Diagnosis of Zollinger-Ellison syndrome: Increasingly difficult

The cckOMA syndrome and its relation to the Zollinger-Ellison syndrome: a diagnostic challenge

OBJECTIVE

Among patients with enteropancreatic neuroendocrine tumor syndromes only one case with a cholecystokinin (CCK) secreting tumor has been reported. She had significant hyperCCKemia leading to a specific syndrome of severe diarrheas, weight loss, repeated duodenal ulcers and a permanently contracted gallbladder with gallstones. There are, however, reasons to believe that further CCKomas exist, for instance among Zollinger-Ellison patients with normal plasma gastrin concentrations. The present review is a call to gastroenterologists for awareness of such CCKoma patients.

METHOD

After a short case report, the normal endocrine and oncological biology of CCK is described. Subsequently, the CCKoma symptoms are discussed with particular reference to the partly overlapping symptoms of the Zollinger-Ellison syndrome. In this context, the diagnostic use of truly specific CCK and gastrin assays are emphasized. The discussion also entails the problem of access to accurate CCK measurements.

CONCLUSION

Obviously, the clinical awareness about the CCKoma syndrome is limited. Moreover, it is also likely that the knowledge about the necessary specificity demands of diagnostic gastrin and CCK assays have obscured proper diagnosis of the CCKoma syndromes in man.

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.

Primary gastrinoma of the gallbladder: a case report and review of the literature

Background

Primary gallbladder gastrinoma is an exceptionally uncommon tumor and is a rare form of neuroendocrine neoplasm. Until now, no cases of primary gallbladder gastrinoma and rare cases of primary gastrinoma from the biliary system have been reported.

Case presentation

We report a case of a 50-year-old woman with watery diarrhea who intermittently received proton pump inhibitors (PPIs) as treatment. A serum gastrin level of 711 pg/ml was recorded after the withdrawal of PPI over 1 week. Enhanced computed tomography (CT) imaging and octreotide imaging uncovered a solitary tumor at the hepatic hilar region. During the laparoscopic surgery, it was determined that the tumor had its origin in the wall of the gallbladder neck, prompting the implementation of a laparoscopic cholecystectomy. Histological analysis revealed a primary neuroendocrine tumor from the neck of the gallbladder. The patient's symptoms disappeared after the surgery with a follow-up of 6 months.

Conclusions

This case confirmed that primary gallbladder gastrinoma represents a distinct nosological entity. Immunohistochemical analysis plays a pivotal role in the diagnostic process. Given the limited understanding of primary gallbladder gastrinoma, our objective is to offer novel insights into this rare disease by delivering distinctive information and highlighting the therapeutic significance of surgical intervention.

Esophageal Perforation Unveiling the Diagnosis of Zollinger-Ellison Syndrome

Gastrinomas are the most common neuroendocrine tumors worldwide and cause a clinical syndrome known as Zollinger-Ellison Syndrome (ZES). Increased acid production resulting from elevated gastrin levels contributes to symptoms such as abdominal pain, heartburn, and diarrhea. However, the non-specificity and overlap in the symptoms with idiopathic peptic ulcer disease and gastroesophageal reflux disease (GERD) can lead to delayed diagnosis. In this case, we describe a patient with a past medical history of GERD and a perforated gastric ulcer who continued to experience symptoms of dyspepsia and had a subsequent esophageal perforation, despite H. pylori eradication and high-dose proton pump inhibitor (PPI) therapy. Multiple ulcers were visualized in the first portion of the duodenum, and metastatic lesions were demonstrable in the liver. Serum gastrin level was elevated to 433 pg/mL. Histology of liver biopsy showed a well-differentiated neuroendocrine tumor, supporting the diagnosis of ZES. This article underscores the significance of considering ZES in the differential in cases of refractory gastric hyperacidity and the importance of early diagnosis with serum gastrin testing to prevent complications such as gastric obstruction, perforation, hemorrhage, esophageal strictures, or rupture and to minimize the risk of metastasis. It is noteworthy that while perforations in cases of ZES typically occur in the duodenum, this particular case is atypical as it had involved the stomach. Furthermore, it was associated with esophageal perforation, likely resulting from forceful and prolonged vomiting caused by persistent dyspepsia.

Effective strategies for adequate control of hormonal secretion in functioning neuroendocrine neoplasms

Neuroendocrine neoplasms are a unique form of malignancies as they can be accompanied by specific functioning hormonal syndromes that can impair survival and quality of life in patients. Functioning syndromes are defined by the combination of specific clinical signs and symptoms in combination with inappropriately elevated circulating levels of hormones. Clinicians should remain vigilant for the presence of functioning syndromes in neuroendocrine neoplasm patients at presentation as well as during follow-up. The correct diagnostic work-up should be initiated in cases of clinical suspicion of a neuroendocrine neoplasm-associated functioning syndrome. Management of a functional syndrome includes options from supportive, surgical, hormonal and antiproliferative treatment modalities. Here, we review the patient and tumour characteristics for each functioning syndrome that should be taken into account when deciding the optimum treatment strategy in neuroendocrine neoplasm patients.

An Overview of Circulating Biomarkers in Neuroendocrine Neoplasms: A Clinical Guide

Neuroendocrine neoplasms (NENs) are a heterogeneous group of diseases that are characterized by different behavior and clinical manifestations. The diagnosis and management of this group of tumors are challenging due to tumor complexity and lack of precise and widely validated biomarkers. Indeed, the current circulating mono-analyte biomarkers (such as chromogranin A) are ineffective in describing such complex tumors due to their poor sensitivity and specificity. In contrast, multi-analytical circulating biomarkers (including NETest) are emerging as more effective tools to determine the real-time profile of the disease, both in terms of accurate diagnosis and effective treatment. In this review, we will analyze the capabilities and limitations of different circulating biomarkers focusing on three relevant questions: (1) accurate and early diagnosis; (2) monitoring of disease progression and response to therapy; and (3) detection of early relapse.

An Overview of Pancreatic Neuroendocrine Tumors and an Update on Endoscopic Techniques for Their Management

The growing importance of advanced endoscopy in the diagnosis and treatment of pancreatic neuroendocrine neoplasms (PanNETs) necessitates a comprehensive understanding of various biochemical markers, genetic testing methods, radiological techniques, and treatment approaches that encompass multiple disciplines within and beyond gastrointestinal oncology. This review aims to highlight key aspects of these topics, with a specific focus on emerging EUS-guided procedures for the management of PanNETs.

European Neuroendocrine Tumor Society 2023 guidance paper for functioning pancreatic neuroendocrine tumour syndromes

This ENETS guidance paper aims to provide practical advice to clinicians for the diagnosis, treatment and follow-up of functioning syndromes in pancreatic neuroendocrine tumours (NET). A NET-associated functioning syndrome is defined by the presence of a clinical syndrome combined with biochemical evidence of inappropriately elevated hormonal levels. Different hormonal syndromes can be encountered in pancreatic NET patients, including insulinoma, gastrinoma as well as the rare glucagonoma, VIPoma, ACTHoma, PTHrPoma, carcinoid syndrome, calcitoninoma, GHRHoma and somatostatinoma. The recommendations provided in this paper focus on the biochemical, genetic and imaging work-up as well as therapeutic management of the individual hormonal syndromes in well-differentiated, grade 1-3, functioning NET with the primary tumour originating in the pancreas, and for specific subtypes also in the duodenum.

Sporadic and MEN1-related gastrinoma and Zollinger-Ellison syndrome: differences in clinical characteristics and survival outcomes

PURPOSE

Gastrinoma with Zollinger-Ellison syndrome (ZES) may occur sporadically (Sp) or as part of the inherited syndrome of multiple endocrine neoplasia 1 (MEN-1). Data comparing Sp and MEN-1/ZES are scanty. We aimed to identify and compare their clinical features.

METHODS

Consecutive patients with ZES were evaluated between 1992 and 2020 among a monocentric Italian patient cohort.

RESULTS

Of 76 MEN-1 patients, 41 had gastroenteropancreatic neuroendocrine neoplasm (GEP-NEN), 18 of whom had ZES; of 320 Sp-GEP-NEN, 19 had Sp-ZES. MEN-1/ZES patients were younger (p = 0.035) and the primary MEN-1/ZES gastrinoma was smaller than Sp-ZES (p = 0.030). Liver metastases occurred in both groups, but only Sp-ZES developed extrahepatic metastases. 13 Sp-ZES and 8 MEN-1/ZES underwent surgery. 8 Sp-ZES and 7 MEN-1/ZES received somatostatin analogs (SSAs). Median overall survival (OS) was higher in MEN-1/ZES than in Sp-ZES (310 vs 168 months, p = 0.034). At univariate-logistic regression, age at diagnosis (p = 0.01, OR = 1.1), G3 grading (p = 0.003, OR = 21.3), Sp-ZES (p = 0.02, OR = 0.3) and presence of extrahepatic metastases (p = 0.001, OR = 7.2) showed a significant association with OS. At multivariate-COX-analysis, none of the variables resulted significantly related to OS. At univariate-logistic regression, age (p = 0.04, OR = 1.0), size (p = 0.039, OR = 1.0), G3 grade (p = 0.008, OR = 14.6) and extrahepatic metastases (p = 0.005, OR = 4.6) were independently associated with progression-free survival (PFS). In multivariate-COX-analysis, only extrahepatic metastases (p = 0.05, OR = 3.4) showed a significant association with PFS. Among SSAs-treated patients, MEN-1/ZES showed better PFS (p = 0.0227). After surgery, the median PFS was 126 and 96 months in MEN-1 and Sp, respectively.

CONCLUSION

MEN-1/ZES patients generally show better OS and PFS than Sp-ZES as well as better SSAs response.

Successful Lifetime/Long-Term Medical Treatment of Acid Hypersecretion in Zollinger-Ellison Syndrome (ZES): Myth or Fact? Insights from an Analysis of Results of NIH Long-Term Prospective Studies of ZES

Analysis of the efficacy/pharmacology of long-term/lifetime medical treatment of acid hypersecretion in a large cohort of ZES patients in a prospective study. This study includes the results from all 303 patients with established ZES who were prospectively followed and received acid antisecretory treatment with either H2Rs or PPIs, with antisecretory doses individually titrated by the results of regular gastric acid testing. The study includes patients treated for short-term periods (<5 yrs), patients treated long-term (>5 yrs), and patients with lifetime treatment (30%) followed for up to 48 years (mean 14 yrs). Long-term/lifelong acid antisecretory treatment with H2Rs/PPIs can be successfully carried out in all patients with both uncomplicated and complicated ZES (i.e., with MEN1/ZES, previous Billroth 2, severe GERD). This is only possible if drug doses are individually set by assessing acid secretory control to establish proven criteria, with regular reassessments and readjustments. Frequent dose changes both upward and downward are needed, as well as regulation of the dosing frequency, and there is a primary reliance on the use of PPIs. Prognostic factors predicting patients with PPI dose changes are identified, which need to be studied prospectively to develop a useful predictive algorithm that could be clinically useful for tailored long-term/lifetime therapy in these patients.

Ga-68 DOTATATE PET/CT in a patient with Zollinger-Ellison syndrome

This case report follows a 70-year-old male patient with Zollinger-Ellison syndrome undergoing computed tomography (CT) for weight loss and surveillance of bilateral adrenal nodules. Incidentally, diffuse gastric and duodenal wall thickening was noted on CT. The patient underwent esophagogastroduodenoscopy with biopsy results showing well-differentiated neuroendocrine tumors (NET) in the stomach and duodenum. Subsequent imaging with gallium-68 DOTATATE PET/CT showed intense tracer uptake in the stomach and proximal duodenum with liver and regional nodal metastases around the superior mesenteric artery. This case outlines the utility of Ga-68 DOTATATE PET/CT in diagnosing, localizing, and staging NET such as gastrinomas.

Use of proton pump inhibitors for the risk of gastric cancer

BACKGROUND

This study aimed to systematically analyze the association between long-term use of proton pump inhibitors (PPIs) and the risk of gastric cancer (GC).

METHODS

We performed a systematic search of articles on the relationship between long-term use of PPIs and the risk of GC from PubMed and EMBASE. We calculated the pooled odds ratio of GC in PPI users compared to non-PPI users using random-effects models.

RESULTS

This meta-analysis included 18 studies from 20 different databases with 4348,905 patients enrolled. In the random effects model, we found that an increased risk of GC among PPI users (OR = 1.94; 95% CI [1.43, 2.64]). The long-term use of PPIs compared with histamine-2 receptor antagonist users did not increase the risk of GC (OR = 1.65; 95% CI [0.92, 2.97]). Stratified analysis showed that PPI users had a significantly increased risk of noncardia GC (OR = 2.53; 95% CI [2.03, 3.15]), but had a relatively small relationship with the risk of gastric cardia cancer. (OR = 1.79; 95% CI [1.06, 3.03]). With the extension of PPI use time, the estimated risk value decreases (<1 year: OR = 6.33, 95% CI [3.76, 10.65]; 1-3 years: OR = 1.82, 95% CI [1.30, 2.55]; >3 years: OR = 1.25, 95% CI [1.00, 1.56]). Despite Helicobacter pylori eradication, the long-term use of PPIs did not alter the increased risk of GC (OR = 2.29; 95% CI [1.57, 3.33]).

CONCLUSION

Our meta-analysis found that PPI use may be associated with an increased risk of GC. Further research on the causal relationship between these factors is necessary.

Radiological Features of Zollinger–Ellison Syndrome: A Report of Two Cases

Hypersecretion of gastrin from duodenal or pancreatic gastrinomas results in a rare clinical entity called Zollinger–Ellison syndrome (ZES). It mostly presents with abdominal pain and diarrhea. ZES may be sporadic or occur in association with multiple endocrine neoplasia type 1. Usually, ZES manifests between 20 and 50 years.

We report two cases of patients who presented with abdominal pain, vomiting, watery diarrhea, and significant weight loss.

Establishing the Association Between Osteoporosis and Peptic Ulcer Disease: A Systematic Review

Osteoporosis is one of the most common metabolic bone diseases. Many studies were conducted to find the association between peptic ulcer disease (PUD), Helicobacter pylori infection, proton-pump inhibitor (PPI) use, and increased risk for fracture, but results remain ambiguous. We performed this systematic review to understand the association between PUD and osteoporosis. We comprehensively searched relevant articles on April 19, 2022, by exploring different databases including PubMed, PubMed Central (PMC), and Medline using relevant keywords. After applying inclusion and exclusion criteria and undergoing quality assessment, we retained 25 studies published in and after 2015. For our systematic review, we included a total of 5,600,636 participants. The studies included in our review demonstrated a significant association between PUD, H. pylori infection, and the risk of osteoporosis. Long-term PPI use was also found to be a risk factor for osteoporosis. Malabsorption of nutrients, increase in inflammatory cytokines, and alterations in hormone status were found to be the notable factors behind the association. Early management of H. pylori infection and cautious use of long-term PPIs may protect against osteoporosis. Further randomized controlled trials (RCTs) are necessary to establish a causal relationship.

Validity of Secretin Stimulation Testing on Proton Pump Inhibitor Therapy for Diagnosis of Zollinger-Ellison Syndrome

INTRODUCTION

Zollinger-Ellison syndrome (ZES) is characterized by gastrinoma-induced hypergastrinemia causing excessive gastric acid secretion. Secretin stimulation tests (SSTs) are required for diagnosis in the majority of patients. Two case reports suggest that proton pump inhibitors (PPIs) cause false SST results. Consequently, PPIs are discontinued to allow hyperchlorhydria to recur; however, uncontrolled acidity can cause life-threatening complications in those with underlying undiagnosed ZES. The aim of this study was to determine whether PPIs influence the validity of SSTs for the diagnosis of ZES.

METHODS

A retrospective chart review was performed. Charts of patients who underwent SSTs were reviewed to determine whether they were performed on or off PPI and the test's accuracy by comparing the results with gold standard tests (diagnostic laboratory testing performed off PPI or surgical pathology consistent with gastrinoma). Sensitivity, specificity, and positive predictive value (PPV) of SST on PPI were calculated and results compared with SST off PPI using noninferiority analyses.

RESULTS

Twenty-eight patients corresponding to 29 SSTs were performed on PPI, and 70 patients corresponding to 107 SSTs were performed off PPI. Most of them were female and white and had multiple endocrine neoplasia type 1. We found no false-positive or false-negative SSTs on PPI. Sensitivity, specificity, and PPV of SSTs on PPI were determined to be noninferior to SSTs off PPI (P ≤ 0.05 for all).

DISCUSSION

In our cohort, SSTs on PPI compared with SSTs off PPI were noninferior for sensitivity, specificity, and PPV. These results suggest that PPI withdrawal before SSTs may not be necessary.

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.

Gastrinoma and Zollinger Ellison syndrome: A roadmap for the management between new and old therapies

Zollinger-Ellison syndrome (ZES) associated with pancreatic or duodenal gastrinoma is characterized by gastric acid hypersecretion, which typically leads to gastroesophageal reflux disease, recurrent peptic ulcers, and chronic diarrhea. As symptoms of ZES are nonspecific and overlap with other gastrointestinal disorders, the diagnosis is often delayed with an average time between the onset of symptoms and final diagnosis longer than 5 years. The critical step for the diagnosis of ZES is represented by the initial clinical suspicion. Hypergastrinemia is the hallmark of ZES; however, hypergastrinemia might recognize several causes, which should be ruled out in order to make a final diagnosis. Gastrin levels > 1000 pg/mL and a gastric pH below 2 are considered to be diagnostic for gastrinoma; some specific tests, including esophageal pH-recording and secretin test, might be useful in selected cases, although they are not widely available. Endoscopic ultrasound is very useful for the diagnosis and the local staging of the primary tumor in patients with ZES, particularly in the setting of multiple endocrine neoplasia type 1. Some controversies about the management of these tumors also exist. For the localized stage, the combination of proton pump inhibitory therapy, which usually resolves symptoms, and surgery, whenever feasible, with curative intent represents the hallmark of gastrinoma treatment. The high expression of somatostatin receptors in gastrinomas makes them highly responsive to somatostatin analogs, supporting their use as anti-proliferative agents in patients not amenable to surgical cure. Other medical options for advanced disease are super-imposable to other neuroendocrine neoplasms, and studies specifically focused on gastrinomas only are scant and often limited to case reports or small retrospective series. The multidisciplinary approach remains the cornerstone for the proper management of this composite disease. Herein, we reviewed available literature about gastrinoma-associated ZES with a specific focus on differential diagnosis, providing potential diagnostic and therapeutic algorithms.

Multiple Endocrine Neoplasia Type 1 and the Pancreas: Diagnosis and Treatment of Functioning and Non-Functioning Pancreatic and Duodenal Neuroendocrine Neoplasia within the MEN1 Syndrome - An International Consensus Statement

The better understanding of the biological behavior of multiple endocrine neoplasia type 1 (MEN1) organ manifestations and the increase in clinical experience warrant a revision of previously published guidelines. Duodenopancreatic neuroendocrine neoplasias (DP-NENs) are still the second most common manifestation in MEN1 and, besides NENs of the thymus, remain a leading cause of death. DP-NENs are thus of main interest in the effort to reevaluate recommendations for their diagnosis and treatment. Especially over the last 2 years, more clinical experience has documented the follow-up of treated and untreated (natural-course) DP-NENs. It was the aim of the international consortium of experts in endocrinology, genetics, radiology, surgery, gastroenterology, and oncology to systematically review the literature and to present a consensus statement based on the highest levels of evidence. Reviewing the literature published over the past decade, the focus was on the diagnosis of F- and NF-DP-NENs within the MEN1 syndrome in an effort to further standardize and improve treatment and follow-up, as well as to establish a "logbook" for the diagnosis and treatment of DP-NENs. This shall help further reduce complications and improve long-term treatment results in these rare tumors. The following international consensus statement builds upon the previously published guidelines of 2001 and 2012 and attempts to supplement the recommendations issued by various national and international societies.

Total gastrectomy for severe proton pump inhibitor-induced hypomagnesemia in a MEN1/Zollinger Ellison syndrome patient

We report here the first case of life-threatening hypomagnesemia in a Zollinger-Ellison syndrome patient with multiple endocrine neoplasia type 1 (MEN1) syndrome. The severe symptomatic hypomagnesemia proved to be due to proton pump inhibitors (PPIs), but withdrawal of PPIs led to early severe peptic complications despite a substitution by histamine H2-receptor antagonist therapy. Simultaneous management of life-threatening hypomagnesemia, severe gastric acid hypersecretion and MEN1-associated gastrinomas was complex. A total gastrectomy was performed in order to definitely preclude the use of PPIs in this frail patient who was not eligible for curative pancreatoduodenal resection.

Perspectives on the current pharmacotherapeutic strategies for management of functional neuroendocrine tumor syndromes

Introduction: In the past, controlling the hormone-excess-state was the main determinant of survival in Functional-Neuroendocrine-Neoplasm-syndromes (F-NENs). This was difficult because the pharmacological-armamentarium available was limited. Recently, new therapeutic strategies have increased but it also generated controversies/uncertainties.Areas covered: The authors briefly review: established/proposed F-NENs; the rationale for treatments; the recommended initial-pharmacotherapeutic-approach to controlling F-NENs hormone-excess-state; the secondary-approaches if the initial approach fails or resistance develops; and the approach to deal with the malignant nature of the NEN. Also discussed are controversies/uncertainties related to new treatments.Expert opinion: Unfortunately, except for patients with insulinomas (>90-95%), gastrinomas (<20-40%), a minority with the other F-panNENs and 0-<1% with Carcinoid-syndrome is curative-surgery possible. Except for insulinomas, gastrinomas, and ACTHomas, long-acting somatostatin-analogs are the initial-pharmacological-treatments for hormone-excess-state. For insulinomas prior to surgery/malignancy, diazoxide is the initial drug-treatment; for gastrinomas, oral PPIs; and for ACTHomas, steroidogenesis inhibitors. There are now several secondary pharmacotherapeutic treatments. Surgery and liver-directed therapies also have a role in selected patients. Particularly promising is the recent results with PRRT for the hormone-excess-state, independent of its anti-growth effect. The sequence to use various agents and the approach to syndrome diagnosis while taking various agents remains unclear/controversial in many cases.

Pancreatic neuroendocrine tumors: A review of serum biomarkers, staging, and management

Pancreatic neuroendocrine tumors (pNETs) are a heterogeneous group of tumors with complicated treatment options that depend on pathological grading, clinical staging, and presence of symptoms related to hormonal secretion. With regard to diagnosis, remarkable advances have been made: Chromogranin A is recommended as a general marker for pNETs. But other new biomarker modalities, like circulating tumor cells, multiple transcript analysis, microRNA profile, and cytokines, should be clarified in future investigations before clinical application. Therefore, the currently available serum biomarkers are insufficient for diagnosis, but reasonably acceptable in evaluating the prognosis of and response to treatments during follow-up of pNETs. Surgical resection is still the only curative therapeutic option for localized pNETs. However, a debulking operation has also been proven to be effective for controlling the disease. As for drug therapy, steroids and somatostatin analogues are the first-line therapy for those with positive expression of somatostatin receptor, while everolimus and sunitinib represent important progress for the treatment of patients with advanced pNETs. Great progress has been achieved in the combination of systematic therapy with local control treatments. The optimal timing of local control intervention, planning of sequential therapies, and implementation of multidisciplinary care remain pending.

Update on the Surgical Treatment of Pancreatic Neuroendocrine Tumors

BACKGROUND AND AIMS

Pancreatic neuroendocrine tumors (PNET) arise from uncontrolled proliferation of neuroendocrine cell and further genetic alterations that may induce hormone secretion such as glucagon/insulin/gastrin/VIP. Their incidence is rapidelly growing, especially because of the frequent incidental diagnosis of small asymptomatic non-functionnal neuroendocrine tumors with the widespread use of cross-sectional imaging. The vast majority of pancreatic neuroendocrine tumors are sporadic but up to 5%-10% of them arise from genetic syndromes, the main one being Multiple Endocrine Neopalsm type 1 (MEN1). Appropriate management of patients with PNET is a complex challenge for surgeons, and require extensive medical collaboration. This review aims to summarize major and recent updates regarding the medico-surgical management of PNETs.

MATERIAL AND METHODS

Review of pertinent English language literature.

RESULTS

This article provides a concise summary of the clinical presentation, diagnosis, surgical management, alternative treatments and follow up of PNETs.

CONCLUSION

PNET are a rare, heterogeneous group of neoplasms with a generally favorable prognosis at least compared to pancreatic adenocarcinoma. Surgical resection is the cornerstone of their management, particularly for localized disease, and should always be discussed in multidisciplinary tumor board.

Les nouvelles techniques diagnostiques des tumeurs neuroendocrines pancréatiques

Les tumeurs neuroendocrines pancréatiques (TNEp) sont des tumeurs développées aux dépens du pancréas et nécessitent un bilan diagnostique spécifique. Le bilan d’imagerie d’une TNEp est utile pour le diagnostic ainsi que pour le traitement chirurgical/médical. Récemment, un certain nombre de progrès ont été réalisés dans le domaine de l’imagerie des TNEp, en particulier en ce qui concerne l’imagerie fonctionnelle utilisant des analogues de la somatostatine radiomarqués. Dans cette mise au point, nous abordons les progrès diagnostiques en nous focalisant sur les avancées des dernières années. Ainsi, il est abordé l’intérêt de l’imagerie conventionnelle (scanner, échographie abdominale, imagerie par résonance magnétique), de l’échoendoscopie et la place de l’imagerie fonctionnelle, principalement avec des analogues de la somatostatine radiomarqués.

Insights into Effects/Risks of Chronic Hypergastrinemia and Lifelong PPI Treatment in Man Based on Studies of Patients with Zollinger-Ellison Syndrome

The use of proton pump inhibitors (PPIs) over the last 30 years has rapidly increased both in the United States and worldwide. PPIs are not only very widely used both for approved indications (peptic ulcer disease, gastroesophageal reflux disease (GERD), Helicobacter pylori eradication regimens, stress ulcer prevention), but are also one of the most frequently off-label used drugs (25–70% of total). An increasing number of patients with moderate to advanced gastroesophageal reflux disease are remaining on PPI indefinitely. Whereas numerous studies show PPIs remain effective and safe, most of these studies are <5 years of duration and little data exist for >10 years of treatment. Recently, based primarily on observational/epidemiological studies, there have been an increasing number of reports raising issues about safety and side-effects with very long-term chronic treatment. Some of these safety issues are related to the possible long-term effects of chronic hypergastrinemia, which occurs in all patients taking chronic PPIs, others are related to the hypo-/achlorhydria that frequently occurs with chronic PPI treatment, and in others the mechanisms are unclear. These issues have raised considerable controversy in large part because of lack of long-term PPI treatment data (>10–20 years). Zollinger–Ellison syndrome (ZES) is caused by ectopic secretion of gastrin from a neuroendocrine tumor resulting in severe acid hypersecretion requiring life-long antisecretory treatment with PPIs, which are the drugs of choice. Because in <30% of patients with ZES, a long-term cure is not possible, these patients have life-long hypergastrinemia and require life-long treatment with PPIs. Therefore, ZES patients have been proposed as a good model of the long-term effects of hypergastrinemia in man as well as the effects/side-effects of very long-term PPI treatment. In this article, the insights from studies on ZES into these controversial issues with pertinence to chronic PPI use in non-ZES patients is reviewed, primarily concentrating on data from the prospective long-term studies of ZES patients at NIH.

Contemporary surgical management of the Zollinger-Ellison syndrome in multiple endocrine neoplasia type 1

About 30% of patients with MEN1 develop a Zollinger-Ellison syndrome. Meanwhile it is well established that the causative gastrinomas are almost exclusively localized in the duodenum and not in the pancreas, MEN1 gastrinomas occur multicentric and are associated with hyperplastic gastrin cell lesions and tiny gastrin-producing micro tumors in contrast to sporadic duodenal gastrinomas. Regardless of the high prevalence of early lymphatic metastases, the survival is generally good with an aggressive course of disease in only about 20% of patients. Symptoms can be controlled medically. The indication, timing, type, and extent of surgery are highly controversial and are discussed in detail in this article by a thorough and critical review of literature. More radical procedures, like partial pancreaticoduodenectomy, are weighed against less aggressive local excision of gastrinomas and the pros and cons of both approaches are discussed in terms of long-term morbidity, biochemical cure, and survival.

Specific and Non-Specific Biomarkers in Neuroendocrine Gastroenteropancreatic Tumors

The diagnosis of neuroendocrine tumors (NETs) is a challenging task: Symptoms are rarely specific, and clinical manifestations are often evident only when metastases are already present. However, several bioactive substances secreted by NETs can be included for diagnostic, prognostic, and predictive purposes. Expression of these substances differs between different NETs according to the tumor hormone production. Gastroenteropancreatic (GEP) NETs originate from the diffuse neuroendocrine system of the gastrointestinal tract and pancreatic islets cells: These tumors may produce many non-specific and specific substances, such as chromogranin A, insulin, gastrin, glucagon, and serotonin, which shape the clinical manifestations of the NETs. To provide an up-to-date reference concerning the different biomarkers, as well as their main limitations, we reviewed and summarized existing literature.

Gastric Neuroendocrine Tumor and Duodenal Gastrinoma With Chronic Autoimmune Atrophic Gastritis

Our group observed the first case of synchronous gastric neuroendocrine tumor (NET) and duodenal gastrinoma with autoimmune chronic atrophic gastritis (CAG), in the absence of Helicobacter pylori infection. Demographic, clinical, endoscopic, and pathologic data were abstracted from the electronic medical record at Mount Sinai Hospital from 2013 to 2015. The patient's anonymity was carefully protected, and informed consent was obtained for publication of protected health information. A 53-year-old woman with hypertension presented to Mount Sinai Hospital in June 2013 for a second opinion for management of gastric and duodenal NETs. After evaluation by gastroenterology and surgery, repeat upper endoscopy with ultrasound and fine-needle aspiration revealed multiple diminutive type I gastric NETs and 2 duodenal NETs, against a background of autoimmune CAG, with biopsy pathology negative for H. pylori. She subsequently underwent a transduodenal resection of the duodenal NETs, confirming low-grade, gastrin-positive, stage T2 duodenal NET. On routine follow-up over the next 2 years, clinical, radiographic, and endoscopic surveillance revealed no recurrent or metastatic gastric or duodenal disease. This first report of synchronous duodenal gastrinoma and gastric NET in the setting of autoimmune CAG can broaden our understanding of gastric NET pathophysiology.

Zollinger-Ellison syndrome. Case report

Introduction: The Zollinger-Ellison syndrome (ZES) is a pathology caused by a neuroendocrine tumor, usually located in the pancreas or the duodenum, which is characterized by elevated levels of gastrin, resulting in an excessive production of gastric acid.Case presentation: A 42-year-old female patient with a history of longstanding peptic ulcer disease, who consulted due to persistent epigastric pain, melena and signs of peritoneal irritation.  Perforated peptic ulcer was suspected, requiring emergency surgical intervention. Subsequently, a tumor lesion in the head of the pancreas was documented and managed with Whipple procedure. The pathology results reported a tumor suggestive of neuroendocrine neoplasm.Discussion: The Zollinger-Ellison syndrome occurs in 0.1 to 3 people per 1 000 000 inhabitants worldwide and is predominant in women between 20 and 50 years of age. It usually appears as a refractory acid-peptic disease or as a complication of gastric acid hypersecretion. Medical therapy is the standard management, being proton pump inhibitors (PPI) the most effective option. Surgery is recommended for sporadic ZES.Conclusions: ZES has a low incidence rate. It is rarely considered in the differential diagnosis of chronic epigastric pain and high clinical suspicion is required to achieve adequate management. This article is highly relevant as it presents a confirmed clinical case of ZES in Colombia, highlighting the importance of producing local scientific literature to improve the diagnosis and treatment of this pathology.

Role of biomarker tests for diagnosis of neuroendocrine tumours

Neuroendocrine tumours (NETs) are neoplasms that arise from neuroendocrine cells. Neuroendocrine cells and their tumours can secrete a wide range of amines and polypeptide hormones into the systemic circulation. This feature has triggered widespread investigation into circulating biomarkers for the diagnosis of NETs as well as for the prediction of the biological behaviour of tumour cells. Classic examples of circulating biomarkers for gastroenteropancreatic NETs include chromogranin A, neuron-specific enolase and pancreatic polypeptide as well as hormones that elicit clinical syndromes, such as serotonin and its metabolites, insulin, glucagon and gastrin. Biomarker metrics of general markers for diagnosing all gastroenteropancreatic NET subtypes are limited, but specific hormonal measurements can be of diagnostic value in select cases. In the past decade, methods for detecting circulating transcripts and tumour cells have been developed to improve the diagnosis of patients with NETs. Concurrently, modern scanning techniques and superior radiotracers for functional imaging have markedly expanded the options for clinicians dealing with NETs. Here, we review the latest research on biomarkers in the NET field to provide clinicians with a comprehensive overview of relevant diagnostic biomarkers that can be implemented in dedicated situations.

Imaging of pancreatic neuroendocrine tumors: recent advances, current status, and controversies

INTRODUCTION

Recently, there have been a number of advances in imaging pancreatic neuroendocrine tumors (panNETs), as well as other neuroendocrine tumors (NETs), which have had a profound effect on the management and treatment of these patients, but in some cases are also associated with controversies. Areas covered: These advances are the result of numerous studies attempting to better define the roles of both cross-sectional imaging, endoscopic ultrasound, with or without fine-needle aspiration, and molecular imaging in both sporadic and inherited panNET syndromes; the increased attempt to develop imaging parameters that correlate with tumor classification or have prognostic value; the rapidly increasing use of molecular imaging in these tumors and the attempt to develop imaging parameters that correlate with treatment/outcome results. Each of these areas and the associated controversies are reviewed. Expert commentary: There have been numerous advances in all aspects of the imaging of panNETs, as well as other NETs, in the last few years. The advances are leading to expanded roles of imaging in the management of these patients and the results being seen in panNETs/GI-NETs with these newer techniques are already being used in more common tumors.

Pregnancy and gastric cancer: diagnostic and treatment dilemma

Gastric cancer in pregnancy is an extremely rare entity. The incidence of gastric cancer is more in elderly patients and higher in the male population. Gastric cancer symptoms can be nausea, vomiting and epigastric discomfort which is similar to early pregnancy symptoms. This leads to a misinterpretation and delay in the diagnosis during pregnancy. Gastric cancer in pregnancy is associated with poor prognosis because of its delayed diagnosis at an advance stage. We present our patient here, with this rare clinical diagnosis and with no suspicion in a young healthy woman.

Hormone secreting gastro-entero-pancreatic neuroendocrine neoplasias (GEP-NEN): When to consider, how to diagnose?

Neuroendocrine neoplasms of the digestive system (GEP-NEN) represent a heterogeneous group of malignancies with various clinical presentation and prognosis. GEP-NENs can potentially affect all organs of the gastrointestinal tract; characteristically they share the biological property to produce and secrete peptides and neuroamines. About 30% of GEP-NENs are hormonally active and can cause specific clinical syndromes. The clinical presentation mainly depends on the primary site of the tumor and its functionality. Because of the wide spectrum of clinical symptoms and their misperceived rarity, diagnosis of GEP-NENs is often delayed for years and tumors are detected first in an advanced stage. Early identification of a specific hormonal syndrome can significantly impact tumor diagnosis and treatment, moreover the preoperative management of NEN hormonal release avoids potential life threatening hormonal crisis. However, GEP-NEN diagnostic work-up is challenging, it requires a multidisciplinary team and needs particular experience; standardized protocols and clinical experience are essential for a proper endocrine diagnostic work-up. In addition to the biochemical diagnostic, further radiologic and endoscopic imaging modalities are required moreover, somatostatin-receptor based functional imaging, using either Octreotide-scintigraphy or novel PET-based techniques with specific isotopes like Ga⁶⁸-DOTA-octreotate, plays an important role for the detection of the primary tumor as well as for the evaluation of the tumor extent.

Diagnosis of Zollinger-Ellison syndrome in the era of PPIs, faulty gastrin assays, sensitive imaging and limited access to acid secretory testing

In recent years the diagnosis of Zollinger-Ellison syndrome (ZES) has become increasingly controversial with several new approaches and criteria proposed, differing from the classical biochemical criterion of inappropriate hypergastrinemia (i.e., hypergastrinemia in the presence of hyperchlorhydria) (Table 1). These changes have come about because of the difficulty and potential dangers of stopping proton pump inhibitors (PPIs) for gastric acid analysis; the recognition than many of the current assays used to assess gastrin concentrations are unreliable; the development of sensitive imaging modalities that detect neuroendocrine tumors (NETs) including an increasing number of the primary gastrinomas; the increased use of percutaneous or endoscopic ultrasound (EUS)-directed biopsies/cytology and the general lack of availability of acid secretory testing. In this article we will discuss the basis for these controversies, review the proposed changes in diagnostic approaches and make recommendations for supporting the diagnosis of ZES in the modern era.

The future: diagnostic and imaging advances in MEN1 therapeutic approaches and management strategies

Prospective randomized data are lacking, but current clinical expert guidelines recommend annual screening examinations, including laboratory assessments and various imaging modalities (e.g. CT, MRI, scintigraphy and EUS) for patients with multiple endocrine neoplasia type 1 (MEN1). Routine screening is proposed to detect and localize neuroendocrine manifestations as early as possible. The goal is timely intervention to improve quality of life and to increase life expectancy by preventing the development of life-threatening hormonal syndromes and/or metastatic disease. In recent years, some studies compared different and new imaging methods regarding their sensitivity and utility in MEN1 patients. This present article reviews the proposed diagnostic tools for MEN1 screening as well as potential future perspectives.

The future: surgical advances in MEN1 therapeutic approaches and management strategies

Multiple endocrine neoplasia type 1 (MEN1) is a hereditary autosomal dominant disorder associated with numerous neuroendocrine tumors (NETs). Recent advances in the management of MEN1 have led to a decrease in mortality due to excess hormones; however, they have also led to an increase in mortality from malignancy, particularly NETs. The main challenges are to localize these tumors, to select those that need therapy because of the risk of aggressive behavior and to select the appropriate therapy associated with minimal morbidity. This must be applied to a hereditary disease with a high risk of recurrence. The overall aim of management in MEN1 is to ensure that the patient remains disease- and symptom-free for as long as possible and maintains a good quality of life. Herein, we review the changes that occurred in the last 20 years in the surgical management of MEN1-associated functional and non-functional pancreatico-duodenal NETs and thymic and bronchial NETs.

Catching the Zebra: Clinical Pearls and Pitfalls for the Successful Diagnosis of Zollinger-Ellison Syndrome

Zollinger-Ellison syndrome (ZES) results from an ectopic gastrin-secreting tumor leading to peptic ulcer disease, reflux, and chronic diarrhea. While early recognition portends an excellent prognosis with >80% survival at 15 years, symptoms are often nonspecific making the diagnosis difficult to establish. Diagnosis involves a series of tests, including fasting gastrin, gastric pH, chromogranin A, and secretin stimulation. Performing these tests in the correct sequence and at the proper time is essential to avoid inaccurate results. Tumor localization is equally nuanced. Although providers have classically used ¹¹¹indium-radiolabeled octreotide with somatostatin receptor scintigraphy to evaluate tumor size and metastases, recent studies have shown superior results with newer imaging modalities. In particular, ⁶⁸gallium (⁶⁸Ga)-labeled somatostatin radiotracers (i.e., ⁶⁸Ga-DOTATOC, ⁶⁸Ga-DOTANOC and ⁶⁸Ga-DOTATATE) used with positron emission tomography/computed tomography can provide excellent results. Endoscopic ultrasound is another useful modality, particularly in patients with ZES in the setting of multiple endocrine neoplasia type 1. This review aims to provide clinicians with an overview of ZES with a focus on both clinical presentation and the proper utilization of the various biochemical and imaging tests available.

Clinical Presentation and Diagnosis of Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors are a rare group of neoplasms that arise from multipotent stem cells in the pancreatic ductal epithelium. Although they comprise only 1% to 2% of pancreatic neoplasms, their incidence is increasing. Most pancreatic neuroendocrine tumors are nonfunctioning, but they can secrete various hormones resulting in unique clinical syndromes. Clinicians must be aware of the diverse manifestations of this disease, as the key step to management of these rare tumors is to first suspect the diagnosis.

Weight Gain in Zollinger-Ellison Syndrome After Acid Suppression

OBJECTIVES

Zollinger-Ellison syndrome (ZES) is characterized by hypergastrinemia and gastric acid hypersecretion resulting in peptic ulcer disease, diarrhea, and weight loss. Acid secretion can be controlled with medication, and biochemical cure is possible with surgery. Data on how these interventions affect patients' weight are lacking. We aimed to determine how medical and surgical acid control affects weight over time.

METHODS

We performed a retrospective cohort study on 60 ZES patients. Acid control was achieved with appropriate-dose proton pump inhibitor (PPI) therapy. Surgery was performed for curative intent when appropriate. Weight change was assessed versus pre-acid control or immediate preoperative weights and expressed as absolute and percent change from baseline at 6, 12, 18, and 24 months.

RESULTS

A total of 30 PPI-controlled patients and 20 surgery-controlled patients were analyzed. Weight gain was noted at all time points while on appropriate-dose PPI therapy (P < 0.005). Of patients who had surgery with curative intent, weight gain was noted at 12 months (7.9%, P = 0.013) and 18 months (7.1%, P = 0.007). There was a trend toward weight gain seen at all time points in the patients who were surgically cured.

CONCLUSIONS

These data represent a novel description of weight gain after acid suppression in ZES.

Pancreatic neuroendocrine tumors: Nosography, management and treatment

Pancreatic neuroendocrine tumors (pNETs) represent about 7% of all NETs, 8.7% of gastroenteropancreatic NETs (GEP-NETs) and 1-2% of all pancreatic neoplasms. In the last two decades, the increased diagnosis of pNETs has generated great interest and the development of different classifications, grading and staging systems. Recently, several trials were performed in order to improve the knowledge of biomarkers and imaging and to provide an early diagnosis, but their role is still under debate. Nowadays, surgery represents the only curative approach for pNETs. Approximately 90% of pNETs are silent and non-functional; therefore, most patients are diagnosed in late stage and present metastatic (60%) or locally unresectable advanced disease (21%) with a poor prognosis. Not many therapeutic options are available for pNETs, with different treatments for G1-G2 and G3 tumors, because these diseases are still rare and trials are made up of few series of patients. At present, medical treatments is controversial. On these bases, we believe that a multidisciplinary team composed of surgeons, oncologists, endocrinologists, radiation oncologists, radiologists, pathologists and medicals nuclear is required. This paper presents a review of present state-of-the-art in the field of pNETs.

EUS is superior for detection of pancreatic lesions compared with standard imaging in patients with multiple endocrine neoplasia type 1

BACKGROUND

In multiple endocrine neoplasia type 1 (MEN1), pancreatic neuroendocrine tumors (pNETs) are the leading MEN1-related cause of death.

OBJECTIVE

To evaluate EUS and (11)C-5-hydroxytryptophan positron emission tomography ((11)C-5-HTP PET), compared with the recommended screening techniques in MEN1 patients for early detection of pNETs.

DESIGN

Cross-sectional study.

SETTING

Tertiary-care university medical center.

PATIENTS

This study involved 41 patients with a proven MEN1 mutation or with one MEN1 manifestation and a mutation carrier as a first-degree family member, with recent screening by abdominal CT or magnetic resonance imaging (MRI) and somatostatin receptor scintigraphy (SRS).

INTERVENTIONS

EUS by using a linear Pentax echoendoscope and Hitachi EUB-525 and (11)C-5-HTP PET.

MAIN OUTCOME MEASUREMENTS

Patient-based and lesion-based positivity for pNET was calculated for all imaging techniques. The McNemar test was used to compare the yield of the 4 imaging techniques.

RESULTS

In 35 of 41 patients, 107 pancreatic lesions were detected in total. EUS detected 101 pancreatic lesions in 34 patients, (11)C-5-HTP PET detected 35 lesions in 19 patients, and CT/MRI + SRS detected 32 lesions in 18 patients (P < .001). (11)C-5-HTP PET performed similarly to CT/MRI + SRS and better compared with SRS only (13 lesions in 12 patients), both at a patient-based and lesion-based level (P < .05).

LIMITATIONS

Single-center study.

CONCLUSION

EUS is superior to CT/MRI + SRS for pancreatic lesion detection in patients with MEN1. In this setting, (11)C-5-HTP PET is not useful. We recommend EUS as the first-choice pancreas imaging technique in patients with MEN1. (

CLINICAL TRIAL REGISTRATION NUMBER

NTR1668.).

From hypomagnesaemia to Zollinger-Ellison syndrome: an adverse effect of a proton pump inhibitor

We describe the case of a 53-year-old man who presented with abdominal pain, diarrhoea and hypomagnesaemia. The hypomagnesaemia proved to be due to gastrointestinal loss as urinary fractional excretion was very low, suggesting non-renal loss. Common causes were discarded and the hypomagnesaemia was attributed to chronic use of the proton pump inhibitor, omeprazole. As such, omeprazole was discontinued and an H2 blocker was given. Several days later the patient presented with upper gastrointestinal bleeding. CT scan demonstrated marked enlargement of the duodenum and proximal jejunum, and abnormal thickening and enhancement of the bowel wall. Urgent oesophagogastroduodenoscopy revealed coffee-ground and bloody contents in the distal oesophagus and stomach, and numerous ulcers along the duodenum and jejunum. A positron emission tomography-CT scan using GA 68-DOTANOC demonstrated increased uptake in the gastroduodenum junction, suggesting a neuroendocrine tumour. Pancreaticoduodenectomy was performed and tumour cells stained positive for gastrin, confirming the tentative diagnosis of Zollinger-Ellison syndrome.

Zollinger-Ellison syndrome: recent advances and controversies

PURPOSE OF REVIEW

To review the recent advances and current controversies in patients with Zollinger-Ellison syndrome (ZES).

RECENT FINDINGS

Recent advances in the management of ZES include: improved understanding of the pathogenesis of gastrinoma and pancreatic neuroendocrine tumors, new prognostic classification systems, new diagnostic algorithms, more sensitive localization studies, new treatment strategies including improved control of gastric acid secretion and role for surgery, and new approaches to patients with advanced disease. Controversies include: the best approach to a patient with hypergastrinemia suspected of possibly having ZES, the appropriate gastrin assay to use, the role of surgery in patients with ZES, especially those with multiple endocrine neoplasia type 1, and the precise order of therapeutic modalities in the treatment of patients with advanced disease.

SUMMARY

This review updates clinicians regarding important advances and controversies required to optimally diagnose and manage patients with ZES.

Pharmacotherapy of Zollinger-Ellison syndrome

INTRODUCTION

The role of pharmacotherapy in the management of patients with Zollinger-Ellison syndrome (ZES) is often equated with the medical management of acid hypersecretion. However, pharmacotherapy is also increasingly involved in the other management areas of these patients.

AREAS COVERED

This paper reviews the role of pharmacotherapy in all aspects of the management of patients with ZES. Newer aspects are emphasized. This includes the difficulty of diagnosing ZES in patients taking proton pump inhibitors. Also covered is the role of pharmacotherapy in controlling acid hypersecretion and other hormonal hypersecretory states these patients may develop, including hyperparathyroidism in patients with multiple endocrine neoplasia type 1 and ZES; tumor localization; and the treatment of advanced metastatic disease. The last includes chemotherapy, liver-directed therapies, biotherapy (somatostatin/interferon), peptide radio-receptor therapy and molecular-targeted therapies including the use of mTor inhibitors (everolimus) and tyrosine kinase inhibitors (sunitinib).

EXPERT OPINION

Pharmacotherapy is now involved in all aspects of the management of patients with ZES, with the result that ZES has progressed from being considered an entirely surgical disease initially to the present where medical treatment plays a major role in almost all aspects of the management of these patients.

Pancreatic neuroendocrine tumors: clinical features, diagnosis and medical treatment: advances

Pancreatic neuroendocrine tumors (pNETs) comprise with gastrointestinal carcinoids, the main groups of gastrointestinal neuroendocrine tumors (GI-NETs). Although these two groups of GI-NETs share many features including histological aspects; over-/ectopic expression of somatostatin receptors; the ability to ectopically secrete hormones/peptides/amines which can result in distinct functional syndromes; similar approaches used for tumor localization and some aspects of treatment, it is now generally agreed they should be considered separate. They differ in their pathogenesis, hormonal syndromes produced, many aspects of biological behaviour and most important, in their response to certain anti-tumour treatment (chemotherapy, molecular targeted therapies). In this chapter the clinical features of the different types of pNETs will be considered as well as aspects of their diagnosis and medical treatment of the hormone-excess state. Emphasis will be on controversial areas or recent advances. The other aspects of the management of these tumors (surgery, treatment of advanced disease, tumor localization) are not dealt with here, because they are covered in other chapters in this volume.