Clinicopathological features and outcome of type 3 gastric neuroendocrine tumours

Gastric Neuroendocrine Tumors and Pernicious Anemia: A Case Report and Literature Review

Gastrointestinal neuroendocrine tumors (GI-NETs) are rare neoplasms, with the gastric (stomach) subtype (G-NETs) representing a significant clinical focus. Type 1 G-NETs are particularly noteworthy due to their relationship with autoimmune atrophic gastritis (AAG) and pernicious anemia (PA), conditions that impact vitamin B12 absorption. This report presents the case of a patient with a type 1 G-NET identified at the initial diagnosis of PA, demonstrating the connection between these conditions. In the literature review, we discuss the general mechanisms underlying PA, including its etiology, pathogenesis, clinical presentations, and diagnostic approaches. Emphasis is placed on the importance of recognizing and diagnosing this condition early, given the treatable nature of the associated gastric neuroendocrine dysregulation. Additionally, the report examines the broad spectrum of G-NETs, with a special emphasis on the characteristics of type 1 tumors. By considering recent developments in the field, we provide an overview of the current understanding of G-NET epidemiology, classification, clinical features, diagnosis, and management strategies.

A case of early-stage type 3 gastric neuroendocrine tumor in the upper body of the stomach: is endoscopic resection feasible?

Although gastric neuroendocrine tumors (NETs) are uncommon compared with gastric carcinomas, the incidence of NETs has been recently increasing. Gastric NETs are classified into three subgroups, and among these, gastrin-independent sporadic type 3 gastric NETs have a poor prognosis because of frequent lymph node or distant metastasis. We experienced a case of an early-stage type 3 gastric NET associated with lymphovascular and submucosal invasion. In a 54 year-old woman, esophagogastroduodenoscopy performed during a health screening identified an elevated lesion of the upper body of the stomach. The results of immunohistochemical analyses of endoscopic biopsy specimens obtained from the lesion were positive for chromogranin A and synaptophysin, indicating an NET. Because the patient's serum gastrin level was normal and she had no predisposing conditions for NET development, the tumor was diagnosed as a type 3 gastric NET. The patient underwent local resection of the tumor and regional lymph node dissection. The resected specimen indicated a diagnosis of type 3 gastric NET with invasion into the submucosa and lymphatic duct. This is an extremely rare case of an early-stage type 3 gastric NET. Our discussion provides insight into the pathogenesis and development of these tumors and the appropriate therapeutic strategy.

Clinical Outcome of Patients with Gastric, Duodenal, or Rectal Neuroendocrine Tumors after Incomplete Endoscopic Resection

Objectives: Our aim was to investigate the clinical outcome of patients with well-differentiated gastric, duodenal, and rectal neuroendocrine tumors after treatment with incomplete endoscopic resection due to the finding of microscopic positive resection margins (R1). Methods: This is a retrospective analysis of consecutive patients with type 1 gastric, non-ampullary non-functioning duodenal, or rectal neuroendocrine neoplasms with positive R1 margins after endoscopic resection. The rate of tumor recurrence and progression-free survival were considered to be the study's main endpoints. Statistical analysis was performed using MedCalc® v.17 software and a p-value of <0.05 was considered significant. A Cox proportional-hazard regression was performed to identify risk factors for disease recurrence/progression. Results: After evaluating 110 patients, a total of 58 patients were included in the final analysis (15 gastric NENs, 12 duodenal NENs, and 31 rectal NENs). After evidence of endoscopic R1 resection had been gathered, 26 patients (44.8%) underwent an endoscopic/surgical extension of the previous resection. Tumor progression (all local recurrences) occurred in five out of fifty-eight patients (8.6%) with a median PFS of 36 months. There were no tumor-related deaths. G2 grading and the gastric primary tumor site were the only features significantly associated with the risk of recurrence of the disease (HR: 11.97 [95% CI: 1.22-116.99], HR: 12.54 [95% CI: 1.28-122.24], respectively). Conclusions: Tumor progression rarely occurs in patients with microscopic positive margin excision (R1) after endoscopic resection and does not seem to affect patients' clinical outcomes.

Gastric neuroendocrine neoplasms

Gastric neuroendocrine neoplasms (gNENs) display peculiar site-specific features among all NENs. Their incidence and prevalence have been rising in the past few decades. gNENs comprise gastric neuroendocrine carcinomas (gNECs) and gastric neuroendocrine tumours (gNETs), the latter further classified into three types. Type I anatype II gNETs are gastrin-dependent and develop in chronic atrophic gastritis and as part of Zollinger-Ellison syndrome within a multiple endocrine neoplasia type 1 syndrome (MEN1), respectively. Type III or sporadic gNETs develop in the absence of hypergastrinaemia and in the context of a near-normal or inflamed gastric mucosa. gNECs can also develop in the context of variable atrophic, relatively normal or inflamed gastric mucosa. Each gNEN type has different clinical characteristics and requires a different multidisciplinary approach in expert dedicated centres. Type I gNETs are managed mainly by endoscopy or surgery, whereas the treatment of type II gNETs largely depends on the management of the concomitant MEN1. Type III gNETs may require both locoregional approaches and systemic treatments; NECs are often metastatic and therefore require systemic treatment. Specific data regarding the systemic treatment of gNENs are lacking and are derived from the treatment of intestinal NETs and NECs. An enhanced understanding of molecular and clinical pathophysiology is needed to improve the management and outcomes of patients' gNETs.

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.

Management of Gastric Neuroendocrine Tumors: A Review

Gastric neuroendocrine tumors (G-NET) are rare tumors arising from enterochromaffin-like cells of the gastric mucosa. They belong to a larger group called gastroenteropancreatic neuroendocrine tumors and are classified as low, intermediate, or high-grade tumors based on their proliferative indices. They are further categorized into three subtypes based on their morphologic characteristics, pathogenesis, and behavior. Types 1 and 2 tumors are characterized by elevated serum gastrin and are usually multifocal. They typically occur in the setting of atrophic gastritis or MEN1/Zollinger Ellison syndrome, respectively. Type 2 tumors are associated with the most symptoms, such as abdominal pain and diarrhea. Type 3 tumors are associated with normal serum gastrin, are usually solitary, and occur sporadically. This type has the most aggressive phenotype and metastatic potential. Treatment and prognosis for G-NET is dependent on their type, size, and stage. Type 1 has the best prognosis, and Type 3 has the worst. This review discusses the presentation, workup, and surgical management of these tumors.

Type 3 gastric neuroendocrine neoplasms: the rising promise of conservative endoscopic management

Gastric neuroendocrine neoplasms (g-NENs) are rare tumors arising from the gastric enterochromaffin-like cells. Recent data suggests an increased detection rate, attributed to more frequent esophagogastroduodenoscopies. While type 3 g-NENs were historically deemed aggressive, emerging research indicates potential for conservative management, especially endoscopic resection, in well-differentiated, small tumors. European guidelines now advocate for endoscopic intervention in selected cases, but North American guidelines remain more conservative. Key factors influencing outcomes are tumor size, grading, and depth of gastric wall infiltration. Endoscopic resection has shown promise for tumors confined to submucosal layers without lymphovascular invasion. Given the complexities, a multidisciplinary team approach is essential for management decisions. Current insights are largely based on retrospective studies, underscoring the need for prospective research to optimize endoscopic approaches.

Endoscopic Management of Gastro-Entero-Pancreatic Neuroendocrine Tumours: An Overview of Proposed Resection and Ablation Techniques

A literature search of MEDLINE/PUBMED was conducted with the aim to highlight current endoscopic management of localised gastro-entero-pancreatic NETs. Relevant articles were identified through a manual search, and reference lists were reviewed for additional articles. The results of the research have been displayed in a narrative fashion to illustrate the actual state-of-the-art of endoscopic techniques in the treatment of NETs. Localised NETs of the stomach, duodenum and rectum can benefit from advanced endoscopic resection techniques (e.g., modified endoscopic mucosal resection, endoscopic full thickness resection, endoscopic submucosal dissection) according to centre expertise. Radiofrequency thermal ablation can be proposed as an alternative to surgery in selected patients with localised pancreatic NETs.

Advances in Endoscopic Diagnosis and Treatment of Gastric Neuroendocrine Neoplasms

Gastric neuroendocrine neoplasms refer to a group of diseases that are relatively rare. They can be classified into three subtypes based on their clinical and histopathological features, and there are significant differences in diagnosis, treatment, and prognosis among the different subtypes. The incidence of gastric neuroendocrine neoplasms has been increasing globally in recent years with the localized disease being particularly evident. Gastrointestinal endoscopy is of irreplaceable importance for the diagnosis and management of g-NENs. Endoscopy with biopsy is the gold standard for the diagnosis of g-NENs. Ultrasound endoscopy can assess the depth of tumor invasion and the presence of lymphatic metastases, which is important for the development of treatment strategies. Meanwhile, for some small and low-risk lesions, endoscopic surveillance or endoscopic resection has satisfactory therapeutic results and prognosis. This means that even though the incidence has increased, advances in endoscopic techniques have allowed more patients to adopt a relatively conservative treatment strategy. However, the criteria for patients suitable for endoscopic surveillance or endoscopic resection remain controversial.

Therapeutic Challenges for Gastric Neuroendocrine Neoplasms: Take It or Leave It?

Background and Objectives: Gastric neuroendocrine neoplasms (gNENs) represent rare but increasingly recognized tumors. They are distinguished into three main clinical types (type-1, type-2, and type-3) according to gastrin level and at histological evaluation in well-differentiated G1, G2, or G3 lesions, as well as poorly-differentiated lesions. Small type-1 and type-2 neoplasms with low proliferation indices demonstrated excellent survival without progression during an extended follow-up period, and for these reasons, active endoscopic observation or endoscopic resection are feasible options. On the other hand, surgery is the treatment of choice for more aggressive type-3, G3, or infiltrating neoplasms. The present study aims to comprehensively review and compare the available therapeutic strategies for gNENs. Materials and Methods: A computerized literature search was performed using relevant keywords to identify all of the pertinent articles with particular attention to gNEN endoscopic treatment. Results: In recent years, different endoscopic resective techniques (such as endoscopic mucosal dissection, modified endoscopic mucosal resection, and endoscopic full-thickness resection) have been developed, showing a high rate of complete resection for advanced and more aggressive lesions. Conclusions: Overall, gNENs represent a heterogeneous group of lesions with varying behavior which require personalized management. The non-operative approach for small type-1 gNENs seems to be feasible and should be promoted. A step-up approach with minimally invasive endoscopic therapies might be proposed, particularly for type-1 gNEN. On the other hand, it is important to recognize the negative prognostic factors in order to identify those rare cases requiring more aggressive approaches. A possible therapeutic algorithm for localized gNEN management is provided.

European Neuroendocrine Tumor Society (ENETS) 2023 guidance paper for gastroduodenal neuroendocrine tumours (NETs) G1-G3

The aim of the present guidance paper was to update the previous ENETS guidelines on well-differentiated gastric and duodenal neuroendocrine tumours (NETs), providing practical guidance for specialists in the diagnosis and management of gastroduodenal NETs. Type II gastric NETs, neuroendocrine carcinomas (NECs), and functioning duodenal NETs are not covered, since they will be discussed in other ENETS guidance papers.

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.

Gastric Neuroendocrine Tumors (g-NETs): A Systematic Review of the Management and Outcomes of Type 3 g-NETs

PURPOSE

to collect data from real-life experiences of the management of type 3 g-NETs and identify possible prognostic factors that may impact the decision-making process.

METHODS

We performed a systematic review of the literature on type 3 g-NET management using the PubMed, MEDLINE, and Embase databases. We included cohort studies, case series, and case reports written in the English language.

RESULTS

We selected 31 out of 556 articles from between 2001 and 2022. In 2 out of the 31 studies, a 10 mm and 20 mm cut-off size were respectively associated with a higher risk of gastric wall infiltration and/or lymph node and distant metastasis at diagnosis. The selected studies reported a higher risk of lymph node or distant metastasis at diagnosis in the case of muscularis propria infiltration or beyond, irrespective of the dimensions or grading. From these findings, size, grading, and gastric wall infiltration seem to be the most relevant factors in management staff making choices and prognoses of type 3 g-NET patients. We produced a hypothetical flowchart for a standardized approach to these rare diseases.

CONCLUSION

Further prospective analyses are needed to validate the prognostic impact of the use of size, grading, and gastric wall infiltration as prognostic factors in the management of type 3 g-NETs.

Endoscopic techniques for gastric neuroendocrine tumors: An update

Gastric neuroendocrine neoplasms (gNENs) are a rare type of gastric neoplasm, even if their frequency is increasing according to the latest epidemiologic revisions of the main registries worldwide. They are divided into three main subtypes, with different pathogeneses, biological behaviors, and clinical characteristics. GNEN heterogeneity poses challenges, therefore these neoplasms require different management strategies. Update the knowledge on the endoscopic treatment options to manage g-NENs. This manuscript is a narrative review of the literature. In recent years, many advances have been made not only in the knowledge of both the pathogenesis and the molecular profiling of gNENs but also in the endoscopic expertise towards innovative treatment options, which proved to be less aggressive without losing the capability of being radical. The endoscopic approach is increasingly applied in the field of gastrointestinal (GI) luminal neoplasms, and this is true not only for adenocarcinomas but also for gNENs. In particular, different techniques have been described for the endoscopic removal of suspected lesions, ranging from classical polypectomy (cold or hot snare) to endoscopic mucosal resection (both with “en bloc” or piecemeal technique), endoscopic submucosal dissection, and endoscopic full-thickness resection. GNENs comprise different subtypes of neoplasms with distinct management and prognosis. New endoscopic techniques offer a wide variety of approaches for GI localized neoplasms, which demonstrated to be appropriate and effective also in the case of gNENs. Correct evaluation of size, site, morphology, and clinical context allows the choice of tailored therapy in order to guarantee a definitive treatment.

Clinical outcomes of gastroduodenal neuroendocrine tumors according to their WHO grade: A single-institutional retrospective analysis

The management of gastroduodenal neuroendocrine tumor (NET) has been controversial between radical surgical resection and local excision including endoscopic resection. A gastroduodenal NET grade (G), measured by their mitotic rate and Ki67 proliferation index, is important to predict prognosis. In this study, we aimed to compare the clinical outcomes of gastroduodenal NET according to grades in order to identify poor prognostic factors of gastroduodenal NETs. Fifty-four gastroduodenal NETs diagnosed between December 2008 and December 2020 in a tertiary referral hospital were retrospectively reviewed. The clinical outcomes of gastroduodenal NETs, according to tumor grades and factors associated with NET G2-3, were analyzed. A total of 52 gastroduodenal NET patients was enrolled. The mean follow-up period was 56.2 ± 40.1 months. The mean size of gastric and duodenal NET was 7.9 ± 11.0 mm and 9.8 ± 7.6 mm, respectively. During the study period, 72.7% (16/22) of gastric NETs and 83.3% (25/30) of duodenal NETS were G1. All G1 gastroduodenal NETs showed no lymph node or distant metastasis during the study periods. All G3 gastroduodenal NETs showed metastasis (one lymph node metastasis and 3 hepatic metastases). Among metastatic NETs, the smallest tumor size was a 13 mm gastric G3 NET. Factors associated with G2-3 NETs were larger tumor size, mucosal ulceration, proper muscle or deeper invasion, and lymphovascular invasion. A small-sized gastroduodenal NET confined to submucosa without surface ulceration may be suitable for endoscopic resection. After local resection of a gastroduodenal NET (G1) without lymphovascular and muscle proper invasion, follow-up examination without radical surgical resection can be recommended. G3 NETs may be treated by radical surgical resection, regardless of tumor size.

Spannungsfeld endoskopische Resektionsverfahren bei GEP-NET // Endoscopic resection for GEP-NET

Neuroendokrine Tumoren des Verdauungstraktes (GEP-NET) sind eine seltene Tumorentität, die häufig als Zufallsbefund diagnostiziert werden. Ein großer Teil dieser Zufallsdiagnosen wird im Rahmen einer endoskopischen Untersuchung gestellt. Während die vollständige Entfernung des Tumors im Sinne einer kurativen chirurgischen Resektion nach onkologischen Kriterien das Standardvorgehen für lokalisierte Tumorerkrankungen ist, kann bei kleinen Tumoren ohne Hinweis und Risiko für eine lymphogene Metastasierung eine endoskopische Abtragung in gleicher Intention erfolgen. Während dies für Magen-, Duodenum- und Rektum-NET der Standard ist, sollten NET des Jejunums und Ileums aufgrund der hohen Metastasierungsrate trotz geringer Tumorgröße regelhaft nicht endoskopisch angegangen werden. Die Grenze für eine endoskopische Resektion ergibt sich sowohl durch die technische Machbarkeit im Sinne des Erreichens einer R0-Resektion, der erwarteten Komplikationen im Sinne von Blutung und Perforationen als auch durch das vermutete Risiko für eine lymphogene Metastasierung. Generell wird eine endoskopische Resektion bei Befunden < 1 cm regelhaft empfohlen, da sowohl die gute technische Machbarkeit als auch das geringe Metastasierungsrisiko für eine endoskopische Resektion sprechen. Bei allen Befunden über 2 cm Größe sind sowohl die technischen Erfolgsaussichten so niedrig als auch das Metastasierungsrisiko so hoch, dass in dieser Situation regelhaft ein chirurgisches Vorgehen erfolgen sollte. Es bleibt somit ein Graubereich bei der Tumorgröße zwischen 1 und 2 cm, wo sowohl endoskopische, aber auch chirurgische Resektionsverfahren sinnvoll eingesetzt werden können. Zunehmend kommen auch gemeinsame Eingriffe im Sinne eines endoskopisch-laparoskopischen Rendezvous-Verfahrens zum Einsatz – insbesondere im Duodenum bieten sich diese Eingriffe an, um eine minimale Resektion mit größtmöglicher R0-Erfolgsrate und niedriger Perforationsrate zu erreichen.

Risk factors for metastasis and survival of patients with T1 gastric neuroendocrine carcinoma treated with endoscopic therapy versus surgical resection

Background

Gastrectomy with lymphadenectomy is recommended for early gastric Neuroendocrine carcinoma (G-NEC). We attempted to determine the prevalence and risk factors of metastasis of T1 G-NEC and compare the long-term survival of patients after receiving endoscopic therapy (ET) and radical surgery.

Methods

In this study, 205 patients in total with T1 G-NEC were collected from the Surveillance Epidemiology and End Result database. Independent predictors of metastasis were identified by Logistic regression analysis, followed by the calculation of both cancer-specific survival (CSS) and overall survival (OS).

Results

Twenty-five patients (12.2%) were burdened with metastasis at initial diagnosis, with a prevalence of 5.2% (3/58) in mucosa lesions and 16.2% (16/99) in submucosa lesions (P = 0.045). No metastasis was detected in lesions with mucosa involvement and tumors ≦ 20 mm (0%, 0/49). The most significant risk factor for metastasis was tumors > 20 mm [odds ratio (OR) 18.64; 95% confidence interval (CI) 4.01–86.68; P < 0.001]. For patients with T1N0M0 G-NEC who received ET or surgery, the 10-year OS was similar between the mucosa extension and submucosa extension groups, which was 91.56% in ET group vs 87.50% in surgery group (P = 0.62) and 57.33% vs 77.83% (P = 0.11), respectively. In addition, the 10-year CSS was also similar between the mucosa extension and submucosa extension groups with 97.30% in ET vs 100% in surgery (P = 0.51) and 97.62% vs 86.49% (P = 0.65).

Conclusions

In G-NEC, tumors > 20 mm were considered as the most significant risk factor for metastasis. ET seemed adequate for the lesions with mucosa involvement and size ≦ 2 cm.

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.

New Developments in Gastric Neuroendocrine Neoplasms

Purpose of Review

Gastric neuroendocrine neoplasms (g-NENs) are a rare type of stomach cancer. The three main subtypes have different pathogeneses, biological behaviours and clinical characteristics, so they require different management strategies. This article will provide an overview of g-NENs and highlight recent advances in the field.

Recent Findings

Molecular profiling has revealed differences between indolent and aggressive g-NENs, as well as a new somatic mutation responsible for some familial type I g-NENs. Novel biomarkers have been developed which will hopefully improve diagnosis, treatment, risk stratification and follow-up. Patient treatment is also changing, as evidence supports the use of less aggressive options (e.g. endoscopic surveillance or resection) in some patients with more indolent tumours.

Summary

g-NEN heterogeneity poses challenges in understanding and managing this rare disease. More basic science research is needed to investigate molecular pathogenesis, and future larger clinical studies will hopefully also further improve treatment and patient outcomes.

Pathogenic ATM Variant-Harbouring Well-Differentiated Aggressive Type 1 Gastric Neuroendocrine Tumour with High-grade Features (G3 NET): a New Addition to the Clinical and Pathological Spectrum of Gastric Neuroendocrine Neoplasms

Gastric type 1 neuroendocrine tumours are considered to have low rates of proliferation and a good prognosis. We report here a patient with an aggressive well-differentiated high-grade gastric neuroendocrine tumour (gastric grade 3 NET), in a context of autoimmune gastritis. Consistent with grade 3 disease, the tumour had a Ki-67 proliferation index of 30%. Targeted next-generation sequencing identified variants of four genes, including a pathogenic ATM variant underlying the differentiation and metastatic potential of the tumour. Liver metastasis was diagnosed during follow-up, and the patient died after 6 years, due to disease progression.

Is local excision sufficient in selected grade 1 or 2 type III gastric neuroendocrine neoplasms?

PURPOSE

Type III gastric neuroendocrine neoplasms (g-NENs) have historically been regarded as aggressive tumours, hence current guidelines advocate radical surgery with lymph node dissection. Data on the roles of endoscopic or less extensive surgical resections are more limited. The aim of our study is to evaluate the clinicopathological features and long-term outcomes of patients undergoing endoscopic or limited surgical resection for localised grade 1 or 2 type III g-NENs when compared to radical surgery.

METHODS

Retrospective analysis of all patients diagnosed with a localised grade 1 or 2 type III g-NENs across six tertiary NEN centers between 2006 and 2019.

RESULTS

Forty-five patients were diagnosed with a potentially resectable grade 1 or 2 type III g-NEN of whom 36 underwent either endoscopic or surgical resection. No statistically significant differences were found between the three resection groups in terms of patient age, tumour location, grade or size. Only tumour size was found to be significantly associated with poor clinical outcome (p = 0.012) and ROC curve analysis identified tumour size >10 mm as a negative predictor (AUC:0.8030, p = 0.0021). Tumours >10 mm were also more likely to be associated with lymph node metastases on imaging and histology (p = 0.039 and p = 0.026 respectively).

CONCLUSIONS

Localised grade 1 or 2 type III g-NENs had a good prognosis in this series. Tumour size >10 mm was the most significant prognostic factor affecting patient outcome. Endoscopic resection or limited surgical resection is feasible and safe in small type III g-NENs which demonstrate favourable grade 1/2, well differentiated histology.

Neuroendocrine Tumors of the Gastrointestinal Tract: A Focused Review and Practical Approach for Gastroenterologists

Neuroendocrine tumors (NETs) are rare tumors derived from the neuroendocrine cell system, and more commonly found in the gastrointestinal (GI) tract. Over the last decades, the incidence of GI-NETs has been steadily increasing, partly due to the expanding indications for endoscopy. Most patients with NETs are asymptomatic, and their NETs are noticed during screening examinations; thus, endoscopists are on the frontline of the diagnosis of GI-NETs. Since GI-NETs are less frequent than other malignancies, the natural history, diagnosis, and management of these tumors may not be fully understood. In this review, we aim to update the endoscopist on key clinical features and management of patients with gastric, duodenal, and rectal NETs.

Gastric Neuroendocrine Tumors: Reappraisal of Type in Predicting Outcome

BACKGROUND

Type I gastric neuroendocrine tumors (GNETs) are typically managed either expectantly or endoscopically. In contrast, locoregional surgery has been recommended for patients with type III GNETs because of the risk of metastasis. This study aimed to identify predictors of outcome independent of type in a contemporary cohort of GNET patients.

METHODS

A single-institution retrospective cohort study of 121 patients with a pathologic diagnosis of primary GNET between January 2009 and June 2019 was performed. GNETs were designated as type 1 (n = 74) if atrophic gastritis was present, or as type III (n = 47) in the absence of atrophic gastritis. Demographic, clinical, and histopathologic factors were examined using Kaplan-Meier and multivariable Cox regression to assess the impact of various factors on recurrence and overall survival.

RESULTS

Median follow-up for the entire cohort was 62.7 months. While there was no difference in OS in patients with different GNET types (p = 0.10), higher tumor grade (p = 0.02) and presence of nodal or distant metastases (p = 0.02) predicted worse survival on multivariable analysis. Among type III GNET patients, those with small (< 0.5 cm), grade 1 lesions ("low-risk") were less likely to develop metastases (0% versus 33%, p < 0.01) and more likely to survive (100% versus 67%, p < 0.01) at 5 years.

CONCLUSIONS

Size and tumor grade predict recurrence and survival in patients with GNETs irrespective of type. Small, low-grade type III GNETs are associated with minimal risk of progression and may be managed accordingly.

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.

Spontaneous intra-abdominal hemorrhage of a well-differentiated, grade 3 gastric neuroendocrine tumor during drug-based treatment

Grade 3, well-differentiated, gastric neuroendocrine tumors (NET G3) are extremely rare. Herein, we report the case of a 64-year-old man with a grade 3 neuroendocrine tumor of the stomach who experienced intra-abdominal bleeding during the course of drug treatment. The patient was referred to our hospital for examination of a gastric tumor that was initially diagnosed by a local medical doctor. Esophagogastroduodenoscopy revealed an elevated lesion with a central ulcer in the upper body of the stomach, and biopsy specimens confirmed the pathological diagnosis of NET G3. Abdominal contrast-enhanced computed tomography (CT) showed a 25-cm, well-defined mass lesion showing heterogeneous enhancement in the liver. A clinical diagnosis of NET G3 with multiple liver metastases was given, after which everolimus was administered in combination with a somatostatin analogue. However, the patient developed sudden-onset epigastric abdominal pain and general fatigue 2 months later, and emergency abdominal contrast-enhanced CT confirmed the presence of intra-abdominal hemorrhage. Following blood transfusion, the patient's symptoms and general condition improved. Although the patient was treated with streptozocin, abdominal CT indicated progression of the liver metastases. Unfortunately, despite receiving best supportive care, the patient died 8 months after the initial of the treatment. To the best of our knowledge, this is the first case of a patient who developed spontaneous hemoperitoneum during drug treatment for a NET G3 to be reported in the English literature. It is essential that additional data be obtained to determine the optimal treatment for this disease.

Endoscopic Treatment of Gastric and Duodenal Neuroendocrine Tumors: Present and Future

Gastric and duodenal neuroendocrine tumors (NETs) are not common; however, there is an increase in the incidence due to increased use of endoscopy. Endoscopic treatment has been applied to treat small NET G1 in the stomach and duodenum. For the endoscopic treatment of NETs, it is necessary to evaluate tumor size, depth of invasion, and lymphatic and distant metastasis. This article will review the current knowledge concerning the endoscopic treatment of gastric and duodenal neuroendocrine tumors.

Is endoscopic resection appropriate for type 3 gastric neuroendocrine tumors? Retrospective multicenter study

BACKGROUND

Gastrectomy with lymphadenectomy is recommended for type 3 gastric neuroendocrine tumors (G-NETs). This study aimed to identify the risk factors for lymph node metastasis (LNM) arising from G-NETs to assess the suitability of endoscopic resection (ER).

METHODS

Nationwide clinicopathological data of patients with type 3 G-NETs who underwent surgery or ER were collected. A single pathologist graded the histological tumor specimens.

RESULTS

Among 176 cases from 53 institutions, 144 were eligible for analysis (90 NET-G1 and 54 NET-G2 grade, 8-mm median-size tumors). Of these, 63 patients had undergone ER (15 with additional surgeries). Histological data regarding LNM were available for 93 surgical patients. LNM was confirmed in 15 (16%) tumors and was correlated with tumor diameter, invasion depth, and tumor grade. LNM was negative in six tumors ≤5 mm, confined to the mucosa or submucosa, with a grade of G1, and without lymphovascular invasion, but the number of cases was too small to propose ER indications. Among 48 patients treated with ER alone, only one developed recurrence; no mortality was observed at follow-up, although many patients were classified with SM2/NET-G2/tumors >5 mm. This suggests that not all LNMs arising from small G-NETs are fatal.

CONCLUSION

Gastrectomy with lymphadenectomy for type 3 G-NETs is recommended on the basis of LNM. However, ER for type 3 G-NETs ≤10 mm, confined to the mucosa or submucosa, with a grade of G1 has shown excellent survival outcomes despite the risk of LNM, and therefore, could be an alternative treatment option.

Epidemiology, Diagnosis, Staging and Multimodal Therapy of Esophageal and Gastric Tumors

Gastric and esophageal tumors are diverse neoplasms that involve mucosal and submucosal tissue layers and include squamous cell carcinomas, adenocarcinomas, spindle cell neoplasms, neuroendocrine tumors, marginal B cell lymphomas, along with less common tumors. The worldwide burden of esophageal and gastric malignancies is significant, with esophageal and gastric cancer representing the ninth and fifth most common cancers, respectively. The approach to diagnosis and staging of these lesions is multimodal and includes a combination of gastrointestinal endoscopy, endoscopic ultrasound, and cross-sectional imaging. Likewise, therapy is multidisciplinary and combines therapeutic endoscopy, surgery, radiotherapy, and systemic chemotherapeutic tools. Future directions for diagnosis of esophageal and gastric malignancies are evolving rapidly and will involve advances in endoscopic and endosonographic techniques including tethered capsules, optical coherence tomography, along with targeted cytologic and serological analyses.

Update on gastroenteropancreatic neuroendocrine tumors

The incidence gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) has dramatically risen over the last three decades, probably due to the increased detection of asymptomatic lesions. The diagnostic work-up for patients with suspected GEP-NENs is based on conventional imaging, endoscopy, pathology, and functional imaging, including ⁶⁸Gallium-DOTATATE PET and ¹⁸F-FDG PET. The choice of the best treatment strategy should be based on the evaluation of tumor-related features and patient's characteristics. A conservative management, consisting of active surveillance or endoscopic resection, has been advocated for patients with small, incidentally discovered, nonfunctioning tumors without features of aggressiveness. On the other hand, surgery with lymphadenectomy, also with a minimally invasive approach, represents the gold standard for the curative treatment of localized disease. Moreover, surgical resection plays an important role also in the context of a multimodal treatment strategy for patients with advanced GEP-NENs. Finally, a wide range of medical therapies, comprising somatostatin analogues, peptide receptor radionuclide therapy, target therapies and several chemotherapy regimens, can be offered to patients with advanced GEP-NENs not amenable of surgical resection, according to the biological and molecular features of their disease.

Patterns of Lymph Node Metastasis in Patients With T1/T2 Gastroduodenal Neuroendocrine Neoplasms: Implications for Endoscopic Treatment

Guidelines have differed in their opinion regarding the indications for endoscopic resection of gastric-neuroendocrine neoplasms (g-NENs) and duodenal-NENs (d-NENs). We examined the association between size and lymph node metastasis (LNM) to identify candidates most suitable for endoscopic resection. We identified 706 patients with T1/T2 g-NENs and 621 patients with T1/T2 d-NENs from the SEER database. The prevalence of LNM and risk factors associated with LNM were analyzed. LNM was present in 8.1% of patients with gastroduodenal neuroendocrine tumors (NETs) and 31.6% of patients with neuroendocrine carcinomas (NECs). Multivariate logistic regression indicated that tumor size >10mm, greater invasion depth, and poor differentiation were independently associated with LNM. In addition, the percentage of g-NETs invading submucosa with LNM increased with tumor size (≤10 mm,3.9%;11-20 mm,8.6%;>20 mm,16.1%). However, in contrast to the low LNM risk in patients with small g-NETs (≤10 mm), we found that LNM rate exceeded 5% even for patients with small submucosal-infiltrating d-NETs. Among patients with nodal-negative g-NETs, the cause specific survival (CSS) was similar for those who received surgical resection and endoscopic resection. Among patients with d-NETs, the CSS was better for those who received endoscopic resection. In conclusion, patients with d-NETs had a higher probability of LNM than those with g-NETs. Endoscopic resection can be utilized for curative treatment of submucosa-infiltrating g-NETs and intramucosal d-NETs when the size is 10 mm or less. These results reinforce the need to search for LNM in lesions that are larger than 10 mm.

Clinicopathological characteristics and prognosis of 77 cases with type 3 gastric neuroendocrine tumours

BACKGROUND

For the rarity of type 3 gastric neuroendocrine tumours (g-NETs), their clinicopathological characteristics and prognosis are not well illustrated.

AIM

To describe the clinicopathological features and outcome of type 3 g-NETs in the Chinese population.

METHODS

Based on the 2019 WHO pathological classification, the clinicopathological characteristics and prognosis of patients with type 3 g-NETs in China were retrospectively analysed.

RESULTS

A total of 77 patients (55.8% of females) with type 3 g-NETs were analysed, with a median age of 48 years (range: 28-79 years). The tumours were mainly located in the gastric fundus/body (83.1%) and were mostly solitary (83.1%), with a median size of 1.5 cm (0.8-3.5 cm). Of these, there were 37 G1 tumours (48.1%), 31 G2 (40.3%), and 9 G3 (11.7%). Ten (13.0%) and 24 (31.2%) patients had lymph node and distant metastasis, respectively. In addition, type 3 g-NETs were heterogeneous. Compared with G1 NETs, G2 NETs had a higher lymph node metastasis rate, and G3 NETs had a higher distant metastasis rate. G1 and G2 NETs with stage I/II disease (33/68) received endoscopic treatment, and no tumour recurrence or tumour-related death was observed within a median follow-up time of 36 mo. Grade and distant metastasis were identified to be independent risk factors for prognosis in multivariable analysis.

CONCLUSION

Type 3 g-NETs are obviously heterogeneous, and the updated WHO 2019 pathological classification may be used to effectively evaluate their biological behaviors and prognosis. Also, endoscopic treatment should be considered for small (< 2 cm), low grade, superficial tumours.

Gastric neuroendocrine tumor: A practical literature review

Gastric neuroendocrine tumors are gastric neoplasms originating from enterochromaffin type cells and are inserted in a larger group, named gastroenteropancreatic neuroendocrine tumors. They are considered rare and variable in terms of their clinical, morphological and functional characteristics and may be indolent or aggressive. They are classified into types I, II and III, according to their pathophysiology, behavior and treatment. Their diagnosis occurs, in most cases, incidentally during upper digestive endoscopies, presenting as simple gastric polyps. Most cases (type I and type II) are related to hypergastrinemia, can be multiple and are treated by endoscopic resection, whenever possible. The use of somatostatin analogs for tumor control may be one of the options for therapy, in addition to total or subtotal gastrectomy for selected cases. Adjuvant chemotherapy is only reserved for poorly differentiated neuroendocrine carcinomas. Although rare, gastric neuroendocrine tumors have an increasing incidence over the years, therefore deserving more comprehensive studies on its adequate treatment. The present study reviews and updates management recommendations for gastric neuroendocrine tumors.

Clinicopathological Features of Gastroesophageal Neuroendocrine Neoplasms

PURPOSE OF REVIEW

Gastroesophageal neuroendocrine neoplasms (NENs) are a rare entity. Recent 2019 WHO classifications reflect our understanding of tumor biology, namely, that distinct molecular characteristics underline tumor behavior and prognosis. Here, we reviewed the evidence for linking molecular findings with the clinicopathological features and treatment of gastroesophageal NENs.

RECENT FINDINGS

Degree of differentiation and Ki-67 proliferation index are required for accurate classification of neuroendocrine tumors and carcinomas but not sufficient to distinguish between the two entities. Resection remains the mainstay treatment for early-stage gastroesophageal neuroendocrine tumors. Additional perioperative therapy may benefit mitotically active tumors. There is a role for somatostatin analogues, especially in the setting of metastatic and symptomatic disease. New radiolabeled somatostatin analogues, immunotherapy, and embolization offer multimodality treatments for distant metastases. We need to understand the specific underlying biology of the various subtypes of gastroesophageal NENs to provide tailored treatment.

Effects of tumor types on treatment strategy formulation and prognostic evaluation of gastric neuroendocrine tumors

Aim: The effects of different types of gastric neuroendocrine tumors (G-NETs) on treatment strategy formulation and prognostic evaluation still remain controversial due to their rarity. Methods: 187 patients diagnosed with G-NETs were subdivided into four types based on the pathophysiology, etiology and presentation. Results: Type I, II G-NETs >1.0 cm and type III, IV G-NETs >2.0 cm are proved with aggressive behavior (p < 0.05). Type III G-NETs with higher Ki-67 index and tumor stage showed more invasive potential than type I and II G-NETs (p < 0.05). Endoscopic resection is the primary treatment for type I, II G-NETs, while surgical combined with chemotherapy is associated with favorable outcomes for type IV G-NETs. Conclusion: The clinical classifications of G-NETs are of great significance for the choice of treatment and the evaluation of prognosis.

Systematic review: management of localised low-grade upper gastrointestinal neuroendocrine tumours

BACKGROUND

Neuroendocrine tumours (NETs) of the stomach and duodenum are rare, but are increasing in incidence. Optimal management of localised, low-grade gastric and duodenal NETs remains controversial.

AIMS

To systematically review recent literature that has evaluated the management of localised low-grade gastric and duodenal NETs.

METHODS

A systematic literature search was conducted. Articles were screened and eligible articles fully assessed. Additional articles were identified through the included articles' reference lists.

RESULTS

Several relevant retrospective case series were identified, but there was considerable heterogeneity between studies and they reported a variety of parameters. Type I gastric NETs had an excellent prognosis and conservative management approaches such as endoscopic surveillance/resection were appropriate in most cases. Many type III gastric NETs were low grade and appeared to have a better prognosis than has previously been appreciated. Endoscopic rather than surgical resection was therefore effective in some patients who had small, low-grade tumours. Duodenal NETs were more heterogenous. Endoscopic resection was generally safe and effective in patients who had small, low-grade, nonfunctional, non-ampullary tumours. However, some patients, especially those with larger or ampullary duodenal NETs, required surgical resection.

CONCLUSIONS

Most type I gastric NETs behave indolently and surgical resection is only rarely indicated. Some type III gastric and duodenal NETs have a worse prognosis, but selected patients who have small, localised, nonfunctional, low-grade tumours are adequately and safely treated by endoscopic resection. Due to the complexity of this area, a multidisciplinary approach to management is strongly recommended.

Tumour type and size are prognostic factors in gastric neuroendocrine neoplasia: A multicentre retrospective study

BACKGROUND

Gastric neuroendocrine neoplasias (gNEN) are defined as type I if associated with atrophic body gastritis and type III when tumour is sporadic. This classification, together with grading and size, plays a crucial prognostic role. Nevertheless, the impact of these features on clinical outcome is not clear.

AIM

To identify factors predicting poor outcome.

PATIENTS AND METHODS

Analysis of type I and type III gNEN. A composite endpoint was defined if tumour-related death or metastases or angioinvasion were observed.

RESULTS

156 gNENs were evaluated: 137 (87.8%) type I and 19 (12.2%) type III. Among type I, 103 were G1 (75.2%) and 34 (24.8%) were G2. In type III group, 8 were G1 (42.1%), 10 were G2 (52.6%), and 1 was G3 (5.3%). Negative endpoint occurred in 18 patients including 10 type III and 8 type I. Male gender (p = 0.032), tumour type (p = 0.003) and size >10 mm (p = 0.024) were predictors for poor outcome, whereas Ki67 was not confirmed on multivariate analysis (p = 0.192). 5-yr survival rates in type I and type III were 100% and 76.2%, respectively (p = 0.0002).

CONCLUSIONS

Tumour size, tumour type and gender affect clinical outcome in gNENs. In contrast to NENs rising from other sites, Ki67 plays a less important role.