-volume center. This multicenter study aimed to compare the outcomes between m-EMR and ESD for rectal NETs, with emphasis on the operator's level. Data of patients with rectal NETs treated using m-EMR or ESD at seven institutions that included general hospitals in Japan were retrospectively reviewed. Patients treated using m-EMR and those treated using ESD were matched for age, sex, lesion size, lesion location, and operator level through propensity score matching. The treatment outcomes were compared between the two groups. In total 304 patients (m-EMR = 178, ESD = 126) were included, with 218 in the matched groups (m-EMR = 109, ESD = 109). The R0 resection rate was not significantly different between the two groups (90.0% vs. 82.3%, P = .221). However, the procedural time was significantly shorter for the m-EMR group than that for the ESD group (6 vs. 26 min, P < .001). No significant difference in adverse events was observed between the two groups (postprocedure bleeding rate: 5.5% vs. 2.8%, P = .335; perforation rate: 0.9% vs. 0.9%, P = 1.00). Subgroup analysis revealed that the R0 resection rate for the trainees was significantly higher in the m-EMR group than in the ESD group (87.9% vs. 64.5%, P = .017). m-EMR is the preferred technique for the treatment of rectal NETs and should be considered, particularly for the trainees.

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.

Gastroenteropancreatic neuroendocrine neoplasms: current development, challenges, and clinical perspectives

Neuroendocrine neoplasms (NENs) are highly heterogeneous and potentially malignant tumors arising from secretory cells of the neuroendocrine system. Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are the most common subtype of NENs. Historically, GEP-NENs have been regarded as infrequent and slow-growing malignancies; however, recent data have demonstrated that the worldwide prevalence and incidence of GEP-NENs have increased exponentially over the last three decades. In addition, an increasing number of studies have proven that GEP-NENs result in a limited life expectancy. These findings suggested that the natural biology of GEP-NENs is more aggressive than commonly assumed. Therefore, there is an urgent need for advanced researches focusing on the diagnosis and management of patients with GEP-NENs. In this review, we have summarized the limitations and recent advancements in our comprehension of the epidemiology, clinical presentations, pathology, molecular biology, diagnosis, and treatment of GEP-NETs to identify factors contributing to delays in diagnosis and timely treatment of these patients.

Comparative Efficacy and Acceptability of Endoscopic Methods for Rectal Neuroendocrine Neoplasms with Low Malignant Potential: A Network Meta-analysis

BACKGROUND/AIMS

 Although endoscopic resection is an effective treatment of rectal neuroendocrine neoplasms (R-NENs) with low malignant potential, there is no consensus on the most recommended endoscopic method. This study aimed to assess the efficacy and acceptability of different endoscopic treatments for R-NENs with low malignant potential.

MATERIALS AND METHODS

 We searched databases for studies on treatments of R-NENs using endoscopic resection. These studies comprised techniques such as endoscopic mucosal resection (EMR), endoscopic submucosal dissection (ESD), modified endoscopic mucosal resection (EMRM), modified endoscopic submucosal dissection (ESDM), and transanal endoscopic microsurgery (TEM). The primary outcomes assessed were histological complete resection (HCR).

RESULTS

 Overall, 38 retrospective studies (3040 R-NENs) were identified. Endoscopic mucosal resection with a cap (EMRC), endoscopic mucosal resection with ligation (EMRL), ESD, ESDM, and TEM demonstrated higher resectability than did EMR in achieving HCR. Endoscopic mucosal resection, EMRC, EMRL, EMRP, EMRD, and EMRU required shorter operation times than did ESD. Endoscopic mucosal resection, EMRC, ESDM, and TEM incurred lower risks than did ESD.

CONCLUSION

 Regarding R-NENs <20 mm with low malignant potential, ESD could be used as the primary treatment. However, TEM may be more effective if supported by economic conditions and hospital facility. With respect to R-NENs <16 mm with low malignant potential, EMRL could be used as the primary treatment. In regard to R-NENs <10 mm with low malignant potential, EMRL, EMRC, and ESD could be used as the primary treatment. However, EMRL and EMRC might be better when operational difficulties and economic conditions were considered.

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.

Clinicopathological characteristics of rectal multiple neuroendocrine neoplasms and literature review

BACKGROUND

There are only a few epidemiological reports available for reference. The clinicopathological features are not clear, so there is no consensus on treating rectal multiple neuroendocrine neoplasms. This study aims to summarize the clinicopathological characteristics and preliminarily discuss the clinical diagnosis and treatment of rectal multiple neuroendocrine neoplasms.

METHODS

This study retrospectively analyzed rectal neuroendocrine neoplasm patients diagnosed and treated at the Fourth Hospital of Hebei Medical University from February 2007 to May 2021. The clinicopathological characteristics of rectal multiple neuroendocrine neoplasms were summarized and analyzed in combination with 14 studies on rectal multiple neuroendocrine neoplasms.

RESULTS

The incidence of RM-NENs accounted for 3.8% of all R-NENs in this study. The number of tumors varied to some extent, the size of tumors was basically no more than 10 mm, and there were more G1 grade tumors. In the analysis of 46 cases with known lymph node metastasis, the difference in lymph node metastasis rate between the number of tumors < 8 and ≥ 8 was statistically significant (p = 0.002).

CONCLUSIONS

The incidence of rectal multiple neuroendocrine neoplasms accounted for 3.8% of all rectal neuroendocrine neoplasms. For rectal multiple neuroendocrine neoplasms, the lymph node metastasis rate was higher when the number of tumors was ≥ 8. The influence of the number of tumors on lymph node metastasis should be considered in the selection of treatment.

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.

Endoscopic mucosal resection with double band ligation versus endoscopic submucosal dissection for small rectal neuroendocrine tumors

BACKGROUND

Endoscopic resection remains an effective method for the treatment of small rectal neuroendocrine tumors (NETs) (≤ 10 mm). Moreover, endoscopic mucosal resection (EMR) with double band ligation (EMR-dB), a simplified modification of EMR with band ligation, is an alternative strategy to remove small rectal NETs.

AIM

To evaluate the feasibility and safety of EMR-dB for the treatment of small rectal NETs (≤ 10 mm).

METHODS

A total of 50 patients with small rectal NETs, without regional lymph node enlargement or distant metastasis confirmed by endoscopic ultrasound, computerized tomography scan, or magnetic resonance imaging, were enrolled in the study from March 2021 to June 2022. These patients were randomly assigned into the EMR-dB (n = 25) group or endoscopic submucosal dissection (ESD) group (n = 25). The characteristics of the patients and tumors, procedure time, devices cost, complete resection rate, complications, and recurrence outcomes were analyzed.

RESULTS

There were 25 patients (13 males, 12 females; age range 28-68 years old) in the EMR-dB group, and the ESD group contained 25 patients (15 males, 10 females; age range 25-70 years old). Both groups had similar lesion sizes (EMR-dB 4.53 ± 1.02 mm, ESD 5.140 ± 1.74 mm; P = 0.141) and resected lesion sizes(1.32 ± 0.52 cm vs 1.58 ± 0.84 cm; P = 0.269). Furthermore, the histological complete resection and en bloc resection rates were achieved in all patients (100% for each). In addition, there was no significant difference in the complication rate between the two groups. However, the procedure time was significantly shorter and the devices cost was significantly lower in the EMR-dB group. Besides, there was no recurrence in both groups during the follow-up period.

CONCLUSION

The procedure time of EMR-dB was shorter compared with ESD, and both approaches showed a similar curative effect. Taken together, EMR-dB was a feasible and safe option for the treatment of small rectal NETs.

Endoscopic treatment and management of rectal neuroendocrine tumors less than 10 mm in diameter

Rectal neuroendocrine tumors (rNETs) measuring less than 10 mm in diameter are defined as small rNETs. Due to the low risk of distant invasion and metastasis, endoscopic treatments, including modified endoscopic mucosal resection, endoscopic submucosal dissection, and other transanal surgical procedures, are effective. This review article proposes a follow-up plan according to the size and histopathology of the tumor after operation.

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.

EMR-P for small rectal neuroendocrine tumors: is it a preferred treatment?

BACKGROUND

The selection of endoscopic treatments for small rectal neuroendocrine tumors is controversial.

OBJECTIVE

To retrospectively compare the effectiveness and safety of precut endoscopic mucosal resection (EMR-P) and endoscopic submucosal dissection (ESD) for small rectal neuroendocrine tumors (NETs).

METHODS

Data from 98 patients with small rectal NETs who were hospitalized at Shenzhen Second People's Hospital between August 2014 and November 2021 were collected. The en bloc resection rate, pathological complete resection rate, radical resection rate, operation time, adverse event rate and hospital stay were compared between the two groups.

RESULTS

The operation time in the EMR-P group was significantly shorter than that in the ESD group. The median hospital stay in the EMR-P group was also significantly shorter than that in the ESD group. There were no significant differences between the two groups in terms of the en bloc resection, complete resection or radical resection rates. There was also no significant difference in the incidence of adverse events between the two groups. The delayed bleeding and delayed perforation rates of the two groups were improved after conservative treatment without surgery. There was no significant difference in the rate of positive vertical margins and horizontal margins between the EMR-P group and the ESD group. No local recurrence or metastasis was found during follow-up.

CONCLUSION

EMR-P is an effective and safe endoscopic treatment for rectal NETs with a diameter of less than 10 mm. EMR-P is a significantly shorter procedure and requires a shorter hospital stay than ESD. EMR-P does not increase the cut margin positivity rate.

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.

Comparison between endoscopic mucosal resection with a cap and endoscopic submucosal dissection for rectal neuroendocrine tumors

Background

The aim of this study is to evaluate and compare the safety and efficacy of endoscopic mucosal resection with a cap (EMR-c) with those of endoscopic submucosal dissection (ESD) for rectal neuroendocrine tumors (R-NETs) ≤ 15 mm in diameter, and to analyze the risk factors of incomplete resection.

Methods

A total of 122 patients who underwent EMR-c or ESD for R-NETs at the Fourth Hospital of Hebei Medical University between February 2007 and December 2020 were invovled in this study. The clinical outcomes of two groups were compared and evaluated.

Results

A total of 122 patients with 128 R-NETs underwent endoscopic resection (EMR-c, 80; ESD, 48). In terms of duration of operation, EMR-c was significantly shorter than ESD (p < 0.001). Univariate analysis and multivariate analysis suggested that tumor diameter ≥ 8 mm was an independent risk factor for incomplete resection in patients with R-NETs in this study.

Conclusions

Both EMR-c and ESD were safe and effective treatments for R-NETs ≤ 15 mm in diameter. In addition, tumor diameter ≥ 8 mm was an independent risk factor for incomplete resection.

Underwater endoscopic mucosal resection for rectal neuroendocrine tumors (with videos): a single center retrospective study

BACKGROUND

Underwater endoscopic mucosal resection (UMER) is a new method of endoscopic resection to completely remove the lesion without submucosal injection. But few attempts have been carried out for rectal neuroendocrine tumors (rectal NETs).

METHODS

We retrospectively investigated data on the tumor characteristics and outcomes of patients with ≤ 10 mm rectal NETs who underwent UEMR or endoscopic submucosal dissection (ESD) from January 2019 to June 2021 in our institute.

RESULTS

The endoscopic resection rate was 100% in both UEMR and ESD groups. The histological complete resection rate of the UEMR group (95.5%) was lower than that of the ESD group (96.4%) with no significant difference. The average operation time, hospitalization time and operation cost of UEMR group were less than those of ESD group (P < 0.05). The incidence of postoperative abdominal pain and abdominal distention in the UEMR group was lower than that in the ESD group (P < 0.05). There was no significant difference in the incidence of delayed bleeding and perforation between the two groups. There was no local recurrence or distant metastasis in the two groups during the follow-up period.

CONCLUSIONS

Both the UEMR and ESD can effectively treat ≤ 10 mm rectal NETs with invasion depth confined to the mucosa and submucosa. UEMR is superior to ESD in operation time, hospitalization time, operation cost, postoperative abdominal pain and abdominal distention.

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.

Prognosis of rectal neuroendocrine tumors after endoscopic resection: a single-center retrospective study

BACKGROUND

The efficacy of endoscopic resection in patients with rectal neuroendocrine tumors (NETs) which are less than 20 mm in diameter remains unclear. This study aimed to investigate the efficacy and outcomes of different types of endoscopic resection in patients with NETs.

METHODS

We performed a retrospective analysis and follow-up on 98 patients who underwent endoscopic resection for rectal NETs between August 2010 and October 2019 at Guangdong Provincial People's Hospital, China. The lesions were preoperatively classified according to their endoscopic morphology and measured by endoscopic ultrasound. Patients were divided into modified endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) groups depending on the endoscopic treatment they received. The en bloc resection rate, histopathological complete resection rate, and the complication rate of the 2 groups were evaluated after the operation. The risk factors for incomplete resection were also analyzed.

RESULTS

The average diameter of the 98 NETs was 6.29±2.90 mm (range, 2-15 mm). The en bloc resection rate of the modified EMR and ESD treatment groups was 97.2% (35/36) and 100% (62/62), respectively. The histopathological complete resection rate was 86.1% (31/36) and 87.1% (54/62), respectively. No tumor recurrence or tumor-related death occurred. There were no statistically significant differences in the rate of histopathological complete resection, perforation, or delayed hemorrhage between the 2 groups (P>0.05). Multivariate analysis demonstrated that the depth of tumor invasion (P=0.007) and tumor diameter (P<0.001) were independent risk factors for histopathological complete resection.

CONCLUSIONS

Modified EMR and ESD are safe and effective endoscopic approaches for the resection of rectal NETs ≤15 mm in diameter. Endoscopic resection requires a comprehensive preoperative evaluation of risk factors including the depth of tumor invasion and tumor diameter.

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.

Comparison of endoscopic therapies for rectal neuroendocrine tumors: endoscopic submucosal dissection with myectomy versus endoscopic submucosal dissection

BACKGROUND

Endoscopic submucosal dissection (ESD) has been a valuable treatment of choice for rectal neuroendocrine tumors (NETs). However, the vertical margin may remain positive after ESD because the neuroendocrine tumors develop in a submucosal tumor (SMT)-like way. Endoscopic submucosal dissection with myectomy (ESD-ME), a new method for rectal NETs, may overcome this problem.

METHODS

From August 2013 to August 2020, the medical records of 69 patients (72 rectal neuroendocrine tumors) who received endoscopic submucosal dissection (ESD) or endoscopic submucosal dissection with myectomy (ESD-ME) for rectal NETs were investigated retrospectively. The characteristics of the patients and tumors, the rate of complete resection, and the rate of complications were analyzed retrospectively.

RESULTS

The ESD-ME group contained 27 patients (12 males, 15 females; age range 29-72 years) and the ESD group contained 42 patients (21 males, 21 females; age range 29-71 years). Both groups had similar mean rectal neuroendocrine tumor diameters (ESD-ME 6.1 ± 1.8 mm, ESD 6.7 ± 2.6 mm; P = 0.219). The procedure time was not different significantly between groups (ESD-ME 21.1 ± 6.3, ESD 19.3 ± 3.1; P = 0.115). The endoscopic complete resection rate did not differ significantly between the ESD-ME and ESD groups (100% for each). The histological complete resection rate was 100% (27 of 27) in the ESD-ME group and 81.0% (34 of 42) in the ESD group (P = 0.043). Delayed bleeding occurred in 1 ESD-ME patient (3.7%) and in 2 ESD patients (4.8%) (P = 1.000). Perforation occurred in 1 ESD-ME patient (3.7%) and the patient was successfully managed by conservative measure, and there was no perforation after ESD (P = 0.391).

CONCLUSIONS

When compared with ESD, ESD-ME resulted in a higher histological complete resection rate, had a similar complication rate, and took similar time to perform. ESD-ME can be considered an effective and safe resection method for rectal NETs < 16 mm in diameter without metastasis.

Tumor Macroscopic Morphology Is an Important Prognostic Factor in Predicting Chemotherapeutic Efficacy and Clinical Outcomes of Patients With Colorectal Neuroendocrine Neoplasms, One Multicenter Retrospective Cohort Study

BACKGROUND AND AIMS

Locally advanced and metastatic colorectal neuroendocrine neoplasm (NEN) is a rare disease with a dismal prognosis. We aimed to explore the value of the macroscopic morphology of NENs in the management of TNM stage II-IV colorectal NENs, which has not been fully elucidated in previous reports.

METHODS

We retrospectively enrolled 125 eligible patients with TNM stage II-IV colorectal NENs who were diagnosed between 2000 and 2020 from three Chinese hospitals. All were categorized into either protruding or ulcerative NEN groups through endoscopic evaluation of their macroscopic morphology. Clinicopathological data were collected and compared between the two groups. Survival analysis was performed to assess the survival outcomes between the two groups.

RESULTS

A total of 77 and 48 patients had protruding and ulcerative NENs, respectively. Patients with ulcerative NENs had a larger median tumor size (P<0.001) and higher median Ki-67 index (P<0.001), and a larger proportion of these patients had grade G3 disease (P=0.001) and poorly differentiated neoplasms (P=0.001), as well as higher frequencies of T3 and T4 tumors (P=0.006) than patients with protruding NENs. In addition, patients with ulcerative NENs showed a much lower response to first-line chemotherapy [50% (95% CI: 27.3% - 72.7%) versus 20% (95% CI: 3.1% - 36.9%), P=0.03] and a worse 3-year progression-free survival (PFS) rate [19.7% (95% CI: 7.2% - 32.2%) versus 49.5% (95% CI: 37.5% - 61.5%), P=0.001] and 3-year overall survival (OS) rate [30.7% (95% CI: 15.6% - 45.8%) versus 76.9% (95% CI: 66.5% - 87.3%), P<0.001] than those with protruding NENs. The multivariate analysis results indicated that the macroscopic shape of NENs was an independent prognostic factor affecting both PFS (HR = 1.760, 95% CI: 1.024 - 3.026, P = 0.04) and OS (HR = 2.280, 95% CI: 1.123 - 4.628, P = 0.02).

CONCLUSIONS

Ulcerative NENs were more malignant and chemotherapy resistant than protruding NENs. Tumor macroscopic morphology is a valuable prognostic factor for stage II-IV colorectal NENs.