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

Transanal endoscopic microsurgery in the treatment of rectal neuroendocrine tumors: a retrospective 10-year single-center experience

PURPOSE

Transanal endoscopic surgery is a recommended full-thickness resection technique for the treatment of rectal neuroendocrine tumors. We aimed to compare the efficacy, safety and follow-up of patients with rectal neuroendocrine tumors treated with transanal endoscopic microsurgery in the primary setting and as salvage therapy after non-radical endoscopic polypectomy.

METHODS

A retrospective analysis of a 10-year database of patients treated with transanal endoscopic microsurgery was performed. The procedure-related measures, including duration of the procedure, adverse events, and patient-related measures, including age, gender, tumor size, grading, and length of follow-up, were obtained. We compared the primary TEM group with the salvage group.

RESULTS

In total, 30 patients with rectal neuroendocrine tumors were included in the study; 13 of them received primary treatment and 17 salvage therapy of the scar. Patients receiving primary treatment were significantly older (60.5 vs. 51.7 years). There were no significant differences in patient gender, tumor size and grading, length of follow-up, hospital stay or procedure time. The R0 resection rate was 92.3% in the primary treatment group. Adverse events were mild or managed with endoscopic treatment. Follow-up was slightly but not significantly longer in the primary treatment group and showed no recurrences in both groups of patients.

CONCLUSIONS

Transanal endoscopic microsurgery is safe and effective for both primary and salvage treatment of rectal neuroendocrine tumors.

Risk factors for residual tumors in histologically incompletely resected rectal neuroendocrine tumors

BACKGROUND

Rectal neuroendocrine tumors (r-NETs) are often misidentified as polyps, leading to inappropriate endoscopic treatment and incomplete resection.

AIMS

This study investigated the occurrence and risk factors of residual r-NETs following salvage local resection (SLR) after incomplete resection.

METHODS

The medical records of 95 patients who underwent SLR for histologically incompletely resected (R1/Rx-resected) r-NETs referred from other hospitals between January 2020 and August 2023 were analyzed.

RESULTS

The residual r-NET rate was 48.4 % (46/95), varying according to the primary resection method: cold forceps polypectomy (CFP), 70.0 % (21/30); conventional polypectomy or endoscopic mucosal resection (EMR), 41.7 % (25/60); and modified EMR or endoscopic submucosal dissection, 0 % (0/5). The residual r-NET rate was 65.7 % for endoscopically incomplete primary resection versus 0 % for endoscopically complete primary resection. Upon multivariate analysis, endoscopically suspected remnant tumors before SLR (odds ratio [OR], 15.56; 95 % confidence interval [CI], 2.94-82.35, p = 0.002) and the use of CFP for primary resection (OR, 3.60; 95 % CI, 1.02-14.52, p = 0.043) were associated with residual r-NETs after SLR.

CONCLUSION

Salvage resection should be considered for R1/Rx-resected r-NET cases with risk factors for residual tumors to lower the likelihood of recurrence.

Endoscopic full-thickness resection: A definitive solution for local complete resection of small rectal neuroendocrine neoplasms

BACKGROUND

Recently, several endoscopic techniques have been used to improve the R0 resection rate of rectal neuroendocrine neoplasms (R-NENs). However, none of these methods can achieve 100% complete resection (CR), particularly in the vertical direction. Endoscopic full-thickness resection (EFTR) has proven to be an effective method for the treatment of submucosal tumors but is seldom utilized in the eradication of R-NENs.

AIM

To review cases of R-NENs removed using EFTR and to evaluate the safety and efficacy of this technique.

METHODS

This retrospective cohort study enrolled 160 patients with pathologically confirmed R-NENs, including 132 who underwent endoscopic submucosal dissection (ESD) and 28 who underwent EFTR. Lesions were categorized as < 1 cm, 1-2 cm, and > 2 cm in size. CR rate, en bloc resection rate, operation time, and complications were evaluated. Subgroup analyses and follow-up were also performed.

RESULTS

EFTR achieved 100% CR rates for lesions < 1 cm and 1-2 cm, compared with 67.0% and 50.0%, respectively, in the ESD group. En bloc resection and successful removal of the R-NENs were achieved in all patients. Meanwhile, EFTR showed performance comparable to ESD in terms of operation time, hospitalization cost, and postoperative adverse events, except for a one-day longer hospital stay. We also analyzed the invasion depth of R-NENs based on full-thickness specimens. The data showed that 80% of lesions (< 1 cm) and 85.7% of lesions (1-2 cm) had invaded the SM3 level or deeper at the time of resection. For ESD specimens, 46.6% (< 1 cm) and 89.3% (1-2 cm) of lesions had infiltrated more than 2000 μm beneath the muscularis mucosae.

CONCLUSION

EFTR has shown superior performance in the resection of small R-NENs compared with that of ESD.

Comparison of endoscopic submucosal dissection and transanal endoscopic microsurgery for stage 1 rectal neuroendocrine tumors

BACKGROUND

Stage 1 rectal neuroendocrine tumors (NETs) are best treated with endoscopic submucosal dissection (ESD) or transanal endoscopic microsurgery (TEM) for local resection.

AIM

To investigate the safety and efficacy of ESD and TEM for local resection of stage 1 rectal NETs.

METHODS

This retrospective observational analysis included patients with clinical stage 1 rectal NETs (cT1N0M0, less than 20 mm) who underwent ESD or TEM. The ESD and TEM groups were matched to ensure that they had comparable lesion sizes, lesion locations, and pathological grades. We assessed the differences between groups in terms of en bloc resection rate, R0 resection rate, adverse event rate, recurrence rate, and hospital stay and cost.

RESULTS

Totally, 128 Lesions (ESD = 84; TEM = 44) were included, with 58 Lesions within the matched groups (ESD = 29; TEM = 29). Both the ESD and TEM groups had identical en bloc resection (100.0% vs 100.0%, P = 1.000), R0 resection (82.8% vs 96.6%, P = 0.194), adverse event (0.0% vs 6.9%, P = 0.491), and recurrence (0.0% vs 3.4%, P = 1.000) rates. Nevertheless, the median hospital stay [ESD: 5.5 (4.5-6.0) vs TEM: 10.0 (7.0-12.0) days; P < 0.001], and cost [ESD: 11.6 (9.8-12.6) vs TEM: 20.9 (17.0-25.1) kilo-China Yuan, P < 0.001] were remarkably shorter and less for ESD.

CONCLUSION

Both ESD and TEM were well-tolerated and yielded favorable outcomes for the local removal of clinical stage 1 rectal NETs. ESD exhibits shorter hospital stay and fewer costs than TEM.

Comparative meta-analysis of cold snare polypectomy and endoscopic mucosal resection for colorectal polyps: assessing efficacy and safety

Colorectal polyps are commonly treated with surgical procedures, with cold snare polypectomy (CSP) and endoscopic mucosal resection (EMR) being the two most prevalent techniques. This meta-analysis (PROSPERO ID: CRD42022336152) aimed to compare the efficacy and safety of CSP and EMR in the management of colorectal polyps. Comprehensive searches were conducted in PubMed, Embase, CINAHL, Web of Science, and Cochrane Library databases, covering publications up until June 2024. The primary outcome was complete resection rate, and secondary outcomes included en bloc resection rate, immediate and delayed bleeding, perforation, and procedure time. The Mantel-Haenszel method was employed for the analysis of binary endpoints, while the inverse variance method was used for continuous outcomes. Subgroup analysis was performed to explore potential sources of heterogeneity. Six studies involving 15,296 patients and 17,971 polyps were included in the meta-analysis. CSP had a significantly lower complete resection rate compared to EMR (OR: 0.44, 95% CI [0.21-0.94], p = 0.0334). However, there was no significant difference between CSP and EMR in en bloc resection rate, perforation, or procedure time. Interestingly, CSP had a significantly lower delayed bleeding rate compared to EMR (OR: 0.45, 95% CI [0.27-0.77], p = 0.0034), but there was no significant difference in immediate bleeding rate. In conclusion, CSP is a safe, efficient, and effective technique comparable to EMR. The choice of technique should be based on the individual patient and polyp characteristics.

An Update on the Management of Rectal Neuroendocrine Neoplasms

OPINION STATEMENT

Rectal neuroendocrine neoplasms (NENs) are increasing in incidence. Most lesions are low grade, well-differentiated neuroendocrine tumours with good long term outcomes. However there is metastatic potential and resection offers the only option for a cure and in most cases should be offered to reduce the risk of metastases. Careful staging of rectal NENs should be performed prior to consideration of resection in order to ensure the appropriate technique is chosen, and reduce the risk of incomplete resection. Resection can be endoscopic or surgical, and selecting the appropriate resection technique relies on tumour characteristics such as size, grade, invasion into the muscularis propria, presence of lymph node involvement or of distal metastases. Some patients may require systemic therapies which may involve somatostatin analogues (SSAs), everolimus, tyrosine kinase inhibitors (TKIs), chemotherapy or peptide receptor radionuclide therapy (PRRT). Due the rarity of these tumours, much of the evidence is based on retrospective reviews or smaller cohort studies. This article is an update of the current evidence available to guide management.

Optimization of endoscopic treatment strategies for R0 resection of rectal neuroendocrine tumors smaller than 10 mm

BACKGROUND

The optimal histologically complete (R0) resection methods of endoscopy for rectal neuroendocrine tumor (NET) ≤ 10 mm remains controversial. We aimed to assess the optimal endoscopic treatments for NETs.

METHODS

The retrospective enrolled patients (n = 208) with rectal NETs were divided into 3 subsets according to pathological tumor size: 2 - 3 mm, 4 - 5 mm, and 6 - 10 mm NETs. Factors associated with R0 resection according to different endoscopic treatments (accidental diagnostic biopsy by cold forceps, endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD)) and tumor size were investigated. All patients underwent follow-up and no local recurrence or metastasis were identified.

RESULTS

A total of 208 patients were enrolled. In patients with 2 - 3 mm NETs, the R0 resection rate was 100.0 % for biopsy, EMR, and ESD. The R0 resection rate for biopsy of 4 - 5 mm and 6 - 10 mm NETs was 34.3 % and 0.0 % respectively, which was inferior to the EMR/ESD rate (4 - 5mm: p < 0.001; 6 - 10 mm: p < 0.001: respectively). For patients with ≤ 10 mm NETs, EMR and ESD had a comparable en bloc (p = 0.082) and R0 resection rates (p = 0.651).

CONCLUSION

Accidental diagnostic biopsy by cold forceps could be considered as the possible treatment for 2 - 3 mm rectal NETs. And for patients with ≤ 10 mm rectal NETs, both EMR and ESD might be sufficient.

A retrospective analysis of 26 cases of duodenal neuroendocrine tumor treated by endoscopic submucosal dissection

BACKGROUND

Duodenal neuroendocrine tumors (D-NETs) are rare but clinically significant tumors that can occur in various parts of the duodenum, including the duodenal papilla. Endoscopic submucosal dissection (ESD) has emerged as a minimally invasive treatment option for D-NETs, offering potential advantages in terms of tumor removal and postoperative recovery. We aimed to retrospectively analyze the clinical characteristics and prognosis of ESD for D-NETs.

METHODS

A total of 26 cases of duodenal neuroendocrine tumors (27 lesions), including duodenal papillary neuroendocrine tumors, were studied retrospectively.

RESULTS

A total of 26 patients with D-NETs (27 lesions) were pathologically diagnosed, and 27 lesions were found by chance during endoscopy. The lesions included duodenal bulbar, descending part, and duodenal papilla. Nineteen tumors were <1 cm (70.4%) in diameter, and eight tumors were 1-2 cm (29.6%) in diameter. There were five cases of duodenal papilla NETs. G1: 24 (88.8%) and G2: 3 (11.1%). Endoscopic ultrasonography showed that 27 lesions were confined to the submucosa. One case was a neuroendocrine tumor 2 mm inside a tubular adenoma at the papilla. All operations were performed by senior doctors in the department. The total resection rate was 100%, and the incidence of intraoperative bleeding and perforation was 0. Delayed bleeding and perforation were 0. The shortest operation time was 25 min, and the longest was 70 min. Burning tumor cells at the basal resection margin were noted in 11 lesions, necessitating careful pathological assessment. There were 24 cases of G1 type and 3 cases of G2 type. All 26 patients underwent abdominal CT before operation to confirm the absence of lymph node and distal metastasis. One patient with papillary lesion had positive lesion base resection and was treated with additional operation. Temporary biliary and pancreatic duct stents were placed before or after ESD in all five cases of duodenal papillary lesions, and no biliary and pancreatic complications occurred after surgery. Postoperative follow-up gastroscopy and abdominal CT confirmed no recurrence or metastasis during a follow-up period of 3 months to 4.5 years. There was no recurrence or metastasis during a follow-up period of 3 months to 4 ½ years.

CONCLUSION

ESD may be an effective and safe intervention for D-NETs ≤20 mm confined to the mucosa or submucosa of the duodenum, including the papilla. Clinicians should remain vigilant about potential complications during and after surgery. Duodenal ESD treatment NET has high requirements in terms of treatment technology, and clinicians should pay attention to the potential complications of ESD during operation.

Management & surveillance of rectal neuroendocrine tumours: a single-centre retrospective analysis

BACKGROUND

Rectal neuroendocrine tumours (rNETs) are rare but are increasing in incidence. Current management and surveillance recommendations are based on low-grade evidence. Follow-up practices are often inconsistent and costly. This retrospective study analyses a single-centre's experience with rNETs to assess incidence, management practices, outcomes, and guideline adherence.

METHODS

This is a single-centre retrospective study from Queensland Australia, spanning from 2012 to 2023. Twenty-eight rNET cases met inclusion criteria. Examined parameters included incidence, management, outcomes and adherence to European Neuroendocrine Tumour Society (ENETS) guidelines. R1 resection rate was analysed for associations with resection technique and lesion recognition and recurrence rate was assessed in all patients.

RESULTS

This study shows an increasing incidence of rNETs during the study period, reflecting a global trend. R1 resection rate at initial endoscopy was 75%. There was a general lack of advanced endoscopic techniques utilized and poor lesion recognition, however a statistically significant correlation was not established between these factors and an R1 result (P < 0.05). Most patients with an R1 result had subsequent re-resection to render the result R0, however five patients (33%) underwent surveillance with no reports of recurrence on follow-up. Overall, follow-up practices in our cohort were inconsistent and did not adhere to guidelines.

CONCLUSION

rNETs are increasing in incidence, emphasizing the need for standardized management and surveillance. Further training is required for rNET recognition and advanced endoscopic resection techniques. Further research is required to assess long-term outcomes in surveilled R1 cases, understand optimal endoscopic resection techniques and further develop local surveillance guidelines.

Endoscopic management of gastric, duodenal and rectal NETs: Position paper from the Italian Association for Neuroendocrine Tumors (Itanet), Italian Society of Gastroenterology (SIGE), Italian Society of Digestive Endoscopy (SIED)

The present paper reflects the position of the Italian Association for Neuroendocrine Tumors (Itanet), the Italian Society of Gastroenterology (SIGE), and the Italian Society of Digestive Endoscopy (SIED) regarding the management of patients affected by gastric, duodenal, and rectal neuroendocrine neoplasms (NENs) amenable to endoscopic treatment. The key questions discussed in this paper are summarized in Table 1. Data were extracted from the MEDLINE database through searches; expert opinions and recommendations are provided in accordance with the available scientific evidence and the authors' expertise. Recommendations are presented alongside a level of evidence and grade of recommendation based on the GRADE system. This paper specifically focuses on subgroups of NENs considered suitable for endoscopic management according to current international guidelines: i. well-differentiated gastric neuroendocrine tumors (gNET) type 1 < 2 cm and selected cases of type 3; ii. well-differentiated duodenal, non-functioning, non-ampullary NET with size < 2 cm; and well-differentiated rectal NET with size < 2 cm.

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.

Role of Advanced Gastrointestinal Endoscopy in the Comprehensive Management of Neuroendocrine Neoplasms

Neuroendocrine neoplasms (NENs), also called neuroendocrine tumors (NETs), are relatively uncommon, heterogenous tumors primarily originating in the gastrointestinal tract. With the improvement in technology and increasing use of cross-sectional imaging and endoscopy, they are being discovered with increasing frequency. Although traditionally considered indolent tumors with good prognoses, some NENs exhibit aggressive behavior. Timely diagnosis, risk stratification, and management can often be a challenge. In general, small NENs without local invasion or lymphovascular involvement can often be managed using minimally invasive advanced endoscopic techniques, while larger lesions and those with evidence of lymphovascular invasion require surgery, systemic therapy, or a combination thereof. Ideal management requires a comprehensive and accurate understanding of the stage and grade of the tumor. With the recent advancements, a therapeutic advanced endoscopist can play a pivotal role in diagnosing, staging, and managing this rare condition. High-definition white light imaging and digital image enhancing technologies like narrow band imaging (NBI) in the newer endoscopes have improved the diagnostic accuracy of traditional endoscopy. The refinement of endoscopic ultrasound (EUS) over the past decade has revolutionized the role of endoscopy in diagnosing and managing various pathologies, including NENs. In addition to EUS-directed diagnostic biopsies, it also offers the ability to precisely assess the depth of invasion and lymphovascular involvement and thus stage NENs accurately. EUS-directed locoregional ablative therapies are increasingly recognized as highly effective, minimally invasive treatment modalities for NENs, particularly pancreatic NENs. Advanced endoscopic resection techniques like endoscopic submucosal dissection (ESD), endoscopic submucosal resection (EMR), and endoscopic full-thickness resection (EFTR) have been increasingly used over the past decade with excellent results in achieving curative resection of various early-stage gastrointestinal luminal lesions including NENs. In this article, we aim to delineate NENs of the different segments of the gastrointestinal (GI) tract (esophagus, gastric, pancreatic, and small and large intestine) and their management with emphasis on the endoscopic management of these tumors.

The meaning of R1 resection after endoscopic removal of gastric, duodenal and rectal neuroendocrine tumors

INTRODUCTION

Well-differentiated gastric, duodenal, and rectal neuroendocrine neoplasms (NETs) are rare diseases usually managed by endoscopic treatment. Although several endoscopic techniques are available, the number of patients with incomplete (R1) resection is significant.

AREAS COVERED

This review focuses on the meaning of incomplete R1 findings after endoscopic resection in type I gastric NETs; nonfunctioning, non-ampullary duodenal NETs; and small rectal NETs. Data were identified by MEDLINE database search without publication date limitation.

EXPERT OPINION

An incomplete R1 finding may have no significant impact on a patient's clinical outcome, particularly in small G1 type I gastric NETs, which have an indolent course. A 'stepwise approach,' which uses more advanced endoscopic techniques, or minimally invasive surgery may be justified to achieve complete margin-free resection. This approach must balance the tumor features and the procedure-related risk of complications, particularly in the duodenum, where the role of deep endoscopic resections is limited due to the thin duodenal wall. Gastric and rectal NETs that are incompletely removed after initial resection are more easily amenable to deep endoscopic techniques. However, this might not be necessary for patients with comorbidities, elderly, or both due to the uncertainty of how R1 finding impacts a patient's clinical outcome.

European Neuroendocrine Tumor Society (ENETS) 2023 guidance paper for colorectal neuroendocrine tumours

This ENETS guidance paper, developed by a multidisciplinary working group, provides an update on the previous colorectal guidance paper in a different format. Guided by key clinical questions practical advice on the diagnosis and management of neuroendocrine tumours (NET) of the caecum, colon, and rectum is provided. Although covered in one guidance paper colorectal NET comprises a heterogeneous group of neoplasms. The most common rectal NET are often small G1 tumours that can be treated by adequate endoscopic resection techniques. Evidence from prospective clinical trials on the treatment of metastatic colorectal NET is limited and discussion of patients in experienced multidisciplinary tumour boards strongly recommended. Neuroendocrine carcinomas (NEC) and mixed neuroendocrine non-neuroendocrine neoplasms (MiNEN) are discussed in a separate guidance paper.

Current status of the role of endoscopy in evaluation and management of gastrointestinal and pancreatic neuroendocrine tumors

The incidence of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) has increased over the last several decades. In general, NETs are slow-growing neoplasms and the data on the natural history is still evolving. The availability and improved utilization of advanced imaging modalities have allowed the selection of cases suitable for endotherapy. In this regard, endoscopic ultrasound (EUS) has emerged as a central imaging modality to assess the depth of infiltration in gastroduodenal as well as rectal NETs. Enhanced EUS modalities, including contrast-enhanced EUS and EUS elastography, reliably differentiate pancreatic neuroendocrine tumors (PNETs) from adenocarcinomas and may enable prediction of aggressive PNETs. With recent developments in therapeutic endoscopy, a large proportion of GEP-NETs can be safely managed endoscopically. Endoscopic resection techniques, including endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD), allow the safe removal of gastroduodenal and rectal NETs. Recent data indicate that modified EMR techniques may be superior to conventional EMR with regard to histologically complete resection. Device-assisted endoscopic full thickness resection is emerging as a safe and effective technique for upper gastrointestinal as well as rectal NETs. In selected cases with PNETs, who are otherwise unfit for surgery, EUS-guided ablation is increasingly being recognized as a safe treatment option. This review focusses on evidence-based approaches to endoscopic evaluation and the management of GEP-NETs with special emphasis on recent advancements.

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 Resection of Gastrointestinal Neuroendocrine Tumors: Long-Term Outcomes and Comparison of Endoscopic Techniques

INTRODUCTION

Gastrointestinal neuroendocrine tumors (GI-NETs) are being more frequently diagnosed and treated by endoscopic resection (ER) techniques. However, comparison studies of the different ER techniques or long-term outcomes are rarely reported.

METHODS

This was a single-center retrospective study analyzing short and long-term outcomes after ER of gastric, duodenum, and rectal GI-NETs. Comparison between standard EMR (sEMR), EMR with a cap (EMRc), and endoscopic submucosal dissection (ESD) was made.

RESULTS

Fifty-three patients with GI-NET (25 gastric, 15 duodenal, and 13 rectal; sEMR = 21; EMRc = 19; ESD = 13) were included in the analysis. Median tumor size was 11 mm (range 4-20), significantly larger in the ESD and EMRc groups compared to the sEMR group (p < 0.05). Complete ER was possible in all cases with 68% histological complete resection (no difference between the groups). Complication rate was significantly higher in the EMRc group (EMRc 32%, ESD 8%, and EMRs 0%, p = 0.01). Local recurrence occurred in only one patient, and systemic recurrence in 6%, with size ≥ 12 mm being a risk factor for systemic recurrence (p = 0.05). Specific disease-free survival after ER was 98%.

CONCLUSION

ER is a safe and highly effective treatment particularly for less than 12 mm luminal GI-NETs. EMRc is associated with a high complication rate and should be avoided. sEMR is an easy and safe technique that is associated with long-term curability, and it is probably the best therapeutic option for most luminal GI-NETs. ESD appears to be the best option for lesions that cannot be resected en bloc with sEMR. Multicenter, prospective randomized trials should confirm these results.

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.

Risk factors and clinical outcomes of incomplete endoscopic resection of small rectal neuroendocrine tumors in southern China: a 9-year data analysis

Background

The histologically complete resection (CR) rate of small rectal neuroendocrine tumors (RNETs) is unsatisfactory at the first endoscopy. Risk factors and clinical outcomes associated with incomplete resection (IR) have not been explicitly elucidated. This study aims to explore the relevant factors of IR.

Methods

This retrospective study reviewed patients with small RNETs (≤10 mm) in eight centers from January 2013 to December 2021. Clinicopathological characteristics and clinical outcomes were compared between the CR and IR groups, and the polypectomy and advanced treatment groups.

Results

Of the 326 patients included, 83 (25.5%) were diagnosed with IR. Polypectomy (odds ratio [OR] = 16.86), a central depression (OR = 7.50), and treatment in the early period (OR = 2.60) were closely associated with IR. Further analysis revealed that an atypical hyperemic appearance (OR = 7.49) and treatment in the early period (OR = 2.54) were significantly associated with the inappropriate use of polypectomy (both P < 0.05). In addition, a total of 265 (81.3%) were followed up with a median follow-up period of 30.9 months. No death, metastasis, or recurrence was found during the follow-up period.

Conclusions

Polypectomy, a central depression, and treatment in the early period were risk factors for IR. Further, an atypical hyperemic appearance and treatment in the early period were significant predisposing factors for inappropriate choice of polypectomy. For histologically incompletely resected small RNETs, follow-up may be a safe and feasible alternative to rigorous salvage therapy.

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.

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.

State of the Art in Endoscopic Therapy for the Management of Gastroenteropancreatic Neuroendocrine Tumors

OPINION STATEMENT

Gastroenteropancreatic neuroendocrine neoplasms (GEP NENs) comprise a heterogeneous group of slow growing tumors arising from the neuroendocrine cells of the gastrointestinal (GI) tract. Although they are considered relatively rare, their incidence is rising and it is believed that the more frequent use of endoscopy and imaging studies have at least in part contributed to the increased diagnosis especially of localized neoplasms. The management of these neoplasms should be guided by a multidisciplinary NEN team following appropriate staging investigations. Localized neoplasms of the GI tract may be suitable for endoscopic therapy, while patients with pancreatic NENs, unsuitable for surgery, should be considered for endoscopic ultrasound (EUS)-guided ablation. In this review, we discuss the evidence regarding endoscopic resection of luminal NENs and EUS-guided therapy of pancreatic NENs. The efficacy, safety, and other longer-term outcomes of these techniques are summarized. In conclusion, this review of endoscopic therapies for localized NENs may be a useful guide for NEN clinicians and endoscopists who are considering these therapeutic options for the management of focal GEP NENs.

Endoscopic management of subepithelial lesions including neuroendocrine neoplasms: European Society of Gastrointestinal Endoscopy (ESGE) Guideline

1: ESGE recommends endoscopic ultrasonography (EUS) as the best tool to characterize subepithelial lesion (SEL) features (size, location, originating layer, echogenicity, shape), but EUS alone is not able to distinguish among all types of SEL.Strong recommendation, moderate quality evidence. 2: ESGE suggests providing tissue diagnosis for all SELs with features suggestive of gastrointestinal stromal tumor (GIST) if they are of size > 20 mm, or have high risk stigmata, or require surgical resection or oncological treatment.Weak recommendation, very low quality evidence. 3: ESGE recommends EUS-guided fine-needle biopsy (EUS-FNB) or mucosal incision-assisted biopsy (MIAB) equally for tissue diagnosis of SELs ≥ 20 mm in size.Strong recommendation, moderate quality evidence. 4: ESGE recommends against surveillance of asymptomatic gastrointestinal (GI) tract leiomyomas, lipomas, heterotopic pancreas, granular cell tumors, schwannomas, and glomus tumors, if the diagnosis is clear.Strong recommendation, moderate quality evidence. 5: ESGE suggests surveillance of asymptomatic esophageal and gastric SELs without definite diagnosis, with esophagogastroduodenoscopy (EGD) at 3-6 months, and then at 2-3-year intervals for lesions < 10 mm in size, and at 1-2-year intervals for lesions 10-20 mm in size. For asymptomatic SELs > 20 mm in size that are not resected, ESGE suggests surveillance with EGD plus EUS at 6 months and then at 6-12-month intervals.Weak recommendation, very low quality evidence. 6: ESGE recommends endoscopic resection for type 1 gastric neuroendocrine neoplasms (g-NENs) if they grow larger than 10 mm. The choice of resection technique should depend on size, depth of invasion, and location in the stomach.Strong recommendation, low quality evidence. 7: ESGE suggests considering removal of histologically proven gastric GISTs smaller than 20 mm as an alternative to surveillance. The decision to resect should be discussed in a multidisciplinary meeting. The choice of technique should depend on size, location, and local expertise.Weak recommendation, very low quality evidence. 8: ESGE suggests that, to avoid unnecessary follow-up, endoscopic resection is an option for gastric SELs smaller than 20 mm and of unknown histology after failure of attempts to obtain diagnosis.Weak recommendation, very low quality evidence. 9: ESGE recommends basing the surveillance strategy on the type and completeness of resection. After curative resection of benign SELs no follow-up is advised, except for type 1 gastric NEN for which surveillance at 1-2 years is advised.Strong recommendation, low quality evidence. 10: For lower or upper GI NEN with a positive or indeterminate margin at resection, ESGE recommends repeating endoscopy at 3-6 months and another attempt at endoscopic resection in the case of residual disease.Strong recommendation, low quality evidence.

Rectal neuroendocrine tumors: Current advances in management, treatment, and surveillance

Rectal neuroendocrine neoplasms (r-NENs) are considered among the most frequent digestive NENs, together with small bowel NENs. Their incidence has increased over the past few years, and this is probably due to the widespread use of endoscopic screening for colorectal cancer and the advanced endoscopic procedures available nowadays. According to the current European Neuroendocrine Tumor Society (ENETS) guidelines, well-differentiated r-NENs smaller than 10 mm should be endoscopically removed in view of their low risk of local and distant invasion. R-NENs larger than 20 mm are candidates for surgical resection because of their high risk of distant spreading and the involvement of the muscularis propria. There is an area of uncertainty regarding tumors between 10 and 20 mm, in which the metastatic risk is intermediate and the endoscopic treatment can be challenging. Once removed, the indications for surveillance are scarce and poorly codified by international guidelines, therefore in this paper, a possible algorithm is proposed.

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.

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.

OWM, Taglieri E, Koyama FSC, Filho CAMC, Nakagawa WT. Risk Factors for Development of Rectal Neuroendocrine Tumors Longer Than 9 mm: Retrospective Cohort

BACKGROUND

Rectal neuroendocrine tumors (R-NET) represent the most frequent of gastroenteropancreatic neuroendocrine neoplasms (NEN-GEP) according to the United States Surveillance, Epidemiology, and End Results database. With an annual percentage of occurrence increasing to 8.2% of all rectal neoplasms, R-NET affect less than 2% and are reported in only 0.05% to 0.07% of patients undergoing colorectal cancer (CRC) screening. The primary objective of this study was to assess the risk factors associated with R-NET greater than 10 mm. As a secondary objective, it was also aimed to evaluate the response to endoscopic treatment.

METHODS

This was a retrospective study, using data collected through the analysis of medical records of colonoscopies performed from January 2008 to December 2014. Records of polypectomies were identified, and the results were searched for pathological findings of R-NET. We also gathered epidemiological data and outcomes as risk factors for lesions greater than or equal to 10 mm, with local and distant recurrence.

RESULTS

During the study period, 18 218 colonoscopies were performed and 10 865 polypoid lesions were detected and removed, 20 with R-NET anatomopathology. The detection rate was 0.1%. The risk factors associated with major lesions were Japanese ethnicity, the lack of previous cancer diagnosis, and a Ki67 index > 2%. The mean follow-up was 56.6 months, and there was no local lymph node recurrence or distant relapse.

CONCLUSION

This study concludes that endoscopic resection is a good and effective method for treatment of Grade 1 rectal NET smaller than 11 mm, with high cure rates and low rates of local or distant relapse.

Anchoring the snare tip is a feasible endoscopic mucosal resection method for small rectal neuroendocrine tumors

Small rectal neuroendocrine tumors (NETs) can be treated using cap-assisted endoscopic mucosal resection (EMR-C), which requires additional effort to apply a dedicated cap and snare. We aimed to evaluate the feasibility of a simpler modified endoscopic mucosal resection (EMR) technique, so-called anchored snare-tip EMR (ASEMR), for the treatment of small rectal NETs, comparing it with EMR-C. We retrospectively evaluated 45 ASEMR and 41 EMR-C procedures attempted on small suspected or established rectal NETs between July 2015 and May 2020. The mean (SD) lesion size was 5.4 (2.2) mm and 5.2 (1.7) mm in the ASEMR and EMR-C groups, respectively (p = 0.558). The en bloc resection rates of suspected or established rectal NETs were 95.6% (43/45) and 100%, respectively (p = 0.271). The rates of histologic complete resection of rectal NETs were 94.1% (32/34) and 88.2% (30/34), respectively (p = 0.673). The mean procedure time was significantly shorter in the ASEMR group than in the EMR-C group (3.12 [1.97] vs. 4.13 [1.59] min, p = 0.024). Delayed bleeding occurred in 6.7% (3/45) and 2.4% (1/41) of patients, respectively (p = 0.618). In conclusion, ASEMR was less time-consuming than EMR-C, and showed similar efficacy and safety profiles. ASEMR is a feasible treatment option for small rectal NETs.

An evaluation of resectability among endoscopic treatment methods for rectal neuroendocrine tumors <10 mm

BACKGROUND AND STUDY AIMS

With respect to rectal neuroendocrine tumor (NET) resection, it remains unclear which of the following methods is the most effective: conventional endoscopic mucosal resection (cEMR), EMR using a fitted cap (EMR-C), EMR with a ligation band device (EMR-L), or endoscopic submucosal dissection (ESD). Thus, in this study, we aim to retrospectively evaluate the most effective endoscopic resection for rectal NETs < 10 mm.

PATIENTS AND METHODS

In total, 61 consecutive patients with primary rectal NETs < 10 mm in diameter were included in this study; they were then divided into three groups: those with cEMR; those with modified EMR (mEMR) involving EMR-C and EMR-L; and those with ESD. The primary endpoint was to evaluate the difference in the complete en bloc resection rate. The secondary endpoint was to investigate differences in procedure time and complications.

RESULTS

Among the three groups, a significant difference was found in procedure time (cEMR vs ESD, P < .01; mEMR vs ESD, P < .01), en bloc resection rate (cEMR vs mEMR, P = .015), tumor size (mEMR vs ESD, P < .01), percentage of tumor diameter ≥ 5 mm (mEMR vs ESD, P < .01), and complete en bloc resection rate (cEMR vs mEMR, P = .014). Meanwhile, no significant difference was noted in terms of complication rate among the three groups.

CONCLUSION

The mEMR was the most suitable resection method for rectal NETs < 10 mm with respect to the risks and benefits from procedure-related factors, such as complete en bloc resection rate, procedure time, and complication rate.

Effects of endoscopic submucosal dissection on post-operative early treatment effectiveness and serum TAT-2 and GP73 expression levels in patients with early gastric cancer

The present study aimed to explore the effectiveness of endoscopic submucosal dissection (ESD) in the treatment of early gastric cancer (EGC) and its effect on serum tumor-associated trypsin-2 (TAT-2) and Golgi protein 73 (GP73) expression levels to provide a reference for the treatment of EGC. TAT-2 is a proteolytic target enzyme for tumor-associated trypsin inhibitor that has been previously reported to enhance invasion by promoting extracellular matrix degradation. GP73 is a novel type II Golgi membrane protein of unknown function that is expressed in the hepatocytes of patients with adult giant-cell hepatitis. A total of 161 patients with EGC treated at our hospital from April 2013 to February 2014 were selected as the study subjects. Among these, 86 patients underwent ESD (group A) and the remaining 75 underwent endoscopic mucosal resection (group B). Treatment effectiveness, incidence of complications and adverse reactions, operation time, intraoperative blood loss and length of hospital stay, as well as serum TAT-2 and GP73 expression levels, were compared between the two groups. The treatment effectiveness was significantly higher in group A than in group B (P<0.05). However, there was no significant inter-group difference in terms of incidence of complications/adverse reactions (P>0.05). After treatment, serum TAT-2 expression levels decreased in both groups (P<0.05) and serum TAT-2 expression levels were lower in group A than in group B (P<0.05). Furthermore, serum GP73 expression levels were significantly elevated in both groups (P<0.05). Kaplan-Meier survival analysis indicated no significant inter-group difference in the 5-year survival rate (P>0.05). In conclusion, ESD had a good therapeutic effect on EGC and is able to decrease serum TAT-2 expression levels and increase serum GP73 expression levels. The present study was registered into the Chinese Trials Registry (registration no. NCT02157534).

Endoscopic mucosal resection: still a reliable therapeutic option for gastrointestinal neuroendocrine tumors

BACKGROUND

Neuroendocrine tumors (NETs), as a rare and heterogeneous category of solid tumors, feature various morphologies and behaviors. In recent years, the incidence of NETs has continued to increase. Endoscopic mucosal resection (EMR) is one of the therapeutic modalities for the treatment of gastric and rectal NETs.

METHODS

We evaluated patients with well-differentiated NETs of the stomach, duodenum, or rectum between 2011 and 2018. In this study, all cases with tumors confined to the mucosal or submucosal layers and smaller than 20 mm were resected using the EMR technique. We used EUS, CT scan, or MRI to exclude patients with advanced disease. All patients were actively monitored for recurrence according to the recommended protocols.

RESULTS

A total of 36 patients with NETs entered the study; 17 (47.2%) were female and the remaining 19 (52.8%) were male, with a total age range of 20-74 years (mean: 52.47 ± 13.47 years). Among the tumors, 31 cases (86.1%) were G1 and the remaining 5 (13.9%) were G2. Based on the pathology reports, 22 tumors (61.1%) were smaller than 1 cm, while the remaining 14 (38.9%) were between 1-2 cm. Twenty-two patients (61.1%) had a margin of specimen involved with the tumor. No recurrence was observed during the mean follow-up time of 63.5 ± 19.8 months (range: 39-103 months). All 36 cases survived during the study period.

CONCLUSION

Conventional EMR procedure provides low chance of R0 (complete resection) achievement in gastrointestinal NETs smaller than 20 mm and limited to the mucosa or sub mucosa. However, it could be an option if patients are closely followed. Postoperative marginal involvement is not a reliable predictor of disease recurrence, which may be explained by the deleterious effect of heat coagulation and cauterization applied during tumor removal.

Transanal minimally invasive surgery for rectal neuroendocrine tumors

BACKGROUND

There is no literature that mainly searched for rectal neuroendocrine tumor (rNET) using transanal minimal invasive surgery (TAMIS). We report our clinical experiences of TAMIS for rectal neuroendocrine tumors to evaluate the feasibility and safety.

METHODS

Between December 2010 and March 2020, the 25 consecutive patients with rectal neoplasma underwent the TAMIS procedure performed by single laparoscopic surgeon at the two hospitals. Of these, ten patients with rectal neuroendocrine tumors were reviewed retrospectively. The full-thickness excision down to the outer fatty tissues was completed using TAMIS technique. Clinicopathological findings, perioperative and postoperative complications were recorded.

RESULTS

TAMIS for small rNET was successfully completed in all cases. There were seven cases with a tumor size of less than 10 mm, and three cases with a tumor size between 10 and 15 mm. Six patients underwent the primary tumor excision; the remaining four patients underwent resection for the scar after endoscopic procedure. The median surgical duration was 80.5 (53-124) minutes and the median blood loss was 1 (1-12) ml. All removed tumors in the 6 primary excisions were diagnosed as neuroendocrine tumor G1. The margins of specimens were completely free in all cases. Among the four patients after endoscopic procedure, all had no histological evidence of residual tumor. The median length of hospital stay was 7 days postoperatively. There was no post-operative mortality or severe complication. The median length of observation was 54 months. No recurrence, no local or distant metastasis and no mortality of all patients were observed.

CONCLUSIONS

TAMIS is safety and feasible procedure for small rNET. Further experience and clinical trials are needed to fully define the advantages, disadvantages, and indications of TAMIS for rNET.

Digestive Neuroendocrine Neoplasms (NEN): French Intergroup clinical practice guidelines for diagnosis, treatment and follow-up (SNFGE, GTE, RENATEN, TENPATH, FFCD, GERCOR, UNICANCER, SFCD, SFED, SFRO, SFR)

INTRODUCTION

This document is a summary of the French Intergroup guidelines regarding the management of digestive neuroendocrine neoplasms (NEN) published in February 2020 (www.tncd.org).

METHODS

All French medical societies involved in the management of NEN took part in this work. Recommendations were graded into four categories (A, B, C or D), according to the level of evidence found in the literature until May 2019.

RESULTS

The management of NEN is challenging because of their heterogeneity and the increasing complexity of diagnostic and therapeutic procedures. Pathological analysis is required for their diagnostic and prognostic characterization, which mainly relies on differentiation, grade and stage. The two main emergency situations are functioning syndromes and poorly-differentiated carcinoma. Chromogranin A is the main biochemical marker of NET, although of limited clinical interest. Initial characterization relies on morphological and isotopic imaging. The treatment of localized NET relies on watchful follow-up and local or surgical resection depending on its supposed aggressiveness. Treatment options for metastatic disease include surgery, somatostatin analogues, chemotherapy, targeted therapies, organ-driven locoregional therapies and peptide-receptor radionuclide therapy. As specific predictive factors of treatment efficacy are yet to be identified and head-to-head comparisons have not or only rarely been performed, the therapeutic strategy currently depends on prognostic factors. Cumulative toxicity and the impact of treatment on quality of life must be considered since survival is relatively long in most patients with NET.

CONCLUSION

These guidelines are proposed to achieve the most beneficial therapeutic strategy in clinical practice as the therapeutic landscape of NEN is becoming ever more complex. These recommendations are permanently being reviewed.

Advances in the Diagnosis and Management of Well-Differentiated Neuroendocrine Neoplasms

Neuroendocrine neoplasms constitute a diverse group of tumors that derive from the sensory and secretory neuroendocrine cells and predominantly arise within the pulmonary and gastrointestinal tracts. The majority of these neoplasms have a well-differentiated grade and are termed neuroendocrine tumors (NETs). This subgroup is characterized by limited proliferation and patients affected by these tumors carry a good to moderate prognosis. A substantial subset of patients presenting with a NET suffer from the consequences of endocrine syndromes as a result of the excessive secretion of amines or peptide hormones, which can impair their quality of life and prognosis. Over the past 15 years, critical developments in tumor grading, diagnostic biomarkers, radionuclide imaging, randomized controlled drug trials, evidence-based guidelines, and superior prognostic outcomes have substantially altered the field of NET care. Here, we review the relevant advances to clinical practice that have significantly upgraded our approach to NET patients, both in diagnostic and in therapeutic options.

Management of Gastrointestinal Neuroendocrine Tumors

Neuroendocrine neoplasms (NENs) are derived from neuroendocrine cell system and can have benign or malignant characteristics. They are rare tumors, but have been increasing in incidence over the past 40 years. Patients with NENs may develop symptoms due to primary tumor invasion, metastasis, or from secretion of hormonally active tumor substances. Multiple imaging modalities are used for diagnosis and staging, including specialty scans such as ¹¹¹In pentetreotide (Octreoscan) and ⁶⁸Gallium-DOTATATE, along with endoscopy, endoscopic ultrasound, and biochemical marker testing. Treatment involves both surgical approach, for both primary and metastatic lesions, as well as medical management for symptom management and disease progression. This article will review the current clinical knowledge regarding the diagnosis, treatment, and prognosis of these fascinating neoplasms and the associated hormonal syndromes.

Endoscopic, transanal, laparoscopic, and transabdominal management of rectal neuroendocrine tumors

Rectal neuroendocrine tumors (RNET) are rare tumors but their prevalence is constantly increasing due to a prolonged survival and rising incidence related to a growing number of colonoscopies and improved knowledge. Their main prognostic determinant is tumor stage. While most RNET are localized, their management should be tailored depending on the presence or absence of the factors predictive of lymph-node metastases including tumor size, endoscopic aspect, T stage, grade and lymphovascular invasion. Endoscopic ultrasonography is the most relevant technique for locoregional assessment. Low-risk RNET can be treated using advanced endoscopic resection techniques or transanal endoscopic microsurgery, in expert centers because they require technicity and experience. Conversely, radical surgery with lymphadenectomy should be proposed in the presence of any pejorative factor. The long-term evolution of RNET remains to be specified, and prospective studies should be conducted in order to determine the relevance of the current management strategies.