Prospective study of gastrinoma localization and resection in patients with Zollinger-Ellison syndrome

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.

Is gastrinoma a medical disease?

Zollinger-Ellison syndrome (ZES) is a rare disease. Its management concerns symptoms related to the gastric acid overproduction that characterizes the syndrome and to the gastrin-producing tumor(s) usually located in the duodenal wall and/or the endocrine pancreas. Acid hypersecretion is now controlled by the use of powerful antisecretory agents. Management of the malignant process(es) has become the primary goal of modern strategy: it aims first at curing the disease and second at prolonging patient survival by prevention of hepatic metastasis. In patients with the sporadic form of the disease and without liver metastases, it is currently possible to localize and to surgically remove the endocrine tumor(s). This progress has been made feasible by refinements in modern medical imaging. At present, however, disease cure, even in the most favorable conditions, is not be greater than 30 to 50 percent at five years. In patients with ZES integrated in the context of multiple endocrine neoplasia type I, disease cure rate is extremely low, although occasional patient survival can be as good or even better than in the sporadic group. Disseminated malignancy (liver and/or extra-abdominal lymph nodes or bone localization) remains the principal determinant of early death. Surgical treatment is usually precluded in such cases. Liver transplantation has not been successful in these patients.

The biological relevance of gastric neuroendocrine tumors

Gastric neuroendocrine tumors were originally thought to have a low incidence (three percent). Since endoscopic diagnostic procedures have become clinical routine, they are now found more frequently (relative incidence up to 41 percent). In recent years, classifications have been developed that attempt to consider the biological relevance of these tumors. Four types of gastric neuroendocrine tumor may be distinguished: Type 1 gastric neuroendocrine tumor is most common. It is associated with chronic atrophic fundus gastritis, hypergastrinemia and often with pernicious anemia. Usually it is multicentric and smaller than one cm, does not produce any symptoms and has an excellent prognosis. Type 2 gastric neuroendocrine tumor is second in frequency. It has no association with other diseases, is solitary and has no predilection for a particular localization. It may be larger than 1 cm, produce a carcinoid syndrome or Zollinger-Ellison syndrome and have a metastasis rate of up to 30 percent. Type 3 gastric neuroendocrine tumor is rare and always associated with Zollinger-Ellison syndrome and multiple endocrine neoplasia type I. It occurs as multiple lesions in the gastric body fundus and has a lower metastatic rate than type 2 gastric neuroendocrine tumor. Type 4 gastric neuroendocrine tumor corresponds to a small-cell carcinoma.

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.

Metastatic endocrine tumors: is there a place for liver transplantation?

The authors describe their experience with liver transplantation (OLT) for metastatic endocrine tumors (MET) in order to determine reasonable indications for OLT in patients with this disease. Removal of the primary lesion and subsequent liver transplantation were performed in two separate procedures in all patients except one. Only those patients suffering from objective tumor progression and symptoms with no evidence of extrahepatic spread after complete work-up (including endoscopic ultrasonography (US) and 123I-labeled Tyr3-octreotide body scanning) underwent liver transplantation. Fifteen patients were referred for liver transplantation. Seven patients were excluded either because of stability of liver metastases (n = 3), extrahepatic spread, general contraindication (n = 2), or feasibility of aggressive surgical resection (n = 2). Liver transplantation was undertaken in eight patients with carcinoid tumor (n = 4), gastrinoma (n = 3) and glucagonoma (n = 1). Three patients did not survive the surgical procedure itself, whereas two additional patients died from chronic rejection or from recurrent disease. Three patients who received transplants for metastatic carcinoid tumor are alive without biochemical or imaging evidence of disease recurrence at 6, 15, and 52 months. The best indication for transplantation seems to be patients with metastases restricted to the liver and unresponsive to adjuvant therapy after aggressive surgical resection including excision of the primary lesion and reduction of hepatic metastases. In such highly-selected patients, liver transplantation remains a high-risk operation, but it can yield long-term survival.

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.

Helicobacter pylori infection. A reversible cause of hypergastrinemia and hyperchlorhydria which may mimic Zollinger-Ellison syndrome

The present report describes two patients with fasting hypergastrinemia, gastric acid hypersecretion, and Helicobacter pylori gastritis. Provocative testing for Zollinger-Ellison syndrome was negative and imaging studies did not demonstrate an intra-abdominal mass. Following eradication of the Helicobacter pylori infection, the fasting hypergastrinemia resolved in both patients and in one patient the gastric acid hypersecretion also resolved. The implications of this case on the differential diagnosis of Zollinger-Ellison syndrome are discussed.

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.

Endosonography of neuroendocrine tumors of the stomach, duodenum, and pancreas

Neuroendocrine tumors (NETs) of the foregut type are frequently smaller than 2 cm in diameter and mainly located in the pancreas or the gastric and duodenal wall. Conventional cross-sectional imaging techniques, such as transabdominal ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI) are limited by their inability to detect small tumors and especially those located within the gastrointestinal wall. Endoscopic ultrasonography (EUS) allows detailed visualization of the whole pancreas and almost all parts of the gastric and duodenal walls. Therefore, EUS is an important diagnostic tool for the preoperative localization of NETs of the foregut type. Several studies performed in a retrospective manner, as well as two studies performed in a prospective manner, indicate a clear superiority of EUS as compared to CT, US, MRI, and also angiography in detecting NETs of the foregut type. Somatostatin-receptor scintigraphy (SRS) also detects NETs of the foregut type in a very high percentage of cases, and the combination of EUS and SRS appears to increase the sensitivity even more. Thus EUS and also SRS should be employed early if NETs of the foregut type are suspected. Conventional imaging procedures such as US, CT, and MRI should be mainly used to exclude local and distant metastases.

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.

Localisation of neuroendocrine tumours of the upper gastrointestinal tract

In order to localise neuroendocrine tumours of the foregut type (that is, of the stomach, duodenum, and pancreas), 18 patients were studied prospectively by endoscopic ultrasonography, computed tomography, transabdominal ultrasonography, magnetic resonance imaging, and somatostatin receptor scintigraphy. These 18 patients had a total of 25 primary tumour lesions which were verified histologically in tissue obtained by surgery or by ultrasound or endoscopy guided biopsy. Tumours were found in the stomach (n = 1), duodenum (n = 6), pancreas (n = 17), and liver (n = 1). Endoscopic ultrasonography had the highest sensitivity for tumour detection, followed by somatostatin receptor scintigraphy, computed tomography, transabdominal ultrasonography, and magnetic resonance imaging (88%, 52%, 36%, 32%, and 24% respectively). Endoscopic ultrasonography was especially sensitive in tumours smaller than 2 cm in diameter (88% v somatostatin receptor scintigraphy 35%; computed tomography 12%; transabdominal ultrasonography 6%; and magnetic resonance imaging 0%). Of 17 tumours located in the pancreas, endoscopic ultrasonography showed a sensitivity of 94% (somatostatin receptor scintigraphy 47%; computed tomography 47%; transabdominal ultrasonography 41%; and magnetic resonance imaging 29%). Of eight extrapancreatic tumours, six were identified by endoscopic ultrasonography, five by somatostatin receptor scintigraphy, and only one by computed tomography, transabdominal ultrasonography, and magnetic resonance imaging. One neuroendocrine tumour that was not detected by endoscopic ultrasonography was correctly identified by somatostatin receptor scintigraphy. Endoscopic ultrasound allowed correct determination of the tumour size and tumour spread into parapancreatic structures, especially the large vessels (T stage), in all 14 patients operated upon. The lymph node stage (N stage) was correctly determined in 10 of these 14 patients. In summary, endoscopic ultrasonography and somatostatin receptor scintigraphy were the most sensitive imaging methods for the localisation of these tumours and should be used as early diagnostic procedures to accurately stage neuroendocrine tumours of the foregut type.

Parenteral control of gastric acid hypersecretion in patients with Zollinger-Ellison syndrome

Parenteral control of gastric acid hypersecretion in patients with Zollinger-Ellison syndrome is increasingly required; however, existing methods of determining the required dose are cumbersome and not applicable in all centers. A previous study suggested that the required parenteral dose of histamine H2-receptor antagonists correlated with the previous oral dose. In the present study, in 31 patients with Zollinger-Ellison syndrome we evaluated the hypothesis that an effective parenteral histamine H2-receptor antagonist dose could be predicted from the previous oral dose. Twenty-three patients were taking oral ranitidine (mean 1.3 g/day), six patients famotidine (152 mg/day), and two patients cimetidine (1.8 g/day). Each patient was treated with a continuous intravenous infusion of the equivalent dose of ranitidine (mean dose 1 mg/kg/hr with 35% requiring 0.5 mg/kg/hr, 49% 1 mg/kg/hr, 3% 1.5 mg/kg/hr, 10% 2 mg/kg/hr, and 3% 2.5 mg/kg/hr. This dose of ranitidine acutely controlled acid secretion (< 10 meq/hr) in all patients. To evaluate long-term efficacy and safety, 20 patients were maintained on this dose through the peri- and postoperative periods. Mean duration was 7.1 days with 25% treated 3-5 days, 40% 6-8 days, 30% 8-10 days, and 5% > 10 days. The predicted dose continued to control acid secretion in 95% of patients with one patient requiring one dose adjustment. No biochemical, clinical, or hematological toxicity was seen, although ranitidine was stopped in one patient because of skin rash. These results demonstrate that the parenteral dose of ranitidine required to control acid secretion in patients with Zollinger-Ellison syndrome can be predicted from the oral dose.(ABSTRACT TRUNCATED AT 250 WORDS)

Review article: the management of Zollinger-Ellison syndrome

Awareness of the sometimes subtle features of Zollinger-Ellison syndrome is important in order not to miss the diagnosis. Immediately after initial diagnostic tests, the patient should be given antisecretory medication, while tests for the type of Zollinger-Ellison syndrome and tumour extent can be delayed. Acid output should be decreased to < 10 mmol/h to control symptoms and prevent complications. Histamine H2-antagonists remain the best available intravenous therapy but omeprazole is the most effective long-term oral therapy and has proved to be safe in nearly 10 years of continuous use. The management of the gastrinoma has changed in recent years since the discovery that the majority of gastrinomas arise outside the pancreas. Exploratory surgery with tumour resection is the treatment of choice in sporadic Zollinger-Ellison syndrome but there are few indications for surgery in patients with Zollinger-Ellison syndrome and multiple endocrine neoplasia type-1. None of the available therapies for metastatic gastrinoma is very effective.

Assessment and prediction of long-term cure in patients with the Zollinger-Ellison syndrome: the best approach

OBJECTIVE

To identify the best method for determining freedom from disease after gastrinoma resection and for predicting long-term disease-free status in patients with the Zollinger-Ellison syndrome.

DESIGN

Prospective study in consecutive patients.

SETTING

Referral-based clinical research center.

PATIENTS

Eighty-one consecutive patients with the Zollinger-Ellison syndrome who underwent surgical exploration for gastrinoma resection.

INTERVENTION

Patients were evaluated after gastrinoma resection, before discharge, 3 to 6 months after surgery, and yearly thereafter. Evaluation included secretin provocative testing and fasting serum gastrin determinations. Follow-up examinations after the initial postoperative evaluations included a clinical assessment, acid secretion studies, a calcium provocative test, and various imaging studies.

MEASUREMENTS AND MAIN RESULTS

Most patients (96%) had gastrinomas. Freedom from disease was defined by improved symptoms, reduced acid output and antisecretory drug requirements, and a normal gastrin level, normal imaging studies, and negative gastrin provocative studies. Fifty-two percent of patients (n = 42) were disease-free immediately after surgery, 44% at 3 to 6 months, 42% at 1 year, and 35% by 5 years (mean follow-up, 39 months). The secretin provocative test was the first test to become positive in 45% of patients with a recurrence, the serum gastrin determination was the first test to become positive in 36%, and both tests became positive at the same time in 18%. No recurrence was first detected by imaging studies or by calcium provocative testing. Fasting serum gastrin levels and secretin provocative test results at different postoperative times can be used to predict the probability of a patient remaining disease free at 3 years. Patients with a normal gastrin level and a normal secretin provocative test immediately after surgery had a 3-year disease-free probability of 75%, and normal results on both tests at 6 months, 1 year, and 2 years yielded respective probabilities of 88%, 95%, and 100%.

CONCLUSIONS

Both the secretin provocative test and fasting serum gastrin determination are necessary for the early diagnosis of cases of recurrent disease after gastrinoma resection. The calcium provocative test and imaging studies do not detect any recurrences first. Fasting serum gastrin determinations and secretin provocative testing at different postoperative times can be used to predict the probability of a patient remaining disease free at 3 years.

A prospective study of intraoperative methods to diagnose and resect duodenal gastrinomas

OBJECTIVE

This study determined, prospectively, whether duodenotomy (DX) should be routinely performed in explorations for patients with Zollinger-Ellison syndrome (ZES).

SUMMARY BACKGROUND DATA

Duodenal gastrinomas are now being found with increasing frequency in patients with Zollinger-Ellison syndrome. The surgical approach used to detect these tumors is controversial. Some recommend intraoperative endoscopy with transillumination (IOE) at surgery, while others recommend routine DX.

METHODS

Beginning in 1989, the authors prospectively compared the ability of palpation, intraoperative ultrasound (IOUS), IOE, and DX (in that sequence) to detect gastrinomas in 35 consecutive patients with ZES. Each patient also underwent preoperative localization studies.

RESULTS

Thirty-three of 35 patients (94%) had tumor detected and excised; duodenal gastrinomas were excised in 27 patients (77%). The average size of the duodenal tumors was 0.8 cm, significantly smaller (p < 0.005) than the pancreatic and lymph node tumors in this series. Standard palpation after a Kocher maneuver identified 19 of the 31 duodenal tumors (61%) in the 27 patients. IOUS revealed only eight duodenal tumors (26%) and no new lesions. IOE identified 20 duodenal gastrinomas (64%) and 6 new lesions. DX identified 31 duodenal tumors (100%) and 5 additional tumors. The morbidity rate was 17%. One patient had a duodenal fistula after operation (2.8%) and subsequently recovered. No patient died.

CONCLUSIONS

These results demonstrate that the duodenum is the most common location for gastrinoma in patients with ZES (77%) and that DX to detect and remove duodenal gastrinomas should be routinely performed in all explorations for patients with ZES.

Use of selective arterial secretin injection test to guide surgery in patients with Zollinger-Ellison syndrome

It is often difficult to localize gastrinomas in patients with Zollinger-Ellison syndrome (ZES). We have developed a new useful method, the selective arterial secretin injection test (SASI test), for localizing gastrinomas in patients with ZES. The SASI test first determines the arteries feeding the gastrinomas and then locates the gastrinomas. In 12 patients with ZES, the SASI test clearly localized the gastrinomas, while results obtained with computed tomography or portal venous blood sampling had a positive predictability of less than 10%. Following localization with the SASI test, curative resection of gastrinomas was successfully performed on 7 patients who consented to the operation. Each of 3 patients had one duodenal submucosal microgastrinoma and one or more metastatic lymph node; the other 4 patients had 2 to 10 microgastrinomas or large gastrinomas in the duodenum or the pancreas. All 7 patients, who exhibited negative responses with a postoperative secretin test, have been completely cured from 3 months to 4 years postoperatively. The usefulness of the SASI test for preoperative evaluation is demonstrated by the fact that it gives a 100% positive predictability rate as well as a 100% negative predictability rate. Hence the SASI test precisely locates functioning gastrinomas.

Pathologic aspects of gastrinomas in patients with Zollinger-Ellison syndrome with and without multiple endocrine neoplasia type I

During the three decades since the recognition of the Zollinger-Ellison syndrome (ZES), major progress has been made in the diagnosis and treatment of this disease. However, the many failed operations in patients with ZES, the existence of primary lymph node gastrinomas, and the surgical approach of patients with ZES and multiple endocrine neoplasia type I (MEN-I) have remained controversial issues. In this review, our experience with the pathology of immunocytochemically identified gastrinomas in 44 patients with ZES is presented and related to the relevant literature. (1) Gastrinomas occur frequently in the duodenum (> 40%) and are commonly small (< 1 cm). They can therefore easily be missed at surgical exploration; lymph node metastases from such occult gastrinomas may be mistaken for primary tumors. (2) Most pancreatic gastrinomas reside in the head of the gland and have a diameter of 1 to 3 cm. (3) Gastrinomas associated with MEN-I are predominantly of duodenal origin and frequently multicentric; sporadic gastrinomas are single and more often pancreatic. Because MEN-I associated pancreatic tumors seldom contain gastrin, ZES in MEN-I patients is almost never cured by resection of the pancreatic tumors. (4) The metastatic potential of most small duodenal gastrinomas seems to be restricted to the regional lymph nodes.

Use of intraoperative ultrasonography to localize islet cell tumors

Because approximately 50% of insulinomas and a similar proportion of gastrinomas are not evident on preoperative imaging studies, precise intraoperative localization of these small tumors is imperative. Recently the use of high-resolution real-time B-mode ultrasonography has dramatically facilitated the operative detection of pancreatic islet cell tumors. The tumor appears sonolucent compared to the more echo-dense surrounding pancreas. This operative technique has been especially useful in patients with insulinoma because these tumors are generally located within the pancreas. In fact, it is so helpful during explorations for insulinoma some suggest that extensive preoperative localization studies are no longer indicated--that the patient can simply be explored with intraoperative ultrasonography (IOUS). It has not been as useful for gastrinomas because of their common extrapancreatic location. Accumulating evidence suggests that IOUS is an effective tool to aid in the operative localization and resection of pancreatic islet cell tumors. Not only can it precisely localize the tumor, it can accurately document the relation of the tumor to other vital pancreatic structures including ducts, veins, and arteries.

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

The role of magnetic resonance (MR) imaging in patients with pancreatic endocrine tumors such as Zollinger-Ellison syndrome (ZES) is controversial. In the present study we have examined the ability of current MR imaging compared with other imaging modalities, to localize gastrinomas in 43 patients with ZES. All results were subsequently assessed at exploratory laparotomy (N = 34) or by liver biopsy (N = 9). For the 18 patients with metastatic gastrinoma in the liver, MR imaging had a sensitivity of 83%, ultrasound 50%, CT 56%, and angiography 61%. The combination of MR imaging, ultrasound, and CT were the same as MR imaging alone. For MR imaging, both T1 and STIR sequences had equal sensitivity, although tumors were more easily seen with STIR sequences. Specificity of MR imaging was slightly lower (88%) than the other modalities (96-100%) because MR imaging incorrectly identified small hemangiomas as possible tumors in four patients. MR imaging was better than CT in identifying metastatic lesions in the liver. For the localization of primary gastrinoma, assessed in 32 patients, MR imaging had a sensitivity of 25%, ultrasound 19%, CT 28%, all three together 38%, and angiography 59%. Localization of metastatic gastrinoma in the liver or primary gastrinomas in 16 patients was assessed before and after gadolinium-DTPA (0.1 mmol/kg). The sensitivity and specificity of MR imaging was unchanged but bolus injection and rapid MR acquisition techniques were not used. These results indicate that recent advances in MR imaging have greatly improved its sensitivity for the detection and assessment of the extent of metastatic gastrinoma. MR imaging is now the imaging study of choice to assess metastatic pancreatic endocrine tumors in the liver. In contrast, the detection of primary tumors by MR imaging has not improved; therefore, angiography remains the study of choice.

Prospective study of the need for long-term antisecretory therapy in patients with Zollinger-Ellison syndrome following successful curative gastrinoma resection

A long-term cure is now possible in more than 30% of selected patients with Zollinger-Ellison syndrome who undergo gastrinoma resection. The need, however, for continued gastric acid antisecretory therapy in these patients remains controversial. The current study was designed to determine whether post-operative antisecretory therapy is needed in patients who have undergone successful gastrinoma resection and, if so, to attempt to define criteria with which to identify patients who require therapy. Twenty-eight consecutive patients who had previously undergone curative gastrinoma resection were prospectively studied. When antisecretory therapy was discontinued, 43% (12/28) of these patients developed gastro-oesophageal reflux, diarrhoea, acid-peptic symptoms or endoscopic evidence of acid-peptic disease within 2 weeks and were deemed to have failed a trial of antisecretory drug withdrawal. The remaining 57% (16/28) of patients who successfully discontinued antisecretory therapy were followed for a mean time of 31 months after withdrawal of therapy. Analysis of acid output studies pre-operatively, as well as at the time of drug withdrawal, demonstrated that patients who were unable to discontinue antisecretory therapy exhibited higher pre-operative maximal acid output values and higher basal acid output values at the time of attempted drug withdrawal than patients who were able to discontinue therapy. Despite these findings, there was significant overlap in acid output values between groups so that it was not possible to define specific acid output criteria for successful drug withdrawal. Pre-operative clinical characteristics, such as the presence or absence of gastro-esophageal reflux or acid-peptic disease, or post-operative laboratory values, such as the fasting serum gastrin level, did not correlate with the ability to discontinue antisecretory therapy. We conclude that following successful curative gastrinoma resection, 40% of patients still require antisecretory therapy and that both symptom evaluation as well as upper endoscopy should be used to guide attempted drug withdrawal. Although patients who are not able to discontinue therapy have significantly higher acid output measurements than those who are able to discontinue therapy, neither acid output criteria nor any other laboratory or clinical characteristics are able to predict the need for continued antisecretory therapy in these patients.

Biologic behavior of sporadic gastrinoma located to the right and left of the superior mesenteric artery

Among a series of 107 closely followed patients with gastrinoma, 60 patients with sporadic type tumors were identified and evaluated. There were 44 patients (73%) with tumors to the right of the superior mesenteric artery (SMA). Of these, 16 (36%) had extrapancreatic tumors, 28 (64%) had tumor within lymph nodes, and 9 (20%) had multiple tumors. In this group of patients, there were 19 (43%) cures, and only 9 (20%) patients had hepatic metastases. In contrast, in 16 patients (27%) with tumors to the left of the SMA, there were no extrapancreatic tumors, only 3 patients (19%) had tumor within lymph nodes, and 7 (44%) had multiple tumors. In this group, there was only one cure (6%), and nine (56%) patients had hepatic metastases. These findings suggest two distinct populations of sporadic gastrinoma, one to the right (gastrinoma triangle) and the other to the left (outside triangle) of the SMA, which appear to have different biologic behaviors. These differences may reflect divergent etiologies for these two groups of tumors.

Currently used doses of omeprazole in Zollinger-Ellison syndrome are too high

The efficacy of omeprazole increases during the first few days of administration, suggesting that long-term maintenance dose requirements in patients with Zollinger-Ellison syndrome may be lower than those initially established by upward titration. Long-term maintenance doses of omeprazole were prospectively reduced in 37 patients who had been taking omeprazole for 22 +/- 4 months. Successful reduction was defined as reduction to 20 mg once or twice daily with an absence of symptoms, endoscopy without evidence of active acid-peptic disease, and a gastric acid output of < 10 mEq/h. Sixty-eight percent of patients (25/37) were successfully reduced to 20 mg of omeprazole once (18/24) or twice daily (7/13). Ninety-five percent of patients (20/21) without multiple endocrine neoplasia type I, severe gastroesophageal reflux disease, or previous partial gastrectomy had safe reductions of doses. It is concluded that the currently used omeprazole maintenance doses in patients with Zollinger-Ellison syndrome are too high and advocated that the initial dose still be established by acute daily upward titration followed by gradual reduction once control of acid output has been achieved.

The Zollinger-Ellison syndrome. A collective surgical experience

A retrospective study of 90 surgically treated patients with the Zollinger-Ellison syndrome seen from 1958 through 1990 was performed. Fifteen patients had Zollinger-Ellison syndrome as a manifestation of multiple endocrine neoplasia type I. Preoperative tumor localization was positive in 46% of 54 patients studied. Gastrinomas were identified in 66% of patients, 38% of the tumors being malignant. Postoperative eugastrinemia was achieved in 11% of patients after a variety of surgical procedures. Exploratory laparotomy provides the only chance for cure and identifies the significant prognostic factors associated with long-term patient survival: small tumor size, extrapancreatic primary, and absence of tumor metastases.

Clinicopathological characteristics of duodenal microgastrinomas

Duodenal gastrinomas do not seem to behave as malignantly as sporadic pancreatic gastrinomas. Statistical analysis of 49 patients with sporadic pancreatic gastrinoma and 21 patients with sporadic duodenal gastrinoma reported since 1980 in Japan revealed that the incidence of hepatic metastasis was 57% in patients with sporadic pancreatic gastrinoma and only 9% in patients with sporadic duodenal gastrinoma (p less than 0.01). These findings suggest that there is an essential biological differences between duodenal and pancreatic gastrinoma. Five patients with sporadic duodenal microgastrinoma (tumor diameter less than 5mm) in our hospital had no hepatic metastases; however, 4 patients had lymph node metastases. Immunohistochemical study of 5 sporadic duodenal microgastrinomas and 6 sporadic pancreatic gastrinomas revealed that the sporadic duodenal gastrinomas contained significantly fewer insulin-producing or glucagon-producing cells than sporadic pancreatic gastrinomas. The cellular composition of the metastatic lymph nodes from duodenal microgastrinomas was similar to that of the primary tumor. This difference in cellular composition between the duodenal microgastrinomas and the pancreatic gastrinomas suggests that the process of development and differentiation of gastrinoma cells is different.

Localization of pancreatic endocrine tumors by endoscopic ultrasonography

BACKGROUND

After a pancreatic endocrine tumor has been diagnosed on the basis of clinical signs and the results of laboratory tests, localization of the tumor by the usual imaging procedures fails in as many as 40 to 60 percent of patients. Endoscopic ultrasonography, a sensitive test for small carcinomas of the pancreas, might also be useful in patients with endocrine tumors of the pancreas that cannot be localized by conventional methods.

METHODS

We studied 37 patients later shown to have 39 endocrine tumors of the pancreas who had negative results on transabdominal ultrasonography and CT. All the patients underwent endoscopic ultrasonography, and 22 also underwent selective angiography. All the tumors were confirmed by surgical excision and immunohistologic examination; they consisted of 31 insulinomas, 7 gastrinomas, and 1 glucagonoma, 0.5 to 2.5 cm (mean, 1.4 cm) in diameter. All but one of the patients were cured of their disease, as ascertained by at least six months of clinical and laboratory follow-up.

RESULTS

Using endoscopic ultrasonography, we were able to localize 32 of the 39 tumors (sensitivity, 82 percent); no tumor was incorrectly localized. The size of the tumors was very similar (within 2 mm) to that predicted by endoscopic ultrasonography. Among the 22 patients who underwent both angiography and endoscopic ultrasonography, ultrasonography was significantly more sensitive than angiography for tumor localization (sensitivity, 82 percent vs. 27 percent). Among 19 control patients without pancreatic endocrine tumors, endoscopic ultrasonography was negative in 18 (specificity, 95 percent).

CONCLUSIONS

Endoscopic ultrasonography is a highly sensitive and specific procedure for the localization of pancreatic endocrine tumors. It should be considered for the preoperative localization of such tumors once the clinical and laboratory diagnosis has been established.

A case of jejunal gastrinoma diagnosed by percutaneous transhepatic portal venous sampling

A 63-year-old male was admitted to our department for further examination of hypergastrinemia. Secretin provocation test and calcium infusion test suggested Zollinger-Ellison syndrome and percutaneous transhepatic portal venous sampling (PTPVS) demonstrated gastrinoma in the jejunum, although CT, ultrasonography and angiography could not accurately detect the location of the gastrinoma. Laparotomy findings showed a solid tumor 1.5 cm in diameter in the jejunal mesentery 5 cm distal to the ligament of Treitz, and primary gastrinoma was confirmed in the submucosa of the jejunum immediately adjacent to this tumor. An immunohistochemical study using the PAP method revealed gastrin secreting cells in the tumor. In addition to this case of jejunal gastrinoma, a review of literature in Japan and other countries was presented.

Selective intra-arterial methylene blue injection: a novel method of localizing gastrinoma

A 40-year-old woman had persistent Zollinger-Ellison syndrome despite excision of a 4-cm duodenal gastrinoma. Localizing studies including ultrasonography, computed tomography, magnetic resonance imaging, duodenal endoscopy, endoscopic ultrasonography, and intraoperative endoscopic transillumination of the duodenum failed to detect a tumor. Selective intra-arterial methylene blue injection was used to identify a 6-mm gastrinoma in the duodenum, which was locally excised. Postoperatively, the patient had a negative secretin provocative test result. This novel method uses selective arterial secretin injection with hepatic venous gastrin sampling to identify the vessel feeding the gastrinoma. An angiographic catheter is then positioned in this artery. At laparotomy, methylene blue is injected through this catheter to selectively stain the gastrinoma, facilitating its identification. Selective intra-arterial methylene blue injection can enhance intraoperative detection of small gastrinomas and may improve the rate of curative resection in the Zollinger-Ellison syndrome. Further evaluation of this novel localizing technique is warranted.

Curative resection in Zollinger-Ellison syndrome. Results of a 10-year prospective study

Since 1980, 73 patients with Zollinger-Ellison syndrome (ZES) without radiographic evidence of liver metastases were studied on a prospective protocol including medical management of gastric acid hypersecretion, extensive radiographic tumor localization, and exploratory surgery to find and resect gastrinoma for potential cure. Each patient had gastric acid hypersecretion effectively controlled with either H2-blockers or omeprazole. Patients were divided prospectively into two groups, with all patients undergoing the same preoperative localization studies and extensive laparotomy. In contrast to group 1 (1980-1986) (36 patients), group 2 (1987-Oct. 1990) (37 patients) also underwent additional procedures (transillumination and duodenotomy) at surgery to find duodenal gastrinomas. Preoperative imaging studies localized tumor in 38 (52%) patients, and portal venous sampling for gastrin determinations was positive in 49 (67%) patients. Gastrinomas were found and resected in 57 (78%) patients. Significantly more gastrinomas (92% of patients) were found in group 2 than in group 1 patients (64%) (p less than 0.01). This increase was due to increased numbers of duodenal gastrinomas in group 2 than in group 1 patients (43% versus 11%; p less than 0.01). The increased ability to find duodenal gastrinomas did not significantly improve the immediate disease-free rate, which was 58% for all patients. Duodenal primary gastrinomas were found to have a significantly greater incidence of metastases (55%) and a significantly shorter disease-free interval (12 months) than pancreatic gastrinomas (22% and 84 months, respectively) suggesting that duodenal gastrinomas may be more malignant and not more frequently curable than pancreatic gastrinomas. Operations were performed with no deaths and 11% morbidity rate. Long-term follow-up showed that 50% of patients initially rendered disease free would develop recurrent disease by 5 years. Survival was excellent for all patients, and none died of malignant spread of the tumor or uncontrolled peptic ulcer disease, with a mean follow-up of 5 years. This finding is in contrast to patients who presented with metastatic disease on imaging studies and had a 20% 5-year survival rate. This study suggests that all patients with localized sporadic ZES can have the gastric acid hypersecretion managed medically, that overall survival of these patients is excellent, most (78%) can have all gastrinoma found and resected, and some (30%) will be cured (long-term disease-free survival).

Surgical pathology of gastrinoma. Site, size, multicentricity, association with multiple endocrine neoplasia type 1, and malignancy

Specimens from the pancreas and duodenum of 26 patients with sporadic Zollinger-Ellison syndrome (ZES) and 18 patients with multiple endocrine neoplasia type 1 (MEN-1) and hypergastrinemia (17 with ZES) were screened immunocytochemically for gastrinomas. Location, size, multicentricity, and malignancy of the gastrinomas were evaluated. The MEN-1 patients had gastrinomas in the duodenum (nine of 18), pancreas (one of 18), and periduodenal lymph nodes (two of 18). No gastrinoma was identified in six patients. Most duodenal gastrinomas were multiple (five of nine) and smaller than 0.6 cm (six of nine). Lymph node metastases were present in eight of 12 patients. All 26 patients with sporadic ZES had a solitary gastrinoma; 14 were found in the pancreas and had a diameter greater than 2 cm. Ten patients had a duodenal gastrinoma, two with a diameter less than 0.6 cm. In two patients, only periduodenal "lymph node gastrinomas" were detected. Eighteen of the sporadic gastrinomas were malignant. These results suggest that duodenal location and multicentricity of gastrinomas are associated with the MEN-1 syndrome, and solitary gastrinomas, either in the pancreas or the duodenum, are predominantly seen in sporadic ZES.

Zollinger-Ellison syndrome

As clinical experience with patients with ZES has grown, increasing recognition has been made of the broad spectrum of symptoms associated with gastrinomas. Diarrhea and acid-induced esophageal injury have taken their place alongside chronic peptic ulcer disease as indications for screening for gastrinoma. Diagnostic testing should begin with fasting serum gastrin levels and should include intravenous secretin infusion if fasting serum levels of gastrin are nondiagnostic and the patient is not found to be hypochlorhydric. Tumor localization is critical to aid in the identification of patients with potentially curable localized disease. Preoperative evaluation utilizing CT scanning with intravenous contrast should be done early and should be supplemented by other imaging modalities as necessary. Exploratory laparotomy, including a thorough examination of the duodenum and perhaps intraoperative ultrasound, should be performed in all patients with sporadic gastrinoma who lack evidence of extensive metastatic disease on preoperative evaluation. By utilizing this approach, it is likely that at least 20% of patients with ZES can be cured. With the availability of the highly effective H(+)-K(+)-ATPase inhibitor omeprazole, excellent control of symptoms related to gastric acid hypersecretion can be expected. Patients with unresectable gastrinoma may thus avoid potentially morbid antisecretory surgery and be managed with a fairly simple medical regimen. Further developments in the chemotherapeutic management of these patients with unresectable disease should be forthcoming in the future.

Unresolved surgical issues in the management of patients with Zollinger-Ellison syndrome

In the last 10 years, there have been a number of major advances that have markedly changed the management of patients with Zollinger-Ellison syndrome. These advances have been described recently in a number of excellent reviews. After reading each of these reviews, including our own, one is left generally with the impression that most of the important problems and particularly those involving surgery in the treatment of this disease have been resolved; however, in considering the possible problems to address in protocols in the coming years in our patients with Zollinger-Ellison syndrome followed at the National Institutes of Health, it became apparent to us that not only will surgery play an increasingly important role in the management of this disease, but that there are a number of major questions in which various aspects involving surgery are not resolved. Furthermore, resolution of a number of these areas will have applicability to the surgical treatment of other islet cell tumors. The purpose of this article is to call attention to these questions with the hope that other investigators may also consider these and specifically attempt to address some of these issues in the surgical treatment of Zollinger-Ellison syndrome in prospective studies.

Detection of duodenal gastrinomas by operative endoscopic transillumination. A prospective study

The ability of operative endoscopic transillumination of the bowel wall to detect duodenal gastrinoma was evaluated prospectively in 26 patients with the Zollinger-Ellison syndrome. The results were assessed by exploratory laparotomy and compared with the results of other localization techniques. Twelve duodenal gastrinomas were resected from 10 patients. Operative endoscopic transillumination detected 10 of the 12 gastrinomas, a sensitivity of 83%, which was significantly greater (P less than 0.05) than that for either preoperative imaging (25%) or intraoperative ultrasonography and palpation (42%). The sensitivity of operative endoscopic transillumination was a result of the ability to detect focal areas that did not transilluminate on the serosal side of the duodenum, and not the mucosal appearances seen through the endoscope, which were not helpful. Operative endoscopic transillumination detected gastrinomas less than 1 cm in diameter throughout the duodenum. Of the patients in this study, 39% had duodenal gastrinomas, a greater frequency than previously reported. These results indicate that operative endoscopic transillumination is the most sensitive technique yet described for detecting duodenal gastrinomas and should be performed routinely in all patients with the Zollinger-Ellison syndrome who undergo exploratory laparotomy for cure.

Characteristics of duodenal wall gastrinomas

Fifteen patients with duodenal wall gastrinomas (DWGs) and the Zollinger-Ellison syndrome have been treated since 1960. In 6 of 11 patients, DWGs were recognized at operation and totally excised. In four patients, the tumor was subsequently found in the proximal duodenum of the surgical specimens. In 12 patients, DWGs were single and lymph node metastases were present in 8. In three patients, DWGs were multiple and lymph node metastases were present in two. All DWGs were submucosal and all were located in the first or second portions of the duodenum except one found in the fourth portion. Tumor size ranged from 1 to 15 mm, and nine were less than 5 mm. Of 12 patients with single DWGs, 9 have remained eugastrinemic after resection (mean follow-up: 5.5 years). None of the patients with multiple DWGs became eugastrinemic after surgery. DWGs are characteristically single, small or microscopic, submucosal, located in the proximal duodenum, rarely metastasize to the liver, and are usually curable by surgical resection.

The effect of Zollinger-Ellison syndrome and omeprazole therapy on gastric oxyntic endocrine cells

In 1983, all trials of omeprazole in humans were stopped because rats given the drug developed gastric endocrine cell hyperplasia and carcinoid tumors. Further studies in rats showed that drug-induced achlorhydria and hypergastrinemia caused these changes. Because data in humans are limited, we compared the numbers of endocrine cells, as judged by silver staining (argyrophilia), in the gastric mucosa of patients with Zollinger-Ellison syndrome, who are hypergastrinemic, and in normogastrinemic patients with idiopathic acid-peptic diseases. In addition, we analyzed the number of gastric endocrine cells in patients with Zollinger-Ellison syndrome given omeprazole for up to 3 years. Patients with Zollinger-Ellison syndrome had 15.7% +/- 6.9% argyrophil cells in biopsies of gastric oxyntic mucosa, and patients with idiopathic acid-peptic disease had 7.8% +/- 2.3% (P less than 0.01). In patients with Zollinger-Ellison syndrome, the percentage of argyrophil cells was not related to serum gastrin concentration, duration of symptoms, time since diagnosis, basal or maximal acid output, extent of tumor, or age. There was a tendency for patients with multiple endocrine neoplasia type 1 to have a greater percent of argyrophil cells than patients with sporadic Zollinger-Ellison syndrome. Considering the biopsies from both normogastrinemic and hypergastrinemic patients, there was a significant relationship between the percentage of argyrophil cells and the serum concentration of gastrin (P less than 0.01). Patients with Zollinger-Ellison syndrome given omeprazole for up to 3 years developed no significant changes in percentage of argyrophil cells, no carcinoid tumors, and no changes in serum concentrations of gastrin. The present study shows that patients with Zollinger-Ellison syndrome have an increased percentage of argyrophil cells in oxyntic mucosa and that omeprazole does not increase this percentage. In periods of up to 3 years, omeprazole had no effects on gastric morphology in patients with Zollinger-Ellison syndrome.

Intravenous omeprazole in patients with Zollinger-Ellison syndrome undergoing surgery

Twenty patients with Zollinger-Ellison syndrome who were undergoing surgery were studied prospectively to assess the efficacy and safety of IV omeprazole. During the preoperative period, in 19 of 20 patients, omeprazole 60 mg administered as an IV bolus every 12 hours inhibited acid output to less than 5 mEq/h measured in the last hour before the next dose of drug. In one patient, acid output was 25 mEq/h 12 hours after omeprazole, 60 mg, and increasing the dose to 100 mg every 12 hours reduced acid output to less than 5 mEq/h. During the operative and postoperative periods, IV omeprazole controlled gastric acid hypersecretion in all patients for up to 15 days. During this time, all patients received the dose determined preoperatively. No patient developed any clinical, hematological, or biochemical toxicity that could be attributed to omeprazole therapy during the preoperative or postoperative period. The present study demonstrates that omeprazole administered by IV bolus is safe and effective for controlling gastric acid hypersecretion. In contrast to IV histamine H2-receptor antagonists, IV omeprazole has the advantages of not requiring continuous infusion or postoperative dose adjustments. Intravenous omeprazole will become the drug of choice in patients with Zollinger-Ellison syndrome undergoing surgery.

Aberrant hormone production from ovarian neoplasms: strategies for diagnosis and therapy

Syndromes involving peptide or nonsex steroid hormone secretion due to aberrantly located tumors are rare. We report a collected series of 16 patients with ectopic hormone production from ovarian neoplasms, including 3 patients recently encountered at our institution as well as 13 additional cases identified in the recent literature. These tumors included 2 insulin-producing ovarian carcinoids, 1 ACTH-producing pituitary adenoma within a benign ovarian cystic teratoma, 2 cortisol-producing ovarian neoplasms, 8 gastrin-producing ovarian cystadenomata or cystadenocarcinomata, and 3 thyroxine-producing ovarian strumal carcinoids. All patients presented with syndromes of hormone excess. Only 62% of all tumors were localized preoperatively. Following ovarian resection, 87% of patients remained disease-free with a median follow-up period of 1.5 years. In addition to ovariectomy, 8 additional unnecessary ablative procedures were performed in 7 patients. These included distal pancreatectomy, pancreaticoduodenectomy, adrenalectomy, total gastrectomy, selective vagotomy, and subtotal thyroidectomy. Failure to localize the ovarian neoplasm preoperatively was associated with a significantly higher risk of subsequent unnecessary ablative procedures. Because of the potential for the ovary to act as a source of aberrant hormone secretion, we recommend complete preoperative evaluation of the pelvis in female patients presenting with nonlocalizable endocrine tumors.

Anatomic distribution of pancreatic endocrine tumors

Pancreatic endocrine tumors are grouped together by their common histologic, cytochemical, and ultrastructural features. Although useful conceptually, this paradigm has been unable to predict the anatomic location of different tumor types. Successful surgical excision of these tumors would be facilitated by an improved understanding of their anatomic distribution. Based on the available data, a bimodal distribution of pancreatic endocrine tumors was identified. Cluster 1 (gastrinomas, pancreatic polypeptide (PP)-secreting tumors, somatostatinomas) had 75% of tumors to the right of the superior mesenteric artery, whereas cluster 2 (insulinoma, glucagonoma) had 75% of tumors to the left of the superior mesenteric artery (p less than 0.05). This distribution is similar to that distribution predicted based on the volume density of the corresponding islet cells for insulinoma, glucagonoma, and PP-secreting tumors, but not for somatostatinoma. These findings suggest that pancreatic endocrine tumors are derived from similar cytologic precursors as pancreatic islet cells, and their distribution may be a consequence of embryologic development from either the ventral (cluster 1) or dorsal (cluster 2) pancreatic buds.

Gastrinoma

The Zollinger-Ellison syndrome with its main symptom of massive gastric hypersecretion presents problems with both the medical and surgical approaches to treatment. Successful medical treatment depends on a life-long commitment to rigid medication schedules requiring careful ongoing supervision and is subject to pitfalls of compliance, drug side effects, drug resistance, and complications of persistent tumor growth. Surgical therapy carries risks of operative mortality and complications. If a low operative mortality can be maintained and the nutritional results after total gastrectomy are good, then it is the authors' opinion that the permanent relief from dangers of hypersecretion afforded by total gastrectomy makes surgery a worthwhile approach. Based on our operative experience in 34 patients and interpretation of the experience of others, we believe that resection of all tumor that can be resected, combined with total gastrectomy, is safe and dependable. The results compare well with those of long-term medical management.

APUD update

Apudomas are a diffuse group of tumors that have interested surgeons for a long time. With recent developments in their radiological localization and pharmacological control, they are now treated in a truly multidisciplinary approach. In this chapter, recent developments in the radiological, surgical, and medical approaches to these tumors are reviewed. Emphasis is placed on how non-surgical developments have affected the surgical treatment of specific apudomas. Resulting changes in surgical philosophy are also reviewed.

Gastrinoma excision for cure. A prospective analysis

The role of surgery in the treatment of gastrinoma is unclear. The purpose of this study was to determine prospectively the surgical cure rate using a controlled clinical trial. Eleven patients who fit the entry criteria underwent abdominal exploration and attempted tumor resection for cure. A historical control group was used for comparison. Cure was defined as: (1) normal serum gastrin level, (2) no response to intravenous secretin, (3) no symptoms when antisecretory medications are stopped, and (4) no tumor recurrence on follow-up examination. Tumors found in both groups tended to be small (1.5 cm vs. 2.2 cm), multiple (71% vs. 40%), and in lymph nodes (70% vs. 70%). All tumors identified were located anatomically within the gastrinoma triangle. Tumors were found in 10 of 11 patients (91%) in the study group, and significantly more patients had their tumors excised for cure as compared to controls (82% vs. 27%, p less than 0.05). The current prospective cure rate for gastrinoma is higher than previously appreciated and tumors within lymph nodes do not preclude curative resection.