Medical management of patients with Zollinger-Ellison syndrome who have had previous gastric surgery: a prospective study

Long-Term Proton Pump Inhibitor-Acid Suppressive Treatment Can Cause Vitamin B12 Deficiency in Zollinger-Ellison Syndrome (ZES) Patients

Whether the long-term treatment of patients with proton pump inhibitors (PPIs) with different diseases [GERD, Zollinger-Ellison syndrome (ZES), etc.] can result in vitamin B12 (VB12) deficiency is controversial. In this study, in 175 patients undergoing long-term ZES treatment with anti-acid therapies, drug-induced control acid secretory rates were correlated with the presence/absence of VB12 deficiency, determined by assessing serum VB12 levels, measurements of VB12 body stores (blood methylmalonic acid (MMA) and total homocysteine[tHYC]), and other features of ZES. After a mean of 10.2 yrs. of any acid treatment (5.6 yrs. with PPIs), 21% had VB12 deficiency with significantly lower serum and body VB12 levels (p < 0.0001). The presence of VB12 deficiency did not correlate with any feature of ZES but was associated with a 12-fold lower acid control rate, a 2-fold higher acid control pH (6.4 vs. 3.7), and acid control secretory rates below those required for the activation of pepsin (pH > 3.5). Over a 5-yr period, the patients with VB12 deficiency had a higher rate of achlorhydria (73% vs. 24%) and a lower rate of normal acid secretion (0% vs. 49%). In conclusion, in ZES patients, chronic long-term PPI treatment results in marked acid hyposecretion, resulting in decreased serum VB12 levels and decreased VB12-body stores, which can result in VB12 deficiency.

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.

The North American Neuroendocrine Tumor Society Consensus Guidelines for Surveillance and Medical Management of Pancreatic Neuroendocrine Tumors

This article is the result of the North American Neuroendocrine Tumor Society consensus conference on the medical management of pancreatic neuroendocrine tumors from July 19 to 20, 2018. The guidelines panel consisted of medical oncologists, pathologists, gastroenterologists, endocrinologists, and radiologists. The panel reviewed a series of questions regarding the medical management of patients with pancreatic neuroendocrine tumors as well as questions regarding surveillance after resection. The available literature was reviewed for each of the question and panel members voted on controversial topics, and the recommendations were included in a document circulated to all panel members for a final approval.

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.

Causes of death and prognostic factors in multiple endocrine neoplasia type 1: a prospective study: comparison of 106 MEN1/Zollinger-Ellison syndrome patients with 1613 literature MEN1 patients with or without pancreatic endocrine tumors

Multiple endocrine neoplasia type 1 (MEN1) is classically characterized by the development of functional or nonfunctional hyperplasia or tumors in endocrine tissues (parathyroid, pancreas, pituitary, adrenal). Because effective treatments have been developed for the hormone excess state, which was a major cause of death in these patients in the past, coupled with the recognition that nonendocrine tumors increasingly develop late in the disease course, the natural history of the disease has changed. An understanding of the current causes of death is important to tailor treatment for these patients and to help identify prognostic factors; however, it is generally lacking.To add to our understanding, we conducted a detailed analysis of the causes of death and prognostic factors from a prospective long-term National Institutes of Health (NIH) study of 106 MEN1 patients with pancreatic endocrine tumors with Zollinger-Ellison syndrome (MEN1/ZES patients) and compared our results to those from the pooled literature data of 227 patients with MEN1 with pancreatic endocrine tumors (MEN1/PET patients) reported in case reports or small series, and to 1386 patients reported in large MEN1 literature series. In the NIH series over a mean follow-up of 24.5 years, 24 (23%) patients died (14 MEN1-related and 10 non-MEN1-related deaths). Comparing the causes of death with the results from the 227 patients in the pooled literature series, we found that no patients died of acute complications due to acid hypersecretion, and 8%-14% died of other hormone excess causes, which is similar to the results in 10 large MEN1 literature series published since 1995. In the 2 series (the NIH and pooled literature series), two-thirds of patients died from an MEN1-related cause and one-third from a non-MEN1-related cause, which agrees with the mean values reported in 10 large MEN1 series in the literature, although in the literature the causes of death varied widely. In the NIH and pooled literature series, the main causes of MEN1-related deaths were due to the malignant nature of the PETs, followed by the malignant nature of thymic carcinoid tumors. These results differ from the results of a number of the literature series, especially those reported before the 1990s. The causes of non-MEN1-related death for the 2 series, in decreasing frequency, were cardiovascular disease, other nonendocrine tumors > lung diseases, cerebrovascular diseases. The most frequent non-MEN1-related tumor deaths were colorectal, renal > lung > breast, oropharyngeal. Although both overall and disease-related survival are better than in the past (30-yr survival of NIH series: 82% overall, 88% disease-related), the mean age at death was 55 years, which is younger than expected for the general population.Detailed analysis of causes of death correlated with clinical, laboratory, and tumor characteristics of patients in the 2 series allowed identification of a number of prognostic factors. Poor prognostic factors included higher fasting gastrin levels, presence of other functional hormonal syndromes, need for >3 parathyroidectomies, presence of liver metastases or distant metastases, aggressive PET growth, large PETs, or the development of new lesions.The results of this study have helped define the causes of death of MEN1 patients at present, and have enabled us to identify a number of prognostic factors that should be helpful in tailoring treatment for these patients for both short- and long-term management, as well as in directing research efforts to better define the natural history of the disease and the most important factors determining long-term survival at present.

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.

Current management of the Zollinger-Ellison syndrome

In summary, ZES is a syndrome caused by gastrinoma, usually located within the gastrinoma triangle and associated with symptoms of peptic ulcer disease, GERD, and diarrhea. The diagnosis of ZES is made by measuring fasting levels of serum gastrin, BAO, and the secretin stimulation test. Because of the high association of ZES and MEN1, HPT must be excluded by obtaining a serum calcium and parathyroid hormone level. Treatment of ZES consists of medical control of symptoms with PPIs and evaluation for potentially curative surgical intervention. Noninvasive imaging studies including SRS, CT, and MRI should be performed initially to evaluate for metastases and identify resectable disease. Invasive imaging modalities such as EUS may be performed to further evaluate primary tumors. IOUS, palpation, and duodenotomy are used for intraoperative localization of gastrinomas. In patients with MEN1, surgical resection should be pursued only if there is an identifiable tumor larger than 2 cm and after surgery for the primary hyperparathyroidism (3 1/2-gland parathyroidectomy). All patients with resectable localized sporadic gastrinoma should undergo surgical exploration, even those with biochemical evidence but negative imaging studies. Tumor is most commonly found in the duodenum, and the cure rate is high. In patients with liver metastases, surgery should be considered if all identifiable tumor can be safely removed. A multidisciplinary approach including surgical and nonsurgical therapies should be taken in patients with advanced disease.

Diagnosis of Zollinger-Ellison syndrome: increasingly difficult

In the present paper the increasing difficulty of diagnosis of Zollinger-Ellison syndrome (ZES) due to issues raised in two recent papers is discussed. These issues involve the difficulty and need to withdraw patients suspected of ZES from treatment with Proton Pump Inhibitors (omeprazole, esomeprazole, lansoprazole, rabeprazole, pantoprazole) and the unreliability of many gastrin radioimmunoassays. The clinical context of each of these important issues is reviewed and the conclusions in these articles commented from the perspective of clinical management.

Diagnosis and Treatment of Gastrinomas in Multiple Endocrine Neoplasia Type 1 (MEN-1)

Multiple endocrine neoplasia type 1 (MEN-1) is a rare autosomal-dominant disease. It is associated with a broad range of endocrine tumours, most frequently arising in the parathyroid glands, the pituitary and the pancreas. Most neuroendocrine tumours will be diagnosed in the pancreas as non-functioning neuroendocrine tumours or insulinomas. Forty-two percent of the patients will develop a gastrin-secreting neuroendocrine tumour, a gastrinoma. Gastrinomas in MEN-1 tend to be small, multiple and preferentially located in the duodenum. This paper will focus on the specific characteristics of gastrinomas in the setting of MEN-1 compared to sporadic gastrinomas. The developments in understanding the tumorigenesis of these tumours and the consequences for diagnosis and therapy will be discussed.

NANETS treatment guidelines: well-differentiated neuroendocrine tumors of the stomach and pancreas

Well-differentiated neuroendocrine tumors (NETs) of the stomach and pancreas represent 2 major subtypes of gastrointestinal NETs. Historically, there has been little consensus on the classification and management of patients with these tumor subtypes. We provide an overview of well-differentiated NETs of the stomach and pancreas and describe consensus guidelines for the treatment of patients with these malignancies.

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.

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.

Role of acid suppressants in patients with Zollinger-Ellison syndrome

Virtually all symptoms in patients with Zollinger-Ellison syndrome are due to acid hypersecretion, thus the control of acid secretion is the first and most important step in the management of patients with this syndrome. Antisecretory medication is prescribed as soon as the diagnosis of Zollinger-Ellison syndrome is made, as patients may bleed or perforate with little warning. Acid output is reduced to less than 10 mmol/h to heal mucosal lesions, but in patients with a Billroth I or II gastrectomy and those with severe oesophagitis and stricture formation, acid output is reduced to less than 5 or less than 1 mmol/h. Acid output and not symptomatic response is a reliable guide of the adequacy of therapy. In sufficient doses, all H2-receptor antagonists are useful; however, side effects associated with cimetidine therapy limit its use. The ratio of potencies of cimetidine:ranitidine:famotidine is 1:4:32. Ranitidine given as a 50-mg intravenous bolus, followed by a continuous infusion of 0.5 mg.kg/h, controls acid hypersecretion acutely in patients with Zollinger-Ellison syndrome. Acid output is checked after 4 h, and the dose increased until acid output is less than 10 mmol/h. In 70% of patients with Zollinger-Ellison syndrome, 1 mg.kg/h reduces acid output to less than 10 mmol/h; however, doses up to 4 mg.kg/h have been used. When patients are switched to oral ranitidine, a useful dosage conversion is to administer 1.5 times the total daily intravenous dose in four equal doses every 6 h. Four doses of oral drug are given before the infusion is stopped. Six hours after the first/last oral dose, acid output is checked. In our patients, the mean dose of ranitidine was 2100 mg/day (range, 450-9200 mg/day). No serious toxicity was observed. Omeprazole, which has a long duration of action and is a potent inhibitor of gastric acid secretion, has simplified management. Once-daily dosing is sufficient in most patients, and a reasonable starting dose is 60 mg daily. The dose may be increased to 120 mg once daily; if this dosage fails to control acid secretion, 60 mg is administered every 12 h. In our studies, the median dose was 90 mg/day (range, 20-120 mg/day). Omeprazole was more effective than H2-receptor antagonists in providing symptom relief and mucosal healing and did not cause significant toxicity. In particular, no gastric carcinoid tumours developed during four years of use. Omeprazole is, therefore, the treatment of choice for control of acid secretion in patients with Zollinger-Ellison syndrome.(ABSTRACT TRUNCATED AT 400 WORDS)

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

In two-thirds of patients with Zollinger-Ellison syndrome (ZES), fasting serum gastrin (FSG) levels overlap with values seen in other conditions. In these patients, gastrin provocative tests are needed to establish the diagnosis of ZES. Whereas numerous gastrin provocative tests have been proposed, only the secretin, calcium, and meal tests are widely used today. Many studies have analyzed gastrin provocative test results in ZES, but they are limited by small patient numbers and methodologic differences. To address this issue, we report the results of a prospective National Institutes of Health (NIH) study of gastrin provocative tests in 293 patients with ZES and compare these data with those from 537 ZES and 462 non-ZES patients from the literature. In 97%-99% of gastrinoma patients, an increase in serum gastrin post secretin (Delta secretin) or post calcium (Delta calcium) occurred. In NIH ZES patients with <10-fold increase in FSG, the sensitivity/specificity of the widely used criteria were as follows: Delta secretin > or =200 pg/mL (83%/100%), Delta secretin >50% (86%/93%), Delta calcium > or =395 pg/mL (54%/100%), and Delta calcium >50% (78%/83%). A systematic analysis of the sensitivity and specificity of other possible criteria for a positive secretin or calcium test allowed us to identify a new criterion for secretin testing (Delta > or =120 pg/mL) with the highest sensitivity/specificity (94%/100%) and to confirm the commonly used criterion for calcium tests (Delta > or =395 pg/mL) (62%/100%). This analysis further showed that the secretin test was more sensitive than the calcium test (94% vs. 62%). Our results suggest that secretin stimulation should be used as the first-line provocative test because of its greater sensitivity and simplicity and lack of side effects. In ZES patients with a negative secretin test, 38%-50% have a positive calcium test. Therefore the calcium test should be considered in patients with a strong clinical suspicion of ZES but a negative secretin test. Furthermore, we found that some clinical (diarrhea, duration of medical treatment), laboratory (basal acid output), and tumoral (size, extent) characteristics correlate with the serum gastrin increase post secretin and post calcium. However, using the proposed criteria, the result of these provocative tests (that is, positive or negative) is minimally influenced by these factors, so secretin and calcium provocative tests are reliable in patients with different clinical, laboratory, and tumor characteristics. A systematic analysis of meal testing showed that 54%-77% of ZES patients have a <50% postprandial serum gastrin increase. However, 9%-20% of ZES patients had a >100% increase post meal, causing significant overlap with antral syndromes. Furthermore, we could not confirm the usefulness of meal tests for localization of duodenal gastrinomas. We conclude that the secretin test is a crucial element in the diagnosis of most ZES patients, the calcium test may be useful in selected patients, but the meal test is not helpful in the management of ZES. For secretin testing, the criterion with the highest sensitivity and specificity is an increase of > or =120 pg/mL, which should replace other criteria commonly used today.

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.

Three-year oral pantoprazole administration is effective for patients with Zollinger-Ellison syndrome and other hypersecretory conditions

BACKGROUND

Zollinger-Ellison syndrome and idiopathic hypersecretion are gastrointestinal hypersecretory conditions requiring long-term maintenance.

AIMS

The safety and efficacy data for short-term (6-month) treatment of Zollinger-Ellison syndrome and idiopathic hypersecretion with oral pantoprazole were previously published. This study extends the initial observations to 3 years.

METHODS

The primary efficacy end point for this report was the control of gastric acid secretion in the last hour before the next dose of oral pantoprazole (acid output of <10 mmol/h; <5 mmol/h in subjects with prior acid-reducing surgery). Dose titration was permitted to a maximum of 240 mg per 24 h.

RESULTS

Twenty-four subjects completed the study. The acid output of 28 of 34 subjects was controlled at initial enrolment. The mean acid output rates were <10 mmol/h throughout the 36 months of treatment for 90-100% of the patients. The majority of the patients were controlled with b.d. doses of 40 or 80 mg pantoprazole at 36 months (acid output was controlled in 24 of 24 subjects). Pantoprazole was generally well tolerated with minimal adverse events reported.

CONCLUSIONS

Maintenance oral pantoprazole therapy up to 3 years at dosages of 40-120 mg b.d. was effective and well tolerated in patients with Zollinger-Ellison syndrome and other hypersecretory conditions.

Patients with multiple endocrine neoplasia type 1 with gastrinomas have an increased risk of severe esophageal disease including stricture and the premalignant condition, Barrett's esophagus

CONTEXT

Multiple endocrine neoplasia type 1 (MEN1) patients frequently develop Zollinger-Ellison syndrome (MEN1/ZES). Although esophageal reflux symptoms are common in these patients, little is known about long-term occurrence of severe peptic esophageal disease including strictures and Barrett's esophagus (BE).

OBJECTIVE

The objective of the study was to prospectively analyze the frequency of severe peptic esophageal disease in ZES patients with and without MEN1.

SETTING

The study was conducted at a tertiary care research center.

PATIENTS

Two hundred ninety-five patients (80 = MEN1/ZES, 215 = sporadic ZES) participated in a prospective study.

INTERVENTIONS AND OUTCOME MEASURES

Assessment of MEN1, acid hypersecretion, upper gastrointestinal endoscopy/biopsies, and tumor status were measured initially and at each follow-up. Esophageal manometry was performed in 89 patients. Frequency and type of esophageal disease were correlated with clinical/laboratory/tumoral features of ZES/MEN1.

RESULTS

In MEN1/ZES patients, esophageal stricture was 3-fold higher, BE 5-fold higher, and dysplasia 8-fold higher, and one patient died of esophageal adenocarcinoma. Esophageal symptoms were more frequent or severe in MEN1/ZES, but known risk factors for severe esophageal disease and ZES-specific features did not differ between MEN1/ZES and sporadic ZES. In MEN1/ZES, the onset of ZES was 10 yr earlier, and H2-antagonists were used longer and at lower doses. MEN1/ZES patients with esophageal disease differed from those without in that ZES diagnosis was delayed longer, esophageal symptoms were more frequent or severe, hiatal hernias were more frequent, esophagitis or pyloric scarring was more common, basal acid output was higher, and hyperparathyroidism was underdiagnosed.

CONCLUSIONS

This study shows that MEN1/ZES patients have a higher incidence of severe esophageal disease including the premalignant condition BE and identifies factors important for their pathogenesis that need to be incorporated into their long-term treatment.

Duodenal neuroendocrine tumors: Classification, functional syndromes, diagnosis and medical treatment

Duodenal neuroendocrine tumors (NETs) comprise 2-3% of all GI endocrine tumors and are increasing in frequency. These include gastrinomas, somatostatinomas, nonfunctional NETs, gangliocytic paragangliomas, and poorly differentiated NE carcinomas. Although, the majority are nonfunctional, these tumors are a frequent cause of Zollinger-Ellison syndrome and can cause other clinical hormonal syndromes (carcinoid, Cushing's, etc.). In this chapter, their epidemiology, clinical aspects, localization, diagnosis and medical treatment are reviewed including the latest advances in each area.

Clinical outcome using lansoprazole in acid hypersecretors with and without Zollinger-Ellison syndrome: a 13-year prospective study

BACKGROUND & AIMS

Unremitting gastric acid and pepsin hypersecretion causes serious persistent and relapsing lesions, but the natural history with medical treatment alone has not been well-defined. The aims of this study were to heal and prevent relapse of acid/peptic lesions during acid suppression and to analyze benefits and risks during long-term lansoprazole treatment.

METHODS

Sixty-seven patients (49 with Zollinger-Ellison syndrome [ZES], 18 without), with basal acid output (BAO) >15 mmol/h or >5 mmol/h if post-antrectomy (n = 9, all ZES), were treated with individually optimized doses of lansoprazole (7.5-450 mg/day; median, 75 mg/day) to reduce BAO to <5 mmol/h or <1 mmol/h post-antrectomy and underwent endoscopy every 3-6 months for up to 13 years (median, 6.25 years).

RESULTS

Before treatment, 94% had duodenal ulcer, 64% had esophagitis, 60% had 1 or more bleeding episodes, 13% had perforated ulcers, 90% had pain, 60% had heartburn, and 40%-48% had diarrhea, vomiting, and/or weight loss. Forty-seven patients (70%) remained symptom- and lesion-free, whereas 13 (20%) had mild, transient relapses, and 7 (10%) had more complicated relapses. Overall, symptoms were reduced 90+%; ulcer or esophagitis relapsed in 4.8% of patients/year, unrelated to Helicobacter pylori , whereas complications declined to <2%/y. Post-antrectomy ZES patients had 3.6-fold higher relapse rates than unoperated ZES patients (67% vs 18%, respectively). With BAO >5 mmol/h in intact patients, relative risk of relapse was 4.1, confidence interval 2.1-8.1, P < .001. Twenty patients died, 3 as a result of ZES (2 metastatic gastrinomas).

CONCLUSIONS

With individually optimized medical suppression of acid secretion, 90% of patients had good to excellent long-term outcomes without surgery, with an annualized total relapse rate of <5%.

Multiple endocrine neoplasia type 1 and Zollinger-Ellison syndrome: a prospective study of 107 cases and comparison with 1009 cases from the literature

In patients with multiple endocrine neoplasia type 1 (MEN1), the most common functional pancreatic endocrine tumor (PET) syndrome is Zollinger-Ellison syndrome (ZES). ZES has been well studied in its sporadic form (that is, without MEN1); however, there are limited data on patients with MEN1 and ZES (MEN1/ZES), and the long-term natural history is largely unknown. To address this issue we report the results of a prospective long-term National Institutes of Health (NIH) study of 107 MEN1/ZES patients and compare our results with those of 1009 MEN1/ZES patients in 278 case reports and small series in the literature. Patients were clinically, radiologically, and biochemically evaluated yearly for all MEN1 manifestations (mean follow-up, 10 yr; range, 0.1-31 yr). Compared with patients from the literature, the NIH MEN1/ZES patients more frequently had pituitary (60%) and adrenal (45%) disease and carcinoid tumors (30%), but had equal frequency of hyperparathyroidism (94%), thyroid disease (6%), or lipomas (5%). Twenty-five percent of both the NIH and the literature patients lacked a family history of MEN1; ZES was the initial clinical manifestation of MEN1 in 40%. ZES onset preceded the diagnosis of hyperparathyroidism in 45%. However, ZES was rarely (8%) the only initial manifestation of MEN1 if careful testing was done. ZES occurred before age 40 years in 50%-60% of the current patients, in contrast to older studies. The diagnosis of ZES is delayed 3-5 years from its onset and is delayed as long as in sporadic ZES cases. Pituitary disease and carcinoid tumors (gastric > bronchial, thymic) are more frequent than generally reported, whereas a second functional PET is uncommon. In patients with MEN1/ZES without a family history of MEN1, the MEN1 manifestations are not as severe. This study shows that MEN1/ZES patients differ in many aspects from those commonly reported in older studies involving few MEN1/ZES patients. In this study we have identified a number of important clinical and laboratory features of MEN1/ZES that were not previously appreciated, which should contribute to earlier diagnosis and improve both short- and long-term management.

Maintenance oral pantoprazole therapy is effective for patients with Zollinger-Ellison syndrome and idiopathic hypersecretion

OBJECTIVE

Maintenance proton pump inhibitor (PPI) therapy is effective for gastric acid hypersecretory states, although data with pantoprazole are limited. The aim of this study was to evaluate the safety and efficacy of long term p.o. pantoprazole in individuals with hypersecretion.

METHODS

All subjects had Zollinger-Ellison syndrome or idiopathic hypersecretion. Baseline acid output was measured in the presence of prior maintenance antisecretory therapy before pantoprazole exposure. The starting dose was 40 mg b.i.d. in most cases, and the dose was adjusted to document control within the first 2 wk of therapy. The maximal allowable dose was 240 mg daily. Acid output was measured on day 28 and then quarterly from month 3. The primary efficacy endpoint was documented control of acid secretion at 6 months, i.e., acid output in the last 1 h before the next dose of therapy of <10 mEq/h (<5 mEq/h in subjects with prior acid-reducing surgery).

RESULTS

A total of 26 subjects had Zollinger-Ellison syndrome (six with multiple endocrine neoplasia syndrome type 1) and nine had idiopathic hypersecretion. Pre-enrollment therapy included omeprazole in 27 subjects and lansoprazole in eight, and 82.4% of subjects were controlled on their prior regimens. With upward dose titration, acid output was controlled in all subjects by day 10 and in all but two (6%) at the 6-month time point. Median acid secretion on therapy at 6 months was <2 mEq/h (mean 2.2 mEq/h; range 0-10.5 mEq/h) at a dose of 40 mg b.i.d. for 24 subjects, 80 mg b.i.d. for seven subjects, and 120 mg b.i.d. for two subjects. During the course of the study, five subjects required doses of 240 mg daily. Pantoprazole was generally well tolerated. No cases of anterior optic ischemic neuropathy occurred. Five subjects died during follow-up, all because of events unrelated to the study drug.

CONCLUSIONS

Maintenance p.o. pantoprazole therapy at a dose of 80-240 mg/day in divided doses was both effective and generally well tolerated for patients with Zollinger-Ellison syndrome and idiopathic hypersecretion.

Optimal Treatment of Zollinger-Ellison Syndrome and Related Conditions in Elderly Patients

Zollinger-Ellison syndrome is characterised by refractory peptic ulcer disease, severe diarrhoea and gastric acid hypersecretion associated with an islet-cell tumour of the pancreas (gastrinoma). The true incidence and prevalence of this rare disease is unknown; in the US, the frequency is one per one million people and the age at presentation varies from 7 to 90 years. Zollinger-Ellison syndrome is sporadic in 62-80% of cases and in 20-38% of cases is associated with multiple endocrine neoplasia type 1 (MEN 1). The diagnosis of Zollinger-Ellison syndrome is certain when the plasma gastrin is >1000 pg/mL and the basal acid output is >15 mEq/h in patients with an intact stomach, >5 mEq/h in gastrectomised patients, or when this hypergastrinemia is associated with a pH <2. The treatment is based on control of gastric acid hypersecretion and of the malignant tumour and its possible metastases. Proton pump inhibitors are the most effective antisecretory drugs and can be administered in the elderly at high dosages without drug-related adverse effects. As an initial therapy, daily dosages of omeprazole 80-100 mg or pantoprazole 40-160 mg are employed. In long-term treatment the doses can be greatly reduced once effective control of the gastric output has been established. Intravenous proton pump inhibitors may be administered when patients cannot take oral therapy, particularly in acute conditions. All sporadic localised gastrinomas should be excised if possible. When liver metastases are also present, their debulking may improve symptoms and survival, and facilitate medical treatment. There is some controversy as to the surgical approach for gastrinomas associated with MEN 1. Somatostatin analogues can be useful in reducing gastric acid hypersecretion, serum gastrin and gastric enterochromaffin-like (ECL) cells and can thus contribute to treating the disease more effectively. Their antiproliferative effect can be used in treating liver metastases. Chemotherapy is not the therapy of choice in patients with gastrinomas and is indicated only in those with malignant progressive disease; interferon alpha, embolisation and chemoembolisation are not advisable for the elderly. The treatment of elderly Zollinger-Ellison syndrome patients, similarly to all elderly oncological patients, should be based on the use of comprehensive geriatric assessment. This will enable the clinician to define the functional status of the elderly person, to decide whether the patient can tolerate surgery and/or the stress of antineoplastic therapy, and finally, to determine whether this patient can tolerate an aggressive treatment for Zollinger-Ellison syndrome or whether the only possible choice is palliative relief of symptoms.

Progression of gastric enterochromaffin-like cells growth in Zollinger-Ellison syndrome and atrophic body gastritis patients

BACKGROUND

Enterochromaffin-like cell hyperplasia of the gastric body mucosa occurs in hypergastrinaemic conditions such as atrophic body gastritis and Zollinger-Ellison syndrome. However, the time course of change or factors involved are not known.

AIMS

To compare the rate of change of enterochromaffin-like cell proliferation in patients with atrophic body gastritis and Zollinger-Ellison syndrome.

PATIENTS

From a consecutive series of atrophic body gastritis and Zollinger-Ellison syndrome patients, studied at the time of first diagnosis, 10 atrophic body gastritis (4 with pernicious anaemia) and 14 Zollinger-Ellison syndrome (4 with multiple endocrine neoplasia type 1) patients were followed-up for a median time of 48 months.

METHODS

At entry and during follow-up patients underwent: plasma gastrin determination, endoscopic sampling of body mucosa for qualitative assessment of enterochromaffin-like cell hyperplasia pattern and degree of glandular atrophy, qualitative and morphometric analyses of body mucosa endocrine cells.

RESULTS

At time of diagnosis, enterochromaffin-like cell lesions were more severe in atrophic body gastritis than in Zollinger-Ellison syndrome. During follow-up, no significant variations were observed in gastrin values, enterochromaffin-like cell patterns and grade of body mucosa atrophy in atrophic body gastritis. In contrast, gastrin levels were significantly increased [median 1200 (235-2625) vs 1947 (225-5200) pg/ml; p<0.001)] as was total volume density of enterochromaffin-like cells [median 1.60 (0.53-4.06) vs 3.18 (1.35-21.13)% of mucosal epithelial component; (p<0.005)] in Zollinger-Ellison syndrome. Micronodular hyperplasia of enterochromaffin-like cells, present in only one patient at diagnosis, was observed in 8 Zollinger-Ellison syndrome patients at follow-up.

CONCLUSIONS

These data suggest that the progression of enterochromaffin-like cell growth in human gastric mucosa requires an increase of and/or a prolonged exposure to severe hypergastrinaemia.

Minor effects of Helicobacter pylori on gastric secretion and dose of lansoprazole during long-term treatment in ZE and non-ZE acid hypersecretors

BACKGROUND

Helicobacter pylori infection may increase or decrease acid secretion and may augment proton pump inhibitor efficacy. Pepsin effects have not been reported. In Zollinger-Ellison syndrome (ZE) specifically, H. pylori has been reported to decrease acid.

AIM

To examine H. pylori effects on secretion and dose of medication in hypersecretors (basal acid output > 15 mmol/h) undergoing long-term treatment with individually optimized lansoprazole doses.

METHODS

Sixty-five patients (47 ZE and 18 non-ZE), treated for > 3 months to 10 years, were tested every 6 months with endoscopy, gastric analysis and serum gastrin.

RESULTS

Forty-three per cent were H. pylori-positive. Acid, pepsin and gastrin were not different between H. pylori-positive and H. pylori-negative patients before or during long-term lansoprazole treatment. Initially, H. pylori-positive patients required less lansoprazole than H. pylori-negative patients (68 +/- 6 vs. 96 +/- 8 mg/day), but after 3 years the doses converged (83 vs. 86 mg/day). The disappearance of H. pylori in 15 patients caused no significant changes in acid, pepsin, gastrin or lansoprazole dose in the following 4 years.

CONCLUSIONS

H. pylori had no significant initial or long-term physiological or potential clinical effects on acid or pepsin secretion or gastrin in these acid hypersecretors.

Long-term lansoprazole control of gastric acid and pepsin secretion in ZE and non-ZE hypersecretors: a prospective 10-year study

BACKGROUND

The majority of patients with Zollinger-Ellison syndrome require lifelong treatment with proton pump inhibitors.

AIMS

To determine the efficacy of lansoprazole control of acid and pepsin secretion over the long term in Zollinger-Ellison syndrome and non-Zollinger-Ellison syndrome hypersecretors.

METHODS

Sixty-three hypersecretors (basal acid output > 15 mmol/h), 46 Zollinger-Ellison syndrome and 17 non-Zollinger-Ellison syndrome, with a total history of 15.4 and 19.2 years, respectively, were entered into a long-term prospective study using lansoprazole. Sixty-one were studied every 3 months for 1 year and then every 3-6 months up to 10 years during lansoprazole treatment with endoscopy, serum gastrin and gastric analysis, measuring both basal and stimulated pH and acid and pepsin secretion. Doses were individually optimized and adjusted to keep the basal acid output at < 5 mmol/h in intact patients and < 1 mmol/h in antrectomized Zollinger-Ellison syndrome patients.

RESULTS

The dose of lansoprazole could not be predicted a priori from pre-treatment acid or pepsin output, serum gastrin, prior omeprazole dose or diagnosis or prior complications. The median dose was approximately 80 mg/day, with a wide range from 15 mg every other day to 360 mg/day, and generally stabilized by 12 months. However, as doses were adjusted over time for indications, almost half the patients required higher doses. With adjustments, the basal acid output was maintained in the target range in > 90% of intact patients and in 80% of antrectomized patients. Gastric juice pH increased from approximately 1.2 before therapy to > 3.4 during therapy. Serum gastrin in Zollinger-Ellison syndrome patients, after excluding five outliers, did not change over the course of therapy, but doubled in non-Zollinger-Ellison syndrome patients. There were no adverse events due to lansoprazole, and routine laboratory studies remained normal.

CONCLUSIONS

The dose of lansoprazole for hypersecretors cannot be predicted, and thus needs to be optimized empirically on an individual basis. With continued periodic adjustments, almost half the patients required increased doses, while safe dose reduction was possible in only one-quarter. When individually optimized, lansoprazole proved to be safe and effective in the control of secretion for the treatment of both Zollinger-Ellison syndrome and non-Zollinger-Ellison syndrome hypersecretors for up to 10 years.

Zollinger-Ellison syndrome. Clinical presentation in 261 patients

We prospectively evaluated the initial presenting symptoms in 261 patients with Zollinger-Ellison syndrome (ZES) over a 25-year period. Twenty-two percent of the patients had multiple endocrine neoplasia-type 1 (MEN-1) with ZES. Mean age at onset was 41.1 +/- 0.7 years, with MEN-1 patients presenting at a younger age than those with sporadic ZES (p < 0.0001). Three percent of the patients had onset of the disease < age 20 years, and 7% > 60 years. A mean delay to diagnosis of 5.2 +/- 0.4 years occurred in all patients. A shorter duration of symptoms was noted in female patients and in patients with liver metastases. Abdominal pain and diarrhea were the most common symptoms, present in 75% and 73% of patients, respectively. Heartburn and weight loss, which were uncommonly reported in early series, were present in 44% and 17% of patients, respectively. Gastrointestinal bleeding was the initial presentation in a quarter of the patients. Patients rarely presented with only 1 symptom (11%); pain and diarrhea was the most frequent combination, occurring in 55% of patients. An important presenting sign that should suggest ZES is prominent gastric body folds, which were noted on endoscopy in 94% of patients; however, esophageal stricture and duodenal or pyloric scarring, reported in numerous case reports, were noted in only 4%-10%. Patients with MEN-1 presented less frequently with pain and bleeding and more frequently with nephrolithiasis. Comparing the clinical presentation before the introduction of histamine H2-receptor antagonists (pre-1980, n = 36), after the introduction of histamine H2-receptor antagonists (1981-1989, n = 118), and after the introduction of proton pump inhibitors (PPIs) (> 1990, n = 106) demonstrates no change in age of onset; delay in diagnosis; frequency of pain, diarrhea, weight loss; or frequency of complications of severe peptic disease (bleeding, perforations, esophageal strictures, pyloric scarring). Since the introduction of histamine H2-receptor antagonists, fewer patients had a previous history of gastric acid-reducing surgery or total gastrectomy. Only 1 patient evaluated after 1980 had a total gastrectomy, and this was done in 1977. The location of the primary tumor in general had a minimal effect on the clinical presentation, causing no effect on the age at presentation, delay in diagnosis, frequency of nephrolithiasis, or severity of disease (strictures, perforations, peptic ulcers, pyloric scarring). Disease extent had a minimal effect on symptoms, with only bleeding being more frequent in patients with localized disease. Patients with advanced disease presented at a later age and with a shorter disease history (p = 0.001), were less likely to have MEN-1 (p = 0.0087), and tended to have diarrhea more frequently (p = 0.079). A correct diagnosis of ZES was made by the referring physician initially in only 3% of the patients. The most common misdiagnosis made were idiopathic peptic ulcer disease (71%), idiopathic gastroesophageal reflux disease (GERD) (7%), and chronic idiopathic diarrhea (7%). Other less common misdiagnosis were Crohn disease (2%) and various diarrhea diseases (celiac sprue [3%], irritable bowel syndrome [3%], infectious diarrhea [2%], and lactose intolerance [1%]). Other medical disorders were present in 55% of all patients; patients with sporadic disease had fewer other medical disorders than patients with MEN-1 (45% versus 90%, p < 0.00001). Hyperparathyroidism and a previous history of kidney stones were significantly more frequent in patients with MEN-1 than in those with sporadic ZES. Pulmonary disorders and other malignancies were also more common in patients with MEN-1. These results demonstrate that abdominal pain, diarrhea, and heartburn are the most common presenting symptoms in ZES and that heartburn and diarrhea are more common than previously reported. The presence of weight loss especially with abdominal pain, diarrhea, or heartburn is an important clue suggesting the presence of gastrinoma. The presence of prominent gastric body folds, a clinical sign that has not been appreciated, is another important clue to the diagnosis of ZES. Patients with MEN-1 presented at an earlier age; however, in general, the initial symptoms were similar to patients without MEN-1. Gastrinoma extent and location have minimal effects on the clinical presentation. Overall, neither the introduction of successful antisecretory therapy nor widespread publication about ZES, attempting to increase awareness, has shortened the delay in diagnosis or reduced the incidence of patients presenting with peptic complications. The introduction of successful antisecretory therapy, however, has dramatically decreased the rate of surgery in controlling the acid secretion and likely led to patients presenting with less severe symptoms and fewer complications. (ABSTRACT TRUNCATED)

Intravenous pantoprazole rapidly controls gastric acid hypersecretion in patients with Zollinger-Ellison syndrome

BACKGROUND & AIMS

Parenteral control of gastric acid hypersecretion in conditions such as Zollinger-Ellison syndrome (ZES) or idiopathic gastric acid hypersecretion is necessary perioperatively or when oral medications cannot be taken for other reasons (e.g., during chemotherapy, acute upper gastrointestinal bleeding, or in intensive care unit settings).

METHODS

We evaluated the efficacy and safety of 15-minute infusions of the proton pump inhibitor pantoprazole (80-120 mg every 8-12 hours) in controlling acid output for up to 7 days. Effective control was defined as acid output >10 milliequivalents per hour (mEq/h) (<5 mEq/h in patients with prior acid-reducing surgery) for 24 hours.

RESULTS

The 21 patients enrolled had a mean age of 51.9 years (range, 29-75) and a mean disease duration of 8.1 years (range, <0.5-21); 13 were male, 7 had multiple endocrine neoplasia syndrome type I, 4 had undergone acid-reducing surgery, 2 had received chemotherapy, and 13 had undergone gastrinoma resections without cure. Basal acid output (mean +/- SD) was 40.2 +/- 27.9 mEq/h (range, 11.2-117.9). In all patients, acid output was controlled within the first hour (mean onset of effective control, 41 minutes) after an initial 80-mg intravenous pantoprazole dose. Pantoprazole, 80 mg every 12 hours, was effective in 17 of 21 patients (81%) for up to 7 days. Four patients required upward dose titration, 2 required 120 mg pantoprazole every 12 hours, and 2 required 80 mg every 8 hours. At study end, acid output remained controlled for 6 hours beyond the next expected dose in 71% of patients (n = 15); mean acid output increased to 4.0 mEq/h (range, 0-9.7). No serious or unexpected adverse events were observed.

CONCLUSIONS

Intravenous pantoprazole, 160-240 mg/day administered in divided doses by 15-minute infusion, rapidly and effectively controlled acid output within 1 hour and maintained control for up to 7 days in all ZES patients.

A retrospective study of the usefulness of acid secretory testing

BACKGROUND

Gastric analysis is useful for diagnosing and monitoring the control of hypersecretory conditions and to distinguish appropriate from inappropriate causes of hypergastrinaemia. Pentagastrin, used to measure maximal acid output (MAO), is no longer available in the USA.

METHODS

We examined the University of Pennsylvania Health System gastric analysis database, which includes demographic data, study indications, gastric analysis, and serum gastrin and secretin testing results according to referral indications, paying specific attention to discordant basal acid output (BAO) and MAO measurements.

RESULTS

One hundred and twenty-four gastric analyses were performed in 103 patients (42 males, mean age 47.5 years, 14 with prior acid-decreasing surgery). Recurrent ulceration or pain unresponsive to antisecretory therapy was the indication in 42 patients. Twelve were hypersecretory, including three each with isolated elevations of BAO or MAO. Hypergastrinaemia was the indication in 35 patients. Five were hypersecretory (four with Zollinger-Ellison syndrome), three had isolated MAO elevations and 16 were hypo- or achlorhydric, indicating appropriate hypergastrinaemia. Of the seven patients with isolated MAO elevations, two had clear benefit from the stimulated portion of the study (four additional patients had equivocal benefit).

CONCLUSIONS

Gastrin concentrations cannot be interpreted without knowledge of acid secretory capacity. MAO measurement has a small but significant benefit over measuring BAO alone.

Management of the Zollinger-Ellison syndrome in patients with multiple endocrine neoplasia type 1

Zollinger-Ellison syndrome (ZES) is the most common symptomatic pancreatic endocrine tumour in patients with MEN-1. Besides the treatment of the usual endocrinopathies seen in patients with MEN-1, the treatment of the ZES requires attention be paid to controlling the gastric acid hypersecretion, to dealing with the gastrinomas per se which are malignant in 18-60% of cases, and to the diagnosis and treatment of gastric carcinoid tumours, that are increasingly seen in these patients. In this article the current management of each of the areas is reviewed and what is known or uncertain discussed, based on our studies at the NIH and data from others. Data from 231 patients including 45 with MEN-1 and 186 without MEN-1 is contrasted in this report. Gastric acid hypersecretion has been controlled in all patients medically with MEN-1 and ZES at the NIH for up to 22 years. The current drugs of choice are H+-K+ ATPase inhibitors and twice a day dosing is recommended. Periods of parenteral drug therapy (surgery, etc.) and pregnancy require important modifications. The appropriate surgical therapy of the gastrinoma is controversial. Eighty per cent of patients have a duodenal gastrinoma and 20-30% have a pancreatic tumour. Recent studies suggest gastrinoma enucleation combined with duodenotomy rarely results in cure. Aggressive surgery (Whipple resection) can result in cure of gastrinoma but effect on survival is unclear. There are important differences in gastrinoma location, extent, and percentage with aggressive disease in patients with or without MEN-1, which are discussed. Confusion has occurred because of lack of information on the natural history of the gastrinoma compared to the other pancreatic endocrine tumours that occur in MEN-1 and survival data from patients with and without MEN-1 is contrasted. The occurrence of gastric carcinoids in patients with and without MEN-1 with ZES is contrasted and the areas of certainty and disagreement reviewed.

Gastrointestinal endocrine tumours. Gastrinoma

Since the description of the Zollinger-Ellison syndrome in two patients in 1955, there have been significant advances in the understanding of its pathogenesis, natural history, relationship to multiple endocrine neoplasia type 1, diagnosis, methods of tumour localization and management. The main focus in treatment is now shifting from management of the gastric acid hypersecretory state which can now be controlled medically in almost every patient, to the management of the gastrinoma. Recent studies are beginning to provide insights into the natural history of gastrinomas, factors that are associated with invasiveness in some gastrinomas, defining the role of surgery in managing patients with different disease extents, or with MEN 1 and being able to provide insights into molecular abnormalities that may be important in their pathogenesis. In this article each of these advances is briefly reviewed with emphasis primarily on recent advances.

A prospective study of the effectiveness of low dose omeprazole as initial therapy in Zollinger-Ellison syndrome

BACKGROUND

The proton pump inhibitors (omeprazole and lansoprazole) are the drugs of choice for the medical management of gastric acid hypersecretion in Zollinger-Ellison syndrome (ZES). These drugs are safe for long-term therapy but are acid-labile and high doses are expensive. The recommended starting dose of omeprazole is 60 mg/day. However, it has been shown in recent studies that the maintenance dose of omeprazole could be safely reduced to 20 mg once or twice a day in more than two-thirds of patients with ZES. The purpose of this study is to determine if an initial starting dose of omeprazole 20 mg/day is safe and effective in patients with ZES.

METHODS

Forty-nine consecutive patients with ZES being treated with ranitidine for at least 2 weeks were admitted to the NIH. Omeprazole 20 mg was started on day 1 of the admission and ranitidine discontinued 4 h after the first dose. Gastric acid output was measured for 1 h prior to the next omeprazole dose on day 2, then on day 3 if the value was > 10 mmol/h on the previous day. If acid-peptic symptoms developed or the gastric acid output remained > 10 mmol/h on day 3, the patient was considered to have failed omeprazole 20 mg/day initial therapy and the dose titrated daily to achieve adequate control of acid-peptic symptoms and gastric secretion.

RESULTS

In 33 of the 49 patients (68%) omeprazole 20 mg/day was successful as initial therapy. Sixteen patients (32%) failed this initial omeprazole dose (eight patients owing to persistent peptic symptoms and eight patients owing to inadequate acid control). The final daily omeprazole dose required in these patients was 40 mg in eight patients (16%), 60 mg in one patient (2%) and 80 mg in seven patients (14%). Basal acid output (BAO) was the only clinical or laboratory feature that was significantly different between the two groups in which low dose initial omeprazole therapy was or was not successful; all patients with basal acid output < 20 mmol/h had a successful outcome.

CONCLUSIONS

Because of the need to rapidly control gastric acid hypersecretion owing to the high risk of complications from peptic ulcer disease, patients with ZES should continue to be started on omeprazole 60 mg/day and the dose adjusted by acute titration methods as is currently recommended. After a maintenance dose is established, attempts should be undertaken to reduce the dose to 20 mg/ day once or twice a day. Only the minority of patients with ZES in whom basal acid output is known to be < 20 mmol/h (20% of patients) should be started on a low initial omeprazole dose.

Zollinger-Ellison syndrome: diagnosis and management

Patients with peptic ulcer disease who do not have Helicobacter pylori infection or a history of NSAID use may have the syndrome. Acid secretion can be controlled medically, and tumor resection may be curative in selected patients.

Islet cell tumors of the pancreas

Pancreatic endocrine neoplasms are a heterogeneous group of tumors that produce active hormones and result in distinct clinical syndromes. For the most part, they are malignant and require sophisticated diagnostic and localization techniques in order to identify their presence. Delays in diagnosis are the rule rather than the exception. Improvements in the diagnosis of gastrinomas and insulinomas appear to result in an increase in resectability rates. The widespread availability of intraoperative ultrasonography, as well as improved knowledge of the location of these tumors, has also had an impact on improved cure rates. With heightened awareness of these syndromes, increasing numbers of patients can be identified and more effective treatments developed for the refractory and recurrent tumors.

Palliative operations for patients with unresectable endocrine neoplasia

No good randomized studies exist for many types of endocrine tumors to prove that surgery increases the survival of patients with these tumors. However, many case reports and our own experience suggest that it does. Therefore, surgery may be performed to potentially increase the survival of patients with metastatic and localized malignant endocrine tumors. Subsequently, these tumors may still recur locally or distantly. Therefore, surgery is usually a palliative procedure but is occasionally curative. Because endocrine tumors secrete hormonal substances resulting in particular syndromes, debulking surgery may be necessary to control hormonal syndromes. The location of a tumor may cause mass symptoms that can also be relieved by surgery. Thus, many patients with malignant endocrine neoplasia benefit from aggressive surgery. The surgeon must determine the resectability of the tumor as well as the operative morbidity and benefit to the patient before proceeding.

Advances in the management of patients with Zollinger-Ellison syndrome

A detailed description of recent advances in the management of patients with Zollinger-Ellison syndrome (ZES) is presented. The clinical presentation is reviewed, and newer diagnostic tools, both preoperative and intraoperative, are discussed. An update on surgical management is presented, including indications for abdominal exploration, intraoperative localization techniques, surgical excision, and the approach to patients with metastases or in whom no tumor is found. New strategies in the medical management of ZES also are reviewed. An update on patient survival is presented, and a review of the management of patients with multiple endocrine neoplasia type 1 and ZES is discussed.

Management of patients with Zollinger-Ellison syndrome

Zollinger-Ellison syndrome (ZES) is caused by gastrin-secreting tumors called gastrinomas. Patients commonly present with peptic ulcer disease and may have recurrent, multiple, and atypically located ulcers, e.g. in the jejunum. Alternatively, severe diarrhea may be the only presenting symptom. Patients with multiple endocrine neoplasia Type I (MEN-I) and ZES become symptomatic at an earlier age than patients with sporadic ZES. Patients with ZES have elevated fasting serum gastrin concentrations (> 100 pg/ml) and basal gastric acid hypersecretion (> 15 mEq/h). The secretin stimulation test is the best test to distinguish ZES from other conditions resulting in elevated gastrin levels. Gastric acid hypersecretion can be controlled in virtually all patients with H2-receptor antagonists or omeprazole, thus rendering total gastrectomy unnecessary. Computed tomography (CT), magnetic resonance imaging (MRI), radionuclide octreotide scanning, endoscopic ultrasound, and the selective arterial secretin injection test are the recommended imaging studies for localization of gastrinoma; nevertheless, 50% of gastrinomas are not evident on preoperative imaging studies. All patients with sporadic gastrinoma who do not have unresectable metastatic disease should undergo exploratory laparotomy for potential curative resection. With increased awareness of duodenal tumors, gastrinoma can be found in 80-90% of patients. Surgery may be the most effective treatment for metastatic gastrinoma if most or all of the tumor can be resected. The management of patients with MEN-I and ZES remains controversial. Some clinicians advocate an aggressive surgical approach, whereas others have had little success in rendering patients eugastrinemic.

Zollinger-Ellison syndrome can be the initial endocrine manifestation in patients with multiple endocrine neoplasia-type I

PURPOSE

To determine whether patients with multiple endocrine neoplasia type I (MEN-I) can initially present with Zollinger-Ellison syndrome (ZES), and to learn whether ZES exhibits any distinguishing features when it occurs as a first manifestation of MEN-I.

PATIENTS AND METHODS

Sixty patients who had been referred to a clinical research center with ZES were examined by cohort analysis. Twenty-eight had MEN-I and 32 did not. In patients with MEN-I, we analyzed the temporal relationships between the clinical and biochemical manifestations of ZES and the other endocrinopathies associated with the neoplasia. To determine whether patients who had ZES as a first manifestation of MEN-I (n = 8) had any distinguishing clinical characteristics, we compared them to a cohort of patients with established sporadic ZES (n = 32) matched for age, sex, and time since the onset of symptoms consistent with ZES.

RESULTS

Of the 28 patients with ZES and MEN-I, 11 initially presented with ZES and hyperparathyroidism (HP) and 1 with evidence only for pituitary disease. Eight patients (29%) presented with features of ZES and developed clinical and biochemical evidence for HP later, while the same number developed these 2 endocrinopathies in the opposite order. In whichever order ZES and HP occurred, the time from the diagnosis of the first to the diagnosis of the second was similar. It ranged from 9 to 177 months in patients who presented with ZES first, and from 12 to 264 months in patients who presented with HP first. At the time of initial diagnosis, the patients who presented with ZES as a manifestation of MEN-I had no distinguishing ZES-related symptoms, biochemical assays, or tumor imaging results compared to the cohort of patients who had the syndrome sporadically.

CONCLUSION

Patients with MEN-I can initially present with a symptomatic pancreatic endocrine tumor syndrome without any other disease manifestations. In patients with ZES and MEN-I, up to one third may present with ZES without evidence of any other endocrinopathy. Consequently, patients with presumed sporadic ZES should undergo continual biochemical screening for other endocrinopathies characteristic of MEN-I and, in the future, genetic studies for the MEN-I gene.

Use of omeprazole in Zollinger-Ellison syndrome: a prospective nine-year study of efficacy and safety

H+, K(+)-ATPase inhibitors such as omeprazole are the antisecretory agents of choice for the management of gastric acid hypersecretory states, including the Zollinger-Ellison syndrome. However, long-term follow-up data on the overall efficacy and safety of these agents in large numbers of patients are lacking. In the current study we examined the long-term efficacy and safety of omeprazole in 116 patients with Zollinger-Ellison syndrome treated with oral omeprazole at a single centre for up to 114 months (mean +/- S.E.M. = 38 +/- 3 months). The initial omeprazole maintenance dose was established according to the acute upward dose titration method in 89/116 patients (77%). Gastric acid output was effectively controlled using 60 mg of omeprazole once daily in 41/89 patients (46%) and 22/89 patients (25%) required twice daily omeprazole therapy. The mean ranitidine equivalent dose for patients who required 60 mg omeprazole once daily (2.5 +/- 0.2 g/day) was significantly lower than the mean ranitidine equivalent dose for patients who required more than 60 mg omeprazole once daily (4.3 +/- 0.3 g/day). Long-term omeprazole maintenance therapy was discontinued in 36/116 patients (31%) but in no cases was discontinuation due either to drug-induced side-effects or uncontrolled gastric acid output. Fasting serum gastrin levels were significantly elevated above pre-treatment levels at only one time point during follow-up and were likely due to tumour growth rather than a drug effect. The final long-term omeprazole maintenance doses were lower than the initial doses but correlated closely with the pre-omeprazole basal acid output (r = 0.41, P < 0.001) and ranitidine equivalent dose requirements (r = 0.49, P < 0.001). We conclude that omeprazole effectively and safely controls gastric acid hypersecretion in all patients with Zollinger-Ellison syndrome for up to nine years without evidence by tachyphylaxis.