Carcinoid tumors of the gastrointestinal tract: trends in incidence in England since 1971

Update in the management of gastroenteropancreatic neuroendocrine tumors

Neuroendocrine neoplasms are a diverse group of neoplasms that can occur in various areas throughout the body. Well-differentiated neuroendocrine tumors (NETs) most often arise in the gastrointestinal tract, termed gastroenteropancreatic neuroendocrine tumors (GEP-NETs). Although GEP-NETs are still uncommon, their incidence and prevalence have been steadily increasing over the past decades. The primary treatment for GEP-NETs is surgery, which offers the best chance for a cure. However, because GEP-NETs are often slow-growing and do not cause symptoms until they have spread widely, curative surgery is not always an option. Significant advances have been made in systemic and locoregional treatment options in recent years, including peptide-receptor radionuclide therapy with α and β emitters, somatostatin analogs, chemotherapy, and targeted molecular therapies.

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.

Proton Pump Inhibitors and Cancer Risk: A Comprehensive Review of Epidemiological and Mechanistic Evidence

Background: Proton pump inhibitors (PPIs) are commonly prescribed long-acting drugs used to treat acid reflux, gastroesophageal reflux disease (GERD), and peptic ulcers. Recently, concerns have been raised about their safety, particularly due to the association between long-term PPI use and cancer development. Multiple comprehensive studies have consistently suggested a noteworthy link between prolonged PPI usage and an increased risk of developing gastric, esophageal, colorectal, and pancreatic cancers, yet the precise underlying mechanism remains elusive. Methods: First, we review the extensive body of research that investigates the intricate relationship between cancer and PPIs. Then, we predict PPI toxicity using the prodrug structures with the ProTox-II webserver. Finally, we predict the relative risk of cancer for each PPI, using PubMed citation counts of each drug and keywords related to cancer. Results: Our review indicates that prolonged PPI use (exceeding three months) is significantly associated with an elevated risk of cancer, while shorter-term usage (less than three months) appears to pose a comparatively lower risk. Our review encompasses various proposed mechanisms, such as pH and microbiome alterations, vitamin and mineral malabsorption, hypergastrinemia, and enterochromaffin-like cell proliferation, while ProTox-II also suggests aryl hydrocarbon receptor binding. Potentially, the PubMed citations count suggests that the PPIs omeprazole and lansoprazole are more associated with cancer than pantoprazole and esomeprazole. In comparison, the H2R blocker, famotidine, is potentially less associated with cancer than PPIs, and may serve as a safer alternative treatment for periods beyond 3 months. Conclusions: Despite the well-established cancer risk associated with PPIs, it is notable that these medications continue to be widely prescribed for periods longer than 3 months. Thus, it is of paramount importance for clinicians and patients to thoughtfully evaluate the potential risks and benefits of long-term PPI usage and explore alternative treatments before making informed decisions regarding their medical management.

A retrospective study comparing minimally invasive versus open surgical resection of small intestinal neuroendocrine neoplasms at a tertiary referral center

INTRODUCTION

Neuroendocrine neoplasms (SI-NEN) are the commonest malignancies of the small intestine. Traditionally, surgical treatment for SI-NEN has been open surgery.

PURPOSE

The purpose of this study was to compare minimally invasive surgery (MIS) with the traditional open surgery approach for treating SI-NEN in a Swedish population.

METHODS

Patients with histopathological confirmed SI-NEN who underwent open surgery or MIS resection within 2009-2021 were extracted from the hospital's medical records.

RESULTS

65 patients were included in this study, with 35 (54 %) undergoing MIS and 30 (46 %) undergoing open surgery. We found no statistically significant difference (p = 0.173) in the frequency of R0 resections (MIS group n = 34 (97 %), open surgery group n = 26 (87 %)). Nor was there a significant difference (p = 0.101) when comparing the median number of resected lymph nodes (MIS group n = 13.5, open surgery group n = 10). A post-operative paralytic ileus was more often reported (p = 0.052) in the MIS group (n = 9, 26 %) compared to the open surgery group (n = 2, 7 %). In light of this, the days of hospital stay did not differ significantly (MIS group median = 6, IQR (5-8), open surgery group median = 6, IQR (5-9)). The Kaplan-Meier analysis did not reveal differences concerning cancer-related deaths (p = 0.109).

CONCLUSION

The results from this study support that a MIS approach for the treatment of SI-NEN may not be inferior to open surgery. The higher number of resected lymph nodes and R0 resections may even speak in favor for a MIS approach. More studies with a longer time of observation are needed to further support this conclusion.

Prevalence of Neuroendocrine Tumours (NET) in Patients Undergoing Appendicectomy for Acute Appendicitis: A Tertiary Care Study

Introduction Acute appendicitis is one of the common causes of acute abdomen in adults, which is managed widely with appendicectomy. Neuroendocrine tumours are the most common appendiceal tumours diagnosed incidentally on appendicectomy specimens.  Methods  Demographic data, presenting complaints, indications for appendicectomy, and the histology findings based on histopathological reports of the patients who have undergone appendicectomy for appendicitis at surgical units of Teaching Hospital, Jaffna, from 1st of January 2019 to 31st of December 2022 were retrospectively analyzed.  Results Of the 1341 histopathology reports, 0.2% (n=3) were neuroendocrine tumours (NET). The mean age of the patients with NET was 48.6, and 66.6% of them were females. All three NETs identified in appendicectomy specimens were well differentiated and smaller than 2 cm. All three had negative resection margins and were managed only with appendicectomy.  Conclusion  NETs of the appendix are the commonest appendiceal neoplasms. The majority of them are diagnosed incidentally in appendicectomy specimens. Surgical management of the tumours is either by appendicectomy or hemicolectomy, which depends mainly on tumor size. Surgical decisions should be tailor-made to the patients based on multi-disciplinary team decisions.

Site-specific trends in gastroenteropancreatic neuroendocrine neoplasms in Bavaria, Germany

INTRODUCTION

Neuroendocrine neoplasms (NEN) are rare and heterogeneous epithelial tumors, occurring throughout the body. For gastroenteropancreatic (GEP)-NEN, rising incidence rates were reported for the last decades, with underlying causes remaining largely unexplained. We evaluated NEN trends stratifying by their histologic subtypes.

METHODS

Incident cases of GEP-NEN diagnosed between 2005 and 2019 were retrieved from the prospective, population-based Bavarian Cancer Registry. GEP-NEN were divided in their histologic subtypes, that is, neuroendocrine tumors (NET) G1, NET G2/G3, other NET versus small-cell neuroendocrine carcinoma (NEC), large-cell NEC, and other NEC. We calculated annual age-standardized incidence rates (ASIRs) per 100,000 persons for the total of GEP-NEN, NEN histologic subtypes, and tumor sites. We used an annual percentage change (APC) approach including a joinpoint analysis to investigate NEN incidence trends.

RESULTS

ASIR of GEP-NEN rose from 2.2 in 2005 to 4.8 in 2019, characterized by a significant increase until 2012 (APC 2005-2012: 10.1%), followed by modest rise (APC 2012-2019: 1.5%). In the last decade, this increase was mainly driven by the rise of NET G1 and G2/G3, while incidence for NEC declined. Over the study period, ASIR increased significantly for all GEP-sites except the colon. APCs were largest for the stomach, the appendix, the pancreas, and the rectum.

CONCLUSIONS

This study found a significant increase in the incidence of GEP-NET. Though this development may partially be attributable to the increased use of advanced detection techniques and changes in NEN classification, further research should also focus on the identification of NEN risk factors.

Clinical features and outcomes of appendiceal neuroendocrine tumours: 10 year audit from the Irish NET Centre of Excellence

Appendiceal neuroendocrine tumours (aNETs) are rare neoplasms of the gastrointestinal tract often diagnosed incidentally at the time of appendicectomy. Appendicectomy is considered curative in the majority of cases but guidelines recommend right-sided hemicolectomy (RHC) for those with specific high-risk features despite no data supporting a survival benefit. We performed a retrospective search of multi-disciplinary tumour board and pathology databases from 2012 to 2022 to identify cases of aNET treated at our centre. Follow-up data were obtained from the electronic healthcare records. A total of 142 cases of aNET were included for analysis. Mean age at presentation was 34, of which 76% were female and 92% of aNETs were located in the tip/middle of the appendix; 90% were grade 1, and 93% had R0 resection. Tumour size was <1 cm in 54%, 1-2 cm in 36%, >2 cm in 9%. A total of 43 patients (30%) underwent RHC with lymph node metastases identified in 16 (37%). Lymph node metastases were associated with tumour size >2 cm (p = .008) and higher tumour grade (p = .041) on multivariate analysis. For aNET 1-2 cm, lymph node metastases were identified in 7/22 who had RHC (32%) with tumour grade the only significant risk factor (p = .046). Distant metastases were identified in 2 cases (1%), diagnosed synchronously and associated with grade 2 tumours. Overall survival for those with lymph node metastases was 100% after a median 4 years. Progression-free survival was 93%, with a single case of disease progression associated with synchronous distant metastases at initial diagnosis. Lymph node metastases in aNET are associated with higher tumour grade and tumour size >2 cm. Disease progression in the setting of lymph node metastases is rare. The significance of lymph node metastases and need for completion RHC remains uncertain.

Relation between WHO Classification and Location- and Functionality-Based Classifications of Neuroendocrine Neoplasms of the Digestive Tract

Practice of neuroendocrine neoplasms (NENs) of the digestive tract, which comprise of a highly diverse group of tumors with a rising incidence, faces multiple biological, diagnostic, and therapeutic issues. Part of these issues is due to misuse and misinterpretation of the classification and terminology of NENs of the digestive tract, which make it increasingly challenging to evaluate and compare the literature. For instance, grade 3 neuroendocrine tumors (NETs) are frequently referred to as neuroendocrine carcinomas (NECs) and vice versa, while NECs are, by definition, high grade and therefore constitute a separate entity from NETs. Moreover, the term NET is regularly misused to describe NENs in general, and NETs are frequently referred to as benign, while they should always be considered malignancies as they do have metastatic potential. To prevent misconceptions in future NEN-related research, we reviewed the most recent terminology used to classify NENs of the digestive tract and created an overview that combines the classification of these NENs according to the World Health Organization (WHO) with location- and functionality-based classifications. This overview may help clinicians and researchers in understanding the current literature and could serve as a guide in the clinic as well as for writing future studies on NENs of the digestive tract. In this way, we aim for the universal use of terminology, thereby providing an efficient foundation for future NEN-related research.

The environmental burden on endocrine neoplasia: a review on the documented impact of endocrine disrupting chemicals

INTRODUCTION

Endocrine-disrupting chemicals (EDCs) have gained more importance in the past decade, mostly due to their role in the pathogenesis of disease, especially in carcinogenesis. However, there is limited literature on the environmental burden on some of the less common endocrine neoplasia.

AREAS COVERED

This review focuses on both observational and experimental studies linking exposure to EDCs and endocrine neoplasia specifically pituitary, thyroid, adrenal and neuroendocrine tumors. Following PRISMA guidelines, a search of English peer-reviewed literature was performed using Medline and Google Scholar, giving preference to recent publications.

EXPERT OPINION

Exposure to EDC occurs not only in the household but also at work, whether it is in the office, factory, or farm and during transport from one location to another. Many studies have evaluated the effect of single environmental agents; however, humans are rarely exposed to only one EDC. Different EDCs and different levels of exposure may interact together to provide either a synergistic and/or an antagonistic disruption on human health, and hence a complex mechanism to elucidate. The ultimate adverse effect is difficult to predict, as it is not only influenced by the degree of exposure, but also by genetics, lifestyle, comorbidities, and other stressors.

Understanding the increasing incidence of neuroendocrine tumors

INTRODUCTION

Neuroendocrine tumors (NETs) are a diverse group of tumors with origins from different primary sites such as gastro-entero-pancreatic, lung and endocrine tissue. Worldwide, their incidence has increased in recent decades. Advances in imaging and better clinical awareness are traditionally attributed to this trend; however, other factors such as genetic and environmental contributors are appreciated as well.

AREAS COVERED

The purpose of this article is to review the worldwide epidemiologic trends in incidence of NET through the decades and discuss the various factors potentially contributing to the observed changes in incidence trends.

EXPERT OPINION

Overall, the incidence of NET has increased across the globe over the last few decades. Although multiple genetics and environmental factors have been proposed, the majority of this increase in incidence is secondary to earlier detection. Future studies will help in more accurate assessments and an improved understanding of disease incidence among patients with different grades and differentiation.

Prognostic differences in grading and metastatic lymph node pattern in patients with small bowel neuroendocrine tumors

PURPOSE

Neuroendocrine tumors of the small intestine (si-NET) describe a heterogenous group of neoplasms. Based on the Ki67 proliferation index si-NET are divided into G1 (Ki67 < 2%), G2 (Ki67 3-20%) and rarely G3 (Ki67 > 20%) tumors. However, few studies evaluate the impact of tumor grading on prognosis in si-NET. Moreover, si-NET can form distinct lymphatic spread patterns to the mesenteric root, aortocaval lymph nodes, and distant organs. This study aims to identify prognostic factors within the lymphatic spread patterns and grading.

METHODS

Demographic, pathological, and surgical data of 208 (90 male, 118 female) individuals with si-NETs treated at Charité University Medicine Berlin between 2010 and 2020 were analyzed retrospectively.

RESULTS

A total of 113 (54.5%) specimens were defined as G1 and 93 (44.7%) as G2 tumors. Interestingly, splitting the G2 group in two subgroups: G2 low (Ki67 3-9%) and G2 high (Ki67 10-20%), displayed significant differences in overall survival (OS) (p = 0.008) and progression free survival (PFS) (p = 0.004) between these subgroups. Remission after surgery was less often achieved in patients with higher Ki67 index (> 10%). Lymph node metastases (N +) were present in 174 (83.6%) patients. Patients with isolated locoregional disease showed better PFS and OS in comparison to patients with additional aortocaval and distant lymph node metastases.

CONCLUSION

Lymphatic spread pattern influences patient outcome. In G2 tumors, low and high grading shows heterogenous outcome in OS and PFS. Differentiation within this group might impact follow-up, adjuvant treatment, and surgical strategy.

Updates in the diagnosis and management of small-bowel tumors

Small-bowel tumors represent a rare entity comprising 0.6% of all new cancer cases in the US, and only 3% of all gastrointestinal neoplasms. They are a heterogenous group of neoplasms comprising of about forty different histological subtypes with the most common being adenocarcinoma, neuroendocrine tumors, stromal tumors and lymphomas. Their incidence has been reportedly increasing over recent years, partly owing to the advances and developments in the diagnostic modalities. Small-bowel capsule endoscopy, device assisted enteroscopy and dedicated small-bowel cross-sectional imaging are complimentary tools, supplementing each other in the diagnostic process. Therapeutic management of small-bowel tumors largely depends on the histological type and staging at diagnosis. The aim of the present review article is to discuss relevant advances in the diagnosis and management of small-bowel tumors.

Surgical aspects of small intestinal neuroendocrine tumors

Small intestinal neuroendocrine tumors (NETs) are a heterogeneous group of epithelial tumors with a predominant neuroendocrine differentiation. Although NETs are usually considered rare neoplasms, small intestinal NETs are the most common primary malignancy of the small bowel, with an increasing prevalence worldwide during the course of the past few decades. The indolent nature of these tumors often leads to a delayed diagnosis, resulting in over one-third of patients presenting with synchronous metastases. Primary tumor resection remains the only curative option for this type of tumor. In this review article, the various surgical aspects for the excision of small intestinal NETs are discussed.

Neuroendocrine Neoplasms of the Gastrointestinal Tract versus Neuroendocrine Neoplasms of the Gynaecological Tract-Comparison of the Risk Factors and Non-Surgical Treatment Efficacy

Neuroendocrine tumours of the gastrointestinal tract are rare. The incidence has increased in recent years due to improvements in diagnostic methods for detecting these lesions. These tumours have a poor prognosis, especially when detected at an advanced stage. The basis of the treatment is resection, and non-surgical treatments are also standard in the treatment process. The situation is similar in even rarer neuroendocrine tumours of the reproductive tract, which are associated with an equally poor prognosis. In this article, we focus on learning about the risk factors (including genetic mutations) that increase the risk of the disease and comparing the effectiveness of non-surgical treatments-chemotherapy, radiotherapy, peptide receptor radionuclide therapy, somatostatin analogues, and immunotherapy. The efficacy of these treatments varies, and immunotherapy appears to be a promising form of treatment; however, this requires further research.

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.

Factors Predicting Type I Gastric Neuroendocrine Neoplasia Recurrence: A Single-Center Study

Type I gastric neuroendocrine neoplasms (gNENs) are associated with atrophic gastritis and have a high recurrence rate, which means frequent endoscopies are required. The objective of this study was to identify factors predicting the local recurrence of type I gNENs. The clinical course and the pathological and biochemical data of patients with type I gNENs treated at Bnai Zion Medical Center between 2006 and 2022 were analyzed retrospectively. Twenty-seven type I gNENs were evaluated. The follow-up period was 41 months (range: 11–288 months). Recurrence of the tumor occurred in 13/27 (48%) patients after 35 months (median (M), interquartile range (IQR): 21–67.5). Serum gastrin levels were significantly higher in patients with recurrent disease versus patients with non-recurrent disease (788 vs. 394 ng/L; p = 0.047), while the Ki-67 index was significantly lower in patients with recurrent disease versus patients with non-recurrent disease (1% vs. 3.5%; p = 0.035). Tumor size, mitotic count, and serum chromogranin A levels did not correlate with recurrence. The present study emphasizes the role of gastrin in the pathogenesis of gNEN recurrence and highlights the debate regarding the ability of the Ki-67 index to predict the clinical course of this disease.

Analysis of Patients with NET G1/G2 Neuroendocrine Tumors of the Small Intestine in the Course of Carcinoid Heart Disease-A Retrospective Study

Neuroendocrine neoplasms of the small intestine (SI-NENs) are one of the most commonly recognized gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs). Carcinoid heart disease (CHD) is the primary cause of death in patients with the carcinoid syndrome (CS). The aim of this retrospective study was to evaluate possible factors impacting upon overall survival (OS) in subjects with both neuroendocrine tumors (NETs) G1/G2 of the small intestine (SI-NET) and CHD. Enrolled in our study of 275 patients with confirmed G1/G2 SI-NET, were 28 (10%) individuals with CHD. Overall survival was assessed using the Kaplan-Meier method. The Cox-Mantel test was used to determine how OS varied between groups. A Cox proportional hazards model was used to conduct univariate analyses of predictive factors for OS and estimate hazard ratios (HRs). Of the 28 individuals with confirmed carcinoid heart disease, 12 (43%) were found to have NET G1 and 16 (57%) were found to have NET G2. Univariate analysis revealed that subjects with CHD and without resection of the primary tumor had a lower OS. Our retrospective study observed that patients who presented with CHD and without resection of primary tumor had worse prognosis of survival. These results suggest that primary tumors may need to be removed when feasible, but further research is needed. However, no solid recommendations can be issued on the basis of our single retrospective study.

A Rare Presentation of a Duodenal Neuroendocrine Tumor

Neuroendocrine tumors (NETs), which are a rare type of tumor, are defined as epithelial cells with predominantly neuroendocrine differentiation and consist of a spectrum of tumors emerging from stem cells throughout the body and can occur anywhere in the body. While they are rare, the incidence over the past few decades has increased. Here we present a case of a 64-year-old female who was incidentally found to have a duodenal neuroendocrine tumor. The patient initially presented to the emergency department secondary to syncope and collapse. During her trauma evaluation, an incidental lobulated soft tissue mass inferior to the distal stomach was seen on complete computed tomography (CT) scans. The surgery team was consulted for resection of the mass and an octreotide scan was performed prior to resection to further evaluate the mass and to check for any signs of metastatic disease. The octreotide scan demonstrated intense radiotracer accumulation within the duodenal mass consistent with a neuroendocrine tumor and no areas of abnormal radiotracer accumulation suspicious for metastatic disease. Pathology of the resected mass was positive for a well-differentiated neuroendocrine tumor with an organoid pattern and homogenous oval-round neoplastic cells with a salt-pepper nuclear and pseudo glandular arrangement that was well-circumscribed and partially encapsulated with negative margins. Immunohistochemistry was positive for AE ⅓, CD56, Synaptophysin, and chromogranin and negative for CD117, DOG-1, CD34, and CD45. The prevalence of NETs has increased over the years due to the improvement in diagnostic tools, such as upper gastrointestinal endoscopy. In addition to the fact that the duodenum is a rare location for such tumors, neuroendocrine tumors are also typically found in those under 50 years old. However, our patient was found to have both a duodenal mass and was over the age of 50 at the time of presentation and diagnosis. To date, a consensus on a conclusive treatment of duodenal NETs (D-NETs) has not been reached. This case brings to light the importance of further research in diagnosing and treating neuroendocrine tumors and also raises awareness for clinicians to have this in their differential.

Risk factors and clinical outcomes of incomplete endoscopic resection of small rectal neuroendocrine tumors in southern China: a 9-year data analysis

Background

The histologically complete resection (CR) rate of small rectal neuroendocrine tumors (RNETs) is unsatisfactory at the first endoscopy. Risk factors and clinical outcomes associated with incomplete resection (IR) have not been explicitly elucidated. This study aims to explore the relevant factors of IR.

Methods

This retrospective study reviewed patients with small RNETs (≤10 mm) in eight centers from January 2013 to December 2021. Clinicopathological characteristics and clinical outcomes were compared between the CR and IR groups, and the polypectomy and advanced treatment groups.

Results

Of the 326 patients included, 83 (25.5%) were diagnosed with IR. Polypectomy (odds ratio [OR] = 16.86), a central depression (OR = 7.50), and treatment in the early period (OR = 2.60) were closely associated with IR. Further analysis revealed that an atypical hyperemic appearance (OR = 7.49) and treatment in the early period (OR = 2.54) were significantly associated with the inappropriate use of polypectomy (both P < 0.05). In addition, a total of 265 (81.3%) were followed up with a median follow-up period of 30.9 months. No death, metastasis, or recurrence was found during the follow-up period.

Conclusions

Polypectomy, a central depression, and treatment in the early period were risk factors for IR. Further, an atypical hyperemic appearance and treatment in the early period were significant predisposing factors for inappropriate choice of polypectomy. For histologically incompletely resected small RNETs, follow-up may be a safe and feasible alternative to rigorous salvage therapy.

Management and Survival Analysis of Gastrointestinal Neuroendocrine Tumors by Different Tumor Characteristics: Tertiary Center Experience

BACKGROUND

Gastrointestinal neuroendocrine tumor (GI-NET) is a group of neoplasia consisting of amine and acid producing cells with different hormonal profiles. Although the entire GIS accounts for about 2% of tumors, recent research reveals that the incidence rate has increased. Given the increasing incidence in GI-NETs, more and more extensive research is needed on this subject. In this regard, the demographic and clinicopathological features of the patients diagnosed with GI-NET and their relationship with survival were investigated in the present study.

METHODS

Thirty-four patients diagnosed with GI-NETs between January 2009 and December 2019 at the Department of Gastroenterology, Inonu University Faculty of Medicine were analyzed retrospectively. Gender, age, tumor localization, metastasis status, tumor number, tumor diameter, tumor grade, Ki-67 index, and the relationships of these factors with overall survival were examined.

RESULTS

Of the patients, 61.8% included in the study were male and 38.2% were female. The average age of the patients was 60.74 years. The most common tumor location was in the stomach (26.5%) and liver (26.5%). Apart from this, 17.6% of NETs were seen in the pancreas, 11.8% in the colon, 8.8% in the rectum, 5.9% in the small intestine, and 2.9% in the appendix. No significant relationship was observed between tumor location and gender (p = .326) and age (p = .641). The tumor diameter ranged from 0.2 cm to 13.91 cm, but the average tumor diameter was 3.84 cm. Solitary tumor was found in 51.5% of cases and multiple tumors in 48.5% of cases. The most common grade was Grade 1 with 41.2% of occurrence. The average of Ki-67 index was 18.36%. There was metastasis in 52.9% of cases. The rate of medical treatment was 48.5%. The median overall survival time of the patients was 23.1 months. In addition, 1-year overall survival was 74.9%, 2-year overall survival was 44.6%, and 5-year overall survival was 35.7%. A statistically significant difference was found between tumor grade and the presence of metastasis, and the overall survival (p = .003 and p = .005).

CONCLUSIONS

The tumor grade and the presence of metastasis in gastrointestinal neuroendocrine tumors were found to be the most important prognostic factors affecting overall survival.

Management of upper gastrointestinal symptoms in patients with autoimmune gastritis

PURPOSE OF REVIEW

Autoimmune gastritis is characterized by atrophy of acid secreting parietal cells resulting in achlorhydria. Upper gastrointestinal symptoms are common in autoimmune gastritis and frequently result in prescriptions for acid suppressant medications despite the inability of the stomach to secrete acid. Evidence-based recommendations for management of gastrointestinal symptoms in autoimmune gastritis are lacking.

RECENT FINDINGS

The most common symptoms in patients with autoimmune gastritis are dyspepsia, heartburn, and regurgitation. Gastroesophageal reflux should be confirmed by pH-impedance testing and is typically weakly acid or alkaline. Therapy for reflux focuses on mechanical prevention of reflux (i.e., elevation of the head of the bed and alginates) or when severe, antireflux surgery. The etiology of dyspepsia in autoimmune gastritis is unclear and largely unstudied. In the first half of the 20th century, oral administration of acid to "aid digestion" was widely used with reported success. However, randomized, placebo-controlled trials are lacking. Here, we provide suggestions for attempting gastric acidification therapy.

SUMMARY

Upper GI symptoms are common in autoimmune gastritis. Their pathogenesis and therapy remain incompletely understood. Acid suppressant medications are useless and should be discontinued. A trial of acid replacement therapy is recommended especially in the form of placebo-controlled trials.

Gastrointestinal Neuroendocrine Tumours: A Single-Centre Experience

Objectives

Gastrointestinal neuroendocrine tumours (GI-NETs) are actually malignant tumours, and their most common location of metastasis is the liver. In this study, we define the epidemiologic features of NETs and investigate the demographic factors, clinicopathologic features, survival, and the oncologic results related to GI-NETs.

Materials and Methods

In this 10-year study (2009–2019), all GI and liver NETs were taken out from the pathology records. When classification based on the WHO classification criteria, patients were categorized based on their location, sex, age, and proliferative index. After studying clinical charts of GI-NET cases, a complete panel of IHC markers such as Chromogranin A, ‘Ki67’ and synaptophysin were used. Results: Based on published data, the liver is not a common primary site for NETs; most liver lesions are most likely to have been metastases. The mean age of patients at diagnosis was 52.72 years. In this research, 27.78% of patients had colon NETs and 27.78 liver. Two (11.11%) patients were classified as stage II, seven (38.89%) as stage III, and one (5.56%) as stage IV. After a 120-month follow-up, 13 (72.22%) patients with colorectal NETs were alive, and 5 (27.78%) of the patients had died.

Conclusion

Treatment of colon and rectal NETs is difficult because it affects the patient's initial site of involvement, and this often makes treatment difficult for the patient. With suitable management, the prognosis can be positive with long survival, but it is related to the tumour variation grade, the efficiency of the selected treatment, and also to the patient's adherence to the follow-up.

Sporadic, non-functional, gastrin-producing duodenal neuroendocrine tumors: A retrospective study of an infrequent disease

OBJECTIVES

Non-functioning gastrin-producing neuroendocrine neoplasms (NEN) of the duodenum are rare gastrointestinal tumors without a clinical syndrome due to gastrin production. Their incidence has significantly increased as an incidental finding during endoscopic studies. The aim of this study was to describe the characteristics and prognostic factors of this emergent and infrequent neoplasm.

METHODS

We performed a retrospective observational study based on the duodenal NENs samples with positive staining for gastrin at the Department of Pathology, University Hospital 12-de-Octubre (Madrid, Spain) between 2000 and 2017. Patients with clinically functional tumors ([Zollinger-Ellison syndrome] or gastrin >1000 pg/mL), with previously diagnosed multiple endocrine neoplasia (MEN) syndrome or synchronous neoplasia were excluded. Clinicopathological and therapeutic variables, follow-up, recurrence, and mortality data were collected.

RESULTS

In all, 21 patients were included. Most of the tumors were diagnosed incidentally as a single small polypoid lesion limited to mucosa/submucosa and with a low histological grade. Four (19.0%) patients presented with metastatic involvement at diagnosis (lymphatic and/or hepatic). These four patients also had a high or intermediate mitotic grade and infiltration further than submucosa. Local resection was applied in most cases as curative treatment. There were two cases of tumor recurrence and two tumor-related deaths with a 5-year disease-free survival of 81.0%.

CONCLUSIONS

The majority of these tumors were diagnosed at a localized stage and had a good prognosis with treatment. Nevertheless, given the potential metastatic risk, a close follow-up is necessary, especially in those with aggressive pathological factors such as deep infiltration or high histological grade.

Zufallsbefund NEN Appendix

Neuroendokrine Neoplasien (NEN) der Appendix stellen mit 80% die häufigste Neoplasie dieser Lokalisation dar. In den meisten Fällen werden diese Tumoren als Zufallsbefund nach stattgehabter Appendektomie bei V. a. Appendizitis diagnostiziert. Hierbei handelt es sich meist um hoch differenzierte neuroendokrine Tumoren. Aufgrund ihrer häufigen Lage im Bereich der Appendixspitze sind die NEN der Appendix meist nicht ursächlich für die Appendizitis-typischen Beschwerden.

Die meisten Patienten (80–90%) sind durch die bereits durchgeführte Appendektomie ausreichend onkologisch therapiert. Sollten sich jedoch Risikofaktoren wie eine Tumorgröße > 2 cm, basisnahe Lage, Angioinvasion, Perforation oder Infiltration von Nachbarorganen, Proliferationsindex von > 2% oder eine Infiltration des Mesoappendix von mehr als 3 mm im endgültigen histopathologischen Befund ergeben, so wird eine Nachresektion als onkologische Hemikolektomie rechts empfohlen.

Aufgrund des meist frühen Tumorstadiums bei Diagnosestellung ohne nachgewiesene Lymphknotenmetastasierung weisen Patienten mit einer NEN der Appendix exzellente 5-Jahres-Überlebensraten über alle Tumorstadien hinweg von 70–85% auf.

Defining prognostic parameters of well-differentiated gastric neuroendocrine tumors based on metastatic potential: a two-center experience

Background: Gastric neuroendocrine tumors [gNETs] are heterogeneous tumors and we are still unable to predict the behavior of these tumors. We aim to define the prognostic parameters of well-differentiated gNETs based on metastatic potential and to evaluate the current classification systems. Patients and methods: We retrospectively retrieved 44 well differentiated gNET cases who underwent radical surgery between 2000-2015 at two tertiary-care centers. Results: Among the 44 well-differentiated gNET patients, 17 (38%) patients had metastatic disease to lymph nodes and/or distant sites, while 27 (62%) were confined to the stomach. Higher risk of metastasis was observed with increasing tumor size, grade, depth of invasion and with type-3 and solitary tumors. 30 (68%) patients had type-1 gNET and 14 (32%) had type-3 gNET. Majority of the type-1 cases (76,6%) were Grade 1 [G1] and type-3 cases (78,5%) were Grade 3 [G3]. Type-1 subgroup had no G3 tumor, and type-3 had no G1. Grade 2 [G2] tumors were more controversial, with metastatic and non-metastatic cases. G2 cases with a >10% Ki67 expression or type-3, had a worse prognosis. Although most of the type-1 gNETs had an indolent course, 6 of 30 (20%) patients had metastatic disease. Metastasizing type-1 gNETs were >10 mm in diameter or extended to/beyond the submucosa. Conclusion: Regarding our results, tumor type, grade, size, focality and depth of invasion are the prognostic parameters for gNETs, based on metastatic potential. Besides these parameters, a two-tiered grading system with a 10% Ki-67 proliferation index cut-off value could be considered for right treatment choice.

Neuroendocrine Tumors: a Relevant Clinical Update

PURPOSE OF REVIEW

The field of neuroendocrine oncology has changed much since the time of Oberndorfer first described and coined the term carcinoid. The purpose of this review is to summarize recent findings and highlight clinically relevant updates in the management of NENs, particularly those that are practice changing.

RECENT FINDINGS

Neuroendocrine tumors (NETs) have replaced carcinoid tumor, for the most part. The classification of neuroendocrine neoplasms (NENs) improved, and the epidemiological understanding of this disease group also expanded with global collaborations and maturation of large tumor registries. Clarity in the utility of some NET biomarkers continues to be evolving. Knowledge of molecular drivers of tumorigenesis increases, and scientific/technological advancements lead the way to multiple drug approvals for the treatment of advanced NETs. The incidence and prevalence of NENs continue to increase, and patients are living longer. Better understanding of molecular drivers and further understanding of the role of immunotherapy in NENs will further elevate the level of care and transform care for all patients with NENs.

ENETS standardized (synoptic) reporting for endoscopy in neuroendocrine tumors

Despite efforts from various endoscopy societies, reporting in the field of endoscopy remains extremely heterogeneous. Harmonisation of clinical practice in endoscopy has been highlighted by application of many clinical practice guidelines and standards pertaining to the endoscopic procedures and reporting are underlined. The aim of the proposed "standardised reporting" is to (1) facilitate recognition of gastrointestinal neuroendocrine neoplasms (NEN) on initial endoscopy, (2) to enable interdisciplinary decision making for treatment by a multidisciplinary team, (3) to provide a basis for a standardised endoscopic follow-up which allows detection of recurrence or progression reliably, (4) to make endoscopic reports on NEN comparable between different units, and (5) to allow research collaboration between NEN centres in terms of consistency of their endoscopic data. The ultimate goal is to improve disease management, patient outcome and reduce the diagnostic burden on the side of the patient by ensuring the highest possible diagnostic accuracy and validity of endoscopic exams and possibly interventions.

Rectal Neuroendocrine Neoplasms: Why Is There a Global Variation?

Purpose of Review

This review examines the variation in incidence of rectal neuroendocrine tumours across the globe. Rectal neuroendocrine tumours are a common type of gastrointestinal NET with an increasing incidence reported over the last 30 years.

Recent Findings

There have been a number of publications examining the epidemiology of neuroendocrine tumours across the world. These have utilized a variety of different methodologies to examine both incidence of prevalence of NETs. We review the data published and describe any causative factors and findings regarding the epidemiology of rectal NETs.

Summary

Rectal NETs account for 1–2% of all rectal cancers and are commonly diagnosed between 50–60 years of age. Most lesions are identified by chance at colonoscopy, commonly during colon cancer screening procedures, which is reflected in part in the age at diagnosis. Most lesions are small in size, < 10 mm and can be managed with endoscopic resection rather than requiring surgery. The highest incidence is reported in people of Asian ethnicity, with a tenfold increased incidence reported in some series compared with white population. There is also an increased incidence in Black and Hispanic population as identified through the Surveillance, Epidemiology and End Results (SEER) database. Endoscopic assessment of lesions is variable globally. Future work to better understand the cause of ethnic variation and development of comprehensive cancer registries would be helpful.

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.

Impact of the extent of resection of neuroendocrine tumor liver metastases on survival: A systematic review and meta-analysis

In patients with neuroendocrine tumors with liver metastases (NETLMs), complete resection of both the primary and liver metastases is a potentially curative option. When complete resection is not possible, debulking of the tumour burden has been proposed to prolong survival. The objective of this systematic review was to evaluate the effect of curative surgery (R0-R1) and debulking surgery (R2) on overall survival (OS) in NETLMs. For the subgroup of R2 resections, outcomes were compared by the degree of hepatic debulking (≥ 90% or ≥ 70%). A systematic review of the literature was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines using PubMed, Medline, CINAHL, Cochrane, and Embase databases. Hazard ratios (HRs) were estimated for each study and pooled using a random-effects inverse-variance meta-analysis model. Of 538 articles retrieved, 11 studies (1,729 patients) reported comparisons between curative and debulking surgeries. After pooling these studies, OS was found to be significantly shorter in debulking resections, with an HR of 3.49 (95% confidence interval, 2.70–4.51; p < 0.001). Five studies (654 patients) compared outcomes between ≥ 90% and ≥ 70% hepatic debulking approaches. Whilst these studies reported a tendency for OS and progression-free survival to be shorter in those with a lower degree of debulking, they did not report sufficient data for this to be assessed in a formal meta-analysis. In patients with NETLM, OS following surgical resection is the best to achieve R0-R1 resection. There is also evidence for a progressive reduction in survival benefit with lesser debulking of tumour load.

Nodal metastases in small rectal neuroendocrine tumours

AIM

Rectal neuroendocrine tumours (NETs) are the most common type of gastrointestinal NET. European Neuroendocrine Tumour Society guidelines suggest that rectal NETs measuring ≤10 mm are indolent with low risk of spread. In practice, many patients with lesions ≤1 cm do not undergo complete tumour staging. However, the size of the lesion may not be the only risk factor for nodal involvement/metastases. The aim of this study was to determine if MRI ± nuclear medicine imaging alters tumour stage in patients with rectal NETs ≤10 mm.

METHODS

Patients referred to a tertiary NET centre between 2005 and 2020 who met the inclusion criteria of a rectal NET ≤10 mm, full cross-sectional imaging, primarily an MRI scan and, if abnormal findings were identified, a subsequent ⁶⁸ Ga-DOTATATE positron emission tomography scan were included. All patients were followed up at our institution.

RESULTS

In all, 32 patients with rectal NETs 10 mm or less were included in the study: 16 women; median age 58 years (range 33-71); 47% (n = 15) were referred from bowel cancer screening procedures. The median size of the lesions was 5 mm (range 2-10 mm). 81% (n = 26) were World Health Organization Grade 1 tumours with Ki67 <3%. Radiological staging confirmed nodal involvement in 25% (8/32); two cases had distant metastatic disease. Lymphovascular invasion was present in 3% (1/32) of patients but none demonstrated peri-neural invasion.

CONCLUSION

This study demonstrates that small rectal NETs can develop nodal metastases; therefore it is important to stage these tumours accurately with MRI at baseline and, if there are concerns regarding potential lymph node metastases, to consider ⁶⁸ Ga-DOTATATE positron emission tomography imaging.

Time to give up traditional methods for the management of gastrointestinal neuroendocrine tumours

Neuroendocrine tumors (NETs) are a rare and heterogeneous disease group and constitute 0.5% of all malignancies. The annual incidence of NETs is increasing worldwide. The reason for the increase in the incidence of NETs is the detection of benign lesions, incidental detection due to the highest use of endoscopic and imaging procedures, and higher recognition rates of pathologists. There have been exciting developments regarding NET biology in recent years. Among these, first of all, somatostatin receptors and downstream pathways in neuroendocrine cells have been found to be important regulatory mechanisms for protein synthesis, hormone secretion, and proliferation. Subsequently, activation of the mammalian target of rapamycin pathway was found to be an important mechanism in angiogenesis and tumor survival and cell metabolism. Finally, the importance of proangiogenic factors (platelet-derived growth factor, vascular endothelial growth factor, fibroblastic growth factor, angiopoietin, and semaphorins) in the progression of NET has been determined. Using the combination of biomarkers and imaging methods allows early evaluation of the appropriateness of treatment and response to treatment.

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.

Management of appendiceal neuroendocrine tumors in the light of new guidelines

PURPOSE

Appendiceal neuroendocrine tumors (ANETs) are the most common in the appendix, detected in histopathological appendectomy specimens, which are resected for acute appendicitis. If tumor detection does not show signs of metastatic disease or obvious features of carcinoid syndrome, preoperative diagnosis remains a challenge. However, the treatment and follow-up algorithm change over time. In our study, we aimed to present 10 years of diagnostic and management experience.

MATERIAL AND METHODS

A retrospective study of all patients who underwent emergency appendectomy, with the intention to treat clinically acute appendicitis at Bakirkoy Dr. Sadi Konuk Hospital (Istanbul, Turkey), was undertaken. Patients with diagnoses other than ANETs were excluded. Age, gender, preoperative clinical findings, operative procedure, and histopathological results identified as ANETs were evaluated.

RESULTS

ANETs were detected in 24 patients (0.42%) in the histopathological examination of 5720 appendectomy specimens between December 2011 and October 2020. Mean age of patients was 30 years, with 58.3% female. The majority were located at the tip of appendix (62.5%). Eleven patients (45.83%) were graded as T1, one patient (4.16%) as T2, 11 (41.83%) as T3, and one patient (4.16%) as T4. Secondary hemicolectomy was performed in four patients. Median postoperative follow-up was 43 (17-108) months.

CONCLUSION

In addition, ANETs are rare and largely detected by chance; therefore, precise examination of routine appendectomy specimens is essential for diagnosis. Accurate tumor staging, in light of new algorithms, has an important place in follow-up and treatment management.

Risk factors for progression of appendiceal neuroendocrine tumours: low-stage tumours <5 mm appear to be overwhelmingly indolent and may merit a separate designation

AIMS

Appendiceal well-differentiated neuroendocrine tumours (NETs) are usually incidental and clinically benign. Several studies have reported different risk factors for nodal metastasis. The aim of this study was to investigate our appendiceal NETs (App-NETs) to determine the factors associated with malignant behaviour.

METHODS AND RESULTS

For 120 App-NETs, we reviewed the clinical presentation and follow-up, including serum chromogranin A (CgA) levels, and compiled several microscopic variables. Pathological factors were compared with nodal status and time to biochemical recurrence (elevated serum CgA level) by the use of Cox regression. We also reviewed similar App-NET data in the Surveillance, Epidemiology, and End Results (SEER) Programme. Among our 120 cases, seven patients had positive lymph nodes, and nine developed subsequent elevation of CgA levels; none developed distant metastases or died of disease. Only three patients had grade 2 NETs; none had nodal disease, and one developed an elevated CgA level. Increasing tumour size was associated with an increased risk of nodal disease [odds ratio (OR) 4.99, P = 0.0055). All seven node-positive cases were ≥13 mm. Factors associated with elevated CgA levels included age (OR 1.04, P = 0.041), pT4 disease (OR 10.22, P = 0.033), and nodal disease (OR 24.0, P = 0.012), but not size (OR 2.13, P = 0.072). Of the 1492 reported App-NETs in the SEER database with data on tumour size, 137 (9%) were pN1; only five of these (4%) were coded as being <5 mm.

CONCLUSIONS

Small (<5 mm) App-NETs that do not invade the serosa or mesoappendix appear to be overwhelmingly benign and low-grade, requiring neither Ki67 staining nor synoptic reporting. Given their indolent behaviour, different nomenclature or staging may be more appropriate for these NETs.

A Retrospective Cohort Study of Histology-Proven Neuroendocrine Neoplasms in the Italian Area of Udine

AIMS

The aim of this study was to investigate the epidemiology of histology-proven Neuroendocrine neoplasms (NENs) in an Italian area.

BACKGROUND

NENs are a rare and poorly known disease and the global incidence and prevalence appear to be increasing over the past decades.

OBJECTIVE

The objectives of this study were to estimate the incidence and trends of NENs in a 250,000-inhabitant area in the North-East of Italy in the 1998-2018 period and to compare them with international data.

METHODS

This retrospective cohort study was based on the analysis of anonymous health administrative databases, linked with each other at individual patient level through an anonymous stochastic key. NENs were identified from the anatomical pathology database. The standardized incidence rate (2010ESP and US2000) ± 95% CI per 100,000 were calculated, both annually and globally, for the whole period. Incidence was also calculated for specific anatomical sites and by gender. Trends for the considered periods and sites were summarized through the annual percent change (APC) and average increase (cases per 100,000 per year).

RESULTS

In the 1998-2018 period, the standardized incidence rate of NENs in the area of Udine was 2.49 (APC 3.33). A total of 162 cases were observed (51.2% males). Differences in incidence and trend were observed between sexes. The obtained results were consistent with those reported in other countries, confirming a significant and steady increase in NENs incidence in the last twenty years.

CONCLUSION

This study provides new epidemiological data on NENs in Italy. The observed sex differences deserve further investigations.

Liver-Directed Therapies for Neuroendocrine Neoplasms

PURPOSE OF REVIEW

To comprehensively synthesise and appraise the available evidence regarding therapies for metastatic neuroendocrine neoplasms that exploit the hepatic vasculature to deliver therapy to liver metastases.

RECENT FINDINGS

Various techniques including transarterial embolisation/chemoembolisation (TAE/TACE) and selective internal radiotherapy (SIRT, also termed radioembolisation [RE]) have been examined in patents with neuroendocrine liver metastases. Variations in the radioactive agents for selective internal radiotherapy (SIRT) have been explored, such as the use of Holmium-166, in addition to more established agents such as Yttrium-90. Recent trials have examined the safety and efficacy of combining liver-targeted therapy with systemic treatments, such as peptide receptor radionuclide therapy. More retrospective case series of liver-directed modalities will not provide additional knowledge. Randomised clinical trials have begun to compare the efficacy of different forms of liver-directed therapies, and also their combination with systemic treatment. Their results are expected to guide optimal treatment sequencing within multimodal concepts.

Epidemiology, Incidence, and Prevalence of Neuroendocrine Neoplasms: Are There Global Differences?

PURPOSE OF REVIEW

The purpose of our review is to explore global epidemiologic trends of gastroenteropancreatic (GEP) neuroendocrine tumors (NETs). Specifically, we sought to examine whether there are differences in incidence, prevalence, distribution (by primary tumor site, tumor grade, tumor stage at presentation), and overall survival of GEP NETs between different regions of the world.

RECENT FINDINGS

GEP NET incidence rates are rising steadily in North America, Asia, and Europe, though this rise appears to be most profound in North America. The distribution of GEP NETs differs regionally as in North America small intestinal and rectal NETs are most prevalent, in Asia rectal and pancreatic NETs are most prevalent, and in Europe small intestinal and pancreatic NETs are most prevalent. Overall survival for patients with GEP NETs appears to be improving with time. Some of the global increase in GEP NET incidence can be explained by increased health care utilization. This factor alone, however, does not explain the rise completely. Population-based studies utilizing uniform data collection instruments and a standard pathologic grading system are needed to identify other factors which may be contributing to this phenomenon.

Neuroendocrine Neoplasms: Identification of Novel Metabolic Circuits of Potential Diagnostic Utility

The incidence of neuroendocrine neoplasms (NEN) is increasing, but established biomarkers have poor diagnostic and prognostic accuracy. Here, we aim to define the systemic metabolic consequences of NEN and to establish the diagnostic utility of proton nuclear magnetic resonance spectroscopy (¹H-NMR) for NEN in a prospective cohort of patients through a single-centre, prospective controlled observational study. Urine samples of 34 treatment-naïve NEN patients (median age: 59.3 years, range: 36-85): 18 had pancreatic (Pan) NEN, of which seven were functioning; 16 had small bowel (SB) NEN; 20 age- and sex-matched healthy control individuals were analysed using a 600 MHz Bruker ¹H-NMR spectrometer. Orthogonal partial-least-squares-discriminant analysis models were able to discriminate both PanNEN and SBNEN patients from healthy control (Healthy vs. PanNEN: AUC = 0.90, Healthy vs. SBNEN: AUC = 0.90). Secondary metabolites of tryptophan, such as trigonelline and a niacin-related metabolite were also identified to be universally decreased in NEN patients, while upstream metabolites, such as kynurenine, were elevated in SBNEN. Hippurate, a gut-derived metabolite, was reduced in all patients, whereas other gut microbial co-metabolites, trimethylamine-N-oxide, 4-hydroxyphenylacetate and phenylacetylglutamine, were elevated in those with SBNEN. These findings suggest the existence of a new systems-based neuroendocrine circuit, regulated in part by cancer metabolism, neuroendocrine signalling molecules and gut microbial co-metabolism. Metabonomic profiling of NEN has diagnostic potential and could be used for discovering biomarkers for these tumours. These preliminary data require confirmation in a larger cohort.

Time trends in incidence and survival of small intestinal cancer in Sweden

BACKGROUND

Small intestinal cancer is less common than some other gastrointestinal malignancies. Tumours of different histological types and anatomical sites of origin have therefore often been described together. The aim of this study was to investigate the epidemiology for each of the four main subtypes: duodenal adenocarcinoma (D-AC), duodenal neuroendocrine tumour (D-NET), jejunoileal adenocarcinoma (J/I-AC), and jejunoileal neuroendocrine tumour (J/I-NET).

METHODS

All patients with small intestinal cancer diagnosed between 1960 and 2015 were identified from the Swedish Cancer Register. The age-adjusted incidence rate with incidence rate ratios, as well as overall (OS) and net (NS) survival, were determined and temporal trends were analysed.

RESULTS

The incidence rate was highest for J/I-NET, with 9.98 clinical diagnoses per million in 2010-2015. Clinical diagnosis of D-AC increased more than 10-fold and surpassed J/I-AC as the second most common subtype. D-NET was by far the least common subtype. Diagnosis at autopsy became less common over time, whereas clinical diagnoses increased significantly for all four subtypes. All subtypes except J/I-AC affected men more often than women. The age distribution was similar between subtypes, although patients with adenocarcinomas were slightly older. Survival was generally much better for patients with NET than for those with adenocarcinoma. Both OS and NS showed a negative association with advancing age. Survival improved only for J/I-NET from a 5-year NS of 0.69 in the 1960s to 0.81 in 2010-2015.

CONCLUSION

The incidence of small intestinal cancer is increasing, particularly for D-AC and in the elderly. Survival of patients with small intestinal cancer has improved only for J/I-NET over the last decades.

Racial Differences in Gastroenteropancreatic Neuroendocrine Tumor Treatment and Survival in the United States

OBJECTIVES

The objective of this study was to evaluate racial differences in cancer treatment and survival in gastroenteropancreatic neuroendocrine tumor (GEP-NET) patients.

METHODS

Using the Surveillance, Epidemiology, and End Results Registry, we identified patients with GEP-NETs of the stomach, small intestine (SI), colon, rectum, appendix, and pancreas diagnosed between 1973 and 2014. Demographic, cancer, and treatment information were collected and compared using χ2 tests. Multivariable logistic and Cox regression were used to determine disparities in receiving treatment and overall survival.

RESULTS

We identified 19,031 GEP-NET patients: 2839 were non-Hispanic Blacks, 12,832 non-Hispanic Whites, 2098 Hispanics, and 1262 Asians. African Americans and Hispanics with SI and pancreatic NETs were less likely to be treated with surgery (odds ratio, 0.6; 95% confidence interval [CI], 0.46-0.69; odds ratio, 0.71; 95% CI, 0.51-0.99, respectively). African American race was not an independent predictor of survival; there was a strong trend in stomach, SI, and pancreas NETs (hazard ratio [HR], 1.31; 95% CI, 1-1.7; HR, 1.2; 95% CI, 0.99-1.45; HR, 1.22; 95% CI, 1-1.48, respectively).

CONCLUSIONS

Our study provides evidence of racial disparities in treatment and survival across GEP-NET primary sites and racial groups. Further studies should be performed to improve our understanding of the reason for these disparities.

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Incidence trends of lung and gastroenteropancreatic neuroendocrine neoplasms in Switzerland

The incidence of neuroendocrine neoplasms (NENs) seems to increase worldwide. Long-term, population-based series that consider tumor differentiation are, however, sparse. We assessed the incidence trend of lung and gastroenteropancreatic (GEP) NENs according to the latest International Agency for Research on Cancer/World Health Organization classification over a 41-year time period in two Swiss regions. All cases of lung and GEP NENs recorded in the Vaud and Neuchâtel Cancer Registries from 1976 to 2016 were included. NENs were stratified into well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs). Changes in annual age-standardized incidence rates were calculated for lung and GEP NETs and NECs by sex. Of 4,141 patients diagnosed with NENs, 65% were men. The incidence of lung NETs among men and women increased by 3.9%/year (95% CI: -5.3, 14.1%) and 4.9%/year (0.1, 9.9%), respectively, between 1976 and 2016. The incidence of lung NECs decreased by 2.6%/year (-3.1,-1.8%) in men from 1985 to 2016 whereas it increased in women between 1976 and 1998 by 6%/year (4.2, 7.9%). For GEP NETs, a steady annual increase in incidence occurred between 1976 and 2016 with a magnitude of 1.7% (0.7, 2.7%) in men and 1.3% (0.5, 2.1%) in women. No significant trend in incidence of GEP NECs was found for both sexes. The incidence trends of lung NECs in men and women parallel changes in smoking prevalence in the population. Causes of the increase in incidence of GEP NETs are likely multifactorial. Our study supports the importance of evaluating the epidemiology of NENs by tumor differentiation.

Neuroendocrine neoplasia of the gastrointestinal tract revisited: towards precision medicine

Over the past 5 years, a number of notable research advances have been made in the field of neuroendocrine cancer, specifically with regard to neuroendocrine cancer of the gastrointestinal tract. The aim of this Review is to provide an update on current knowledge that has proven effective for the clinical management of patients with these tumours. For example, for the first time in the tubular gastrointestinal tract, well-differentiated high-grade (grade 3) tumours and mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs) are defined in the WHO classification. This novel classification enables efficient identification of the most aggressive well-differentiated neuroendocrine tumours and helps in defining the degree of aggressiveness of MiNENs. The Review also discusses updates to epidemiology, cell biology (including vesicle-specific components) and the as-yet-unresolved complex genetic background that varies according to site and differentiation status. The Review summarizes novel diagnostic instruments, including molecules associated with the secretory machinery, novel radiological approaches (including pattern recognition techniques), novel PET tracers and liquid biopsy combined with DNA or RNA assays. Surgery remains the treatment mainstay; however, peptide receptor radionuclide therapy with novel radioligands and new emerging medical therapies (including vaccination and immunotherapy) are evolving and being tested in clinical trials, which are summarized and critically reviewed here.

Temporal trends in incidence, evaluation and management of neuroendocrine neoplasms of the appendix: 14 years' experience

BACKGROUND

Information regarding temporal trends in appendiceal neuroendocrine neoplasms (ANEN) is limited. This retrospective study evaluated temporal trends in ANEN incidence and management over a 14-year period.

METHODS

Appendectomy pathology reports from a single tertiary center were reviewed.

RESULTS

During 2005-2018, 8327 appendectomies were performed and 57 ANENs were diagnosed (average age 31.7 ± 17 years; 70.2% women; 17.5% Arab ethnicity; and 22.8% < 18 years of age). The cohort was divided according to year of diagnosis (Period A 2005-2011; Period B 2012-2018). No differences were found in ANEN incidence (0.75% and 0.62%, respectively, p = 0.104), epidemiologic or pathologic characteristics between periods. In period B, pathology reports were more comprehensive and use of specific imaging and biochemical studies was more prevalent. Hemicolectomy rates and results were similar (8 in Period A, 7 in Period B, p = 0.925). All patients remained alive for the duration of follow-up.

CONCLUSIONS

No temporal changes in epidemiological, clinical or pathological features of ANENs were noted. Although clinico-pathological evaluation was more detailed after 2011, there was no change in rates of hemicolectomy or disease prognosis.

Incidence of Appendiceal Malignancies in Sweden Between 1970 and 2012

BACKGROUND

There is limited knowledge about the epidemiology of the major histological subtypes of appendiceal malignancy: adenocarcinoma and neuroendocrine neoplasm of the appendix (A-NEN). The aims of this national cohort study were to assess the prevalence, incidence and trends of appendiceal malignancies in Sweden.

METHOD

All individuals who underwent appendicectomy and all diagnosed with appendiceal malignancy from 1970 to 2012 were identified from the National Patient Register and the Swedish Cancer Registry. Demographic data of the background population were obtained from Statistics Sweden. The incidence rate (IR) and the prevalence of appendiceal malignancy per performed appendicectomy were calculated.

RESULTS

We identified 3774 patients with appendiceal malignancy. IR of A-NEN was 5.8/10⁶ person-years with a peak of 8.4/10⁶ at age 20-30 years, whereafter it plateaued at a somewhat lower level. IR for adenocarcinoma was 3.7/10⁶ person-years, starting at a very low level among the youngest and increasing to 15.4/10⁶ at age 80-89 years. The IR of adenocarcinoma increased from 2.6/10⁶ in 1970-1979 to 5.4/10⁶ in 2010-2012. The IR of A-NEN was stable during the study period. The prevalence per appendicectomy was low for both types of malignancies among the young but increased with age, most dramatically for adenocarcinoma. There was a trend during the study period towards more extensive surgery.

CONCLUSION

Adenocarcinoma is most common and increasing in the elderly, whereas A-NEN affects all ages with a peak in young age. This peak probably reflects removal of occult A-NEN due to the higher appendicectomy frequency in the young.

Management of Locally Advanced and Unresectable Small Bowel Neuroendocrine Tumours

Three subtypes of small bowel neuroendocrine tumours (SBNETs) have been described: Type A: SBNET with resectable mesenteric disease that does not involve the mesenteric root; Type B: "Borderline resectable" SBNET presenting with mesenteric nodal metastases and fibrosis adjacent but not encasing the main trunk of the superior mesenteric artery (SMA) and superior mesenteric vein (SMV); and Type C: "Locally advanced or irresectable" SBNET where tumour deposits and fibrosis encase the SMA and SMV. Type C SBNETs are rare and constitute around 5% of patients in reported series, although this may underestimate the prevalence. In these patients, almost all will present with symptoms of intestinal ischemia or obstruction and symptom management should be a primary main focus of treatment. All patients should be carefully staged with cross-sectional imaging and 68 Ga-dotate positron emission tomography, and discussed at a dedicated neuroendocrine tumour multidisciplinary meeting. Expert surgical review should always be sought as experienced centers have a high rate of successful resection of primary tumours and mesenteric disease. If resection is not feasible, surgical bypass should be considered in patients with a discrete and symptomatic point of obstruction. Non-operative management should emphasize symptomatic treatment with somatostatin analogs, nutritional advice and support and palliative care. Successful neoadjuvant approaches utilizing peptide radionucleide receptor therapy and systemic chemotherapy with everolimus or temazolamide/capecitabine have not been reported.

Gastro-entero-pancreatic neuroendocrine neoplasia: The rules for non-operative management

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) with favorable pathological and clinical features may be considered as indolent lesions, and therefore be amenable to conservative management. According to the primary tumor site, different non-aggressive approaches, based on endoscopic resection or simple active surveillance, can be proposed to selected patients fulfilling specific criteria. Tumor size, Ki67 proliferative index and depth of invasion are markers that can be used in order to identify these subjects. Patients with type I gastric NENs <1 cm as well as those with non-ampullary duodenal NENs <1 cm with no associated syndrome can be safely managed by endoscopic resection. On the other hand, an active surveillance approach is preferred over surgery for patients with asymptomatic, non-functioning pancreatic NENs ≤2 cm without dilation of the main pancreatic duct or bile duct. As far as NENs of the appendix are concerned, appendectomy should be considered as curative when a R0 resection has been achieved in the presence of a tumor ≤1.5 cm, graded as G1 and without lymphovascular invasion. Finally, G1 rectal NENs ≤1 cm without invasion of the muscular layer can be safely treated by endoscopic resection. Therefore, surgeons should be aware of the existence of indolent GEP-NENs, in order to avoid unnecessary operations with associated postoperative complications.

Lights and darks of neuroendocrine tumors of the appendix

INTRODUCTION

Neuroendocrine tumors of the appendix are a relatively frequent type of neuroendocrine tumor, usually detected incidentally after appendectomy. Almost all small slow-growing G1 tumors with no risk factors are cured with appendectomy while the rare and aggressive G3 carcinomas may represent a challenge in terms of management and often lead to a poor outcome. In the middle of the spectrum, a number of tumors present with in-between features and sometimes no clear-cut guidance emerges from the literature for directing the management and follow-up of these patients.

EVIDENCE ACQUISITION

A meticulous review of the literature on neuroendocrine tumors of the appendix, including the recommendations published by the relevant international societies.

EVIDENCE SYNTHESIS

The literature on the neuroendocrine tumors of the appendix appears to be inhomogeneous. Likely this occurs as a consequence of a number of factors, including the mostly retrospective nature of the available data, the heterogeneous records of the same, and some peculiar aspects of the appendiceal neuroendocrine tumors, with evidence of considerable biological and clinical differences in terms of epidemiology, management, and prognosis from the less aggressive tumors to the most aggressive cancers. In particular, some situations concerning tumors in the middle of the biological and clinical spectrum are still poorly defined.

CONCLUSIONS

There are some persisting "grey areas" with regard to the characterization and the clinical management of neuroendocrine tumors of the appendix. An increasing awareness of the biological and clinical aspects of this disease and new, ideally prospective, focused studies might help and clarify some relevant issues that are not fully elucidated yet and could increase the solidity of the guidance for the management and the follow-up of the patients.