Long-term results of endoscopic resection for type I gastric neuroendocrine tumors

Type 2 and type 3 gastric neuroendocrine tumors have high risk of lymph node metastasis: Systematic review and meta-analysis

OBJECTIVES

Lymph node metastasis (LNM) is crucial in determining treatment strategies for gastric neuroendocrine tumors (gNETs). While type 3 is considered more aggressive than types 1 and 2 within the clinical subtype of gNETs, the supporting data were insufficient, due to their rarity. We aimed to study the prevalence and risk factors associated with LNM in gNETs.

METHODS

We searched electronic databases from 1990 to 2023 to identify case-control and cohort studies regarding gNETs resected either endoscopically or surgically. The primary outcome measured was the pooled prevalence of LNM in gNETs. Secondary outcomes included categorizing the prevalence of LNM by clinical subtypes and identifying pathological risk factors associated with LNM in gNETs.

RESULTS

We included 28 studies, involving 1742 patients, among whom 240 had LNM (pooled prevalence rate, 11.8%; 95% confidence interval 7.6-17.9%). The pooled prevalence rates of LNM for type 1, type 2, and type 3 gNETs were 6.0%, 38.5%, and 23.2%, respectively. Type 2 (odds ratio [95% confidence interval] 11.53 [3.46-38.49]) and type 3 (6.88 [3.79-12.49]) gNETs exhibited a higher risk for LNM compared to type 1. Pathological risk factors for LNM included tumor size >10 mm (4.18 [1.91-9.17]), tumor invasion into the muscularis propria or deeper (11.21 [3.50-35.92]), grade 2/grade 3 (5.96 [2.65-13.40]), and lymphovascular invasion (34.50 [6.70-177.51]).

CONCLUSION

We demonstrated that type 2 gNETs, as well as type 3, had a high risk of LNM. Additionally, four pathological risk factors associated with LNM were identified.

Is Endoscopic Resection Essential for Patients with Type 1 Gastric Neuroendocrine Tumor?

Background: The gastric neuroendocrine tumor (g-NET) is now more frequently diagnosed due to the widespread use and advancement of endoscopy. In our study, we aimed to discuss the superiority, if any, between the watch-and-wait approach and endoscopic treatment methods for the controversial management of type 1 g-NETs, as well as to evaluate their long-term outcomes. Materials and Methods: The data of 81 patients who underwent gastroscopy due to complaints related to the upper gastrointestinal system and were diagnosed with type 1 g-NET as a result of biopsy taken from suspicious stomach lesions were examined. After exclusion criteria, 48 patients were included in the study. Patients were categorized into two groups: the watch-and-wait group, where no invasive procedure was performed, and the group that underwent any form of endoscopic resection. Results: Thirty-seven patients were followed up regularly without any treatment. Eleven patients were followed up after endoscopic resection (endoscopic submucosal dissection-endoscopic mucosal resection). Endoscopic resection was performed in 5 of 37 patients with tumor size <10 mm and in 6 of 11 patients with tumor size between 10 and 20 mm. The median follow-up duration for all patients was 5 years, during which no instances of metastasis, tumor progression, or mortality were observed in any patient, regardless of whether they underwent endoscopic resection or not. Conclusion: This outcome prompts a questioning of the necessity for invasive treatment methods such as endoscopic resection, which comes with a relatively high cost and the potential for complications, in this particular patient group.

Factors associated with gastric and duodenal neuroendocrine tumors: A multicenter case-control study

BACKGROUND AND AIMS

The incidence of gastric and duodenal neuroendocrine tumors (GNET and DNET, respectively) is increasing, however associated factors of these diseases are not well known. Here, we investigated the factors associated with GNET and DNET.

METHODS

Patients with GNET and DNET presenting at eight tertiary referral centers between 2001 and 2020 were included and compared with healthy controls who underwent upper endoscopic screening. Clinical factors and laboratory data were analyzed to determine associated factors of GNET and DNET.

RESULTS

Overall, 396 patients with GNET and 193 patients with DNET were included and compared with 1725 healthy controls. Multivariate analysis showed that age (odds ratio [OR] 0.98), diabetes (OR 1.72), hypertension (OR 1.97), low serum high-density lipoprotein cholesterol (HDL-C) levels (OR 2.54), and past/present H. pylori infection (OR 1.46) were significantly associated with GNET. In contrast, DNET was significantly associated with diabetes (OR 1.80), hypertension (OR 1.68), low serum HDL-C levels (OR 2.29), and past/present H. pylori infection (OR 5.42). In the sex-based subgroup analysis in GNET, current smoking was strongly associated in women (OR 9.85), but not in men.

CONCLUSIONS

This study identified several common metabolic factors associated with GNET and DNET. Additionally, some factors had sex-specific associations.

Modern Management of Gastric Neuroendocrine Neoplasms

OPINION STATEMENT

Gastric neuroendocrine neoplasms (G-NENs) are a heterogeneous group of tumors that broadly fall into two groups. The first group, driven by oversecretion of gastrin, are generally multifocal, small, and behave indolently with a low (but non-zero) risk of progression and metastatic spread. They are conventionally categorized into type 1, with endogenous gastric-based overproduction of gastrin, and type 2 G-NEN, with overproduction of gastrin from an extra-gastric gastrin-secreting tumor. The second group, termed type 3 G-NEN, occur spontaneously and are potentially more aggressive, having a clinical course analogous to other neuroendocrine tumors of the gastrointestinal tract. Type 1 G-NEN can be managed with endoscopic surveillance and resection of visible lesions with great success, reserving surgery for the rare high-risk lesion, whereas surgical resection of the causative gastrin-secreting tumor in type 2 G-NEN is usually curative. Type 3 G-NEN is usually managed with formal surgical resection but there is growing evidence that limited surgery or even endoscopic resection in appropriately selected patients with low risk is both safe and effective. A novel subtype of G-NEN, associated with long-term proton pump inhibitor usage, is increasing in incidence. The pathophysiology seems to parallel type 1 G-NEN. In the setting of metastatic disease, which can occur in any subtype but is most common by far in type 3 G-NEN, the lack of trial data unique to G-NEN results in extrapolation of strategies and agents for treatment of non-gastric neuroendocrine disease. The rapid pace of development in this area is likely to benefit the metastatic G-NEN patient as well. As treatment is predicate on type of G-NEN, establishing the etiology of the lesion is crucial but growing knowledge of G-NEN pathophysiology and close collaboration between pathologists, gastroenterologists, radiologists, surgeons, and oncologists have enabled a growing trend towards de-escalation and less-invasive treatment paradigms.

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.

Gastric Neuroendocrine Tumors According to the 2019 World Health Organization Grading System: A Single-Center, Retrospective Study

Background/Aims

Although gastric neuroendocrine tumors (NETs) are uncommon neoplasms, their prevalence is increasing. The clinical importance of the World Health Organization (WHO) classification of gastric NETs, compared with NETs in other organs, has been underestimated. This study aimed to systematically evaluate the clinical and pathologic characteristics of gastric NETs based on the 2019 WHO classification and to assess the survival outcomes of patients from a single-center with a long-term follow-up.

Methods

The medical records of 427 patients with gastric NETs who underwent endoscopic or surgical resection between January 2000 and March 2020 were retrospectively reviewed. All specimens were reclassified according to the 2019 WHO classification. The clinicopathologic characteristics, treatment, and oncologic outcomes of 139 gastric NETs were analyzed.

Results

The patients' median age was 53.0 years (interquartile range [IQR], 46.0 to 63.0 years). The median follow-up period was 36.0 months (IQR, 15.0 to 63.0 months). Of the patients, 92, 44, and 3 had grades 1, 2, and 3 NETs, respectively. The mean tumor size significantly increased as the tumor grade increased (p=0.025). Patients with grades 2 and 3 gastric NETs more frequently had lymphovascular invasion (29.8% vs 10.9%, p=0.005) and deeper tissue invasion (8.5% vs 0%, p=0.012) than those with grade 1 tumors. The overall disease-specific survival rate was 100%. Two patients with grades 2-3 gastric NETs experienced extragastric recurrence.

Conclusions

Although gastric NETs have an excellent prognosis, grade 2 or grade 3 gastric NETs are associated with a larger size, deeper invasion, and extragastric recurrence, which require active treatment.

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.

Chronic Treatment with Somatostatin Analogues in Recurrent Type 1 Gastric Neuroendocrine Tumors

Background: Type 1 gastric neuroendocrine tumors (GC-1) represent an uncommon subtype of neoplasms. Endoscopic resection has been proposed as the treatment of choice; active surveillance may be performed in those smaller than 1 cm, while gastric surgery may be performed for those with frequent recurrences. The antiproliferative effect of somatostatin analogues (SSA) is well known, and their action on GC-1s has been postulated as a chronic treatment to reduce recurrence. Methods: A two-centered, retrospective, observational study that included nine patients (55.6% women) diagnosed with GC-1, receiving long-term treatment with SSA, with a median follow-up from baseline of 22 months, was undertaken. Endoscopic follow-up, extension study, and analytical values of chromogranin A (Cg A) and gastrin were collected. Results: In total, 88.9% of patients presented partial or complete response. Treatment with SSA was the only independent factor with a trend to prevent tumor recurrence (Odds Ratio 0.054; p = 0.005). A nonsignificant tendency toward a decrease in CgA and gastrin was observed; lack of significance was probably related to concomitant treatment with proton pump inhibitors in some patients. Conclusions: Chronic treatment with SSA is a feasible option for recurrent GC-1s that are difficult to manage using endoscopy or gastrectomy. Randomized clinical trials to provide more scientific evidence are still needed.

Endoscopic surveillance alone is feasible and safe in type I gastric neuroendocrine neoplasms less than 10 mm in diameter

PURPOSE

Type I gastric neuroendocrine neoplasms (g-NENs) have a low risk of metastasis and a generally favourable prognosis. Patients with small type I g-NENs (≤10 mm) frequently require no treatment, whereas those with larger polyps usually undergo resection. We evaluated the safety and outcomes of endoscopic surveillance after no initial treatment in selected patients with type I g-NENs.

METHODS

Retrospective analysis of type I g-NEN patients across two European Neuroendocrine Tumour Society Centers of Excellence 2003-2019.

RESULTS

Following initial assessment, 87 of 115 patients with type I g-NEN (75 with polyps ≤10 mm) received no initial treatment and underwent endoscopic surveillance. 79/87 (91%) demonstrated no clinically meaningful change in tumour size or grade over a median 62 month follow up. Only two patients developed NEN progression that required a change in management and two other patients developed gastric adenocarcinoma/high grade dysplasia; all four initially had ≥11 mm g-NENs.

CONCLUSIONS

Patients with ≤10 mm type I g-NENs were unlikely to develop clinically significant tumour progression and in most cases, resection was not needed. The endoscopic surveillance interval could therefore potentially be safely increased to every 2-3 years in such patients. However, lifelong surveillance is still advocated due to the additional risk of developing gastric adenocarcinoma.

Histopathological Landscape of Precursor Lesions of Gastro-Entero-Pancreatic Neuroendocrine Neoplasms

BACKGROUND

Despite the important advances in research on neuroendocrine neoplasms of the gastro-entero-pancreatic tract, their precursor lesions are much less well known.

SUMMARY

This review analyzes the preneoplastic neuroendocrine lesions of the gastro-entero-pancreatic tract, by adopting a coherent anatomical benchmark. In particular, the settings in which neuroendocrine precursor lesions represent well-recognized pathophysiological and morphological entities (with eventual molecular correlates) have been distinguished from the ones in which the nature of preneoplastic changes is still obscure.

KEY MESSAGES

The aim of the paper was to summarize what is known about precursor lesions of gastro-entero-pancreatic neuroendocrine tumors, with the goal of providing a useful tool for future research aimed at obtaining a fuller understanding of the underlying biology and early development of these diseases.

Metastasis Prevalence and Survival of Patients with T1-2 Gastric Neuroendocrine Tumor Treated with Endoscopic Therapy and Surgery

BACKGROUND AND AIM

The selection criteria and long-term outcomes of endoscopic therapy (ET) for gastric neuroendocrine tumors (G-NETs) remain controversial.

METHODS

Using Surveillance, Epidemiology, and End Results (SEER) Program database, we assessed the prevalence of metastasis of early G-NETs and long-term outcomes of ET in G-NET patients with good/moderate differentiation and no muscularis propria (MP) involvement.

RESULTS

A total of 2207 patients with stage T1 and T2 G-NETs were included. The depth of invasion into MP [odds ratio (OR) 4.581, 95% confidence interval (CI) 2.571-8.162; P < 0.001] and size of > 20 mm (OR 5.656, 95% CI 2.002-15.975; P = 0.001) were significantly associated with metastasis. The 5-year overall survival (OS) and cancer-specific survival (CSS) of the ET group were similar to the surgery group (91.11% vs. 91.09%, P = 0.750; 99.26% vs. 99.01%, P = 0.173). In the multivariable Cox proportional hazards regression models adjusting for age, gender, race, year of diagnosis, SEER region, depth of tumor invasion, site of cancer, tumor size, and chemotherapy, procedures employed (ET or surgery) had no significant impact on the OS [hazard ratio (HR) 1.189; 95%CI 0.721-1.961; P = 0.498] and CSS (HR 0.684; 95% CI 0.021-22.727; P = 0.832).

CONCLUSIONS

The long-term outcome of survival did not appear to differ between ET and surgery in G-NETs with good/moderate differentiation, ≤ 20 mm size, and no MP involvement.

AGA Clinical Practice Update on the Diagnosis and Management of Atrophic Gastritis: Expert Review

DESCRIPTION

The purpose of this Clinical Practice Update Expert Review is to provide clinicians with guidance on the diagnosis and management of atrophic gastritis, a common preneoplastic condition of the stomach, with a primary focus on atrophic gastritis due to chronic Helicobacter pylori infection-the most common etiology-or due to autoimmunity. To date, clinical guidance for best practices related to the diagnosis and management of atrophic gastritis remains very limited in the United States, which leads to poor recognition of this preneoplastic condition and suboptimal risk stratification. In addition, there is heterogeneity in the definitions of atrophic gastritis, autoimmune gastritis, pernicious anemia, and gastric neoplasia in the literature, which has led to confusion in clinical practice and research. Accordingly, the primary objective of this Clinical Practice Update is to provide clinicians with a framework for the diagnosis and management of atrophic gastritis. By focusing on atrophic gastritis, this Clinical Practice Update is intended to complement the 2020 American Gastroenterological Association Institute guidelines on the management of gastric intestinal metaplasia. These recent guidelines did not specifically discuss the diagnosis and management of atrophic gastritis. Providers should recognize, however, that a diagnosis of intestinal metaplasia on gastric histopathology implies the diagnosis of atrophic gastritis because intestinal metaplasia occurs in underlying atrophic mucosa, although this is often not distinctly noted on histopathologic reports. Nevertheless, atrophic gastritis represents an important stage with distinct histopathologic alterations in the multistep cascade of gastric cancer pathogenesis.

METHODS

The Best Practice Advice statements presented herein were developed from a combination of available evidence from published literature and consensus-based expert opinion. No formal rating of the strength or quality of the evidence was carried out. These statements are meant to provide practical advice to clinicians practicing in the United States. Best Practice Advice Statements BEST PRACTICE ADVICE 1: Atrophic gastritis is defined as the loss of gastric glands, with or without metaplasia, in the setting of chronic inflammation mainly due to Helicobacter pylori infection or autoimmunity. Regardless of the etiology, the diagnosis of atrophic gastritis should be confirmed by histopathology. BEST PRACTICE ADVICE 2: Providers should be aware that the presence of intestinal metaplasia on gastric histology almost invariably implies the diagnosis of atrophic gastritis. There should be a coordinated effort between gastroenterologists and pathologists to improve the consistency of documenting the extent and severity of atrophic gastritis, particularly if marked atrophy is present. BEST PRACTICE ADVICE 3: Providers should recognize typical endoscopic features of atrophic gastritis, which include pale appearance of gastric mucosa, increased visibility of vasculature due to thinning of the gastric mucosa, and loss of gastric folds, and, if with concomitant intestinal metaplasia, light blue crests and white opaque fields. Because these mucosal changes are often subtle, techniques to optimize evaluation of the gastric mucosa should be performed. BEST PRACTICE ADVICE 4: When endoscopic features of atrophic gastritis are present, providers should assess the extent endoscopically. Providers should obtain biopsies from the suspected atrophic/metaplastic areas for histopathological confirmation and risk stratification; at a minimum, biopsies from the body and antrum/incisura should be obtained and placed in separately labeled jars. Targeted biopsies should additionally be obtained from any other mucosal abnormalities. BEST PRACTICE ADVICE 5: In patients with histology compatible with autoimmune gastritis, providers should consider checking antiparietal cell antibodies and anti-intrinsic factor antibodies to assist with the diagnosis. Providers should also evaluate for anemia due to vitamin B-12 and iron deficiencies. BEST PRACTICE ADVICE 6: All individuals with atrophic gastritis should be assessed for H pylori infection. If positive, treatment of H pylori should be administered and successful eradication should be confirmed using nonserological testing modalities. BEST PRACTICE ADVICE 7: The optimal endoscopic surveillance interval for patients with atrophic gastritis is not well-defined and should be decided based on individual risk assessment and shared decision making. A surveillance endoscopy every 3 years should be considered in individuals with advanced atrophic gastritis, defined based on anatomic extent and histologic grade. BEST PRACTICE ADVICE 8: The optimal surveillance interval for individuals with autoimmune gastritis is unclear. Interval endoscopic surveillance should be considered based on individualized assessment and shared decision making. BEST PRACTICE ADVICE 9: Providers should recognize pernicious anemia as a late-stage manifestation of autoimmune gastritis that is characterized by vitamin B-12 deficiency and macrocytic anemia. Patients with a new diagnosis of pernicious anemia who have not had a recent endoscopy should undergo endoscopy with topographical biopsies to confirm corpus-predominant atrophic gastritis for risk stratification and to rule out prevalent gastric neoplasia, including neuroendocrine tumors. BEST PRACTICE ADVICE 10: Individuals with autoimmune gastritis should be screened for type 1 gastric neuroendocrine tumors with upper endoscopy. Small neuroendocrine tumors should be removed endoscopically, followed by surveillance endoscopy every 1-2 years, depending on the burden of neuroendocrine tumors. BEST PRACTICE ADVICE 11: Providers should evaluate for iron and vitamin B-12 deficiencies in patients with atrophic gastritis irrespective of etiology, especially if corpus-predominant. Likewise, in patients with unexplained iron or vitamin B-12 deficiency, atrophic gastritis should be considered in the differential diagnosis and appropriate diagnostic evaluation pursued. BEST PRACTICE ADVICE 12: In patients with autoimmune gastritis, providers should recognize that concomitant autoimmune disorders, particularly autoimmune thyroid disease, are common. Screening for autoimmune thyroid disease should be performed.

Gastric neuroendocrine neoplasms: A review

Gastric neuroendocrine neoplasms (g-NENs) or neuroendocrine tumors are generally slow-growing tumors with increasing incidence. They arise from enterochromaffin like cells and are divided into four types according to clinical characteristic features. Type 1 and 2 are gastrin dependent, whereas type 3 and 4 are sporadic. The reason for hypergastrinemia is atrophic gastritis in type 1, and gastrin releasing tumor (gastrinoma) in type 2 g-NEN. The diagnosis of g-NENs needs histopathological investigation taken by upper gastrointestinal endoscopy. g-NENs are positively stained with chomogranin A and synaptophysin. Grading is made with mitotic index and ki-67 proliferation index on histopathological analysis. It is crucial to discriminate between types of g-NENs, because the management, treatment and prognosis differ significantly between subtypes. Treatment options for g-NENs include endoscopic resection, surgical resection with or without antrectomy, medical treatment with somatostatin analogues, netazepide or chemotherapy regimens. Follow-up without excision is another option in appropriate cases. The prognosis of type 1 and 2 g-NENs are good, whereas the prognosis of type 3 and 4 g-NENs are close to the prognosis of gastric adenocancer.

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.

Type I Gastric Neuroendocrine Tumor Presenting as Acute Upper Gastrointestinal Bleed

Gastric neuroendocrine tumors (GNETs) are rare and subdivided into type I, type II, and type III. Types I and II are gastrin-dependent and are usually benign, whereas type III is gastrin-independent and more aggressive. Type I accounts for 70-80% of all GNETs. Most of them are asymptomatic and incidentally detected on endoscopy. It can sometimes present with iron and B12 deficiency, dyspepsia, and less commonly with an upper GI bleed. We present a case of type I GNET who came to the hospital with melena and esophagogastroduodenoscopy (EGD) showing a 3-cm bleeding polyp and histopathology revealing a well-differentiated neuroendocrine tumor with angioinvasion.

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.

Comparison of Endoscopic Techniques in the Management of Type I Gastric Neuroendocrine Neoplasia: A Systematic Review

Background. Endoscopic resection is considered the treatment of choice for type I gastric neuroendocrine neoplasia (gNEN) given its indolent behaviour; however, the favoured endoscopic technique to remove these tumours is not well established. Aims. This systematic review is aimed at investigating the best endoscopic management for type I gNEN. Methods. PubMed Central/Medline and Scopus were systematically searched for records up to August 31, 2020. Results. After screening the 675 retrieved records, 6 studies were selected for the final analysis. The main endoscopic resection techniques described were endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD). Overall, 112 gNENs were removed by EMR and 77 by ESD. Both techniques showed similar results for complete and en bloc resection (97.4% and 98.7%; 92.3% and 96.3% with ESD and EMR, respectively). ESD was associated with a higher rate of complications than EMR (11.7% vs. 5.4%), but this difference was not statistically significant ( $p=0.17$ ). The rates of recurrence during follow-up were 18.2% and 11.5% for EMR and ESD, respectively. Conclusions. To date, there are no sufficient data showing superiority of a given endoscopic technique over others. Both ESD and EMR seem to be effective in the management of type I gNEN, with a relatively low rate of recurrence.

Gastric Carcinoid: The Invisible Tumor!

Neuroendocrine tumor (NET) of the stomach or gastric carcinoid (GC) is a rare tumor derived from enterochromaffin-like (ECL) cells of the stomach and is more common in women after the fifth decade of life. The incidence of GC has been recently trending up. While most GC are visible lesions upon direct visualization on endoscopy, one-fourth of these tumors are intramucosal and not readily identified on upper endoscopy. Thus, a complete gastric map with biopsies of antrum, body, and fundus is required to confirm the presence of carcinoid growth. Herein we report a rare case of GC which was identified on a random gastric biopsy specimen.

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.

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.

Response and relapse rates after treatment with long-acting somatostatin analogs in multifocal or recurrent type-1 gastric carcinoids: A systematic review and meta-analysis

BACKGROUND

Type-1 gastric neuroendocrine tumors represent a recurring disease and long-acting somatostatin analogs can inhibit both gastrin release and endocrine cell proliferation. The efficacy and timing of this treatment are still unclear. We performed a systematic review of the literature to clarify the role of somatostatin analog treatment in type-1 gastric neuroendocrine tumors.

METHODS

A computerized literature search was performed using relevant keywords to identify all the pertinent articles published in the last 15 years.

RESULTS

Eight studies were included in this systematic review on somatostatin analogs in type-1 gastric neuroendocrine tumors. A complete response rate ranged from 25-100%. When only the six prospective studies were considered, no significant heterogeneity was observed, and the pooled cumulative complete response rate was 84.5% (confidence interval 73.8-92.8). Three studies evaluated the type-1 gastric neuroendocrine tumor recurrence, with a cumulative relapse rate of 30.2% (confidence interval 13.1-50.6) after 34 months.

CONCLUSION

Somatostatin analogs, namely lanreotide and octreotide, have an excellent response rate, with a good safety profile in selected type-1 gastric neuroendocrine tumors, which cannot be safely managed by endoscopic follow-up or resection due to multiple or frequently recurring disease. After therapy discontinuation, the cumulative relapse rate observed after a median 34-month follow-up was relatively high (30.2%).

Autoimmune metaplastic atrophic gastritis and association with neuroendocrine tumors of the stomach

Autoimmune metaplastic atrophic gastritis (AMAG) previously called type A chronic gastritis is an immune-mediated chronic inflammatory disease characterized by the immune-mediated destruction of gastric parietal cells in the fundus and body of the stomach. AMAG is an uncommon disease that often presents with hematological manifestations and may lead to the development of gastric carcinoids. AMAG can be reliably diagnosed by antibody assays, functional serology, and histology. The understanding of the disease process is essential for the detection and management of hematological complications and gastric lesions. The prevalence of AMAG is on the rise and subsequently gastric carcinoids. However, this association is not well recognized in clinical practice, and management and diagnosis of AMAG and gastric carcinoids remain suboptimal. In the current review, we will discuss the pathophysiology, diagnosis and management of AMAG. A special focus is given to the association between AMAG and gastric carcinoids. We will also review the management options of type 1 gastric carcinoids.

Gastric neuroendocrine neoplasms type 1: A systematic review and meta-analysis

BACKGROUND

To date, the histopathological parameters predicting the risk of lymph node (LN) metastases and local recurrence, associated mortality and appropriateness of endoscopic or surgical resection in patients with gastric neuroendocrine neoplasms type 1 (GNENs1) have not been fully elucidated.

AIM

To determine the rate of LN metastases and its impact in survival in patients with GNEN1 in relation to certain clinico-pathological parameters.

METHODS

The PubMed, EMBASE, Cochrane Library, Web of Science and Scopus databases were searched through January 2019. The quality of the included studies and risk of bias were assessed using the Newcastle-Ottawa Scale (NOS) in accordance with the Cochrane guidelines. A random effects model and pooled odds ratios (OR) with 95%CI were applied for the quantitative meta-analysis.

RESULTS

We screened 2933 articles. Thirteen studies with 769 unique patients with GNEN1 were included. Overall, the rate of metastasis to locoregional LNs was 3.3% (25/769). The rate of LN metastases with a cut-off size of 10 mm was 15.3% for lesions > 10 mm (vs 0.8% for lesions < 10 mm) with a random-effects OR of 10.5 (95%CI: 1.4 -80.8; heterogeneity: P = 0.126; I 2 = 47.5%). Invasion of the muscularis propria was identified as a predictor for LN metastases (OR: 17.2; 95%CI: 1.8-161.1; heterogeneity: P = 0.165; I 2 = 44.5%), whereas grade was not clearly associated with LN metastases (OR: 2; 95%CI: 0.3-11.6; heterogeneity: P = 0.304; I 2 = 17.4%). With regard to GNEN1 local recurrence, scarce data were available. The 5-year disease-specific survival for patients with and without LN metastases was 100% in most available studies irrespective of the type of intervention. Surgical resection was linked to a lower risk of recurrence (OR: 0.3; 95%CI: 0.1-1.1; heterogeneity: P = 0.173; I 2 = 31.9%). The reported complication rates of endoscopic and surgical intervention were 0.6 and 3.8%, respectively.

CONCLUSION

This meta-analysis confirms that tumor size ≥ 10 mm and invasion of the muscularis propria are linked to a higher risk of LN metastases in patients with GNEN1. Overall, the metastatic propensity of GNEN1 is low with favorable 5-year disease-specific survival rates reported; hence, no clear evidence of the prognostic value of LN positivity is available. Additionally, there is a lack of evidence supporting the prediction of local recurrence in GNEN1, even if surgery was more often a definitive treatment.

Gastric neuroendocrine neoplasias: manifestations and comparative outcomes

Although gastric neuroendocrine neoplasias (gNEN) are an orphan disease, their incidence is rising. The heterogeneous clinical course powers the ongoing discussion of the most appropriate classification system and management. Prognostic relevance of proposed classifications was retrospectively analysed in 142 patients from a single tertiary referral centre. Baseline, management and survival data were acquired for statistical analyses. The distribution according to the clinicopathological typification was gNEN-1 (n = 86/60.6%), gNEN-2 (n = 7/4.9%), gNEN-3 (n = 24/16.9%) and gNEN-4 (n = 25/17.6%), while hypergastrinemia-associated gNEN-1 and -2 were all low-grade tumours (NET-G1/2), formerly termed sporadic gNEN-3 could be subdivided into gNEN-3 with grade 1 or 2 and gNEN-4 with grade 3 (NEC-G3). During follow-up 36 patients died (25%). The mean overall survival (OS) of all gNEN was 14.2 years. The OS differed statistically significant across all subgroups with either classification system. According to UICC 2017 TNM classification, OS differed for early and advanced stages, while WHO grading indicated poorer prognosis for NEC-G3. Cox regression analysis confirmed the independent prognostic validity of either classification system for survival. Particularly careful analysis of the clinical course of gNEN-1 (ECLomas, gastric carcinoids) confirmed their mostly benign, but recurrent and extremely slowly progressive behaviour with low risk of metastasis (7%) and an efficient long-term control by repetitive endoscopic procedures. Our study provides evidence for the validity of current classifications focusing on typing, grading and staging. These are crucial tools for risk stratification, especially to differentiate gNEN-1 as well as sporadic gNET and gNEC (gNEN-3 vs -4).

Surgical Intervention in Gastric Carcinoid is Associated With Improved Survival in Local and Regional Disease

INTRODUCTION

Gastric carcinoid is a rare entity with complex management options. This study aims to determine if surgical intervention in patients with local, regional, and metastatic gastric carcinoid is associated with prolonged survival.

MATERIALS AND METHODS

The California Cancer Registry merged with the California Office of Statewide Health Planning and Development was queried for patients with a diagnosis of gastric carcinoid (2000 to 2011). Clinicopathologic characteristics, management, and outcomes were evaluated.

RESULTS

There were 1012 patients with a diagnosis of gastric carcinoid identified. The median age was 63 (range, 18 to 99) and the majority of patients were women (615, 60.7%). Most patients had localized disease (644, 64%), whereas 9.4% (95) had regional and 13.4% (133) had distant metastases at diagnosis. The majority of patients underwent gastric surgery (56.7%, n=574 vs. 43.2%, n=438). Prolonged survival was associated with gastric surgery in patients with both local (median survival not reached; P<0.0001) and regional disease (27 mo with surgery vs. 5 mo with no surgery; P=0.0007). In patients who underwent gastrectomy and resection of hepatic metastasis, the survival approached those patients who had surgery for only regional disease (26 vs. 27 mo, P=0.8721).

CONCLUSIONS

Although the biology of the disease is the most significant predictor of overall outcome, when technically feasible and where comorbidities allow, aggressive endoscopic or surgical intervention should be offered for local and locoregional diseases, respectively.

Type 1 Gastric Neuroendocrine Tumor Found on Endoscopic Polypectomy

Gastric neuroendocrine tumors (GNET) are rare gastric neoplasms accounting for <1% of all gastric neoplasms. The World Health Organization (WHO) categorized these neoplasms as types 1-3 to help predict malignant potential and long-term survival and guide management. Improved outcomes have been shown with endoscopic resections, but further studies are needed to confirm the best approach. We present a case of a 56-year-old woman who demonstrated the classic features of type one GNET with mucosal and submucosal involvement in the setting of primary atrophic gastritis, secondary hypergastrinemia, and underlying pernicious anemia. In general, standardizing treatment has been difficult due to a variable presentation.

Efficacy and safety of endoscopic submucosal dissection for gastrointestinal neuroendocrine tumors: a 10-year data analysis of Northern China

Objective: Endoscopy is the main method to treat gastrointestinal neuroendocrine tumors (GI-NETs), but the specific indications are still controversial. We aim to investigate the clinical outcomes of GI-NETs patients who experienced endoscopic submucosal dissection (ESD). Methods: We retrospectively reviewed the clinical features and prognosis of 65 GI-NETs patients who underwent ESD between 2008 and 2018. Results: A total of 65 patients diagnosed with GI-NETs pathologically, bearing 75 lesions, were found by endoscopy incidentally for other symptoms. The locations of these lesions were stomach (n = 24), duodenal bulb (n = 4) and rectum (n = 47). The diameter of 75 tumors were as follows: size ≤ 1 cm (78.7%), 1 cm < size ≤ 2 cm (17.3%), 2 cm < size ≤ 3.5 cm (4.0%). Endoscopic ultrasonography (EUS) suggested that 72 lesions were confined to submucosa and 3 lesions invaded into muscularis propria. The rates of en bloc resection and complete resection were all 100% and the rates of intraoperative bleeding and perforation were 2.7% and 1.3%, respectively. None of the 65 patients had lymph nodes and distant metastasis during the period of study. Conclusion: For GI-NETs without lymph nodes and distant metastases, the lesion confined to submucosa with the diameter ≤1 cm is absolute indication of ESD. For rectal neuroendocrine tumors limited in submucosa with the diameter between 1 and 2 cm, and Type 1 gastric neuroendocrine tumors predicted to be T2, ESD should be prioritized to preserve gastrointestinal volume and function at initial treatment.

Clinical features and outcomes of gastric neuroendocrine tumors after endoscopic diagnosis and treatment: A Digestive Endoscopy Society of Tawian (DEST)

Gastric neuroendocrine tumors (GNETs) are a heterogeneous group of neoplasm with varying biological characteristics. This study aimed to investigate the clinical features and outcomes of GNET patients after endoscopic diagnosis and treatment in a multicenter registry. Patients with GNETs confirmed histologically were recruited from 17 hospitals between January 2010 and April 2016 in Taiwan. Clinical, laboratory, radiological, endoscopic, pathological data, treatment strategies, follow-up periods, and survivals were collected retrospectively. Totally 187 (107 female, 80 male) patients were recruited. Mean ( ± standard deviation [SD]) age and size of tumors were 63.2-year-old ( ± 14.6) and 2.3-cm ( ± 3.0). World Health Organization (WHO) grading were 93 (49.7%) G1, 26 (13.9%) G2, 40 (21.4%) G3, and 28 (15.0%) unknown. G3 patients were older (mean ± SD, 71.6 ± 12.4 vs. 60.9 ± 14.3/56.7 ± 15.4 years), larger (6.1 ± 4.0 vs.1.2 ± 1.3/2.4 ± 2.5 cm), more distally located (35.0% vs. 7.6%/15.4%), lower proportion of superficial lesions (17.5% vs. 61.9%/53.8%) and higher rates of lymphovascular invasion (32.5% vs. 3.2%/7.7%) than G1/G2. There was no nodal or distant organ metastases despite different grading of lesions≦10 mm and those <20 mm limited to mucosa and submucosa layers. GNETs larger than 20 mm with G1, G2, and G3 had lymph node (LN) metastatic rates of 21.4%, 30.0%, and 59.3%, respectively. Survivals were different between grading for those >20 mm (log-rank test P = .02). Male gender (P = .01), deeper invasion (P = .0001), nodal (P < .0001), and distant organ metastases (P = .0001) were associated with worse outcome. In conclusion, treatment strategies for GNET should be decided by grading, size, invasiveness, and LN metastasis risk. Curative endoscopic resection is feasible for G1/2 lesions less than 20 mm and limited to mucosa/submucosa layers without lymphovascular invasion.

How should incidental NEN of the pancreas and gastrointestinal tract be followed?

Neuroendocrine gastro-entero-pancreatic neoplasms (GEP-NENs) constitute a heterogeneous group of tumors, whose incidence has increased over the years. The most frequent site for primary disease is the stomach followed by small and large intestine, and pancreas. In the last decade, a dramatic growing in the incidence of small, incidental GEP-NENs has been recorded. In parallel, an increasing attitude toward more conservative approaches instead of surgical management has being widely spreading. This is particularly true for small, asymptomatic, pancreatic NEN as for these tumor forms an active surveillance has proven to be safe and feasible. Primary site and biological features of the neoplasms lead to different strategies and indications for surveillance and follow-up. This review focuses on the current evidence on modality and timing of surveillance and conservative treatment of incidentally discovered lesions.

Subtype classification and management of gastric neuroendocrine neoplasms

Gastric neuroendocrine neoplasms (g-NENs) are a group of heterogeneous tumors arising from endocrine cells in the stomach. Because of the low incidence, clinical misdiagnosis and mismanagement of g-NENs may occasionally occur. In this review, I summarize the epidemiology, pathology, tumor staging, clinical classification, diagnostic algorithm, treatment and prognosis of g-NENs, to explain the standard diagnosis and management, as well as the latest advances in g-NEN research. The author advocates the four-type classification of g-NENs, and emphasizes that type 1 g-NENs are a recurrent disease which needs long-term follow-up. Molecular mechanism of recurrence of and medical therapy for type 1 g-NENs are the future research direction for neuroendocrine neoplasms.

A knockin mouse model for human ATP4aR703C mutation identified in familial gastric neuroendocrine tumors recapitulates the premalignant condition of the human disease and suggests new therapeutic strategies

By whole exome sequencing, we recently identified a missense mutation (p.R703C) in the human ATP4a gene, which encodes the proton pump responsible for gastric acidification. This mutation causes an aggressive familial type I gastric neuroendocrine tumor in homozygous individuals. Affected individuals show an early onset of the disease, characterized by gastric hypoacidity, hypergastrinemia, iron-deficiency anemia, gastric intestinal metaplasia and, in one case, an associated gastric adenocarcinoma. Total gastrectomy was performed as the definitive treatment in all affected individuals. We now describe the generation and characterization of a knockin mouse model for the ATP4a^R703C mutation to better understand the tumorigenesis process. Homozygous mice recapitulated most of the phenotypical alterations that were observed in human individuals, strongly suggesting that this mutation is the primary alteration responsible for disease development. Homozygous mice developed premalignant condition with severe hyperplasia, dysplasia and glandular metaplasia in the stomach. Interestingly, gastric acidification in homozygous mice, induced by treatment with 3% HCl acid in the drinking water, prevented (if treated from birth) or partially reverted (if treated during adulthood) the development of glandular metaplasia and dysplasia in the stomach and partially rescued the abnormal biochemical parameters. We therefore suggest that, in this model, achlorhydria contributes to tumorigenesis to a greater extent than hypergastrinemia. Furthermore, our mouse model represents a unique and novel tool for studying the pathologies associated with disturbances in gastric acid secretion.

Summary: Gastric pathologies in an ATP4a knockin mouse model of a mutation responsible for the development of gastric neuroendocrine tumors in humans are prevented and reverted by adding HCl to drinking water.

A 15-year experience with gastric neuroendocrine tumors: Does type make a difference?

BACKGROUND

Gastric neuroendocrine tumors (GNETs) are rare and classified into three types by disease etiology and typical behavior.

METHODS

The aim was to describe outcomes after GNET resection at a single institution from 2000 to 2014, stratified by tumor type. Given the small patient number, P-values were not assigned.

RESULTS

Of 22 patients, 12 patients (55%) had Type 1, none (0%) had Type 2, and 10 (45%) had Type 3 tumors. Compared to Type 3, Type 1 patients were younger (mean age: 52 vs. 59 years) with similar rates of endoscopic resection (25% vs. 20%). Type 1 GNETs often had multiple tumors (60% vs. 10%) and were not poorly differentiated (0% vs. 11%). Only 33% of Type 1 had nodal metastases compared to 71% of Type 3. Type 1 GNETs presented with metastatic disease less often (17% vs. 40%). Three year recurrence-free survival was 33% for Type 1 compared to 86% for Type 3. Disease-specific survival at 3-years was 100% and 75% for Types 1 and 3, respectively.

CONCLUSION

Type 1 GNETs are often indolent and multifocal without nodal involvement, but have high recurrence risk. Type 3 is more aggressive with increased nodal involvement; nodal evaluation should be routinely performed. Determination of GNET type is paramount to treating patients with this rare disease. J. Surg. Oncol. 2016;114:576-580. © 2016 Wiley Periodicals, Inc.

Current progress in diagnosis and therapy of neuroendocrine neoplasms of the digestive system

Neuroendocrine neoplasms (NENs) are a group of heterogeneous, biologically diverse, rare malignancies originated from the peptidergic neurons and neuroendocrine cells. In recent years, the incidence of NENs has been increasing gradually. They typically arise in the pancreas and gastrointestinal tract. Chromogranin A (CgA) has long been used as an important broad-spectrum marker for the identification of NENs. The diagnosis is based on histopathology demonstrating neuroendocrine features such as positive staining for chromogranin A and specific hormones such as gastrin, proinsulin, vasoactive intestinal peptide (VIP) and glucagon. In addition, radiological modalities including computed tomography (CT), positron emission tomography and computed tomography (PET/CT), magnetic resonance imaging (MRI), ultrasound (US), endoscopic ultrasound (EUS), and somatostatin receptor scintigraphy (SRS) can help establish a diagnosis. Surgery is still one of the cornerstones in the management of NENs. This article reviews the current progress in the diagnosis and therapy of NENs of the digestive system, including the pathological features and clinical diagnostic modalities for primary esophageal, gastric, duodenal, small intestinal, appendiceal, colonic, rectal, hepatic, gallbladder, extrahepatic bile duct, and pancreatic NENs, according to a revised system of classification, nomenclature and grading of NENs proposed by the fourth edition of "World Health Organization (WHO) classification of tumours of the digestive system" in 2010, and consensus of diagnosis and treatment of gastroenteropancreatic NENs (GEP-NENs) proposed by the Chinese Society of Clinical Oncology (CSCO) in 2013.

Clinical management of patients with gastric neuroendocrine neoplasms associated with chronic atrophic gastritis: a retrospective, multicentre study

To provide data regarding clinical presentation, pathological features, management, and response to different treatments of patients with type I gastric neuroendocrine tumors in stages 0-2A. The study design consist of an Italian multicentre, retrospective analysis of patients with type I gastric neuroendocrine tumors managed with different therapeutic approaches: surgery, endoscopic surveillance, endoscopic resection, or somatostatin analog therapy. Among the 97 patients included, 3 underwent surgery, 45 (46.4%) radical endoscopic resection of the neoplastic lesions, 13 (13.4%) follow-up with upper endoscopy, and 36 (37.1%) somatostatin analog therapy. At the end of the follow-up, all patients were alive and there was no evidence of metastatic disease. Somatostatin analog therapy resulted in a complete response in 76.0% of the patients and stable disease in 24.0%. A prolonged period of therapy, the use of a full dose of somatostatin analogs and higher gastrin levels at diagnosis were related to a complete response to the therapy. The recurrence rate was 26.3% in patients treated with somatostatin analog therapy and 26.2% in patients treated with endoscopic resection, without a statistically significant difference in terms of disease-free survival. Regarding recurrence of the disease, no statistical difference was found according to type of therapy, number of neoplastic lesions, and 2010 WHO classification. The only risk factor for tumor recurrence was a short period of medical treatment. In conclusion, our study suggested that endoscopic surveillance, endoscopic resection and somatostatin analog therapy represent valid options in the management of patients with type I gastric neuroendocrine tumors in stages 0-2A.

Intermittent treatment of recurrent type-1 gastric carcinoids with somatostatin analogues in patients with chronic autoimmune atrophic gastritis

BACKGROUND

Optimal management and treatment of type-1 gastric carcinoids is under debate.

AIMS

This prospective study evaluates the outcome of patients with recurrent type-1 gastric carcinoids treated with somatostatin analogues.

METHODS

From 2000 to 2013, among a population of 107 chronic atrophic gastritis patients, 25 (20% males, median age 62 years) developed type-1 gastric carcinoids and underwent regular clinical and endoscopic follow-up (median 77 months, range 6-165) after the initial treatment. Those patients showing recurrent disease were treated with somatostatin analogues until carcinoid disappearance.

RESULTS

12/25 patients (33% males, median age 65 years) showed recurrent gastric carcinoids and were treated with somatostatin analogues for a median duration of 12 months. Median gastrin and chromogranin A levels, which were 802 pg/mL and 33 U/L, respectively, decreased to 299 pg/mL (p=0.002) and 15.6 U/L (p=0.001) at the end of the treatment. Gastric carcinoids disappeared after a median length of treatment of 12 months. After a median time of 19.5 months from somatostatin analogues discontinuation, 4/12 patients (25% males, median age 56 years) showed a further recurrence. A new cycle of treatment was performed successfully.

CONCLUSIONS

This study confirms that type-1 gastric carcinoids are a recurring disease and somatostatin analogues, administered on 12-month cycles, represent an effective treatment.

Somatostatin analogs for gastric carcinoids: For many, but not all

Gastric carcinoids (GCs) are classified as: type I, related to hypergastrinemia due to chronic atrophic gastritis (CAG), type II, associated with Zollinger-Ellison syndrome in multiple endocrine neoplasia type 1, and type III, which is normogastrinemic. The management of type-I gastric carcinoids (GC1s) is still debated, because of their relatively benign course. According to the European Neuroendocrine Tumor Society guidelines endoscopic resection is indicated whenever possible; however, it is not often feasible because of the presence of a multifocal disease, large lesions, submucosal invasion or, rarely, lymph node involvement. Therefore, somatostatin analogs (SSAs) have been proposed as treatment for GC1s in view of their antisecretive, antiproliferative and antiangiogenic effects. However, in view of the high cost of this therapy, its possible side effects and the relatively benign course of the disease, SSAs should be reserved to specific subsets of "high risk patients", i.e., those patients with multifocal or recurrent GCs. Indeed, it is reasonable that, after the development of a gastric neuroendocrine neoplasm in patients with a chronic predisposing condition (such as CAG), other enterochromaffin-like cells can undergo neoplastic proliferation, being chronically stimulated by hypergastrinemia. Therefore, definite indications to SSAs treatment should be established in order to avoid the undertreatment or overtreatment of GCs.

Endoscopic diagnosis and management of type I neuroendocrine tumors

Type I gastric neuroendocrine tumors (TI-GNETs) are related to chronic atrophic gastritis with hypergastrinemia and enterochromaffin-like cell hyperplasia. The incidence of TI-GNETs has significantly increased, with the great majority being TI-GNETs. TI-GNETs present as small (< 10 mm) and multiple lesions endoscopically and are generally limited to the mucosa or submucosa. Narrow band imaging and high resolution magnification endoscopy may be helpful for the endoscopic diagnosis of TI-GNETs. TI-GNETs are usually histologically classified by World Health Organization criteria as G1 tumors. Therefore, TI-GNETs tend to display nearly benign behavior with a low risk of progression or metastasis. Several treatment options are currently available for these tumors, including surgical resection, endoscopic resection, and endoscopic surveillance. However, debate persists about the best management technique for TI-GNETs.

Chronic gastritis - an update

Helicobacter pylori is the main aetiologic factor for chronic gastritis worldwide. The degree of inflammation and the evolution of this form of chronic gastritis can vary largely depending on bacterial virulence factors, host susceptibility factors and environmental conditions. Autoimmune gastritis is another cause of chronic inflammation in the stomach, which can occur in all age groups. This disease presents typically with vitamin B12 deficiency and pernicious anaemia. The presence of anti-parietal cell antibodies is highly specific for the diagnosis. The role of H. pylori as a trigger for autoimmune gastritis remains uncertain. Other rare conditions for chronic gastritis are chronic inflammatory conditions such as Crohn's disease or on the background of lymphocytic or collagenous gastroenteropathies.