Prospective comparative study of ability of MR imaging and other imaging modalities to localize tumors in patients with Zollinger-Ellison syndrome

Current Management of Neuroendocrine Tumour Liver Metastases

PURPOSE OF REVIEW

This article aims to illustrate the current state of investigations and management of liver metastases in patients with Neuroendocrine Neoplasms. Neuroendocrine tumours (NETs) are rising in incidence globally and have become the second most prevalent gastrointestinal malignancy in UK and USA. Frequently, patients have metastatic disease at time of presentation. The liver is the most common site of metastases for gastro-enteropancreatic NETs. Characterisation of liver metastases with imaging is important to ensure disease is not under-staged.

RECENT FINDINGS

Magnetic resonance imaging and positron emission tomography are now becoming standard of care for imaging liver metastases. There is an increasing armamentarium of therapies available for management of NETs and loco-regional therapy for liver metastases. The data supporting surgical and loco-regional therapy is reviewed with focus on role of liver transplantation. It is important to use appropriate imaging and classification of NET liver metastases. It is key that decisions regarding approach to treatment is undertaken in a multidisciplinary team and that individualised approaches are considered for management of patients with metastatic NETs.

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.

Primary retroperitoneal neuroendocrine tumor with nonspecific presentation: A case report

Primary retroperitoneal tumors are a rare entity of human neoplasms, with primary retroperitoneal neuroendocrine tumors being even more rare. They are usually metastatic and rarely seen as a primary tumor. We report a case of primary retroperitoneal neuroendocrine tumor in a 55-year-old lady, who presented with chronic abdominal pain. Computed tomography showed a retroperitoneal mass and biopsy confirmed the diagnosis of primary retroperitoneal neuroendocrine tumor. Primary retroperitoneal neuroendocrine tumors are rare tumors. Radiology plays a crucial part in the diagnosis of such tumors with the CT scan considers the best imaging modality for diagnosis. Surgical resection remains the definite treatment of retroperitoneal neuroendocrine tumors. Chemotherapy is used for unresectable differentiated tumors.

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

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

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.

Preoperative tumor studies using MRI or CT in patients with clinically suspected insulinoma

PURPOSE

Insulinomas are rare tumors that originate from the islet cells of the pancreas. The aims of this study were to localize insulinomas preoperatively using CT and/or MRI in correlation with postoperative pathological results.

PATIENTS AND METHODS

Between December 2001 and June 2010, 27 consecutive patients with clinically suspected insulinoma were surgically treated in our university hospital. Preoperative CT (14 of 27 patients) and MRI studies (14 of 27 patients, one patient had both MRI and CT), operation reports, intraoperative ultrasonography reports, and pathological diagnoses were analyzed retrospectively. For each lesion, images were analyzed based on the presence of enhancement or the characteristics of signal intensities. Pathologic correlation was available for all the lesions.

RESULTS

The female: male ratio was 2.9, with a mean age of 47.5 years (range 12-82) . Preoperative tumor localization was achieved by means of MRI and CT. A focal pancreatic lesion, which was hypointense on T(1)-weighted sequences, was detected on all the MR images (14 of 27 patients; 100%). These lesions were isointense (4 cases) to slightly hyperintense (10 of 14 cases) on T(2)-weighted sequences. In T(1)-weighted fat-suppressed contrast-enhanced sequences, there were two types of enhancement: homogeneously hyperintense lesions (in 10 of 14 cases) or peripherally hyper-, centrally isointense (in 4 of 14 cases). On all the CT images (14 of 27 patients), there was no detectable lesion on precontrast series; on arterial series in 13 of 14 patients (arterial series has not been done in one patient), lesions enhanced hypervascular in contrast to the rest of the pancreas with a mean enhancement of 147 HU (range 113-248) and 95 HU (range 65-141), respectively. On venous series in 13 of 14 patients (venous series has not been done in one patient), there was an enhanced lesion in contrast to the rest of the pancreas with a mean enhancement of 110 HU (range 91-151) and 86 HU (range 65-137), respectively. Intraoperative ultrasonography was performed in 11 of 27 patients to localize the tumor, which correlated with the results of the mentioned preoperative studies. Tumor size ranged from 9 × 11 to 31 × 37 mm. Enucleation was carried out in 14 patients, Whipple in 5, segmental resection in 3 and left distal pancreatectomy in 5 patients. The mortality rate was 0. Pathological findings were insulinoma or neuroendocrine tumors in 26 of 27 cases. One patient had a pathological finding of chronic pancreatic disease with intraepithelial neoplasia (grade 1A).

CONCLUSION

We conclude that the preoperative localization of insulinoma in clinically suspected patients can be made on the basis of MRI and/or CT studies. A hallmark lesion is hypointense in T(1)-weighted sequences, homogeneously or peripherally hyperintense in T(1)-weighted fat-suppressed contrast-enhanced sequence using MRI (100% of cases) or/and a hypervascular enhanced lesion on arterial (100% of CT studies) and on venous series using CT (66.7% of CT studies).

The role of interventional venous sampling in localising neuroendocrine tumours

PURPOSE OF REVIEW

This review focuses on the role of interventional venous sampling in the diagnosis and localization of neuroendocrine tumours (NETs), and its role in relation to conventional and novel imaging techniques.

RECENT FINDINGS

Imaging of NETs has evolved together with advances in imaging technology. Imaging localization plays an important role in the subsequent management of these tumours. This article provides an overview of the application of venous sampling in the localization of NETs, presented with current evidence to support its continued role in the diagnostic work-up of pituitary, parathyroid, pancreatic, adrenal and ovarian endocrine disease.

SUMMARY

Interventional venous sampling continues to be a highly sensitive modality in the localization of NETs. Although significant advances in noninvasive anatomic and functional imaging modalities have reduced the reliance of this well established technique, the latest literature continues to support its important role in the diagnostic armament of these unique and rare tumours.

Imaging of gastroenteropancreatic neuroendocrine tumors

Imaging of gastroenteropancreatic neuroendocrine tumors can be broadly divided into anatomic and functional techniques. Anatomic imaging determines the local extent of the primary lesion, providing crucial information required for surgical planning. Functional imaging, not only determines the extent of metastatic disease spread, but also provides important information with regard to the biologic behavior of the tumor, allowing clinicians to decide on the most appropriate forms of treatment. We review the current literature on this subject, with emphasis on the strengths of each imaging modality.

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.

Localisation and staging of gastrin producing tumours using cross-sectional imaging modalities

Cross sectional imaging in the assessment of gastrinomas has three major applications: Tumor localization (sporadic gastrinoma, MEN I) in patients undergoing primary or secondary surgery. Staging of metastasized tumors, especially assessment of lymph nodes and liver metastases, possibly including a risk analysis prior to liver resection. Post-surgery follow-up and monitoring of bio- or chemotherapy. Detection of primary tumors is strongly correlated with their size. However, the sensitivity of surgical assessment of the mostly small tumors by experienced surgeons is much higher than that of any imaging modality. Of all imaging modalities, endoultrasonography (EUS) followed by Somatostatin receptor scintigraphy (SRS) is the most sensitive modality for the assessment of pancreatic tumors in asymptomatic patients suffering from a MEN-I syndrome. Scintigraphy has the highest sensitivity in tumors of symptomatic patients and in the assessment of metastases. CT and MRI are only second line diagnostic modalities. Their sensitivity is largely dependent on the selection of patients. As a potential application, 3D reconstruction of nearly isotropic CT data sets for the risk assessment prior to liver resection is currently developing. Due to the absent radiation exposure, MRI is increasingly utilized to monitor the response of metastases under systemic therapy, e.g. in clinical trials.

Cyto-reduction of neuroendocrine tumours using Sandostatin LAR in combination with Infergen: results of a case series

Historically, limited trials evaluating biotherapy in treating metastatic neuroendocrine tumours have yielded mixed results. In this study, the efficacy of a novel combination therapy featuring longacting Sandostatin LAR plus alpha-interferon was evaluated. In a prospective case series, 12 patients with unresectable metastatic neuroendocrine tumours refractory to treatment initiated therapy with Infergen and Sandostatin LAR. Radiological response was followed serially at 3-month intervals. A biochemical response was considered significant if marker levels decreased by > or = 50% compared with baseline. Inhibition of tumour growth lasting for greater than 3 months (mean response 22.6+/-17.7 months) was seen in eight patients. Complete tumour regression was observed in one patient, lasting for 40 months; three patients exhibited partial tumour regression (mean response 29.3+/-24.0 months), and four patients maintained a stable tumour response (mean response 13.3+/-9.2 months). Four patients showed no response to therapy (mean response 5.0+/-6.0 months). All enrolled patients are alive currently. The biochemical response seen in seven patients did not correlate with the radiological response. These results suggest that the novel combination of longacting Sandostatin LAR with an alpha-interferon may be at least as effective as either combination therapy with short-acting octreotide or monotherapy with Sandostatin LAR.

Imaging of neuroendocrine tumours (CT/MR/US)

Neuroendocrine tumours may be broadly divided into pancreatic endocrine tumours (PETs) and carcinoid neuroendocrine tumours (NETs). In both cases, patients may present with a clinical syndrome related to hormone secretion by the tumour. In these cases, cross-sectional imaging plays an important role in the localization of the primary tumour, the detection of metastases, and the assessment of response to treatment. Computed tomography (CT) is established as the primary modality, although following technological advances detection rates on magnetic resonance imaging (MRI) are now challenging those of CT. Endoscopic ultrasound has an important role in the preoperative assessment of the pancreas where a small functioning tumour or the possibility of multiple tumours is suspected. The sensitivity for the detection of small functioning tumours depends upon optimal technique, whichever modality is used. Non-functioning tumours frequently present late with mass effect, as there is no accompanying clinical syndrome. Carcinoid neuroendocrine tumours are most frequently localized on CT. MRI is usually used as a problem-solving tool. As technology evolves, detection rates may continue to improve, and the highest sensitivities may be achieved by a combination of different modalities.

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.

CT/MRI of neuroendocrine tumours

Neuroendocrine tumours (NETs) are often thought to be rare and rather recherché cancers which are of little concern to the general physician, surgeon or radiologist because of their rarity and esoteric nature. In fact, while relatively uncommon, the total group of gastro-entero-pancreatic (GEP) tumours incorporates the spectrum of all types of carcinoids, including bronchial carcinoids, and the whole gamut of islet-cell tumours. Some of these may present as functioning tumours, with a plethora of hormonal secretions and concomitant clinical syndromes, and GEPs in general have an incidence around 30 per million population per year. This means that in the whole European Union, for example, there will be in the region of 12,000 new patients every year presenting with one or another manifestation of these tumours. Furthermore, the comparatively long survival of many of these patients, compared to more common adenocarcinomas or epithelial tumours, implies that the point prevalence is also not inconsiderable. However, it is undoubtedly true that these tumours can be difficult to identify, especially in their early stages, and it is then that radiological investigation becomes of paramount importance. Having taken into account all these considerations, most investigators would initiate investigation of a suspected or biochemically proven islet-cell tumour with cross-sectional imaging-either CT or MRI. This will clearly identify the larger lesions, allow assessment of the entire abdomen, and provide valuable information on the presence of hepatic metastates.

Pancreatic tumors in children: radiologic-pathologic correlation

Pancreatic neoplasms are rare in children and have a different histologic spectrum and prognosis than those in adults. In general, these tumors are well demarcated with expansile rather than infiltrating growth patterns. They may be quite large at diagnosis, and central cystic necrosis is common. They infrequently cause biliary duct obstruction. The imaging appearance of each neoplasm reflects its pathologic features. Pancreatoblastoma is the most common pancreatic neoplasm in young children. At imaging, pancreatoblastomas are heterogeneous and often multilocular with hyperechoic and enhancing septa. Solid-pseudopapillary tumor occurs in adolescent girls. It is heterogeneous in internal architecture, with a mixture of solid and cystic hemorrhagic and necrotic elements. This tumor is distinguished by its fibrous capsule and hemorrhagic nature, which are best shown at magnetic resonance imaging as a dark rim on T1- or T2-weighted images and hyper-intense foci on T1-weighted images, respectively. Islet cell tumors in children are insulinomas or gastrinomas. These tumors manifest early due to hormonal syndromes and are distinguished by their small size, homogeneous appearance, and intense enhancement with intravenous contrast material. All pancreatic neoplasms in children are capable of producing metastases, usually to the liver and lymph nodes; however, on the whole, these tumors have a better clinical outcome than most pancreatic tumors in adults. Knowledge of the differential diagnosis of pancreatic masses in children and their relatively good prognosis may promote correct preoperative diagnosis and appropriate treatment.

Resolved and unresolved controversies in the surgical management of patients with Zollinger-Ellison syndrome

OBJECTIVE

Highlight unresolved controversies in the management of Zollinger-Ellison syndrome (ZES).

SUMMARY BACKGROUND DATA

Recent studies have resolved some of the previous controversies including the surgical cure rate in patients with and without Multiple Endocrine Neoplasia-type1 (MEN1), the biological behavior of duodenal and pancreatic gastrinomas, role of imaging studies to localize tumor, and gastrectomy to manage acid output.

METHODS

Review of the literature based on computer searches in Index Medicus, Pubmed and Ovid.

RESULTS

Current controversies as identified in the literature include the role of endoscopic ultrasound (EUS), surgery in ZES patients with MEN1, pancreaticoduodenectomy (Whipple procedure), lymph node primary gastrinoma, parietal cell vagotomy, reoperation and surgery for metastatic tumor, and the use of minimally invasive surgical techniques to localize and remove gastrinoma.

CONCLUSIONS

It is hoped that future studies will focus on these issues to improve the surgical management of ZES patients.

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.

Gastric secretion in Zollinger-Ellison syndrome. Correlation with clinical expression, tumor extent and role in diagnosis--a prospective NIH study of 235 patients and a review of 984 cases in the literature

We prospectively studied 235 patients with Zollinger-Ellison syndrome (ZES) (205 without and 30 with prior acid-reducing surgery) and compared the results with 984 patients from 182 reports in the literature. The aims of the study were to evaluate the sensitivity of proposed acid secretory criteria for the diagnosis of ZES, propose new criteria, evaluate the variability and methodology of gastric secretory testing, and correlate the symptoms and signs of ZES, tumor extent, and primary tumor size and location with the degree of gastric acid hypersecretion. Multiple endocrine neoplasia-type 1 (MEN1) occurred in 22% of patients. The mean basal acid output (BAO) in patients without and with prior acid-reducing surgery was 41.2 +/- 1.7 mEq/hr (range, 1.6-118.3 mEq/hr) and 27.6 +/- 3.5 mEq/hr (range 5.9-102.9 mEq/hr), respectively. In patients with MEN1, those with female gender, Hispanic, or Asian race had lower BAOs. Diarrhea, esophageal stricture, and pyloric scarring were associated with a higher BAO. Neither other symptoms nor the tumor extent, primary tumor location, or size correlated with the magnitude of acid hypersecretion. ZES diagnosis was delayed a mean of 5.5 +/- 0.4 yr. Patients who were misdiagnosed as having either Crohn or celiac disease had higher BAOs. The sensitivities from our study and the literature review of the proposed BAO criteria for the diagnosis of ZES in patients without previous gastric acid-reducing surgery were 91% and 90% for BAO > or = 15 mEq/hr, 86% and 82% for BAO > or = 18 mEq/hr, 69% and 67% for BAO > 25 mEq/hr, and < 60% for BAO > 31 mEq/hr, respectively. The specificities of all the proposed BAO criteria were high. Both the criterion of BAO > or = 15 mEq/hr and BAO > or = 18 mEq/hr had good specificities and equal sensitivity. With prior acid-reducing surgery, the sensitivities in our study and from the literature review were 100% and 81% for BAO > or = 5 mEq/hr, 73% and 45% for BAO > 14.4 mEq/hr, and 37% and 31% for BAO > 19.2 mEq/hr, respectively. The reported mean specificity for the criterion of BAO > or = 5 mEq/hr was 85%, while it was 100% for the other 2 criteria. The maximal acid output (MAO) criterion of > 70 mEq/hr had sensitivities in the present National Institutes of Health (NIH) study and the literature review of 39% and 31%, respectively, and the criterion of MAO > 100 mEq/hr had a sensitivity of < 15% in patients with no prior acid-reducing surgery. The proposed criterion of BAO/MAO ratio > 0.6 had a low sensitivity. The proposed criterion of the ratio of basal and maximal acid H+ concentration (BAC/MAC ratio) > or = 0.6 had an excellent sensitivity-- > or = 89% in patients with or without previous acid-reducing surgery. The reported specificity for both the BAO/MAO criterion and the BAC/MAC criterion were similar, but BAC/MAC had a better sensitivity. Combination criteria of BAO generally did not improve sensitivity. The criterion of pH < or = 1 was met by only 27% of patients, and pH < or = 0.96 by 21% of patients with previous acid-reducing surgery. For patients with MEN1 with no prior acid-reducing surgery, the sensitivities were lower compared with patients with the sporadic form of ZES. The mean gastric volume in patients without prior acid-reducing surgery was 314 +/- 10 mL/hr and 247 +/- 25 mL/hr in patients with prior acid-reducing surgery. A basal volume criteria of > 160 mL/hr in patients without prior acid-reducing surgery occurred in > 86% of patients, and > 140 mL/hr in 87% of patients with prior acid-reducing surgery; these, thus, are neglected findings that have good sensitivities. Our analysis shows criteria based on MAO, pH, and BAO/MAO ratio do not have high sensitivities and thus are not useful. In patients without prior acid-reducing surgery, the criteria of BAO > or = 15 mEq/hr, BAC/MAC ratio > or = 0.6, and basal gastric volume > 160 mL/hr are useful for the diagnosis of ZES and have good specificities. In patients with prior acid-reducing surgery, the criteria of BAO > or = 5 mEq/hr, BAC/MAC ratio > or = 0.6, and basal gastric volume > 140 mL/hr have high sensitivities. In patients with sporadic ZES without acid-reducing surgery, the criterion of BAO > or = 18 mEq/hr is recommended as it has a similar sensitivity but higher specificity than the criterion of BAO > or = 15 mEq/hr. Only 1 patient in either data set (NIH or the literature) with or without previous acid-reducing surgery had a basal gastric pH > 2, therefore this finding essentially excludes the diagnosis of ZES. Gastric secretory measurements for 30 minutes, but not 15 minutes, give results comparable to those for a full hour. On the basis of these results, a number of gastric secretory criteria are proposed, including some for the first time, and alterations in methodology are proposed that should prove useful in the diagnosis of ZES.

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)

Detection of small, functional islet cell tumors in the pancreas: selection of MR imaging sequences for optimal sensitivity

PURPOSE

To determine the sensitivity and specificity of magnetic resonance (MR) imaging for depicting pancreatic small, functional islet cell tumors and the minimum number of sequences for expedient diagnosis.

MATERIALS AND METHODS

Twenty-eight patients clinically suspected to have functional islet cell tumors underwent T1- and T2-weighted spin-echo (SE) MR imaging with and without fat suppression, T2-weighted fast SE imaging, and spoiled gradient-echo (GRE) imaging before and after injection of gadopentetate dimeglumine. Sensitivity, specificity, and the best and minimum number of sequences for definitive diagnosis were determined.

RESULTS

MR images depicted proved islet cell tumors in 17 of 20 patients (sensitivity, 85%). Images were true-negative in eight patients with negative follow-up examination results for more than 1 year. Specificity was 100%; positive predictive value, 100%; and negative predictive value, 73%. Among 20 patients with tumor, T1-weighted SE images with fat suppression and nonenhanced spoiled GRE images each showed lesions in 15 (75%); T2-weighted conventional SE with fat suppression, in 13 (65%); gadolinium-enhanced spoiled GRE, in 12 (60%); and T2-weighted fast SE, in seven of 10 patients (70%).

CONCLUSION

MR imaging accurately depicts small islet cell tumors. T2-weighted fast SE and spoiled GRE sequences usually suffice. Gadolinium-enhanced sequences are needed only if MR imaging results are equivocal or negative.

The effect of Zollinger-Ellison syndrome and neuropeptide-secreting tumors on the stomach

Zollinger-Ellison syndrome (ZES) is caused by a tumor that secretes gastrin and is the most common of the malignant islet cell tumors. ZES leads to hypergastrinemia, which, in turn, causes an overproduction of gastric acid and results in complications of peptic ulcer disease. Of all the islet cell tumors, gastrinoma tumors have undergone the most extensive study, providing a model of tumor management. Increased awareness and improved biochemical and radiologic techniques mean that these disorders are being recognized in more patients. Advances in the management of gastric acid secretion and new localization methods have significantly reduced the morbidity and mortality associated with ZES. The use of intravenous proton pump inhibitors such as pantoprazole will make surgical and perioperative management more favorable for patients. Radiologic and nuclear medicine studies permit the detection of the majority of islet cell tumors and improve the ability for surgical resection. With the recent cloning of the gene for multiple endocrine neoplasia type I (MEN-I) and the recognition of tumor markers associated with the development of islet cell tumors, early detection of these tumors may someday be possible.

Endosonography in decision making and management of gastrointestinal endocrine tumors

OBJECTIVE

gastroenteropancreatic (GEP) neuroendocrine tumors, suspected on clinical basis, are often difficult to localize. We report our experience with endoscopic ultrasonography (EUS) in the preoperative localization of pancreatic endocrine tumors (PETs), compared to other imaging modalities, and in staging and following up carcinoid tumors (CTs) of the gastrointestinal (GI) wall.

METHODS

50 patients (20 males; mean age 54 years), 39 with suspected PETs and 11 with GI CTs underwent EUS (Olympus GF-UM2 or GF-UM3). EUS data could be compared with resected specimens in 25 out of the 39 PETs and five out of the 11 CTs.

RESULTS

in the PETs group 42 tumors (35<20 mm) were removed: 23 in the pancreas, eight in the duodenum, and 11 in the lymph nodes. EUS correctly localized 20 out of the 23 (87%) pancreatic tumors, included 11 out of the 12 (91.6%) insulinomas, three out of the eight (37.5%) duodenal gastrinomas, and ten out of the 11 (90.9%) metastatic lymph nodes. Furthermore EUS accurately evaluated the depth of parietal invasion of CTs in three out of four patients (75%) (two after and one prior to endoscopic resection). In three patients EUS was confirmed as normal on resected specimens (two pancreas and one stomach). In the PETs group, a correct localization was obtained by ultrasonography (US) only in 17.4% of cases, by computed tomography (CT) in 30.4%, by magnetic resonance imaging (MRI) in 25%, by angiography in 26.6%, and by somatostatin receptor scintigraphy in 15.4%.

CONCLUSION

EUS must be considered the first-intention method in localizing PETs and is helpful in decision making and management of GEP endocrine tumors.

Prospective study of the clinical course, prognostic factors, causes of death, and survival in patients with long-standing Zollinger-Ellison syndrome

PURPOSE

The long-term clinical course of unselected patients with gastrinomas as well as other functional pancreatic endocrine tumors (PETs) in whom the excess-hormone state is controlled is largely unknown. To address this issue, patients with gastrinomas were assessed.

PATIENTS AND METHODS

Two hundred twelve patients with Zollinger-Ellison syndrome (ZES) were prospectively studied. All had controlled acid hypersecretion and were assessed yearly, with a mean follow-up period of 13.8+/-0.6 years (range, 0.1 to 31 years). Annual assessments of possible factors that might affect prognosis or treatment approaches were performed, such as those for tumor size and location; the presence, location, and extent of metastases; and the occurrence of ectopic Cushing's syndrome or another PET syndrome. Deaths were categorized as ZES-related or non-ZES-related and classified into different causes.

RESULTS

Thirty-one percent of patients died, all of non-acid-related causes. One half died of a ZES-related cause; they differed from those who died of non-ZES deaths by having a large primary tumor, more frequently a pancreatic tumor; lymph node, liver, or bone metastases; ectopic Cushing's syndrome; or higher gastrin levels. The extent of liver metastases correlated with survival rate. The presence of liver metastases alone only moderately decreased survival time; however, the additional development of bone metastases or ectopic Cushing's syndrome markedly decreased survival rate.

CONCLUSIONS

In ZES, gastrinoma growth is now the main single determinant of long-term survival, with one half of patients dying a gastrinoma-related death and none an acid-related death. Large primary tumors that are pancreatic in location, the development of liver metastases, (especially if associated with bone metastases or Cushing's syndrome), and the extent of liver metastases are all important prognostic factors. The identification of these factors allows the recognition of subgroups that can be used to tailor antitumor treatment approaches.

Cost effectiveness of EUS for preoperative localization of pancreatic endocrine tumors

BACKGROUND

Endoscopic ultrasonography (EUS) is highly accurate in the localization of small pancreatic tumors. We determined the cost effectiveness of EUS used early in the preoperative evaluation of pancreatic endocrine tumors.

METHODS

In a study with a case-control design, 36 patients (19 men, 17 women) who underwent preoperative EUS were matched retrospectively with 36 patients who underwent surgical exploration immediately before the introduction of EUS. The number, cost, and effectiveness of preoperative localization studies, days of hospitalization, and surgical and anesthesia times were assessed.

RESULTS

The EUS group had reduced charges for preoperative localization studies: $2620 versus $4846 per patient (p < 0.05), largely because of reductions in the number of diagnostic angiograms and venous sampling procedures performed. Surgical and total anesthesia times were decreased, as were the number of preoperative admissions for angiographic procedures. The cost-effectiveness ratio for the EUS group was $3144 per tumor localized compared with $5628 per tumor localized for the group treated before EUS became available (p < 0.05).

CONCLUSION

EUS is highly accurate in the localization of pancreatic neuroendocrine tumors and is cost effective when used early in the preoperative localization strategy. EUS decreased the need for additional invasive tests and avoided unnecessary morbidity and resource consumption. EUS should play a primary role in preoperative localization of pancreatic neuroendocrine tumors.

Prospective study of somatostatin receptor scintigraphy and its effect on operative outcome in patients with Zollinger-Ellison syndrome

OBJECTIVE

To determine the relative abilities of somatostatin receptor scintigraphy (SRS) and conventional imaging studies (computed tomography, magnetic resonance imaging, ultrasound, angiography) to localize gastrinomas before surgery in patients with Zollinger-Ellison syndrome (ZES) subsequently found at surgery, and to determine the effect of SRS on the disease-free rate.

SUMMARY BACKGROUND DATA

Recent studies demonstrate that SRS is the most sensitive imaging modality for localizing neuroendocrine tumors such as gastrinomas. Because of conflicting results in small series, it is unclear in ZES whether SRS will alter the disease-free rate, which gastrinomas are not detected, what factors contribute to failure to detect a gastrinoma, or whether the SRS result should be used to determine operability in patients without hepatic metastases, as recently recommended by some investigators.

METHODS

Thirty-five consecutive patients with ZES undergoing 37 exploratory laparotomies for possible cure were prospectively studied. All had SRS and conventional imaging studies before surgery. Imaging results were determined by an independent investigator depending on surgical findings. All patients underwent an identical surgical protocol (palpation after an extensive Kocher maneuver, ultrasound during surgery, duodenal transillumination, and 3 cm duodenotomy) and postoperative assessment of disease status (fasting gastrin, secretin test imaging within 2 weeks, at 3 to 6 months, and yearly), as used in pre-SRS studies previously.

RESULTS

Gastrinomas were detected in all patients at each surgery. Seventy-four gastrinomas were found: 22 duodenal, 8 pancreatic, 3 primaries in other sites, and 41 lymph node metastases. The relative detection order on a per-patient or per-lesion basis was SRS > angiography, magnetic resonance imaging, computed tomography > ultrasound. On a per-lesion basis, SRS had greater sensitivity than all conventional studies combined. SRS missed one third of all lesions found at surgery. SRS detected 30% of gastrinomas < or =1.1 cm, 64% of those 1.1 to 2 cm, and 96% of those >2 cm and missed primarily small duodenal tumors. Tumor size correlated closely with SRS rate of detection. SRS did not increase the disease-free rate immediately after surgery or at 2 years mean follow-up.

CONCLUSIONS

SRS is the most sensitive preoperative imaging study for extrahepatic gastrinomas in patients with ZES and should replace conventional imaging studies as the preoperative study of choice. Negative results of SRS for localizing extrahepatic gastrinomas should not be used to decide operability, because a surgical procedure will detect 33% more gastrinomas than SRS. SRS does not increase the disease-free rate. In the future, more sensitive methods to detect small gastrinomas, especially in the duodenum and in periduodenal lymph nodes, or more extensive surgery will be needed to improve the postoperative disease-free rate in ZES.

Gastrinoma: State of the Art

BACKGROUND: The Zollinger-Ellison syndrome, implicating a gastrinoma, was first recognized as a disease entity in 1955. At that time, total gastrectomy was the most common treatment approach. Advances in several aspects of the disease have occurred since that time. METHODS: The authors reviewed the changes that have developed since 1955 in the diagnosis, imaging studies, operative and nonoperative management, and follow-up of patients with this disease. RESULTS: The presence of a gastrinoma can be confirmed by a secretin stimulation test. A variable number of patients have hyperparathyroidism as part of the multiple endocrine neoplasm syndrome type 1 (MEN 1). Localization of the primary gastrinoma has been assisted by selective angiography, endoscopic ultrasonography, and the octreotide scan. H2-blockers or omeprazole, sometimes at high doses, usually controls acid secretion. Surgical removal of the primary gastrinoma is performed when feasible, and parathyroidectomy is indicated in those patients with hyperparathyroidism in the MEN 1 syndrome. Follow-up is facilitated by measurement of fasting serum gastrin levels. CONCLUSIONS: Several innovations have improved our capability to diagnose and effectively manage patients with gastrinoma.

Definition of the role of somatostatin receptor scintigraphy in gastrointestinal neuroendocrine tumor localization

There are six major steps in the management of patients with neuroendocrine tumors (NETs) (carcinoids and pancreatic endocrine tumors). One of the steps that is increasing in its importance is the need to assess primary tumor location and tumor extent in these patients. Without such information, it is not possible to adequately manage these patients. Conventional imaging studies (CT scan, MRI, ultrasound, angiography), functional localization studies measuring hormonal gradients, endoscopic ultrasound, and most recently, somatostatin receptor scintigraphy (SRS) with [125I-DTPA-DPhe1]-octreotide have all been advocated to localize NETs in different studies. Whereas it is now established that for all NETs, except insulinomas, SRS has the greatest sensitivity, it remains unclear whether this increased sensitivity translates into increased clinical usefulness. It, therefore, remains unclear based on fiscal and clinical considerations what should be the recommended algorithm for the use of the different localization methods. To address this issue, we have recently performed two prospective studies on patients with gastrinomas. In this paper, the methods and results of each are summarized and based on these results, an algorithm for localization studies in NETs is proposed. One study assessed the role of SRS in management in 122 patients and shows that the use of SRS changed management in 47 percent of patients according to six different criteria when the patients were stratified according to their principal management problem. Determining whether liver metastases were present is one of the major goals of tumor localization studies and is frequently a source of confusion because of the difficulty in distinguishing small NETs liver metastases from hemangiomas. In the second study, the ability of SRS and other tumor localization methods to distinguish these two possibilities was assessed in 15 patients with small hemangiomas and 15 patients with small hepatic metastases (mean size 1.3 cm). SRS correctly identified 93 percent of the patients with liver metastases and was not positive in any patient with a hemangioma, suggesting it was not a liver metastases. SRS had greater negative and positive predictive value than conventional studies. Based on these two studies, and SRS's greater sensitivity and fiscal considerations, it is proposed that SRS should be the initial tumor imaging study in all NETs except insulinomas, and algorithms for the use of other localization studies in both NETs and insulinomas are proposed.

Comparative analysis of diagnostic techniques for localization of gastrointestinal neuroendocrine tumors

In vitro studies have shown that gastroenteropancreatic tumors, with the exception of insulinomas, have a high density of somatostatin receptors and can be imaged in vivo using somatostatin receptor scintigraphy (SRS) with either [123I-Tyr3]octreotide or [111In DTPA,DPhe1]octreotide. However, the sensitivity in relation to conventional imaging studies (ultrasound, CT, MRI, angiography) remains unclear. To address this question, we performed a prospective study of 80 patients with gastrinomas where SRS was compared with other conventional imaging techniques for detecting extrahepatic gastrinomas or liver metastases. Extrahepatic gastrinomas were identified by SRS in 58 percent of patients, whereas conventional imaging studies detected gastrinomas in 9 percent to 48 percent of patients. In detecting hepatic metastases in 24 patients with histologically-proven metastases, SRS was positive in 92 percent; ultrasound, CT or angiography in 42 percent to 62 percent; and MRI in 71 percent of patients. These results are compared with other studies in detecting gastrinomas as well as series including other PETs, excluding insulinomas, with insulinomas alone, and with carcinoid tumors. An analysis of the ability of SRS to identify gastrinomas found in different sites at surgery was performed. The role of endoscopic ultrasound (EUS) in detecting various PETs, in comparison to that of SRS, is yet to be established, particularly for extrapancreatic PETs. Therefore, the results of EUS in various studies containing patients with PETs are compared to those with SRS and conventional imaging studies. These data suggest that EUS is the first choice of localization methods for detecting insulinoma, which is an intrapancreatic tumor in almost all cases. In other PETs there still is not sufficient data to establish the relative roles of EUS and SRS.

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.

Differentiation between multiple liver hemangiomas and liver metastases of gastrinomas: value of enhanced MRI

PURPOSE

Hepatic metastases of neuroendocrine tumors are known to mimic hemangiomas on nonenhanced SE MR sequences. The usefulness of MR examination with gadolinium injection to identify lesions was prospectively evaluated.

METHOD

Nine patients with multiple liver metastases of gastrinomas were compared with six patients showing multiple liver hemangiomas. Patients underwent unenhanced T2-weighted SE, T1-weighted SE, and FLASH sequences, followed by enhanced sequential FLASH sequences and a 5 min delayed T1-weighted SE sequence.

RESULTS

On T2-weighted SE sequence, all hemangiomas displayed the same typical morphology as a sharply defined, homogeneous, high signal intensity lesion, but this pattern was also observed for some or all of the lesions in seven of nine patients with gastrinoma metastases. Dynamic FLASH sequences were accurate for lesions larger than 2 cm, hemangiomas displaying a nodular peripheral enhancement with centripetal filling in, and metastases displaying either an initial homogeneous or a regular peripheral enhancement. Precise assessment of lesions smaller than 2 cm remained equivocal. Delayed T1-weighted. SE sequence (performed at least 5 min after Gd-chelate injection) was the most accurate technique to identify metastases by showing hypo- or isointensity signal, whereas all hemangiomas were hyperintense.

CONCLUSION

Postcontrast delayed T1-weighted sequence is the primary technique to differentiate equivocal cases of hemangiomas from metastases of gastrinoma.

Indium-111-pentetreotide scanning versus conventional imaging techniques for the localization of gastrinoma

BACKGROUND

The present study evaluates 111In-pentetreotide scanning as a method for detection of gastrinomas. Operative findings serve as the benchmark for comparison of the efficacy of 111In-pentetreotide versus conventional imaging studies.

METHODS

Twelve patients (seven female and five male; age, 37 to 80 years) with histologic confirmation of gastrinoma underwent thin section dynamic computed tomography (CT) scanning and 111In-pentetreotide scanning. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 111In-pentetreotide and CT scanning are compared on the basis of tumor size and location.

RESULTS

Thirty discrete foci of intrahepatic and extrahepatic tumors were detected at operation. CT scanning detected three of nine pancreaticoduodenal lesions, whereas eight of these nine extrahepatic primary tumors were imaged by 111In-pentetreotide scanning. No false-positive 111In-pentetreotide scans were noted. The sensitivity of CT scanning for detection of metastatic disease was 56% versus 94% for the 111In-pentetreotide scan. Successful CT imaging was highly dependent on tumor size. No tumor smaller than 1 cm was imaged by CT, whereas four of seven lesions greater than 1 cm were imaged by 111In-pentetreotide scintigraphy. The smallest gastrinoma imaged by 111In-pentetreotide scanning was a 4 mm duodenal tumor.

CONCLUSIONS

111In-pentetreotide scanning was superior to CT scanning for localizing gastrinomas. Further studies are required to determine whether 111In-pentetreotide scans will complement or replace traditional imaging methods.

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: past, present and future controversies

It is fitting that the Zollinger-Ellison syndrome (ZES) be included in the Lester Dragstedt Symposium because Dr. Dragstedt had a long-time interest in this disease, having been one of the five discussants of the original article and subsequently reporting with Dr. Oberhelman on nine cases. The approach to therapy of ZES has been controversial from the beginning, and a number of controversies remain. In this article, four different controversies are analyzed from the prospective of the past (Zollinger-Dragstedt era, 1955-1980), present and what may happen in the future in light of recent results. Specifically analyzed are: 1) the role of gastric surgery in the management; 2) whether gastrinoma removal without aggressive resection in patients with ZES without MEN-I is the preferred surgical therapy; 3) whether patients with MEN-I should undergo routine surgical exploration; and 4) whether most gastrinomas will be localized preoperatively. An analysis of recent advances suggests there may be marked changes in the future from our current and our past approaches.

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.

An evaluation of human recombinant alpha interferon in patients with metastatic gastrinoma

BACKGROUND

Metastatic gastrinoma is becoming increasingly recognized in patients with Zollinger-Ellison Syndrome. The mean 5-year survival of these patients is < 20%. Chemotherapeutic regimens are of limited benefit. The aim of this study was to evaluate the use of interferon in these patients because a preliminary report suggested it might be effective.

METHODS

The efficacy and toxicity of interferon was assessed in 13 consecutive Zollinger-Ellison syndrome patients with liver metastases. Patients were treated with human recombinant alpha interferon (5 million IU, subcutaneously [SC]) daily and followed up at 3-month intervals with multiple imaging studies. At each follow-up, toxicity of therapy was assessed and fasting serum gastrin concentrations were obtained.

RESULTS

No patient showed a reduction in tumor size at any follow-up. One patient died after 2 months. At 6 months, six patients (46%) had stable tumor size in the liver, although new bone metastases developed in one patient. Three patients showed stable disease for up to 21 months. Changes in serum gastrin correlated with tumor response at 6 months. All patients developed some side effects of therapy. Thirty-one percent required dose reduction, and one patient (8%) had to have interferon therapy interrupted briefly.

CONCLUSIONS

These results fail to define a therapeutic role for interferon in the treatment of metastatic gastrinoma.