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.

Is lymphatic invasion of microrectal neuroendocrine tumors an incidental event?:A case report

BACKGROUND A rectal neuroendocrine tumor(rNET)is a malignant tumor originating from neuroendocrine cells.Currently,tumor size is the primary basis for assessing tumor risk.CASE SUMMARY This article reports the case of a 46-year-old male patient who underwent a colonoscopy that found a 3 mm rectal polypoid bulge.The pathological examination of a sample collected with biopsy forceps revealed a neuroendocrine tumor.Further endoscopic submucosal dissection rescue therapy was used.The presence of lymphatic vessels indicated that the tumor had infiltrated the negative resection margin.The lesion was located in the distal rectum near the anal canal.Therefore,to ensure the patient’s quality of life,follow-up observation was conducted after full communication with the patient.No tumor recurrence or distant metastasis has been found during the 13-mo follow-up after surgery.CONCLUSION Despite the presence of lymphatic invasion and extremely small diameter rNETs in our case,this phenomenon may not imply a higher risk of distant lymph node and organ metastasis.

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

BACKGROUND Endoscopic resection remains an effective method for the treatment of small rectal neuroendocrine tumors(NETs)(≤10 mm).Moreover,endoscopic mucosal resection(EMR)with double band ligation(EMR-dB),a simplified modification of EMR with band ligation,is an alternative strategy to remove small rectal NETs.AIM To evaluate the feasibility and safety of EMR-dB for the treatment of small rectal NETs(≤10 mm).METHODS A total of 50 patients with small rectal NETs,without regional lymph node enlargement or distant metastasis confirmed by endoscopic ultrasound,computerized tomography scan,or magnetic resonance imaging,were enrolled in the study from March 2021 to June 2022.These patients were randomly assigned into the EMR-dB(n=25)group or endoscopic submucosal dissection(ESD)group(n=25).The characteristics of the patients and tumors,procedure time,devices cost,complete resection rate,complications,and recurrence outcomes were analyzed.RESULTS There were 25 patients(13 males,12 females;age range 28-68 years old)in the EMR-dB group,and the ESD group contained 25 patients(15 males,10 females;age range 25-70 years old).Both groups had similar lesion sizes(EMR-dB 4.53±1.02 mm,ESD 5.140±1.74 mm;P=0.141)and resected lesion sizes(1.32±0.52 cm vs 1.58±0.84 cm;P=0.269).Furthermore,the histological complete resection and en bloc resection rates were achieved in all patients(100%for each).In addition,there was no significant difference in the complication rate between the two groups.However,the procedure time was significantly shorter and the devices cost was significantly lower in the EMRdB group.Besides,there was no recurrence in both groups during the follow-up period.CONCLUSION The procedure time of EMR-dB was shorter compared with ESD,and both approaches showed a similar curative effect.Taken together,EMR-dB was a feasible and safe option for the treatment of small rectal NETs.

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.

Characteristics and long-term prognosis of patients with rectal neuroendocrine tumors

AIM: To analyze the clinicopathologic characteristics and prognostic factors of rectal neuroendocrine tumors.

Rectal neuroendocrine tumor with uncommon metastatic spread:A case report and review of literature

Neuroendocrine tumors of the gastrointestinal tract are rare neoplasms. Rectal neuroendocrine tumors consist approximately the 5%-14% of all neuroendocrine neoplasms in Europe. These tumors are diagnosed in relatively young patients,with a mean age at diagnosis of 56 years. Distant metastases from rectal neuroendocrine tumors are not very common. Herein we describe a case of a rectal neuroendocrine tumor which metastasized to the lung,mediastinum and orbit. This case underscores the importance of early identification and optimal management to improve patient's prognosis. Therefore,the clinical significance of this case is the necessity of physicians' awareness and education regarding neuroendocrine tumors' diagnosis and management.

Risk factors of lymph node metastasis in rectal neuroendocrine tumors

Objective The aim of this study was to investigate the risk factors of lymph node metastasis in rectal neuroendocrine neoplasms(RNENs).Methods We enrolled 168 patients with RNENs as the research object,and their clinicopathological and survival data were collected.The risk factors affecting lymph node metastasis were analyzed retrospectively,and independent risk factors affecting prognosis were evaluated.Results Analysis showed that age,tumor diameter,tumor function,grade,and T stage were correlated with lymph node metastasis(P<0.05).Multiple logistic regression analysis showed that tumor size,grade,and T stage were independent risk factors for lymph node metastasis in patients with RNENs.Kaplan-Meier analysis showed that the 5-year overall survival(OS)of patients with lymph node metastasis was 40.0%(10/25),and that of patients without lymph node metastasis was 93.0%(133/143).The prognosis of RNENs patients with lymph node metastasis along with patients with large tumor diameter and high grade was poor.Cox multivariate analysis showed that tumor diameter(HR=1.985,P=0.008),grade(HR=3.416,P=0.004),T stage(HR=2.413,P=0.014),and lymph node metastasis(HR=3.119,P=0.000)were independent risk factors affecting the prognosis of patients with RNENs.Conclusion Tumor size,grade,and T stage are the main risk factors for lymph node metastasis and prognosis in patients with RNENs.These risk factors should be fully evaluated before surgery.

Radical Operation and Everolimus Therapy for Rectal Neuroendocrine Tumor with Liver Metastases: A Case Report with Review of the Literature

Neuroendocrine tumors (NETs) are often misdiagnosed because they can involve any part of the body and have non-specific symptoms. Here, we report a case of a 39-year-old man with rectal neuroendocrine tumor (RNET) and hepatic metastases treated with a combination of radical surgery and Everolimus therapy. The patient complained of abdominal distension, pain, and constipation of one month duration. Enhanced CT scan of the abdomen, colonoscopy and Biopsy findings confirmed the diagnosis of rectal neuroendocrine tumor. As the anatomical structures were clear and the masses seemed to be resectable, we decided to initiate treatment with radical operation and Everolimus therapy. The patient has responded well to the treatment with no evidence of recurrence after 4 years of follow-up. This case is interesting because of the rarity of this neoplasm and its initial misdiagnosis as a giant hepatic carcinoma (hepatoma). It also demonstrates that a combination of curative surgical resection and Everolimus is a good option in a patient with large colorectal neuroendocrine tumors and massive hepatic metastases.

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(10mm)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.

Gastrointestinal neuroendocrine tumors in 2020

Gastrointestinal neuroendocrine tumors are rare slow-growing tumors with distinct histological,biological,and clinical characteristics that have increased in incidence and prevalence within the last few decades.They contain chromogranin A,synaptophysin and neuron-specific enolase which are necessary for making a diagnosis of neuroendocrine tumor.Ki-67 index and mitotic index correlate with cellular proliferation.Serum chromogranin A is the most commonly used biomarker to assess the bulk of disease and monitor treatment and is raised in both functioning and non-functioning neuroendocrine tumors.Most of the gastrointestinal neuroendocrine tumors are non-functional.World Health Organization updated the classification of neuroendocrine tumors in 2017 and renamed mixed adenoneuroendocrine carcinoma into mixed neuroendocrine neoplasm.Gastric neuroendocrine tumors arise from enterochromaffin like cells.They are classified into 4 types.Only type I and type II are gastrin dependent.Small intestinal neuroendocrine tumor is the most common small bowel malignancy.More than two-third of them occur in the terminal ileum within 60 cm of ileocecal valve.Patients with small intestinal neuroendrocrine tumors frequently show clinical symptoms and develop distant metastases more often than those with neuroendocrine tumors of other organs.Duodenal and jejunoileal neuroendocrine tumors are distinct biologically and clinically.Carcinoid syndrome generally occurs when jejuno-ileal neuroendocrine tumors metastasize to the liver.Appendiceal neuroendocrine tumors are generally detected after appendectomy.Colonic neuroendocrine tumors generally present as a large tumor with local or distant metastasis at the time of diagnosis.Rectal neuroendocrine tumors are increasingly being diagnosed since the implementation of screening colonoscopy in 2000.Gastrointestinal neuroendocrine tumors are diagnosed and staged by endoscopy with biopsy,endoscopic ultrasound,serology of biomarkers,imaging studies and functional somatostatin scans.Various treatment options are available for curative and palliative treatment of gastrointestinal neuroendocrine tumors.