Classification, clinicopathologic features and treatment of gastric neuroendocrine tumors

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.

Correlation between clinicopathological characteristics and the clinical prognosis of patients with gastroenteropancreatic neuroendocrine tumors

Gastroenteropancreatic (GEP) neuroendocrine tumors (NETs) are one of the most common types of NETs, accounting for 65-75% of all NETs. However, epidemiological characteristics of patients with GEP-NETs in China are still lacking. The present retrospective study aimed to investigate the local epidemiology of GEP-NETs and assess the prognostic factors in China. The data of 267 patients with GEP-NETs who were admitted to the First Affiliated Hospital of Bengbu Medical College (Bengbu, China) and the Affiliated Hospital of West Anhui Health Vocational College (Lu'an, China) were retrospectively reviewed. The clinical and pathological characteristics of the patients, as well as follow-up information, were collected, and the 5-year survival rate was calculated. Kaplan-Meier curves and log-rank analysis were used to analyze the prognostic factors. The stomach (100/267; 37.5%) was the most common site of GEP-NETs and the liver (25/39; 64.1%) was the most common metastatic site. A total of 166 (62.2%) and 219 (82.0%) patients had positive results for chromogranin A (CgA) and synaptophysin (Syn), respectively. The percentage of patients with tumor grade G1, G2 and G3 was 33.3, 21.0 and 45.7%, respectively. The 5-year overall survival rate was 79.7%, and the age, tumor site, distant metastasis and tumor grading upon diagnosis were all prognostic factors. In conclusion, the present case series investigated the epidemiology and prognostic factors of GEP-NETs in China. CgA and Syn could be used as diagnostic markers for NETs and the stomach was the most common primary tumor site. Lymph node metastasis, tumor site, distant metastasis and tumor grading were important prognostic factors.

GASTRIC NEUROENDOCRINE TUMOR: WHEN SURGICAL TREATMENT IS INDICATED?

BACKGROUND

Gastric neuroendocrine tumors are a heterogeneous group of neoplasms that produce bioactive substances. Their treatment varies according to staging and classification, using endoscopic techniques, open surgery, chemotherapy, radiotherapy, and drugs analogous to somatostatin.

AIMS

To identify and review cases of gastric neuroendocrine neoplasia submitted to surgical treatment.

METHODS

Review of surgically treated patients from 1983 to 2018.

RESULTS

Fifteen patients were included, predominantly female (73.33%), with a mean age of 55.93 years. The most common symptom was epigastric pain (93.3%), and the mean time of symptom onset was 10.07 months. The preoperative upper digestive endoscopy (UDE) indicated a predominance of cases with 0 to 1 lesion (60%), sizing ≥1.5 cm (40%), located in the gastric antrum (53.33%), with ulceration (60%), and Borrmann III (33.33%) classification. The assessment of the surgical specimen indicated a predominance of invasive neuroendocrine tumors (60%), with angiolymphatic invasion in most cases (80%). Immunohistochemistry for chromogranin A was positive in 60% of cases and for synaptophysin in 66.7%, with a predominant Ki-67 index between 0 and 2%. Metastasis was observed in 20% of patients. The surgical procedure most performed was subtotal gastrectomy with Roux-en-Y reconstruction (53.3%). Tumor recurrence occurred in 20% of cases and a new treatment was required in 26.67%.

CONCLUSIONS

Gastric neuroendocrine tumors have a low incidence in the general population, and surgical treatment is indicated for advanced lesions. The study of its management gains importance in view of the specificities of each case and the need for adequate conduct to prevent recurrences and complications.

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.

An Unusual Cause of GI Blood Loss

Chronic gastrointestinal bleeding is the leading cause of iron deficiency anemia in developed countries, and most occult bleeds are attributed to upper gastrointestinal tract lesions, which are broadly categorized into mass lesions, vascular, infectious, and inflammatory abnormalities. Gastric polyps account for an exceedingly small portion of these lesions but are of clinical importance because of the risk for progression to malignancy. We describe a patient found to have a gastric foveolar-type adenoma as a rare cause of iron deficiency anemia, with an incidentally found gastric neuroendocrine tumor.

Clinical Complete Response of Recurrent Gastric Cancer after Third-line CPT-11 Chemotherapy

A 75-year-old man underwent distal gastrectomy for advanced gastric cancer in September 2018. During the adjuvant chemotherapy, computed tomography (CT) revealed recurrence sites in the liver and para-aortic lymph nodes. Therefore, chemotherapy was initiated. After first-line (capecitabine with oxaliplatin) and second-line (paclitaxel with ramucirumab) treatments, nivolumab was used as third-line chemotherapy. This treatment showed a strong effect against the tumor. However, following an immune-related adverse effect (irAE) because of nivolumab, the therapy was halted. The irAE was diagnosed with central adrenal insufficiency that was controllable by oral intake of steroids. CPT-11 was started and showed a similarly strong effect to that observed for nivolumab. Eventually, the recurrent tumor lesions became too small to be detected by CT. We discontinued CPT-11 at the request of the patient. Even after discontinuation, no recurrent sites have been observed, allowing us to declare a case of clinical complete response (cCR). In conclusion, even if irAEs occur in a patient, continuing chemotherapy should be considered. However, if cCR is achieved, discontinuation of chemotherapy might be a strategic treatment option.

Unsuspected gastric glomus tumour

Gastric glomus tumours (GGTs) are rare predominantly benign, mesenchymal neoplasms that commonly arise from the muscularis or submucosa of the gastric antrum and account for <1% of gastrointestinal soft-tissue tumours. Historically, GGT has been difficult to diagnose preoperatively due to the lack of unique clinical, endoscopic and CT features. We present a case of an incidentally identified GGT in an asymptomatic man that was initially considered a neuroendocrine tumour (NET) by preoperative fine-needle aspiration biopsy with focal synaptophysin reactivity. An elective robotic distal gastrectomy and regional lymphadenectomy were performed. Postoperative review by pathology confirmed the diagnosis of GGT. GGTs should be considered by morphology as a differential diagnosis of gastric NET on cytology biopsy, especially if there is focal synaptophysin reactivity. Additional staining for SMA and BRAF, if atypical/malignant, can help with this distinction. Providers should be aware of the biological behaviour and treatment of GGTs.

[Difficulties in diagnosis of neuroendocrine tumors of the gastrointestinal tract]

We present diagnosis and complex minimally invasive surgical treatment of a patient with long-standing neuroendocrine tumor of the upper gastrointestinal tract. We followed-up a 50-year-old female patient after endoscopic resection of polypoid neoplasm of the stomach for 2 non-organ retroperitoneal neoplasms in the area of hepatogastric ligament. After a comprehensive examination and minimally invasive surgery including laparoscopic resection of retroperitoneal neoplasms, immunohistochemical examination, PET-CT and targeted endoscopic ultrasound of the stomach, we diagnosed a highly differentiated gastric neuroendocrine tumor with metastases into lymph nodes of hepatogastric ligament. Combination of endoscopic and morphological diagnosis with rigorous histological examination of specimen provided correct diagnosis and reasonable strategy of aggressive minimally invasive surgical treatment.

Neuroendocrine neoplasm imaging: protocols by site of origin

With the relatively low incidence of neuroendocrine neoplasms (NEN), most radiologists are not familiar with their optimal imaging techniques. The imaging protocols for NENs should be tailored to the site of origin to accurately define local extension of NEN at time of staging. Patterns of spread and recurrence should be taken into consideration when choosing protocols for detection of recurrence and metastases. This paper will present the recommended CT and MRI imaging protocols for gastro-enteric and pancreatic NENs based on site of origin or predominant pattern of metastatic disease, and explain the rationale for MRI contrast type, contrast timing, as well as specific sequences in MRI. We will also briefly comment on PET/CT and PET/MRI imaging protocols.

Metastatic multiple gastric neuroendocrine tumors with a long history of proton pump inhibitor use: A case report

It is widely accepted that gastric neuroendocrine tumors (NETs) develop due to enterochromaffin-like (ECL) cell proliferation following exposure to hypergastrinemia, which causes hyperplastic-dysplastic-neoplastic changes. Here we describe the case of a 46-year-old female patient diagnosed with metastatic NETs by liver biopsy and evaluated at an external center. At our hospital, nodular structures extending from the cardia to the antrum were observed by gastroscopy, considered the primary tumor focus. Histopathological examination revealed a trabecular-insular pattern, with microNETs consisting of monotone cells with round-oval nuclei and surrounding neuroendocrine cell hyperplasia foci and fundic gland polyps. The patient had a history of regular proton pump inhibitor (PPI) use for 10 years and a serum gastrin of 9240 pg/mL. A 3-cm metastatic lesion in the left lobe of the liver was observed in whole-body imaging with octreotide. By gastrectomy, we observed a large number of nodular lesions in the corpus-antrum and a 3-cm diameter lesion in the hepatectomy material. Histopathological examination revealed NETs in multiple foci with submucosal invasion in the stomach. The Ki-67 proliferative index was 3%. Metastatic tumors of similar morphology were found in the liver and three of the greater curvature lymph nodes. We made a diagnosis of multiple gastric NETs (Grade 2). In Type I gastric NETs, the neuroendocrine cell proliferation spectrum up to NET is observed as a result of hypergastrinemia due to atrophic gastritis. Also, in experimental studies, prolonged hypergastrinemia has been reported to cause ECL cell neoplasms in animals treated with PPIs. Although our case could be accepted as Type 1 NET, the possibility of developing NET secondary to long-term PPI use should also be considered.

RUNDC3A/SNAP25/Akt signaling mediates tumor progression and chemoresistance in gastric neuroendocrine carcinoma

Gastric neuroendocrine carcinoma (GNEC), a heterogeneous group of neuroendocrine neoplasms (NENs) derived from gastric neuroendocrine cells, has been shown to be more aggressive and chemoresistant in gastric cancer, which contributes to the poor prognosis. We analysed transcriptome profiles of tumor/non-tumor tissue from GNEC patients and GNEC cell lines to explore the underlying mechanisms. Our results suggest a critical role for synaptosomal-associated protein 25 kDa (SNAP25) in GNEC. SNAP25 was found to stabilize Akt via modulating its monoubiquitination. We further identified RUN domain containing 3A (RUNDC3A) as an upstream molecule that regulates SNAP25 expression, which is associated with tumor progression and chemoresistance in GNECs. Moreover, these findings were extended into multiple NENs including neuroendocrine carcinomas in the intestinal tract, lungs and pancreas. Identifying the RUNDC3A/SNAP25/Akt axis in NENs may provide a novel insight into the potential therapeutic target for patients with NENs.

An unusual association of folic acid deficiency with gastric neuroendocrine tumor type I

The association of gastric neuroendocrine tumour type I with macrocytic anaemia due to vitamin B12 deficiency is commonly encountered. The etiological cause of macrocytic anaemia must always be precisely established for the subsequent treatment guidance. We present the case of a 63-year-old patient admitted for marked physical asthenia, palpitations, abdominal pain, flatulence, paresthesia in the upper and lower limbs and concentration difficulties. Clinical examination revealed pale, dry skin, Hunter's glossitis, and tachycardic heart sounds. Bloodwork showed pancytopenia with macrocytic normochromic anaemia, vitamin B12 within normal limits, but with low folic acid levels. The reticulocyte crisis was documented on day three after initiating folic acid treatment. Exploration by upper digestive endoscopy and colonoscopy described multiple polypoid tumours in the greater curvature of the stomach. The histopathological and immunohistochemical examination lead to the diagnosis of gastric neuroendocrine tumours (NET) type G1. To our knowledge, there are no reports about an association of this type of tumour with folate deficiency-induced anaemia.

Management of type-I gastric neuroendocrine neoplasms: A 10-years prospective single centre study

BACKGROUND

This study aimed to evaluate the outcome of patients with type 1 gastric neuroendocrine neoplasia (T1gNENs) treated with different endoscopic approaches.

METHODS

Patients were managed with endoscopic surveillance at regular intervals. Resection was performed by forceps or cold snare in tumours < 10 mm, otherwise mucosal resection (EMR) or submucosal dissection (ESD) were done.

RESULTS

127 T1gNENs, detected in 80 patients, were included. 87.4% of them were <5 mm, whereas 8.7% were 6-10 mm, 3.1% were 11-20 mm, and 0.8% was >20 mm. Ki67 <3%% was found in 85.8% tumours, whereas it was 3%-20% in the remaining 14.2% lesions. Noninterventional management (surveillance without radical resection) was performed in 15 patients (18.7%) with T1gNENs <5 mm. None of them underwent disease progression during follow-up. among the 65 patients treated by radical endoscopic resection, 37 patients (56.9%) had disease recurrence. 48.5% T1gNENs were removed by forceps, 16.8% by cold snare, 31.7% by EMR and 3% by ESD. The recurrence rate was similar among the different endoscopic techniques used.

CONCLUSIONS

The management of T1gNENs may be planned based on tumour size. T1gNENs < 5 mm for which the initial removal is not radical could be followed up by noninterventional endoscopic surveillance.

RUNDC3A regulates SNAP25-mediated chemotherapy resistance by binding AKT in gastric neuroendocrine carcinoma (GNEC)

Gastric neuroendocrine carcinoma (GNEC) is a common type of neuroendocrine carcinoma (NEC) with a poor prognosis and limited therapeutic options. The underlying mechanisms of chemoresistance in patients with GNEC and those with NEC are largely unknown, and thus, reliable biomarkers and therapeutic targets that could improve treatment outcomes in patients with NECs are lacking. The aim of this study was to identify specific targets and investigate their roles in GNEC progression and treatment resistance. Differentially expressed genes (DEGs) were identified in GNEC specimens and were further analysed by focusing on their roles in chemoresistance. Gene Ontology (GO) and pathway enrichment analyses of GNEC DEGs revealed that synapse-related function was the most prominent cellular function perturbed in GNEC. SNAP25 was identified as the target gene involved in most of the enriched pathways. In vitro and in vivo experiments showed that SNAP25 plays a role in proliferation and chemoresistance in GNEC cell lines. AKT has been identified as a downstream target, and SNAP25 binds to AKT protein and promotes AKT protein half-life. Further analysis of other types of NEC as well as small cell lung cancer, which resembles NEC on a molecular level, has identified RUNDC3A as an upstream molecule that regulates SNAP25 expression and the associated phenotypes that could enhance chemoresistance in NECs. Our results show that SNAP25 expression in GNEC is mediated by RUNDC3A and promotes GNEC progression and chemoresistance via posttranslational modification of AKT. Thus, our results suggest that the RUNDC3A/SNAP25/Akt axis could be a potential therapeutic target in GNEC.

Gastric and Duodenal Neuroendocrine Tumor Incidentally Found on Endoscopy During the Evaluation of Iron-Deficiency Anemia

Neuroendocrine tumors (NET) are a small fraction of overall gastrointestinal (GI) malignancies. Recently the incidence of NETs has increased due to advancements in diagnostic modality. While solid tumors are easily visible on routine endoscopy, identifying endocrine tumors can be difficult, and low incidence and non-specific presentation can be easily missed on upper gastrointestinal endoscopy (UGIE). The management differs based on the type of tumor and location, but the overall prognosis is good. We present a 59-year-old male with multiple NETs throughout the GI tract, diagnosed on repeat esophagogastroduodenoscopy (EGD) with endoscopic ultrasound (EUS) showing multiple gastric folds. A biopsy of multiple nodules was taken to diagnose type I NET with grade 2 differentiation finally. The mucosal nodules were resected with a band ligator, and surveillance endoscopy was recommended.

Gastric neuroendocrine neoplasms and precursor lesions: Case reports and literature review

RATIONALE

Gastric neuroendocrine neoplasms (g-NENs) represent a distinctive group of gastric tumors, stratified into different prognostic categories according to different histological characteristics, put forth in the 2018 World Health Organization classification system. The clinical presentations, as well as pathological features, represent important data in establishing the type of the tumor, in estimating the tumor behavior, and in selecting the best therapeutic strategy. In our case series we presented different clinical scenarios that may be encountered in practice regarding gastric NENs. We performed a literature review and discussed diagnostic strategy, current classification system, precursor lesions, and therapeutic options in g-NENs.

PATIENT CONCERNS

The first patient was a 41-year-old female with weight loss, persistent dyspeptic complaints and a history of pernicious anemia. In the second clinical case a 61-year-old man was admitted with heartburn, abdominal pain, diarrhea and mild iron deficiency anemia. The third patient was a 56-year-old male with a history of neoplasia, admitted for weight loss, dyspeptic complaints, and liver metastases.

DIAGNOSIS

All the 3 patients underwent upper endoscopy with targeted biopsies. Histopathological and laboratory evaluation, together with imagistic evaluation (abdominal ultrasound, endoscopic ultrasound, and magnetic resonance imaging) allowed the distinction between 3 different types of gastric tumors: type 1 enterochromaffin-like-cell G1 NET, type 2 enterochromaffin-like-cell G2 NET, and type 3 G2 NET with liver metastases.

INTERVENTIONS

Endoscopic polypectomy of the largest lesion was performed in patient with type 1 g-NET and autoimmune chronic atrophic gastritis, followed by regular endoscopic surveillance with biopsies. In type 2 g-NET associated with pancreatic gastrinoma, pancreaticoduodenectomy with total gastrectomy were performed. In type 3 g-NET, detected in metastatic stage, oncologic therapy was performed.

OUTCOMES

The patients follow-up was selected according to tumor behavior, from regular endoscopic surveillance to oncology follow-up. The prognosis was good in case 1, whilst poorer outcomes were associated with more aggressive tumors in case 2 and case 3.

LESSONS

g-NENs are rare tumors with distinct clinical and histological features. Our case series emphasized the role of close collaboration between clinician and pathologist, as well as the importance of a detailed pathology report.

Endocrine and paracrine characteristics of neuroendocrine prostate cancer

Prostate cancer is a common malignancy affecting men worldwide. While the vast majority of newly diagnosed prostate cancers are categorized as adenocarcinomas, a spectrum of uncommon tumor types occur including those with small cell and neuroendocrine cell features. Benign neuroendocrine cells exist in the normal prostate microenvironment, and these cells may give rise to primary neuroendocrine carcinomas. However, the more common development of neuroendocrine prostate cancer is observed after therapeutics designed to repress the signaling program regulated by the androgen receptor which is active in the majority of localized and metastatic adenocarcinomas. Neuroendocrine tumors are identified through immunohistochemical staining for common markers including chromogranin A/B, synaptophysin and neuron specific enolase (NSE). These markers are also common to neuroendocrine tumors that arise in other tissues and organs such as the gastrointestinal tract, pancreas, lung and skin. Notably, neuroendocrine prostate cancer shares biochemical features with nerve cells, particularly functions involving the secretion of a variety of peptides and proteins. These secreted factors have the potential to exert local paracrine effects, and distant endocrine effects that may modulate tumor progression, invasion, and resistance to therapy. This review discusses the spectrum of factors derived from neuroendocrine prostate cancers and their potential to influence the pathophysiology of localized and metastatic prostate cancer.

A Modified T-stage Classification for Gastric Neuroendocrine Tumors

BACKGROUND

The eighth edition of the American Joint Committee on Cancer (AJCC) staging manual's TNM staging classification for gastric neuroendocrine tumors has been shown to have poor prognostic discriminability. The aim of present study was to propose a modified T-stage classification, and externally validate its performance in a separate population data registry.

METHODS

A modified T-stage classification with tumor size and extent of tumor invasion was generated from the National Cancer Database between 2004 and 2014 (n = 1249). External validation was performed using the Surveillance, Epidemiology, and End Results registry between 1973 and 2013 (n = 539).

RESULTS

In the National Cancer Database population, using the AJCC T-stage classification, the 5-y survival rates were 85.7%, 80.8%, 64.5%, and 46.1% in T1, T2, T3, and T4 patients respectively (P < 0.001). These rates were more contrasting with the modified T-stage (mT) classification at 87.0%, 78.2%, 59.0%, and 40.3% respectively (P < 0.001). When patients within each of the AJCC T stages were stratified by mT stages, significant survival heterogeneity was observed within each of the AJCC T2 to T4 stages (P < 0.01). Conversely, when mT stages were stratified by AJCC T stage, no survival difference was observed in any of the mT stages (P > 0.05). The same analyses were performed using Surveillance, Epidemiology, and End Results data, and all the observed results were validated.

CONCLUSION

The current AJCC T stage classification categorizes patients into groups with heterogenous prognosis, thus failing to serve as an effective staging tool. A modified T-stage classification demonstrated significantly improved stratification for patients with gastric neuroendocrine tumors.

Gastric Neuroendocrine Tumor Mimicking Gastrointestinal Stromal Tumor: A Case Report

Gastric neuroendocrine tumors (NETs) are rare lesions that arise from enterochromaffin-like cells of the gastric mucosa. Gastric NETs are classified into 3 types of NETs and poorly differentiated neuroendocrine cancers. Most gastric NETs usually present as hemispherical, yellowish, polypoid lesions with a central depression and often as subepithelial tumors (SETs) because they are confined within the submucosal layer. Here, we report a case of gastric NET presenting as SET mimicking a gastrointestinal stromal tumor (GIST). Endoscopy revealed a 2.3-cm-sized SET with intact surface mucosa, and endoscopic ultrasonography showed a homogeneous hypoechoic lesion with a well-circumscribed margin. Typical features of gastric NET, such as yellowish mucosal changes or central ulceration, were not observed. GIST was suspected, and a laparoscopic wedge resection was performed. The final diagnosis was gastric NET with grade 2 differentiation.

Gastroenteropancreatic neuroendocrine neoplasms G3: Novel insights and unmet needs

According to the 2019 WHO pathology grading system, high-grade gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) can be divided into well differentiated neuroendocrine tumors G3 (NETs G3) and poorly differentiated neuroendocrine carcinomas (NECs). GEP-NETs G3 and GEP-NECs present significant differences in driver genes and disease origin. NETs G3 and NECs have been confirmed to be two distinct diseases with different genetic backgrounds, however, this issue remains controversial. The prognosis of NETs G3 is significantly better than that of NECs. The differential diagnosis of GEP-NETs G3 and GEP-NECs should be combined with the patient's medical history, tumor histopathology, Ki-67 index, DAXX/ATRX, TP53 and Rb expression as well as other immunohistochemical indicators. In addition, the treatment strategies of these two subgroups are very different. Here, we summarize recent findings focused on the genomics, clinical manifestations, diagnosis, treatment and other aspects of high-grade GEP-NENs (G3). This review may help further our understanding of the carcinogenesis, diagnosis and treatment of GEP-NENs G3.

Progression From Antral G-Cell Hyperplasia to Gastric Neuroendocrine Tumor in a Patient With Autoimmune Gastritis

Autoimmune metaplastic atrophic gastritis is caused by immune-mediated destruction of gastric parietal cells. This leads to the absence of gastric acid production, which causes compensatory hyperplasia of gastric antral G-cells leading to hypergastrinemia. The excess gastrin binds to enterochromaffin-like cells causing hyperplasia, which may progress to dysplasia and rarely to gastric neuroendocrine tumors. We present a rare case of autoimmune metaplastic atrophic gastritis associated with G-cell hyperplasia showing the full developmental spectrum of enterochromaffin-like cell proliferation from hyperplasia to dysplasia to neuroendocrine tumor.

What is New in the 2019 World Health Organization (WHO) Classification of Tumors of the Digestive System: Review of Selected Updates on Neuroendocrine Neoplasms, Appendiceal Tumors, and Molecular Testing

CONTEXT.—

The 5th edition of the World Health Organization classification of digestive system tumors discusses several advancements and developments in understanding the etiology, pathogenesis, and diagnosis of several digestive tract tumors.

OBJECTIVE.—

To provide a summary of the updates with a focus on neuroendocrine neoplasms, appendiceal tumors, and the molecular advances in tumors of the digestive system.

DATA SOURCES.—

English literature and personal experiences.

CONCLUSIONS.—

Some of the particularly important updates in the 5th edition are the alterations made in the classification of neuroendocrine neoplasms, understanding of pathogenesis of appendiceal tumors and their precursor lesions, and the expanded role of molecular pathology in establishing an accurate diagnosis or predicting prognosis and response to treatment.

Gastric Neuroendocrine Tumor

Gastric neuroendocrine tumor (gNET) is a rare carcinoid of the stomach whose incidence is increasing due to widespread use of upper gastrointestinal endoscopy (UGIE). There are four types of gNETs with different management strategies and prognosis. Here, we present a patient who came with abdomen pain and intermittent melena. UGIE showed a sessile polyp in the stomach. The patient subsequently underwent polypectomy and was symptomatically relieved.

Histopathological classification and follow-up analysis of chronic atrophic gastritis

BACKGROUND

The pathological diagnosis and follow-up analysis of gastric mucosal biopsy have been paid much attention, and some scholars have proposed the pathological diagnosis of 12 kinds of lesions and accompanying pathological diagnosis, which is of great significance for the treatment of precision gastric diseases, the improvement of the early diagnosis rate of gastric cancer, and the reduction of missed diagnosis rate and misdiagnosis rate.

AIM

To perform a histopathological classification and follow-up analysis of chronic atrophic gastritis (CAG).

METHODS

A total of 2248 CAG tissue samples were collected, and data of their clinical characteristics were also gathered. Based on these samples, the expression levels of Mucin 1 (MUC1), MUC2, MUC5AC, and MUC6 in CAG tissue were tested by immunohistochemical assay. Moreover, we followed these patients for up to four years. The difference between different stages of gastroscopic biopsy was observed.

RESULTS

Through observation, it is believed that CAG should be divided into four types, simple type, hyperplasia type, intestinal metaplasia (IM) type, and intraepithelial neoplasia (IEN) type. Simple CAG accounted for 9.1% (205/2248), which was more common in elderly people over 60 years old. The main change was that the lamina propria glands were reduced in size and number. Hyperplastic CAG accounted for 29.1% (654/2248), mostly occurring between 40 and 60 years old. The main change was that the lamina propria glands were atrophy accompanied by glandular hyperplasia and slight expansion of the glands. IM CAG accounted for 50.4% (1132/2248), most of which increased with age, and were more common in those over 50 years. The atrophy of the lamina propria glands was accompanied by significant IM, and the mucus containing sialic acid or sulfate was distinguished according to the nature of the mucus. The IEN type CAG accounted for 11.4% (257/2248), which developed from the previous types, with severe gland atrophy and reduced mucus secretion, and is an important precancerous lesion.

CONCLUSION

The histological typing of CAG is convenient to understand the property of lesion, determine the follow-up time, and guide the clinical treatment.

Gastric neuroendocrine tumor with Helicobacter pylori-associated chronic gastritis

INTRODUCTION

Development of gastric neuroendocrine neoplasms in subjects infected with Helicobacter pylori is rare and it occurs through pathogenetic mechanisms related to gastrin.

PRESENTATION OF CASE

We report a case of gastric neuroendocrine tumor in a patient infected with Helicobacter pylori and normal gastrin levels. He was treated by endoscopic mucosal dissection after eradication of Helicobacter pylori infection. Histologically the tumor was consistent with a grade 2 well differentiated neuroendocrine tumor. It was characterized by the presence of lymphoid aggregates around and inside the neoplasia.

DISCUSSION

Helicobacter pylori-associated chronic gastritis can rarely cause the development of gastric neuroendocrine tumors through mechanisms unrelated to gastrin.

CONCLUSION

The one related to a chronic Helicobacter pylori infection may be considered a distinct type of gastric neuroendocrine tumor.

The band and slough technique is effective for management of diminutive type 1 gastric and duodenal neuroendocrine tumors

Background and study aims  Endoscopic resection is recommended as initial treatment for early-stage gastric and duodenal neuroendocrine tumors (G-NETs and D-NETs). However, it can cause serious adverse events. We aimed to evaluate the efficacy and safety of the band and slough (BAS) technique as a novel and less aggressive endoscopic therapy for management of such tumors. Four patients, three diagnosed with < 10-mm D-NET and one with 10-mm type I G-NET, were treated with the BAS technique without endoscopic resection. Initial follow-up endoscopy at 3 months was done to assess for residual tumor. Subsequent endoscopic surveillance was performed. After one session of banding, all patients achieved complete remission at 3-month follow-up. No tumor recurrence was detected on repeat biopsy at 12-month surveillance endoscopy. None of the patients developed any adverse events including bleeding or perforation. The BAS technique may prove to be a safe and effective endoscopic therapy for diminutive, non-metastatic type 1 G-NETs and D-NETs. Studies of larger scale and longer follow-up periods are needed to corroborate these findings.

Prognostic value of the 2017 World Health Organization Classification System for gastric neuroendocrine tumors: A single-center experience

BACKGROUND/AIMS

Gastric neuroendocrine tumors (G-NETs) are rare tumors, but their incidence is gradually increasing. Despite the existence of many classification systems, determining prognosis and planning treatment in patients with G-NETs remains a clinical challenge. In this study, the prognostic value of the World Health Organization (WHO) 2017 grading system and the effect of surgery on survival in low grade neuroendocrine tumors were investigated.

MATERIALS AND METHODS

G-NETs who were diagnosed between January 2000 and May 2017 were included in the study. Patients' demographic characteristics, treatment details, and survival data were obtained from medical charts. Pathological samples were re-classified according to the WHO 2017 grading system.

RESULTS

Of the total 94 evaluated patients, 50 (53.2%) were classified with G1 NETs, 37(39.4%) with G2 NETs, 4(4.2%) with well-differentiated G3 NETs, and the remaining 3 patients with poorly differentiated G3 neuroendocrine carcinoma (NEC). The median follow-up time was 83.2 months. There was a statistically significant difference in 5-year progression free survival (PFS) between G1 tumors (100%) and G2 tumors (76%) (p<0.001). However, there was no statistically significant deference in 5-year overall survival rate (OS) for G1 (97%) and G2 (82%) tumors (p=0.141). When G2 and G1 NETs were compared according to their surgical approach, radical surgery was more frequently performed in patients with G2 tumors (p<0.001). However, radical surgery did not improve PFS in G1 and G2 NETs.

CONCLUSION

The WHO 2017 NET classification system may have low prognostic value for determining the prognosis of patients with G1 and G2 tumors. Radical surgery for G1 and G2 NETs did not improve PFS in our study.

[Gastric neuroendocrine tumors]

Gastrointestinal neuroendocrine tumors are rare neoplasms. Currently, incidence of gastric neuroendocrine tumors (gNETs) is being significantly increased. There are 3 groups of gNETs: types I, II and III. Each type has important features regarding clinical picture, prognosis and treatment strategy. Type I is the most common (70-80%) and associated with chronic atrophic gastritis including autoimmune gastritis and Helicobacter associated atrophic gastritis. Type II (5-6%) is associated with multiple endocrine neoplasia type I and Zollinger-Ellison syndrome (MEN I - ZES). Both types are characterized by hypergastrinemia and small tumor dimension. These neoplasms are multiple and mostly benign. On the contrary, NETs type III (10-15%) is not associated with hypergastrinemia and represented by single large neoplasms. Tumors are malignant as a rule. Therefore, surgical resection and chemotherapy are preferred for these tumors. Endoscopic surgery followed by observation is acceptable for almost all NETS type I and II. At the same time, this approach is advisable only for small and highly differentiated neoplasms type III.

Natural history of autoimmune atrophic gastritis: a prospective, single centre, long-term experience

BACKGROUND

Autoimmune atrophic gastritis (AAG) is an immune-mediated disorder characterised by destruction of gastric oxyntic mucosa AIM: To explore gastric histopathological evolution in a cohort of AAG patients over a prolonged follow-up METHODS: Single centre prospective study enrolling consecutive patients with histologically confirmed AAG between 2000 and 2018. All AAG patients undergoing endoscopic follow-up every 1-3 years were classified as having stages 1, 2 or 3 according to atrophy severity (mild, moderate and severe). AAG patients with either glandular or neuroendocrine dysplasia/neoplasia were classified as having stage 4. Disease stage progression, and changes in serum anti-parietal cell antibody (PCA), chromogranin A and gastrin-17 were assessed.

RESULTS

In total, 282 AAG patients (mean age 60.3 years; F:M ratio 2.4:1; median follow-up 3 years, interquartile range 1-7) were enrolled. All patients with stages 1 or 2 progressed to stage 2 or 3 over time with a steady trend (P = .243) and regression from a severe to a milder stage was never noticed. Disease progression of patients with stages 1 or 2 occurred within the first 3 years. PCA positivity rate did not change over time. Stage 3 patients had higher gastrin-17 levels compared to patients with stages 1 and 2 (median 606 vs 295 pg/mL; P < .001). In stage 3, the hazard ratio for the risk of developing stage 4 was 6.6 (95% CI 1.5-29; P = .001).

CONCLUSIONS

AAG is a steadily progressive disease, in which stages 1 and 2 always progress to stage 3. The risk of developing a complicated disease stage is greater in patients with more severe gastric lesions.

Pathologic Complete Response After Neoadjuvant Chemoradiation in a Patient with Gastric Neuroendocrine Cancer

Neuroendocrine tumors are about 0.5% of all malignancies. Specifically, for gastrointestinal (GI) malignancies, neuroendocrine tumor incidence is approximately 1%-2% per year. Gastric neuroendocrine neoplasms are rare and consist of various tumor types with differing histomorphology, pathogenesis, and biological behavior. Following surgery, post-operative chemotherapy is generally considered the standard of care. Our case report demonstrates the potential benefit of neoadjuvant concurrent chemoradiotherapy prior to surgery for a malignant gastric neuroendocrine tumor. While radiotherapy has been demonstrated to possibly provide a survival benefit in the treatment of GI neuroendocrine tumors, its use in treatment, particularly neoadjuvantly, needs to be further assessed.

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.

An atypical type I gastric neuroendocrine tumor

BACKGROUND

Gastric neuroendocrine tumors (GI-NETs) are rare lesions, usually discovered incidentally during endoscopy. Based on their pathology, there are 4 types of GI-NETs. Type I are multiple small polypoid lesions with central ulceration located in the gastric body or the fundus, associated with atrophic gastritis usually noninvasive and very rarely metastatic. We report on a rare case of a gastric NET arising from the muscularis propria layer of the pyloric ring.

CASE REPORT

We present the case of a 65-year old woman with a history of alcoholic cirrhosis, investigated for melena. Upper endoscopy revealed a 30 mm submucosal pedunculated polypoid lesion located on the pylorus protruding in the duodenum, with normal overlying mucosa, fundic gastric atrophy and multiple small polyps at this level, with no active bleeding. CT scan did not reveal any distant metastases. An ultrasound endoscopy was performed, and a round hypoechoic heterogeneous solitary mass, evolving from the pyloric muscle was described. Considering a 30-mm tumor evolving from the gastric muscle layer in the absence of local invasion and with no distant metastases we decided against an endoscopical resection and we referred the patient to surgery. A laparoscopic wedge resection was performed. The pathology report described a 30/25 mm welldifferentiated neuroendocrine tumor invasive in the muscularis mucosa (pT3).

CONCLUSIONS

Usually, type I neuroendocrine tumors are located in the body or the fundus of the stomach without submucosal invasion. The interesting feature in our case was that the tumor originated from the pylorus, making it an atypical presentation for a neuroendocrine tumor.

Gastric carcinoids: Does type of surgery or tumor affect survival?

BACKGROUND

Gastric carcinoids are rare neuroendocrine tumors of the gastrointestinal tract. They are typically managed according to their etiology. However, there is little known about the impact of surgical strategy on the long-term outcomes of these patients.

METHODS

All patients who underwent resection of gastric carcinoids at 8 institutions from 2000 to 2016 were analyzed retrospectively. Tumors were stratified according to subtype (I, II, III, IV) and resection type (local resection, LR or formal gastrectomy, FG). Clinicopathological parameters, recurrence-free (RFS) and overall survival (OS) were compared between groups.

RESULTS

Of 79 patients identified with gastric carcinoids, 34 had type I lesions associated with atrophic gastritis, 4 had type II lesions associated with a gastrinoma, 37 had type III sporadic lesions, and 4 had type IV poorly-differentiated lesions. The mean age of presentation was 56 years in predominantly Caucasian (77%) and female (63%) patients. Mean tumor size was 2.4 cm and multifocal tumors were found in 24 (30%) of patients with the majority occurring in those with type I tumors. Lymph node positive tumors were seen in 15 (19%) patients and 7 (8%) had M1 disease; both most often in type IV followed by type III tumors. R0 resection was achieved in 56 (71%) patients while 15 (19%) had R1 resections and 6 (8%) R2 resections. Patients with type I and III tumors were equally likely to have a LR (50% and 43% respectively) compared to FG while those with type II and IV all had FG with one exception. Type IV tumors had the poorest RFS and OS while Type II tumors had the most favorable RFS and OS (p < 0.04 and p < 0.0004, respectively). While there was no difference in RFS in those patients undergoing FG versus LR, OS was worse in the FG group (p < 0.017). This trend persisted when type II and type IV groups were excluded (p < 0.045).

CONCLUSION

Gastric carcinoid treatment should be tailored to tumor type, as biologic behavior rather than resection technique is the more important factor contributing to long-term outcomes.

Further Classification for Node-Positive Gastric Neuroendocrine Neoplasms

BACKGROUND

For gastric neuroendocrine neoplasms (GNEN), the current AJCC lymph node (N) stage classifies patients into N0/N1 disease (with/without locoregional nodal metastases); however, this does not account for the number of involved nodes. The objective of this study was to evaluate the prognostic significance of the number of involved locoregional nodes among resected GNEN.

METHODS

The National Cancer Database (2004-2014) was queried for GNEN patients who had undergone partial/total gastrectomy with known nodal status. Nearest-neighborhood grouping was used to identify survival clusters by number of metastatic nodes and to use these groupings to construct a new N classification (pN). External validation was performed using the SEER database. Kaplan-Meier analysis and Cox regression models were used to assess the prognostic strength of the pN classification.

RESULTS

One thousand two hundred seventy-five patients met study inclusion criteria. Patients with 1-6 positive nodes (pN1) demonstrated a distinct survival pattern from patients with > 6 positive nodes (pN2) as well as those with no positive nodes (N0) {5-year OS N0: 80% (95% CI 77-83%) vs. 65% (95% CI 61-69%) vs. 43% (95% CI 33-53%), p < 0.001}. On external validation, the pN classification demonstrated strong discriminatory ability for survival {5-year OS N0: 70% (95% CI 65-75%) vs. pN1:53% (95% CI 46-59%) vs. pN2:18% (95% CI 9-29%), p < 0.001}. On multivariable analysis, the pN classification remained an independent predictor of OS.

CONCLUSIONS

The number of metastatic lymph nodes is an independent prognostic factor in GNEN. Current AJCC N1 disease contains two groups of patients with distinctive prognoses, hence needs to be subclassified into pN1 (1-6 positive lymph nodes) and pN2 (> 6 positive nodes).

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.

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.

Gastric neuroendocrine neoplasm with late liver metastasis

Gastric neuroendocrine neoplasms (GNENs) are classified into three types according to their aetiology. We present a clinical case of a female patient of 66 years and a well-differentiated (grade 2), type 3 GNEN with late liver metastasis (LM). The patient underwent surgical excision of a gastric lesion at 50 years of age, without any type of follow-up. Sixteen years later, she was found to have a neuroendocrine tumour (NET) metastatic to the liver. The histological review of the gastric lesion previously removed confirmed that it was a NET measuring 8 mm, pT1NxMx (Ki67 = 4%). ⁶⁸Ga-DOTANOC PET/CT reported two LM and a possible pancreatic tumour/gastric adenopathy. Biopsies of the lesion were repeatedly inconclusive. She had a high chromogranin A, normal gastrin levels and negative anti-parietal cell and intrinsic factor antibodies, which is suggestive of type 3 GNEN. She underwent total gastrectomy and liver segmentectomies (segment IV and VII) with proven metastasis in two perigastric lymph nodes and both with hepatic lesions (Ki67 = 5%), yet no evidence of local recurrence. A ⁶⁸Ga-DOTANOC PET/CT was performed 3 months after surgery, showing no tumour lesions and normalisation of CgA. Two years after surgery, the patient had no evidence of disease. This case illustrates a rare situation, being a type 3, well-differentiated (grade 2) GNEN, with late LM. Despite this, it was possible to perform surgery with curative intent, which is crucial in these cases, as systemic therapies have limited efficacy. We emphasise the need for extended follow-up in these patients.

Learning points

GNENs have a very heterogeneous biological behaviour.Clinical distinction between the three types of GNEN is essential to plan the correct management strategy.LMs are rare and more common in type 3 and grade 3 GNEN.Adequate follow-up is crucial for detection of disease recurrence.Curative intent surgery is the optimal therapy for patients with limited and resectable LM, especially in well-differentiated tumours (grade 1 and 2).

Multilayered heterogeneity as an intrinsic hallmark of neuroendocrine tumors

Neuroendocrine tumors (NETs) comprise a complex and highly heterogeneous group of neoplasms that can arise all over the body, originating from neuroendocrine cells. NETs are characterized by a general lack of symptoms until they are in advanced phase, and early biomarkers are not as available and useful as required. Heterogeneity is an intrinsic, pivotal feature of NETs that derives from diverse causes and ultimately shapes tumor fate. The different layers that conform NET heterogeneity include a wide range of distinct characteristics, from the mere location of the tumor to its clinical and functional features, and from its cellular properties, to the core signaling and (epi)genetic components defining the molecular signature of the tumor. The importance of this heterogeneity resides in that it translates into a high variability among tumors and, hence, patients, which hinders a more precise diagnosis and prognosis and more efficacious treatment of these diseases. In this review, we highlight the significance of this heterogeneity as an intrinsic hallmark of NETs, its repercussion on clinical approaches and tumor management, and some of the possible factors associated to such heterogeneity, including epigenetic and genetic elements, post-transcriptional regulation, or splicing alterations. Notwithstanding, heterogeneity can also represent a valuable and actionable feature, towards improving medical approaches based on personalized medicine. We conclude that NETs can no longer be viewed as a single disease entity and that their diagnosis, prognosis and treatment must reflect and incorporate this heterogeneity.

Factors related to gastric neuroendocrine tumors

INTRODUCTION AND AIMS

An association between long-term use of proton pump inhibitors and the development of gastric neuroendocrine tumors has been reported, but it is still a subject of debate. The aims of the present study were to determine the presence of this association in a Mexican population and to identify the risk factors for developing gastric neuroendocrine tumors.

MATERIALS AND METHODS

A case-control study was conducted, in which the cases were patients with a histopathologic diagnosis of gastric neuroendocrine tumor and the controls were patients evaluated through upper endoscopy. The controls were paired by age, sex, and endoscopic examination indication. Proton pump inhibitor use was considered prolonged when consumption was longer than 5 years.

RESULTS

Thirty-three patients with gastric neuroendocrine tumor and 66 controls were included in the study. Eighteen (54.5%) patients in the case group were women, as were 39 (59%) of the patients in the control group. The median age of the patients in the case group was 55 years (minimum-maximum range: 24-82) and it was 54 years (minimum-maximum range:18-85) in the control group. A greater number of patients in the gastric neuroendocrine tumor group presented with gastric atrophy (p<0.0001) and autoimmune atrophic gastritis (p=0.0002), compared with the control group. No association between gastric neuroendocrine tumor and prolonged proton pump inhibitor use, sex, smoking, gastroesophageal reflux disease, Helicobacter pylori infection, diabetes mellitus, or autoimmune diseases was found in the univariate analysis.

CONCLUSIONS

The results of our study showed no association between proton pump inhibitor use for more than 5 years and the development of gastric neuroendocrine tumor. The presence of gastric atrophy and autoimmune atrophic gastritis was associated with gastric neuroendocrine tumor development.

Predictive Value of Asphericity in Pretherapeutic [111In]DTPA-Octreotide SPECT/CT for Response to Peptide Receptor Radionuclide Therapy with [177Lu]DOTATATE

PURPOSE

The purpose of this study was to assess the value of the spatial heterogeneity of somatostatin receptor (SSR) volume, quantified as asphericity (ASP), and to predict response to peptide receptor radionuclide therapy (PRRT) in patients with metastatic gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN).

PROCEDURES

From June 2011 to May 2013, patients suffering from GEP-NEN who underwent pretherapeutic [¹¹¹In-DTPA⁰]octreotide scintigraphy (Octreoscan®) prior to [¹⁷⁷Lu-DOTA⁰-Tyr³]octreotate ([¹⁷⁷Lu]DOTATATE)-PRRT were enrolled in this retrospective evaluation. SSR expression in 20 NEN patients was qualitatively and quantitatively assessed using the Krenning score, the metastasis to liver uptake ratio (M/L ratio), and ASP at baseline. Response to PRRT was evaluated based on lesions, which were classified as responding lesions (RL) and non-responding lesions (NRL) after 4- and 12-month follow-ups. The values of the Krenning score, M/L ratio, and ASP for response prediction were compared by using the Mann-Whitney U test, Kruskal-Wallis test, and receiver operating characteristic (ROC) curves.

RESULTS

Seventy-seven metastases (liver, n = 40; lymph node, n = 24; bone, n = 11; pancreas, n = 2) showed SSR expression. A higher ASP level was significantly associated with poorer response at both time points. ROC analyses revealed the highest area under the curve (AUC) for discrimination between RL and NRL for ASP after 4 months (AUC 0.97; p = 0.019) and after 12 months (AUC 0.96; p < 0.001), followed by the Krenning score (AUC 0.74; p = 0.082 and AUC 0.85; p < 0.001, respectively) and M/L ratio (AUC 0.77; p = 0.107 and AUC 0.82; p < 0.001). The optimal cutoff value for ASP was 5.12 % (sensitivity, 90 %; specificity, 93 %).

CONCLUSION

Asphericity of SSR-expressing lesions in pretherapeutic single-photon emission computed tomography with integrated computed tomography (SPECT/CT) is a promising parameter for predicting response to PRRT in gastroenteropancreatic neuroendocrine neoplasms.

Multiple Neuroendocrine Tumors in Stomach and Duodenum in a Multiple Endocrine Neoplasia Type 1 Patient

A 67-year-old woman with a history of subtotal parathyroidectomy, distal pancreatectomy, and total splenectomy 23 years prior underwent surgical gastric resection for neuroendocrine tumors of the stomach and duodenum. Meticulous examination of the entire stomach and duodenum revealed multiple scattered, minute neuroendocrine tumors. To the best of our knowledge, this is the first case report of a patient diagnosed with gastroduodenal neuroendocrine tumors associated with multiple endocrine neoplasia type 1 (MEN 1) in whom complete histologic mapping of the whole gastrectomy specimen was performed. The presence of MEN 1-associated neuroendocrine tumors in the stomach is very rare, but should be considered in patients diagnosed with MEN 1 who present with a new tumor in the stomach.

Gastrointestinal manifestations of neuroendocrine tumours: their investigation and management

The incidence of neuroendocrine tumours (NETs) is on the rise in the UK. Patients with NETs need to be managed by a team of clinical specialties. There are a number of challenging gastrointestinal (GI) manifestations related to NETs that can occur in these patients, but a limited literature base exists to guide clinicians.Whilst life expectancy can be several years for patients with NETs, the GI symptoms can have a significant impact on their quality of life. It is therefore imperative to be familiar with the common GI manifestations associated with NETs, so symptoms can be appropriately managed with an overall aim of restoring the patient's quality of life.

Autoimmune atrophic gastritis: current perspectives

At present there is no universally accepted classification for gastritis. The first successful classification (The Sydney System) that is still commonly used by medical professionals was first introduced by Misiewicz et al in Sydney in 1990. In fact, it was the first detailed classification after the discovery of Helicobacter pylori by Warren and Marshall in 1982. In 1994, the Updated Sydney System was proposed during the International Workshop on the Histopathology of Gastritis followed by the publication in The American Journal of Surgical Pathology by Dixon et al. Using the new classification, distinction between atrophic and nonatrophic gastritis was revised, and the visual scale grading was incorporated. According to the Updated Sydney System Classification, atrophic gastritis is categorized into multifocal (H. pylori, environmental factors, specific diet) and corpus-predominant (autoimmune). Since metaplasia is a key histological characteristic in patients with atrophic gastritis, it has been recommended to use the word “metaplastic” in both variants of atrophic gastritis: autoimmune metaplastic atrophic gastritis (AMAG) and environmental metaplastic atrophic gastritis. Although there are many overlaps in the course of the disease and distinction between those two entities may be challenging, the aim of this review article was to describe the etiology, epidemiology, pathogenesis, diagnosis, clinical manifestations and treatment in patients with AMAG. However, it is important to mention that H. pylori is the most common etiologic factor for the development of gastritis in the world.

Netazepide, a gastrin/cholecystokinin-2 receptor antagonist, can eradicate gastric neuroendocrine tumours in patients with autoimmune chronic atrophic gastritis

AIMS

Netazepide, a gastrin/cholecystokinin 2 receptor antagonist, once daily for 12 weeks reduced the number of tumours and size of the largest one in 16 patients with autoimmune chronic atrophic gastritis (CAG), achlorhydria, hypergastrinaemia and multiple gastric neuroendocrine tumours (type 1 gastric NETs), and normalized circulating chromogranin A (CgA) produced by enterochromaffin-like cells, the source of the tumours. The aim was to assess whether longer-term netazepide treatment can eradicate type 1 gastric NETs.

METHODS

After a mean 14 months off netazepide, 13 of the 16 patients took it for another 52 weeks. Assessments were: gastroscopy; gene-transcript expression in corpus biopsies using quantitative polymerase chain reaction; blood CgA and gastrin concentrations; and safety assessments.

RESULTS

While off-treatment, the number of tumours, the size of the largest one, and CgA all increased again. Netazepide for 52 weeks: cleared all tumours in 5 patients; cleared all but one tumour in one patient; reduced the number of tumours and size of the largest one in the other patients; normalized CgA in all patients; and reduced mRNA abundances of CgA and histidine decarboxylase in biopsies. Gastrin did not increase further, confirming that the patients had achlorhydria. Netazepide was safe and well tolerated.

CONCLUSIONS

A gastrin/cholecystokinin 2 receptor antagonist is a potential medical and targeted treatment for type 1 gastric NETs, and an alternative to regular gastroscopy or surgery. Treatment should be continuous because the tumours will regrow if it is stopped. Progress can be monitored by CgA in blood or biomarkers in mucosal biopsies.

Management of gastric and duodenal neuroendocrine tumors

Gastrointestinal neuroendocrine tumors (GI-NETs) are rare neoplasms, like all NETs. However, the incidence of GI-NETS has been increasing in recent years. Gastric NETs (G-NETs) and duodenal NETs (D-NETs) are the common types of upper GI-NETs based on tumor location. G-NETs are classified into three distinct subgroups: type I, II, and III. Type I G-NETs, which are the most common subtype (70%-80% of all G-NETs), are associated with chronic atrophic gastritis, including autoimmune gastritis and Helicobacter pylori associated atrophic gastritis. Type II G-NETs (5%-6%) are associated with multiple endocrine neoplasia type 1 and Zollinger-Ellison syndrome (MEN1-ZES). Both type I and II G-NETs are related to hypergastrinemia, are small in size, occur in multiple numbers, and are generally benign. In contrast, type III G-NETs (10%-15%) are not associated with hypergastrinemia, are large-sized single tumors, and are usually malignant. Therefore, surgical resection and chemotherapy are generally necessary for type III G-NETs, while endoscopic resection and follow-up, which are acceptable for the treatment of most type I and II G-NETs, are only acceptable for small and well differentiated type III G-NETs. D-NETs include gastrinomas (50%-60%), somatostatin-producing tumors (15%), nonfunctional serotonin-containing tumors (20%), poorly differentiated neuroendocrine carcinomas (< 3%), and gangliocytic paragangliomas (< 2%). Most D-NETs are located in the first or second part of the duodenum, with 20% occurring in the periampullary region. Therapy for D-NETs is based on tumor size, location, histological grade, stage, and tumor type. While endoscopic resection may be considered for small nonfunctional D-NETs (G1) located in the higher papilla region, surgical resection is necessary for most other D-NETs. However, there is no consensus regarding the ideal treatment of D-NETs.