Histogenesis and natural history of gut neuroendocrine tumors: present status

Role of Mediterranean diet in endocrine diseases: a joint overview by the endocrinologist and the nutritionist

PURPOSE

The purpose of this review is to examine the current evidence on the potential role of Mediterranean diet (MD) in the prevention and management of endocrine disorders and to highlight the importance of interdisciplinary collaboration between endocrinologists and nutritionists.

METHODS

A literature search was conducted using PubMed and Google Scholar databases to identify relevant studies published in English. Studies were selected based on their relevance to the role of MD in the prevention and management of endocrine disorders. The search terms included "Mediterranean diet," "endocrine disorders," "thyroid disorders," "gonadal disorders," and "neuroendocrine tumors".

RESULTS

The studies reviewed suggest that MD may have a beneficial effect in the prevention and management of various endocrine disorders, including thyroid disorders, gonadal disorders, and neuroendocrine tumors. MD has been associated with decreased risk of nodular thyroid disease and thyroid cancer, improved male and female reproductive health, and a potential role in the management of neuroendocrine tumors. MD's anti-inflammatory and antioxidant properties, as well as its high levels of phytochemicals, may play a role in its beneficial effects.

CONCLUSION

Interdisciplinary collaboration between endocrinologists and nutritionists is essential for the optimal management of endocrine disorders, including the potential role of MD in their prevention and management. While further research is needed, the current evidence suggests that MD may have a protective effect against endocrine disorders, and its incorporation into dietary recommendations may be beneficial.

Multidisciplinary Approach to the Diagnosis of Occult Primary Neuroendocrine Neoplasm: A Clinical Challenge

Approximately 11% to 14% of subjects with neuroendocrine neoplasms (NENs) have metastatic lesions with unknown primary origin (UPO), with the majority of UPO-NENs found in the small bowel. Herein, we assessed the available literature on UPO-NENs, focusing on clinical presentation and diagnostic techniques to identify the primary site. The identification of the primary tumor is important as it affects the prognosis; however, the clinical presentation can be non-specific in non-functioning forms. In the presence of metastatic disease, the histological sample is fundamental to obtain immunohistochemical markers that might orientate the clinician in the search for the primary tumor through radiology, functional imaging and endoscopic techniques. In summary, multidisciplinary management plays a key role in UPO-NENs, even more than in other NENs. Molecular biology and gene-expression profiling represent areas of great interest which might be developed in the near future for both the diagnosis and the treatment of these neoplasms.

Prognostic value of the neutrophil/lymphocyte ratio in enteropancreatic neuroendocrine tumors

Accessible prognostic tools are needed to individualize treatment of neuroendocrine tumors (NETs). Data suggest neutrophil/lymphocyte ratios (NLRs) have prognostic value in some solid tumors, including NETs. In the randomized double-blind CLARINET study (NCT00353496; EudraCT 2005-004904-35), the somatostatin analog lanreotide autogel/depot increased progression-free survival (PFS) compared with placebo in patients with inoperable or metastatic intestinal and pancreatic NETs (grades 1–2, Ki-67 < 10%). The exploratory post-hoc analyses presented here evaluated the prognostic value of NLR in the CLARINET study cohort, in the context of and independently from treatment. Kaplan–Meier PFS plots were generated for patients with available NLR data, in subgroups based on NLR values, and 24-month survival rates were calculated. P values and hazard ratios for prognostic effects were generated using Cox models. 31216222 Baseline characteristics were balanced between lanreotide autogel/depot 120 mg (n = 100) and placebo (n = 101) arms. Irrespective of treatment, raw 24-month PFS rates were comparable across subgroups based on NLR tertiles [37.3% (low), 38.8% (middle), 38.8% (high); n = 67 per group] and NLR cutoff of 4 [38.1% (NLR ≤ 4; n = 176), 40.0% (NLR > 4; n = 25)]. Furthermore, NLRs were not prognostic in Cox models, irrespective of subgroups used. The therapeutic effect of lanreotide autogel/depot 120 mg was independent of NLRs (P > 0.1). These exploratory post-hoc analyses in patients with advanced intestinal and pancreatic NETs contrast with previous data suggesting NLR has prognostic potential in NETs. This may reflect the inclusion of patients with lower-grade tumors or use of higher NLR cutoff values in the current analysis.

Trends in incidence of small bowel cancer according to histology: a population-based study

BACKGROUND

Small bowel cancer is not a single entity. Population-based studies taking into account histological diversity are scarce. The aim of this study was to report on their trends in incidence by histology in France over the past 20 years.

METHODS

All patients with a small bowel cancer diagnosed in 15 French administrative areas covered by a registry from the network of French cancer registries (FRANCIM) were included. Age-standardized incidence rates were estimated using the world standard population. Incidence rates were calculated by gender, age group, histology, and 5-year period.

RESULTS

The overall age-standardized incidence rates were 1.46/100,000 inhabitants in men and 0.9/100,000 inhabitants in women. Adenocarcinoma was the most common histological type (38%), followed by neuroendocrine tumors (35%), lymphoma (15%) and sarcoma (12%). Age at diagnosis and tumor location differed between adenocarcinoma and neuroendocrine tumors. The incidence of all four tumor types increased significantly over the 20-year period, with the exception of lymphoma in men. The annual percentage change for neuroendocrine tumors was 3.89% in men and 3.61% in women; for sarcoma, it was 3.38% and 4.08%, respectively. The incidence of adenocarcinoma and lymphoma also increased in women with an annual percentage change of 3.05% and 3.32%, respectively.

CONCLUSION

Small bowel cancer incidence has increased over time. This increase occurred with different amplitudes and patterns in the four major histological types. The improvement in imaging techniques could partly explain this increase. It is necessary to determine whether predisposing conditions may contribute to this change.

Diagnostic Approaches to Neuroendocrine Neoplasms of Unknown Primary Site

Neuroendocrine neoplasms (NENs) arise from cells of neuronal and endocrine differentiation. While they are a rare entity, an increasing proportion of patients with NEN present with metastatic disease and no evident primary site using routine imaging or histopathology. NENs of unknown primary site have a poorer prognosis, often due to the challenge of selecting appropriate evidence-based management. We review the available literature and guidelines for the management of NENs of unknown primary site including clinical features, biochemical tests, histopathology, imaging, surgical exploration and localised and systemic treatments. We also discuss novel molecular techniques currently under investigation to aid primary site identification.

Gastroenteropancreatic neuroendocrine neoplasms and inflammation: A complex cross-talk with relevant clinical implications

Neuroendocrine neoplasms (NENs) are a group of tumors originating from the neuroendocrine system. They mainly occur in the digestive system and the respiratory tract. It is well-know a strict interaction between neuroendocrine system and inflammation, which can play an important role in NEN carcinogenesis. Inflammatory mediators, which are produced by the tumor microenvironment, can favor cancer induction and progression, and can promote immune editing. On the other hand, a balanced immune system represents a relevant step in cancer prevention through the elimination of dysplastic and cancer cells. Therefore, an inflammatory response may be both pro- and anti-tumorigenic. In this review, we provide an overview concerning the complex interplay between inflammation and gastroenteropancreatic NENs, focusing on the tumorigenesis and clinical implications in these tumors.

Synchronous Pancreatic Serous Cystic Neoplasm and Duodenal Neuroendocrine Tumor: Case Report and Review of the Literature

Simultaneous presence of pancreatic serous cystic neoplasms and neuroendocrine neoplasms is rare. We present a case with the incidental finding of a duodenal neuroendocrine tumor (NET) with 2 lymph node metastases in a Whipple resection specimen performed to remove a pancreatic cystic neoplasm that postoperatively turned out to represent a serous cystic neoplasm (SCN). The patient was a 75-year-old female. She presented with loss of appetite and weight. Preoperative contrast-enhanced computed tomography scan of the abdomen showed a multicystic lesion in the head of pancreas. On histologic examination of the resection specimen, a pancreatic SCN was found, and in addition in 2 peripancreatic lymph nodes, metastases from a NET. Further examination of the resected specimen revealed a duodenal NET. Review of the literature revealed only one prior study with 4 cases of pancreatic SCN associated with a duodenal NET. In 1 of the 4 cases, the patient had von Hippel-Lindau disease. Our report emphasizes the importance of careful examination of pancreatic resection specimens including the peripancreatic lymph nodes also when dealing with SCNs, as coexisting and more malignant tumors may otherwise be missed.

Mesenteric Tumor Deposits in Midgut Small Intestinal Neuroendocrine Tumors Are a Stronger Indicator Than Lymph Node Metastasis for Liver Metastasis and Poor Prognosis

Mesenteric tumor deposits (MTDs) are not included in the American Joint Committee on Cancer (AJCC) staging system for midgut small intestinal neuroendocrine tumors (NETs). We examined the prognostic significance of MTDs associated with midgut NETs. Hematoxylin and eosin slides from 132 resected jejunal/ileal NETs were reviewed for AJCC tumor stage, lymph node (LN) metastasis, MTDs, and hepatic metastases. MTDs were defined as discrete irregular mesenteric tumor nodules discontinuous from the primary tumor. Clinical or pathologic evidence of metastases and survival data were abstracted from electronic medical records. The cohort included 72 male and 60 female patients with a median age of 60 years. LN metastasis, MTDs, and liver metastasis were present in 80%, 68%, and 58% of patients, respectively. Female sex and presence of MTDs were independent predictors of liver metastasis. The odds ratio for hepatic metastasis in the presence of MTDs was 16.68 (95% confidence interval [CI], 4.66-59.73) and 0.81 (95% CI, 0.20-3.26) for LN metastasis. Age, MTDs, and hepatic metastasis were associated with disease-specific survival (DSS) in univariate analysis. Primary tumor histologic grade, pT3/T4 stage, and LN metastasis were not associated with DSS. Multivariate analysis of liver metastasis-free survival stratified by tumor grade showed that MTDs were associated with adverse outcomes. The hazard ratio for MTDs was 4.58 (95% CI, 1.89-11.11), compared with 0.98 (95% CI, 0.47-2.05) for LN metastasis. MTDs, but not LN metastasis, in midgut NETs are a strong predictor for hepatic metastasis and are associated with poor DSS.

Recent Updates on Neuroendocrine Tumors From the Gastrointestinal and Pancreatobiliary Tracts

CONTEXT

-Gastrointestinal (GI) and pancreatobiliary tracts contain a variety of neuroendocrine cells that constitute a diffuse endocrine system. Neuroendocrine tumors (NETs) from these organs are heterogeneous tumors with diverse clinical behaviors. Recent improvements in the understanding of NETs from the GI and pancreatobiliary tracts have led to more-refined definitions of the clinicopathologic characteristics of these tumors. Under the 2010 World Health Organization classification scheme, NETs are classified as grade (G) 1 NETs, G2 NETs, neuroendocrine carcinomas, and mixed adenoneuroendocrine carcinomas. Histologic grades are dependent on mitotic counts and the Ki-67 labeling index. Several new issues arose after implementation of the 2010 World Health Organization classification scheme, such as issues with well-differentiated NETs with G3 Ki-67 labeling index and the evaluation of mitotic counts and Ki-67 labeling. Hereditary syndromes, including multiple endocrine neoplasia type 1 syndrome, von Hippel-Lindau syndrome, neurofibromatosis 1, and tuberous sclerosis, are related to NETs of the GI and pancreatobiliary tracts. Several prognostic markers of GI and pancreatobiliary tract NETs have been introduced, but many of them require further validation.

OBJECTIVE

-To understand clinicopathologic characteristics of NETs from the GI and pancreatobiliary tracts.

DATA SOURCES

-PubMed (US National Library of Medicine) reports were reviewed.

CONCLUSIONS

-In this review, we briefly summarize recent developments and issues related to NETs of the GI and pancreatobiliary tracts.

Is the prevalence of colonic neuroendocrine tumors increased in patients with inflammatory bowel disease?

Inflammatory bowel disease (IBD) patients may bear an increased neuroendocrine tumor (NET) risk. These tumors are mostly reported as coincidental findings during surgery. We aimed to determine the prevalence of colonic NET in a Dutch nationwide IBD cohort and calculate the prevalence rate ratios (PRR) compared with the general Dutch population. Our second aim was to investigate whether a high bowel surgery rate in IBD could result in a high PRR for NET. The Dutch Pathology Registry (PALGA) was searched to identify all IBD patients with colonic NET in The Netherlands between 1991 and 2011. We determined the prevalence and PRR of colonic NET in a 20-year period. For our second aim, we compared NET prevalence in colonic resection specimens between IBD cases and non-IBD controls (diverticulitis and ischemia). We identified 51 IBD patients who developed colonic NET resulting in a prevalence of 60.4-89.3 per 100,000 patients in a 20-year period with a PRR of 2.8-4.1. However, adjusted for resection type, sex and age, a higher NET prevalence was shown in diverticulitis (OR 5.52, 95% CI 3.47-8.78) and ischemia (OR 1.97, 95% CI 1.09-3.58) compared with IBD. Our key finding is that NET are more prevalent in IBD patients compared with the general population (PRR 2.8-4.1). This might be attributed to a high rate of incidental NET as IBD patients frequently undergo intestinal surgery. A lower adjusted NET prevalence in colonic resection specimens for IBD compared to ischemia and diverticulitis supports this hypothesis.

Gastric secretion

PURPOSE OF REVIEW

This review summarizes the past year's literature regarding the neural, paracrine, hormonal, and intracellular regulation of gastric acid secretion.

RECENT FINDINGS

Gastric acid facilitates the digestion of protein as well as the absorption of iron, calcium, vitamin B12, and certain medications. High gastric acidity, in combination with pepsin and lipase, kills ingested microorganisms and may play a role in preventing bacterial overgrowth, enteric infection, and possibly spontaneous bacterial peritonitis, community-acquired pneumonia, and infection with Mycobacterium tuberculosis. Stimulants of acid secretion include histamine, gastrin, acetylcholine, and ghrelin. Inhibitors include somatostatin, gastric inhibitory polypeptide, calcitonin gene-related peptide, and adrenomedullin. Helicobacter pylori stimulates or inhibits depending upon the time course of infection and the area of the stomach predominantly infected. Proteins implicated in H-K-ATPase membrane trafficking include myosin IIB, F-actin, ezrin, and Rab GTPases.

SUMMARY

Our understanding of the regulation of gastric acid secretion continues to advance. Such knowledge is crucial for the management of acid-peptic disorders and the development of novel medications, such as cholecystokinin-2 receptor antagonists.