Serum gastrin in Zollinger-Ellison syndrome: II. Prospective study of gastrin provocative testing in 293 patients from the National Institutes of Health and comparison with 537 cases from the literature. evaluation of diagnostic criteria, proposal of new criteria, and correlations with clinical and tumoral features

Treatment strategies for Zollinger-Ellison syndrome

BACKGROUND

Zollinger-Ellison syndrome (ZES) is a rare disorder caused by tumor secretion of the hormone gastrin, which results in gastric acid hypersecretion and secondarily complicated peptic ulcer and diarrhea. Until the development of H(2)-receptor antagonists and later proton pump inhibitors (PPIs), the disease was virulent, often associated with ulcer-related mortality, and the mainstay of treatment was total gastrectomy.

OBJECTIVE

To evaluate current approaches to diagnosis and therapy, focusing on the role of PPIs.

METHODS

An extensive literature search through PubMed using the search term 'Zollinger-Ellison syndrome' from 1964 to the present was performed. Primary articles were identified, and pertinent articles obtained from the reference lists were also examined.

RESULTS/CONCLUSIONS

The clinical manifestations of ZES are well described, but overlaps with other more common disorders delay diagnosis. The use of abdominal imaging with somatostatin receptor scintigraphy and endoscopic ultrasound has improved tumor staging. PPI therapy is remarkably effective in controlling gastric acid hypersecretion, thereby reducing morbidity and potential mortality of this syndrome. The dose of drug necessary to control symptoms is highly variable but, even when used in high doses for prolonged periods of time, the disease remained controlled with very few drug-related side effects.

Reoperative surgery in sporadic Zollinger-Ellison Syndrome: longterm results

BACKGROUND

Most patients with Zollinger-Ellison Syndrome (ZES), even those in whom gastrinoma is found and resected at initial operation, will suffer from persistent or recurrent disease in longterm followup. There is currently no consensus about managing patients with recurrent or persistent ZES. Our unit has historically maintained an aggressive approach toward monitoring and reoperation for patients with sporadic ZES.

STUDY DESIGN

We performed a review of a consecutive series of patients evaluated and managed at our institution between 1970 and 2007 for ZES. "Biochemical cure" was defined as normal serum gastrin assays and negative imaging studies. Reoperations were performed for elevations in serum gastrin assays and positive findings on imaging studies.

RESULTS

Fifty-two patients with sporadic ZES were analyzed. Median followup was 14 years. Among patients with sporadic ZES, 37 patients underwent operative management. The most common operations were resection of duodenal gastrinoma (n=8) and total gastrectomy (n=7). Nine patients underwent 15 reoperations for recurrent or persistent disease. "Biochemical cure" was obtained in four patients (44%) undergoing reoperation for ZES. Three of these patients remained without evidence of recurrence at 4, 9, and 12 years after their curative re-resection. Only one of nine patients who underwent reoperation died of metastatic gastrinoma.

CONCLUSIONS

Primary and reoperative surgery in patients with sporadic ZES results in a significant rate of "biochemical cure." In selected patients with recurrent or persistent disease, reoperation for resection of gastrinoma is associated with excellent longterm survival and is warranted.

Helicobacter pylori-negative nonsteroidal anti-inflammatory drug-negative ulcer

The most important clinical point for dyspeptic H pylori-negative NSAID-absent negative ulcers is to adequately ensure that these common risk factors are indeed absent. Once that is done, further investigations to include the rare causes of ulcer disease need to be performed and exclusion of underlying malignancy ensured. The possibility of the Zollinger Ellison syndrome should be considered, remembering that proton pump inhibitor therapy will mitigate its classical, clinical features.

Review article: Strategies to determine whether hypergastrinaemia is due to Zollinger-Ellison syndrome rather than a more common benign cause

BACKGROUND

As there is considerable overlap between the fasting serum gastrin concentrations found in Zollinger-Ellison syndrome and various common conditions such as Helicobacter pylori infection and acid suppressing medication use, establishing the cause of hypergastrinaemia in individual cases can sometimes be difficult.

AIM

To review the causes of hypergastrinaemia and the role of additional non-invasive investigations in hypergastrinaemic patients.

METHODS

Review of articles following a Pubmed search.

RESULTS

As gastrinomas may cause serious complications and be potentially life threatening, investigation of hypergastrinaemic patients should particularly focus on confirming or refuting the diagnosis of Zollinger-Ellison syndrome. Establishing the cause of hypergastrinaemia may be difficult when there is only a mild-to-moderate elevation of fasting serum gastrin concentration and concurrent treatment with proton pump inhibitor drugs and the presence of H. pylori infection can both confuse the clinical picture. A variety of provocative tests are therefore useful for establishing whether a hypergastrinaemic patient has a gastrinoma and current evidence suggests that the secretin test should be used first line.

CONCLUSIONS

We suggest an algorithm for the investigation of patients found to have an elevated fasting serum gastrin concentration and address the roles of gastrin stimulation tests in current clinical practice.

How I manage H. pylori-negative, NSAID/aspirin-negative peptic ulcers

The first and most important action on encountering a patient with unexplained gastric or duodenal ulceration is to double check that they are truly H. pylori negative and also not taking any ulcerogenic medicines. Once the patient is confirmed to be H. pylori negative and NSAID negative, ensure that biopsies of the ulcer-whether gastric or duodenal-and of the surrounding gastric and duodenal mucosa are obtained to exclude underlying malignancy/lymphoma, Crohn's disease, and unusual infectious agents. If the etiology of the ulceration remains unexplained, an underlying gastrinoma should be considered and excluded. Patients with idiopathic ulcers should be maintained on proton pump inhibitor therapy, and higher doses may be required to control acid secretion and prevent ulcer relapse in these H. pylori-uninfected subjects.

Inherited pancreatic endocrine tumor syndromes: advances in molecular pathogenesis, diagnosis, management, and controversies

Pancreatic endocrine tumors (PETs) can occur as part of 4 inherited disorders, including Multiple Endocrine Neoplasia type 1 (MEN1), von Hippel-Lindau disease (VHL), neurofibromatosis 1 (NF-1) (von Recklinghausen disease), and the tuberous sclerosis complex (TSC). The relative frequency with which patients who have these disorders develop PETs is MEN1>VHL>NF-1>TSC. Over the last few years, there have been major advances in the understanding of the genetics and molecular pathogenesis of these disorders as well in the localization and the medical and surgical treatment of PETs in such patients. The study of PETs in these disorders not only has provided insights into the possible pathogenesis of sporadic PETs but also has presented several unique management and treatment issues, some of which are applicable to patients with sporadic PETs. Therefore, the study of PETs in these uncommon disorders has provided valuable insights that, in many cases, are applicable to the general group of patients with sporadic PETs. In this article, these areas are reviewed briefly along with the current state of knowledge of the PETs in these disorders, and the controversies that exist in their management are summarized briefly and discussed.

Gastrointestinal neuroendocrine tumors: pancreatic endocrine tumors

Pancreatic endocrine tumors (PETs) have long fascinated clinicians and investigators despite their relative rarity. Their clinical presentation varies depending on whether the tumor is functional or not, and also according to the specific hormonal syndrome produced. Tumors may be sporadic or inherited, but little is known about their molecular pathology, especially the sporadic forms. Chromogranin A appears to be the most useful serum marker for diagnosis, staging, and monitoring. Initially, therapy should be directed at the hormonal syndrome because this has the major initial impact on the patient's health. Most PETs are relatively indolent but ultimately malignant, except for insulinomas, which predominantly are benign. Surgery is the only modality that offers the possibility of cure, although it generally is noncurative in patients with Zollinger-Ellison syndrome or nonfunctional PETs with multiple endocrine neoplasia-type 1. Preoperative staging of disease extent is necessary to determine the likelihood of complete resection although debulking surgery often is believed to be useful in patients with unresectable tumors. Once metastatic, biotherapy is usually the first modality used because it generally is well tolerated. Systemic or regional therapies generally are reserved until symptoms occur or tumor growth is rapid. Recently, a number of newer agents, as well as receptor-directed radiotherapy, are being evaluated for patients with advanced disease. This review addresses a number of recent advances regarding the molecular pathology, diagnosis, localization, and management of PETs including discussion of peptide-receptor radionuclide therapy and other novel antitumor approaches. We conclude with a discussion of future directions and unsettled problems in the field.

Neuroendocrine tumors of the gastro-entero-pancreatic system

Gastro-entero-pancreatic (GEP) neuroendocrine tumors (NETs) are rare neoplasms, although their prevalence has increased substantially over the past three decades. Moreover, there has been an increased clinical recognition and characterization of these neoplasms. They show extremely variable biological behavior and clinical course. Most NETs have endocrine function and secrete peptides and neuroamines that cause distinct clinical syndromes, including carcinoid syndrome; however, many are clinically silent until late presentation with mass effects. Investigation and management should be individualized for each patient, taking into account the likely natural history of the tumor and general health of the patient. Management strategies include surgery for cure or palliation, and a variety of other cytoreductive techniques, and medical treatment including chemotherapy, and biotherapy to control symptoms due to hormone release and tumor growth, with somatostatin analogues (SSAs) and alpha-interferon. New biological agents and somatostatin-tagged radionuclides are under investigation. Advances in the therapy and development of centers of excellence which coordinate multicenter studies, are needed to improve diagnosis, treatment and therefore survival of patients with GEP NETs.

Article Commentary: Zollinger–Ellison Syndrome: A Personal Perspective

The odyssey of Zollinger-Ellison Syndrome is one of the most interesting in surgery. From the initial recognition of two patients with severe peptic ulcer disease in 1955 sprung an international dialogue on this unique disease culminating in discovery that gastrin was the hormone secreted by these pancreatic and duodenal tumors. The impact was the birth of a new area of science, “gastrointestinal endocrinology.” Initially, surgeons were challenged by the complexity of the patients and the need to perform total gastrectomy to prevent death from complications of the severe ulcer disease. Later, after the discovery of proton pump inhibitors, total gastrectomy was no longer needed and the surgeon could focus treatment on tumor removal added by radioimmunoassay for gastrin and new imaging modalities. Today, we recognize that all gastrinomas have malignant potential; early surgical removal can reduce the incidence of metastases and improve survival, independent of biochemical cure, in both sporadic and familial forms of the disease.

Biology and treatment of metastatic gastrointestinal neuroendocrine tumors

Neuroendocrine malignancies of the gastroenteropancreatic axis include carcinoid and pancreatic endocrine tumors. These heterogeneous neoplasms arise from the enterochromaffin cells of the gastrointestinal tract and the islet cells of the pancreas. Histologically, most well-differentiated endocrine tumors consist of small, round, monomorphic cells, arranged in islands or trabeculae, with a distinct "salt-and-pepper" pattern of nuclear chromatin. Chromogranin and synaptophysin are useful as immunohistochemical markers of neuroendocrine differentiation. Other common features include the capacity to secrete peptide hormones and biogenic amines. A relatively indolent growth rate is characteristic of most gastrointestinal neuroendocrine tumors, with the exception of poorly differentiated tumors which are usually aggressive. Treatment strategies are designed to limit tumor progression and palliate hormonal syndromes. This article reviews the diverse biologic characteristics of gastrointestinal neuroendocrine tumors and current treatment options for metastatic disease.

Acute nonvariceal upper gastrointestinal bleeding: endoscopic diagnosis and therapy

Acute upper gastrointestinal bleeding is a relatively common,potentially life-threatening condition that causes more than 300,000 hospital admissions and about 30,000 deaths per annum in America. Esophagogastroduodenoscopy is the procedure of choice for the diagnosis and therapy of upper gastrointestinal bleeding lesions. Endoscopic therapy is indicated for lesions with high risk stigmata of recent hemorrhage, including active bleeding, oozing, a visible vessel, and possibly an adherent clot. Endoscopic therapies include injection therapy, such as epinephrine or sclerosant injection; ablative therapy, such as heater probe or argon plasma coagulation; and mechanical therapy, such as endoclips or endoscopic banding. Endoscopic therapy reduces the risk of rebleeding,the need for blood transfusions, the requirement for surgery, and patient morbidity.

A prospective study of gastric carcinoids and enterochromaffin-like cell changes in multiple endocrine neoplasia type 1 and Zollinger-Ellison syndrome: identification of risk factors

CONTEXT

Multiple endocrine neoplasia type 1 (MEN1) patients frequently develop Zollinger-Ellison syndrome (ZES). These patients can develop proliferative changes of gastric enterochromaffin-like (ECL) cells and gastric carcinoids (ECL-cell tumors). ECL-cell changes have been extensively studied in sporadic ZES patients and can be precursor lesions of gastric carcinoids, but little is known about factors influencing their severity or development of carcinoids in MEN1/ZES patients.

OBJECTIVES

Our objective was to prospectively analyze ECL-cell changes and gastric carcinoids (ECL-cell tumors) in a large series of MEN1/ZES patients to detect risk factors and deduct clinical guidelines.

SETTING AND PATIENTS

Fifty-seven consecutive MEN1/ZES patients participated in this prospective study at two tertiary-care research centers.

INTERVENTIONS AND OUTCOME MEASURES

Assessment of MEN1, gastric hypersecretion, and gastroscopy with multiple biopsies was done according to a fixed protocol and tumor status. ECL-cell changes and alpha-human chorionic gonadotropin staining were assessed in each biopsy and correlated with clinical, laboratory, and MEN1 features.

RESULTS

ECL-cell proliferative changes were universally present, advanced changes in 53% and carcinoids in 23%. Gastric nodules are common and are frequently associated with carcinoids. Patients with high fasting serum gastrin levels, long disease duration, or a strong alpha-human chorionic gonadotropin staining in a biopsy are at higher risk for an advanced ECL-cell lesion and/or gastric carcinoid.

CONCLUSIONS

Gastric carcinoids and/or advanced ECL-cell changes are frequent in MEN1/ZES patients, and therefore, regular surveillance gastroscopy with multiple routine biopsies and biopsies of all mucosal lesions are essential. Clinical/laboratory data and biopsy results can be used to identify a subgroup of MEN1/ZES patients with a significantly increased risk for developing gastric carcinoids, allowing development of better surveillance strategies.

Prospective study of surgery for primary hyperparathyroidism (HPT) in multiple endocrine neoplasia-type 1 and Zollinger-Ellison syndrome: long-term outcome of a more virulent form of HPT

BACKGROUND

Primary hyperparathyroidism (HPT) in multiple endocrine neoplasia type 1 (MEN1) patients with Zollinger-Ellison syndrome (ZES) is caused by parathyroid hyperplasia. Surgery for parathyroid hyperplasia is tricky and difficult. Long-term outcome in ZES/MEN1/HPT is not well known.

METHODS

Eighty-four consecutive patients (49 F/35 M) with ZES/MEN1/HPT underwent initial parathyroidectomy (PTX) and were followed at 1- to 3-year intervals.

RESULTS

Age at PTX was 36 +/- 2 years. Mean follow-up was 17 +/- 1 years. Before PTX, mean Ca = 2.8 mmol/L (normal level (nl <2.5), PTH i = 243 pg/mL (nl <65), and gastrin = 6950 pg/mL (nl < 100). Sixty-one percent had nephrolithiasis. Each patient had parathyroid hyperplasia. Fifty-eight percent of patients had 4 parathyroid glands identified. Nine of 84 (11%) had 4 glands removed with immediate autograft, 40/84 (47%) 3 to 3.5 glands, whereas 35/84 (42%) <3 glands removed. Persistent/recurrent HPT occurred in 42%/48% of patients with <3 glands, 12%/44% with 3 to 3.5 glands, and 0%/55% with 4 glands removed. Hypoparathyroidism occurred in 3%, 10%, and 22%, respectively. The disease-free interval after surgery was significantly longer if >3 glands were removed. After surgery to correct the HPT, each biochemical parameter of ZES was improved and 20% of patients no longer had laboratory evidence of ZES.

CONCLUSIONS

HPT/MEN1/ZES is a severe form of parathyroid hyperplasia with a high rate of nephrolithiasis, persistent and recurrent HPT. Surgery to correct the hypercalcemia significantly ameliorates the ZES. Removal of less than 3.5 glands has an unacceptably high incidence of persistent HPT (42%), whereas 4-gland resection and transplant has a high rate of permanent hypoparathyroidism (22%). More than 3-gland resection has a longer disease-free interval. The surgical procedure of choice for patients with HPT/MEN1/ZES is 3.5-gland parathyroidectomy. Careful long-term follow-up is necessary as a significant proportion will develop recurrent HPT.

Sporadically occurring functional pancreatic endocrine tumors: review of recent literature

PURPOSE OF REVIEW

Pancreatic neuroendocrine tumors are rare neoplasms often associated with a clinical syndrome. Their rarity makes a comprehensive study difficult at any single institution, while their uniqueness makes them desirable for investigation. This review summarizes recent information and advancements concerning pancreatic neuroendocrine tumor diagnosis, imaging characteristics, treatment algorithms, and staging.

RECENT FINDINGS

Insulinomas and gastrinomas comprise the majority of functional pancreatic neuroendocrine tumors. Advances in their identification and diagnostic evaluation, imaging techniques, and treatment algorithms are presented. Furthermore, a new staging classification system has been proposed which may significantly improve the ability to conduct future multi-institutional investigations on pancreatic neuroendocrine tumors.

SUMMARY

Although rare, a thorough understanding of pancreatic neuroendocrine tumors is essential for all physicians due to the wide variety of symptoms with which patients present. Currently, patients are often misdiagnosed for extended periods of time. This review summarizes the recently published literature about diagnosis, imaging, treatment, and staging of pancreatic neuroendocrine tumors.

Gastroenteropancreatic neuroendocrine tumours

Gastroenteropancreatic (GEP) neuroendocrine tumours (NETs) are fairly rare neoplasms that present many clinical challenges. They secrete peptides and neuroamines that cause distinct clinical syndromes, including carcinoid syndrome. However, many are clinically silent until late presentation with mass effects. Investigation and management should be highly individualised for a patient, taking into consideration the likely natural history of the tumour and general health of the patient. Management strategies include surgery for cure (which is achieved rarely) or for cytoreduction, radiological intervention (by chemoembolisation and radiofrequency ablation), chemotherapy, and somatostatin analogues to control symptoms that result from release of peptides and neuroamines. New biological agents and somatostatin-tagged radionuclides are under investigation. The complexity, heterogeneity, and rarity of GEP NETs have contributed to a paucity of relevant randomised trials and little or no survival increase over the past 30 years. To improve outcome from GEP NETs, a better understanding of their biology is needed, with emphasis on molecular genetics and disease modeling. More-reliable serum markers, better tumour localisation and identification of small lesions, and histological grading systems and classifications with prognostic application are needed. Comparison between treatments is currently very difficult. Progress is unlikely to occur without development of centers of excellence, with dedicated combined clinical teams to coordinate multicentre studies, maintain clinical and tissue databases, and refine molecularly targeted therapeutics.

Management of sporadic and multiple endocrine neoplasia type 1 gastrinomas

BACKGROUND

Gastrinomas are functional endocrine duodenopancreatic tumours and are responsible for Zollinger-Ellison syndrome (ZES). Clinical presentation, localization techniques and operative management were reviewed.

METHODS

An electronic search of the Medline database was undertaken for articles published in English between January 1987 and May 2007. This timeframe was chosen because of the fundamental changes in operative strategy, antisecretory therapy and localization techniques during this period.

RESULTS AND CONCLUSION

Most gastrinomas are located in the 'gastrinoma triangle', comprising the head of the pancreas, and the first and second parts of the duodenum. Some 20 per cent of gastrinomas occur in association with multiple endocrine neoplasia type 1 (MEN1) and 50-60 per cent of tumours are malignant at the time of diagnosis. Biochemical evidence justifies operation of which duodenotomy is an essential part. Only complete tumour resection allows 5- and 10-year survival rates of 90 per cent. Pylorus-preserving pancreaticoduodenectomy may be the procedure of choice for MEN1-ZES.

Secretin-receptor and secretin-receptor-variant expression in gastrinomas: correlation with clinical and tumoral features and secretin and calcium provocative test results

CONTEXT/OBJECTIVES

The diagnosis of Zollinger-Ellison syndrome requires secretin testing in 60% of patients. Even with secretin, the diagnosis may be difficult because variable responses occur, and 6-30% have negative testing. The basis for variability or negative responses is unclear. It is unknown whether the tumor density of secretin receptors or the presence of a secretin-receptor-variant, which can act as a dominant negative, is important. The aim of this study was to investigate these possibilities.

PATIENTS/METHODS

Secretin-receptor and variant mRNA expression was determined in gastrinomas using real-time PCR from 54 Zollinger-Ellison syndrome patients. Results were correlated with Western blotting, secretin-receptor immunohistochemistry, with gastrin-provocative test results and tumoral/clinical/laboratory features.

RESULTS

Secretin-receptor mRNA was detectible in all gastrinomas but varied 132-fold with a mean of 0.89 +/- 0.12 molecules per beta-actin. Secretin-receptor PCR results correlated closely with Western blotting (r = 0.95; P < 0.0001) and receptor immunohistochemistry (P = 0.0015; r = 0.71). The variant was detected in all gastrinomas, but levels varied 102-fold and were 72-fold lower than the total. Secretin-receptor levels correlated with variant levels, Deltasecretin, but not Deltacalcium and with tumor location, but not growth, extent, or clinical responses. Variant levels did not correlate with the Deltasecretin. Detailed analysis provides no evidence that variant expression modified the secretin-receptor response or accounted for negative tests.

CONCLUSIONS

Secretin-receptor and secretin-receptor-variant expressions occur in all gastrinomas. Because the expression of the total, but not variant, correlated with the secretin results and no evidence for dominant negative activity of the variant was found, our results suggest that the total secretin-receptor density is an important determinant of the secretin test response.

Serum gastrin in Zollinger-Ellison syndrome: I. Prospective study of fasting serum gastrin in 309 patients from the National Institutes of Health and comparison with 2229 cases from the literature

The assessment of fasting serum gastrin (FSG) is essential for the diagnosis and management of patients with the Zollinger-Ellison syndrome (ZES). Although many studies have analyzed FSG levels in patients with gastrinoma, limited information has resulted from these studies because of their small size, different methodologies, and lack of correlations of FSG levels with clinical, laboratory, or tumor features in ZES patients. To address this issue, we report the results of a prospective National Institutes of Health (NIH) study of 309 patients with ZES and compare our results with those of 2229 ZES patients in 513 small series and case reports in the literature. In the NIH and literature ZES patients, normal FSG values were uncommon (0.3%-3%), as were very high FSG levels >100-fold normal (4.9%-9%). Two-thirds of gastrinoma patients had FSG values <10-fold normal that overlap with gastrin levels seen in more common conditions, like Helicobacter pylori infection or antral G-cell hyperplasia/hyperfunction. In these patients, FSG levels are not diagnostic of ZES, and gastrin provocative tests are needed to establish the diagnosis. Most clinical variables (multiple endocrine neoplasia type 1 status, presence or absence of the most common symptoms, prior medical treatment) are not correlated with FSG levels, while a good correlation of FSG values was found with other clinical features (prior gastric surgery, diarrhea, duration from onset to diagnosis). Increasing basal acid output, but not maximal acid output correlated closely with increasing FSG. Numerous tumoral features correlated with the magnitude of FSG in our study, including tumor location (pancreatic > duodenal), primary size (larger > smaller) and extent (liver metastases > local disease). In conclusion, this detailed analysis of FSG in a large number of patients with ZES allowed us to identify important clinical guidelines that should contribute to improved diagnosis and management of patients with ZES.