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

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.

EMR-C is safe and efficient for rectal neuroendocrine tumor, and easily manageable for novice endoscopists of digestive endoscopy center

OBJECTIVE

The objective of this study was to evaluate the effectiveness and safety of endoscopic mucosal resection assisted by a transparent cap (EMR-C) for rectal neuroendocrine tumor (R-NET) by novice endoscopists of digestive endoscopy center.

METHODS

R-NET patients consulted in department of digestive endoscopy center of Guangdong Provincial Peolple's Hospital from 2022 to 2023, were recruited in this study. Novice endoscopists who had no ESD experience before were randomly to accomplish the EMR-C operation. Each novice endoscopist separately completed at least 3 cases after simple training by teachers and the operation time was counted on average. Vertical and horizontal margins of the specimens were further analyzed to determine whether radical resection was successful or not. R-NET patients were followed up at 12 months after operation.

RESULTS

30 cases of R-NET patients (13 males and 17 females, (53.83 ± 13.31) y), originated from the deep or submucosal layers of the intestinal wall mucosa by ultrasound colonoscopy, were recruited in all of our study. 10 novice endoscopists (each for 3 cases) were arranged to complete EMR-C operations by 2 teachers. The average time was (8.87 ± 1.87) minutes and the sections were clean and no bleeding and further clipped by 2-4 metal clips. Pathological and immunohistochemical results were further made to confirm the diagnosis. The en bloc resection rate was 100.00% and the R0 rate was 83.33% (horizontal margins were 100.00% negative and the vertical margins were 83.33% negative). No recurrence was found during the followed up at 12 months after operation.

CONCLUSIONS

EMR-C is safe and efficient for R-NET, and easily manageable for novice endoscopists of digestive endoscopy center.

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.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

Systemic Therapy for Tumor Control in Metastatic Well-Differentiated Gastroenteropancreatic Neuroendocrine Tumors: ASCO Guideline

PURPOSE

To develop recommendations for systemic therapy for well-differentiated grade 1 (G1) to grade 3 (G3) metastatic gastroenteropancreatic neuroendocrine tumors (GEP-NETs).

METHODS

ASCO convened an Expert Panel to conduct a systematic review of relevant studies and develop recommendations for clinical practice.

RESULTS

Eight randomized controlled trials met the inclusion criteria for the systematic review.

RECOMMENDATIONS

Somatostatin analogs (SSAs) are recommended as first-line systemic therapy for most patients with G1-grade 2 (G2) metastatic well-differentiated GI-NETs. Observation is an option for patients with low-volume or slow-growing disease without symptoms. After progression on SSAs, peptide receptor radionuclide therapy (PRRT) is recommended as systematic therapy for patients with somatostatin receptor (SSTR)-positive tumors. Everolimus is an alternative second-line therapy, particularly in nonfunctioning NETs and patients with SSTR-negative tumors. SSAs are standard first-line therapy for SSTR-positive pancreatic (pan)NETs. Rarely, observation may be appropriate for asymptomatic patients until progression. Second-line systemic options for panNETs include PRRT (for SSTR-positive tumors), cytotoxic chemotherapy, everolimus, or sunitinib. For SSTR-negative tumors, first-line therapy options are chemotherapy, everolimus, or sunitinib. There are insufficient data to recommend particular sequencing of therapies. Patients with G1-G2 high-volume disease, relatively high Ki-67 index, and/or symptoms related to tumor growth may benefit from early cytotoxic chemotherapy. For G3 GEP-NETs, systemic options for G1-G2 may be considered, although cytotoxic chemotherapy is likely the most effective option for patients with tumor-related symptoms, and SSAs are relatively ineffective. Qualifying statements are provided to assist with treatment choice. Multidisciplinary team management is recommended, along with shared decision making with patients, incorporating their values and preferences, potential benefits and harms, and other characteristics and circumstances, such as comorbidities, performance status, geographic location, and access to care.Additional information is available at www.asco.org/gastrointestinal-cancer-guidelines.

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.

Optimising Outcomes and Surveillance Strategies of Rectal Neuroendocrine Neoplasms

Rectal neuroendocrine neoplasms are increasing in incidence, in part due to increased endoscopic procedures being performed for bowel cancer screening. Whilst most of these lesions are low-grade well-differentiated neuroendocrine tumours, they can have a varied clinical behaviour. Frequently, these lesions are incorrectly characterised at endoscopy and, therefore, incompletely excised using standard polypectomy techniques. Furthermore, some cases are not fully staged prior to or post resection. In this article we discuss the endoscopic and surgical options available to improve the likelihood of achieving an R0 resection and the staging procedures that should be used in these NETs. We also review factors that may suggest a higher risk of nodal involvement or recurrence. This information may help determine whether endoscopic or surgical resection techniques should be considered. In cases of R1 resection we discuss the management options available and the long-term surveillance options and when these should be offered to patients.

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.

Clinical outcomes and risk factors associated with poor prognosis after endoscopic resection of 10-20 mm rectal neuroendocrine tumors: a multicenter, retrospective study of 10-year experience

BACKGROUND

The efficacy of endoscopic resection for of 10-20 mm rectal neuroendocrine tumor (NET) remains controversial. We aimed to evaluate the clinical outcomes and risk factors associated with poor prognosis after endoscopic resection of 10-20 mm rectal NET and to determine the optimal treatment.

METHODS

Patients who underwent endoscopic resection for rectal NET in four tertiary hospitals were enrolled, and data on with the clinical outcomes and risk factors related to poor prognosis were retrospectively analyzed.

RESULTS

A total of 105 patients who underwent endoscopic submucosal resection (ESD; n = 65, 61.9%), modified endoscopic mucosal resection (mEMR; n = 31, 29.5%), and conventional EMR (cEMR; n = 9, 8.6%) were enrolled. The mean follow-up period was 41.2 ± 21.9 months. In the morphologic findings, the mean diameter was 11.6 mm (range 10-19); the shape was sessile (50.5%) and mixed type (49.5%), and surface depression was observed in 41.9% of patients. In the histologic findings, 87.6% of patients had G1 and 12.4% G2 tumor grade, and 3.8% of patients had lymphovascular invasion. The overall en bloc and histologically complete (R0) resections were 99.1% and 76.2%, respectively. cEMR was a less-frequently developed R0 resection. In the univariate and multivariate analyses for R0 resection, only surface depression was significantly associated. Regional or distant organs metastasis during follow-up developed in three patients (2.9%) and was significantly associated with female sex, redness, G2 tumor grade, and non-ESD methods.

CONCLUSION

Patients who underwent endoscopic resection of 10-20 mm rectal NET had good prognosis; therefore, endoscopic resection can be considered as the first-line treatment, particularly for 10-14 mm rectal NET. However, the risk factors, such as female sex, redness, G2 tumor grade and non-ESD methods, were associated with regional or distant metastases during follow-up. Therefore, patients with these risk factors should be carefully monitored.

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.

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.

Risk Factors and Clinical Outcomes of 54 Cases of Rectal Neuroendocrine Tumors with Incomplete Resection: A Retrospective Single-Center Study

Objective

The present study aimed to analyze the risk factors and clinical outcomes of the incomplete endoscopic resection of rectal neuroendocrine tumors (rNETs).

Methods

This study retrospectively analyzed the cases of 428 patients with rNETs who had undergone endoscopic treatment in the Department of Gastroenterology at the PLA General Hospital, China, between January 2010 and September 2019.

Results

Of the 428 patients with rNETs, 266 were men (62.1%) and 162 were women (37.9%). Of these, 54 had been pathologically diagnosed with positive incisal margins without lymphatic vessel invasion, and the incomplete resection (R1) rate was 12.6%. Among the R1 patients, 28 had received endoscopic submucosal dissection, 22 had received endoscopic mucosal resection, two had received snare resection, and two had undergone removal with forceps. In addition, there were 31 cases of grade G1 R1 resection (11.2%; 31/277), 13 cases of grade G2 R1 resection (23.2%; 13/56), and 10 cases whose grading was not described. The univariate analysis showed the pathological grade was statistically correlated with R1 resection (P < 0.05), and the grade G2 R1 resection rate was higher than that of grade G1. The multivariate logistic regression analysis showed that grade G2 was an independent risk factor leading to R1 resection (P = 0.02). All patients with R1 resection were followed up for 10–110 months, with an average of 38 months. No salvage treatment was performed. The endoscopic monitoring showed there were no recurrences during the follow-up period.

Conclusion

Endoscopic resection is a good option for rNETs, with a high complete resection rate and good prognosis, with rare recurrence even if endoscopic resection is not complete.

Oncological outcomes according to the treatment modality based on the size of rectal neuroendocrine tumors: a single-center retrospective study

BACKGROUND

Owing to an increased number of colonoscopy screenings, the incidence of diagnosed rectal neuroendocrine tumors (NETs) has also increased. Tumor size is one of the most frequently regarded factors when selecting treatment; however, it may not be the determinant prognostic variable. We aimed to evaluate oncological outcomes according to the treatment modality based on the size of rectal NETs.

METHODS

A retrospective analysis was performed on patients who were treated for rectal NETs between March 2000 and January 2016 at the Asan Medical Center, Seoul, Korea. Patients who underwent endoscopic removal, local surgical excision, and radical resection were included. The primary outcome was recurrence-free survival (RFS). Data were specified and analyzed following the 2019 World Health Organization classification (WHO).

RESULTS

A total of 644 patients were categorized under three groups according to the treatment modality used: endoscopic removal (n = 567), surgical local excision (n = 56), and radical resection (n = 21). Of a total of 35 recurrences, 27 were local, whereas eight were distant. The RFS rate did not differ significantly between the treatment groups in the same tumor-size group ([Formula: see text]1 cm group: P = .636, 1-2 cm group: P = .160). For T1 tumors, RFS rate was not different between local excision and radical resection ([Formula: see text]1 cm group: P = .452, 1-2 cm group: P = .700). Depth of invasion, a high Ki-67 index, and margin involvement were confirmed as independent risk factors for recurrence. Among patients treated with endoscopic removal, endoscopic biopsy was a significant factor for worse RFS (P < .001), while tumor size did not affect the RFS.

CONCLUSION

The current guideline recommends treatment options according to tumor size. However, more oncologically important prognostic factors include muscularis propria invasion and a higher Ki-67 index.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Comparison between cap-assisted and ligation-assisted endoscopic mucosal resection for rectal neuroendocrine tumors

Background:

Modified endoscopic mucosal resection (EMR) is considered a treatment option for rectal neuroendocrine tumors (NETs) <10 mm in diameter. In this study, we evaluated the clinical outcomes of cap-assisted EMR (EMR-C) and EMR with a ligating device (EMR-L).

Methods:

We retrospectively analyzed 158 patients with 162 rectal NETs treated endoscopically at a single Korean tertiary hospital between March 2010 and November 2017. We evaluated the rates of endoscopic en bloc resection, histologic complete resection, and procedural complications according to the treatment method.

Results:

Among 162 rectal NETs, 42 were treated with EMR-C and 120 with EMR-L. The endoscopic en bloc resection rate was higher in the EMR-L group than in the EMR-C group (100% vs. 92.9%, P=0.003). A trend was observed towards a superior histologic complete resection rate in the EMR-L group, but it was not statistically significant (92.5% vs. 83.3%, P=0.087). There were no significant differences in procedural complications (P=0.870). In a multivariate analysis, a tumor located ≥10 cm from the anal verge was related to histologic incomplete resection (P=0.039).

Conclusion:

EMR-L may be the preferable treatment method, considering both endoscopic en bloc resection rate and histologic complete resection rate.

Efficacy and safety of hybrid endoscopic submucosal dissection compared with endoscopic submucosal dissection for rectal neuroendocrine tumors and risk factors associated with incomplete endoscopic resection

BACKGROUND

Neuroendocrine tumors (NETs) are rising in prevalence, particularly with the rectal area. This study evaluated and compared the safety and effectiveness of hybrid endoscopic submucosal dissection (ESD) with those of ESD for rectal NETs and risk factors associated with incomplete endoscopic resection.

METHODS

A total of 272 consecutive patients who underwent ESD or hybrid ESD for rectal NETs at the Chinese PLA General Hospital in the period from February 2011 to September 2018 were involved in this study. Data were collected from clinical and endoscopic databases. The procedure time, en bloc resection, complete resection, complication, and recurrence rates were evaluated.

RESULTS

In the hybrid ESD group were 111 patients (who had 119 lesions between them), with a further 161 patients (164 lesions) in the ESD group. No significance was found in baseline characteristics between the two groups. Hybrid ESD had a significantly shorter mean procedure time than ESD (13.2±8.3 vs. 18.1±9.7 min, P=0.000). Hybrid ESD showed similar en bloc resection (99.2% vs. 98.2%; P=0.373), complete resection (94.1% vs. 90.9%, P=0.641), and postprocedural bleeding (2.5% vs. 0.6%, P=0.313) rates to ESD. Univariate and multivariate analysis showed that higher histopathological grade was associated with incomplete resection.

CONCLUSIONS

For rectal NET, both ESD and hybrid ESD are effective and safe forms of treatment. Hybrid ESD provides an alternative option in the treatment of rectal NETs. Further developments are needed to improve the complete resection rate, especially concerning tumors with higher histopathological grade.

Lymphovascular invasion as a prognostic value in small rectal neuroendocrine tumor treated by local excision: A systematic review and meta-analysis

Because rectal neuroendocrine tumors (NETs) are usually small-sized despite of malignant potential, endoscopic resection techniques are recommended. It is unclear whether the lymphovascular invasion (LVI) in the endoscopic resected specimens of small rectal NETs should be indicated for completion surgery. We performed a systematic review and meta-analysis for the incidence of LVI in small rectal NETs (≤20 mm) treated by endoscopic resection and its prognostic impacts. We searched the relevant literature published before January 2019. A total of 21 publications including 1816 patients were enrolled. Overall prevalence of LVI in small rectal NETs was 21.8%. Immunohistochemical method significantly increased the detection rate of LVI up to 35.8% compared than H&E staining only (13.2%). Tumor size more than 5 mm was a risk factor for LVI in small rectal NET, whereas tumor grade did not influence the risk. The LVI in the endoscopic resected specimens was a risk factor for subsequent lymph node metastasis. Separately analyzed in detail, the vascular invasion had a stronger impact on lymph node metastasis than the lymphatic invasion. The prognosis of endoscopically treated rectal NET with LVI was excellent with only 0.3% of recurrence rate during the 5-year follow-up period. LVI is highly prevalent and a risk factor for lymph node metastasis in the small rectal NETs. Endoscopically treated small rectal NETs had excellent short-term prognoses despite of LVI. Immediate completion radical surgery is not absolutely necessary for the LVI-positive small rectal NETs. However, long-term follow-up is recommended for any delayed recurrence.

Endoscopic management of 345 small rectal neuroendocrine tumours: A national study from the French group of endocrine tumours (GTE)

Introduction

Small rectal neuroendocrine tumours are good candidates for endoscopic resection provided that complete pathological resection (R0) is obtained and their risk of metastatic progression is low. We conducted a large multicentre nationwide study to evaluate the outcomes of the management of non-metastatic rectal neuroendocrine tumours ≤2 cm diagnosed endoscopically.

Patients and methods

The medical records, the endoscopic and pathological findings of patients with non-metastatic rectal neuroendocrine tumours ≤2 cm managed from January 2000-June 2018 in 16 French hospitals, were retrospectively analysed. The primary objective was to describe the proportion of R0 endoscopic resections.

Results

A total of 329 patients with 345 rectal neuroendocrine tumours were included, 330 (96%) tumours were managed by local treatments: 287 by endoscopy only and 43 by endoscopy followed by transanal endoscopic microsurgery. The final endoscopic R0 rate was 134/345 (39%), which improved from the first endoscopy (54/225, 24%), to the second (60/100, 60%) and the third endoscopy (20/26, 77%). R0 was associated with endoscopic technique (90% for advanced techniques, 40% for mucosectomy and 17% for polypectomy), but not with tumour or patient characteristics. Twenty patients had metastatic disease, which was associated with tumour size ≥10 mm (odds ratio: 9.1, 95% confidence interval (3.5-23.5)), tumour grade G2-G3 (odds ratio: 4.2, (1.5-11.7)), the presence of muscular (odds ratio: ∞, (11.9-∞)) and lymphovascular invasion (odds ratio: 57.2, (5.6-578.9)).

Conclusions

The resection of small rectal neuroendocrine tumours often requires multiple procedures. Training of endoscopists is necessary in order to better recognise these tumours and to perform the appropriate resection technique.

Comparisons of therapeutic outcomes in patients with nonampullary duodenal neuroendocrine tumors (NADNETs): A multicenter retrospective study

Duodenal neuroendocrine tumors (DNETs) are rare tumors that are occasionally found during upper endoscopies. The incidence of DNETs is increasing, although the data regarding treatment outcomes are insufficient. The aim of this study was to evaluate the treatment outcomes in patients with nonampullary DNETs who underwent endoscopic resection or surgery. We evaluated the medical records of patients who were diagnosed with nonampullary DNETs from 2004 to 2017 in 7 university hospitals. We retrospectively analyzed clinical characteristics and compared therapeutic outcomes based on the endoscopic lesion size and treatment method. We ultimately enrolled 60 patients with nonampullary DNETs who underwent endoscopic and surgical treatments. In the endoscopic treatment group, the en bloc resection, endoscopic complete resection (CR) and pathologic CR rates were 88%, 92%, and 50%, respectively. The endoscopic treatment group was divided into 3 subgroups based on the lesion size (1-5 mm, 6-10 mm, and ≥11 mm). The pathologic CR rate was significantly lower in the subgroup with a lesion size ≥11 mm (0%, P = .003) than those in the other 2 subgroups. Lymphovascular invasion occurred significantly more frequently (33.3%, P = .043) among those with a lesion size ≥11 mm. The pathologic CR rate in the surgical treatment group was higher (90.9%) than that in the endoscopic treatment group (50%, P = .017). Surgical treatment appears to be a more appropriate choice because of the risks of incomplete resection and lymphovascular invasion after endoscopic treatment for lesions larger than 11 mm.