The role of surgery in patients with Zollinger-Ellison syndrome (ZES) managed medically

Fifty years of pancreas cancer care

Resulting from 50 years of innovation, operations for pancreatic neoplasms can now be performed safely, albeit with significant but manageable morbidity. Molecular diagnosis has allowed for the identification of multiple distinct histopathologies with variable natural histories. Observation is now a strategy for selected indolent cysts and some neuroendocrine neoplasms. For ductal pancreatic adenocarcinoma, a long-term cure remains elusive and will require more than surgical resection for meaningful progress.

The Zollinger-Ellison syndrome: is there a role for somatostatin analogues in the treatment of the gastrinoma?

PURPOSE

Analyze the role of somatostatin analogues (SSAs) in the treatment of sporadic and MEN1-related gastrinomas, trying to define whether recent trials have changed the landscape of gastrinoma therapy.

METHODS

We evaluate the rationale of SSA use in the treatment of gastrinomas, summarize the current literature concerning the effect of SSAs on the control of Zollinger-Ellison syndrome (ZES) and gastrinomas tumor progression and discuss their role in the most recent guidelines.

RESULTS

The medical treatment of gastrinoma and related ZES is aimed at controlling acid hypersecretion and tumor progression, in inoperable patients. The use of proton pump inhibitors (PPIs) to control the syndrome is a cornerstone in the ZES therapy. SSAs are not usually indicated for antisecretory purpose, because PPIs are considered the treatment of choice, due to their long lasting high efficacy and oral availability. The antiproliferative effect of SSAs has been established by two placebo-controlled trials that have clearly demonstrated a significant increase in progression free survival in patients affected by non-functioning well-differentiated advanced neuroendocrine tumors (NETs). The recent ENETS guidelines recommend the use of SSAs in advanced well differentiated NETs as antiproliferative agents.

CONCLUSIONS

The high sstr-expression in gastrinomas make them highly responsive to SSAs and support the use of such drugs to counteract the tumour growth in patients not amenable to surgical cure. Unfortunately, limited data, mainly case reports or small series, support the use of SSAs in advanced gastrinomas, therefore, it is difficult to quantify their ability to control tumour growth and disease progression.

Reoperative surgery for the Zollinger-Ellison syndrome

It is clear that a properly performed initial operation is the key to success in the management of a patient with ZES. However, reoperation is frequently a consideration in the management of patients with ZES because high rates of persistent and recurrent disease are manifest even with modern imaging and surgical approaches. In carefully selected patients, reoperation can result in durable biochemical cure and improved survival and should be considered. A thorough knowledge of the natural history of the sporadic form of ZES and ZES in the context of MEN-1, patterns of presentation, and sites of metastases are necessary to achieve the best outcome in patients with this unusual disease.

Reoperative surgery in sporadic Zollinger-Ellison Syndrome: longterm results

BACKGROUND

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

STUDY DESIGN

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

RESULTS

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

CONCLUSIONS

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

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.

A follow-up study of patients with Zollinger-Ellison syndrome in the period 1966-2002: effects of surgical and medical treatments on long-term survival

AIM

To evaluate the clinical history of a series of patients with Zollinger-Ellison syndrome (ZES) in the period 1966 to 2002, before and after the introduction of the current antisecretive H2 receptor antagonists and proton pump inhibitors into clinical practice.

PATIENTS AND METHODS

The study involved 18 ZES patients (9 males; mean age, 43 years; range, 12-70 years), 8 with Type 1 multiple endocrine neoplasia (MEN-1), diagnosed on the basis of standard criteria. We considered the type, number and effectiveness of surgical interventions before and after appropriate treatment, the localization of the gastrinoma, the presence of associated diseases, the causes of death, and the duration of survival.

RESULTS

Total gastrectomy (but not antrectomy and vagotomy) and full compliance to antisecretory treatment reduced the number of operations from 29 to 9. One patient was cured (5.5%), whereas relapsing gastrinomas occurred in 4 patients and associated diseases or complications in ten. Death was related to ZES in 5 patients and to other causes in 4.

CONCLUSIONS

Curing gastrinoma or appropriately inhibiting gastric acid hypersecretion in ZES patients prevent death and favors long-term survival, regardless of gastrin levels and the size or number of tumors.

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.

Current diagnosis and management of Zollinger-Ellison syndrome

The treatment of patients with Zollinger-Ellison syndrome (ZES) has undergone dramatic evolution during the past decade. Although initially regarded as an incurable tumor, resection of gastrinoma for potential cure has been reported in 30% to 40% of selected patients in recent series. Conversely, although definitive control of acid hypersecretion is achieved by total gastrectomy, histamine (H2)-receptor antagonists and the newly introduced agents omeprazole and somatostatin analogues allow effective medical therapy of gastric acid overproduction. Confirmation of the diagnosis is best achieved with the I.V. secretin stimulation test, and tumor localization techniques are mandatory to identify candidates for operative tumor resection. Intraoperative sonography and careful exploration are required for tumor removal; successful tumor resection is associated with prolonged survival. The majority of patients (60%) are still found to have malignant disease at the time of diagnosis, but 10-year overall survival commonly exceeds 40%. The presence of multiple endocrine neoplasia type I (MEN-I) is seen in 10% to 25% of patients; correction of hypercalcemia alone may have therapeutic benefit in some ZES patients, and while gastrinoma resection is rarely possible, MEN-I patients demonstrate prolonged survival. The choice of medical rather than surgical therapy for acid hypersecretion depends on the suitability of each patient for careful and repeated endoscopic and chemical studies, versus the likelihood of a successful postoperative outcome. Socioeconomic, geographic, and related medical factors in each case may dictate the form of long-term antisecretory therapy. Exploration for possible tumor resection is indicated for virtually all patients who have no documented metastatic disease.

Microgastrinomas of the duodenum. A cause of failed operations for the Zollinger-Ellison syndrome

Gastrinomas are now being detected at an earlier stage than was formerly the case. Furthermore, with the ability to control acid secretion, emphasis has been placed on identifying gastrinoma patients who are potentially curable by tumor resection rather than by palliative gastrectomy. Despites estimates suggesting that 20-40% of sporadic gastrinoma patients can be successfully resected for cure, as many as 40% of such patients have occult tumors that elude detection. In an effort to better localize gastrinomas, we have used percutaneous transhepatic venous (THVS) gastrin sampling over the past 10 years. From 1978 to 1988, THVS was used in 46 patients in whom there was no other evidence of metastatic gastrinoma by conventional studies. Gastrinomas were found at operation in all but one patient. The purpose of this report is to emphasize that occult tumors are most often found in the duodenal wall, and frequently they may be no greater than 2 mm in diameter. Five recent cases illustrate that these small tumors or microgastrinomas may be the sole source of hypergastrinemia and can be cured by local excision. These recent cases emphasize that microgastrinomas are not usually palpable through the duodenal wall. They may be detected only after duodenotomy and meticulous evaluation of the mucosa by eversion and direct palpation. Duodenotomy and intraluminal exploration should be considered an essential component of the operation for patients with extrapancreatic gastrinomas.

Localization and resection of gastrinomas in Zollinger-Ellison syndrome

From 1971-1986, 24 patients were diagnosed as having Zollinger-Ellison syndrome (ZES) and 22 patients had laparotomy. Of this group, gross tumor was identified in 15 of 22 patients. Ten of 15 patients had resection of their gastrinomas with the specific aim of curing the disease. This group had responded favorably to either cimetidine or ranitidine before operation. Preoperative transhepatic portal venous sampling (PVS) with gastrin determinations was performed in six patients; three patients had this procedure twice. The tumor was correctly localized by PVS in five of six patients. In four of six patients, the tumor was easily found at surgery. In two of six patients (33%) PVS was vital to intraoperative decisions. Criteria for biochemical cure are normal periodic fasting gastrin and secretin infusion tests. Of the 10 patients who had resection for potential cure, two patients failed within 48 hours of surgery on the basis of an elevated fasting serum gastrin level in one patient and a positive secretin infusion test in the other patient. Eight patients were considered cured with follow-up from 6 months through 15 years. Of the eight cured patients, the tumors were located as follows: four were extraintestinal and extrapancreatic, four were in the duodenal wall, one patient had a tumor located in the uncinate process of the pancreas, and one tumor was located in a lymph node along the lesser curve of the stomach. Two patients had mobilization of the pancreas and duodenum for a "blind" pancreatoduodenectomy based on preoperative PVS (2 procedures each patient). In one patient a 3-mm gastrinoma was enucleated from the posterior uncinate process. The second patient had pancreatoduodenectomy with findings of two duodenal wall gastrinomas. Both patients remained cured of ZES beyond 2 years. It is concluded that PVS does indeed locate some tumors before operation, even those not easily found at surgery. ZES can be cured by an aggressive approach combining preoperative tumor localization and tumor resection. Of the eight patients biochemically and perhaps biologically cured, follow-up was greater than four years in five patients, greater than two years in two patients, and beyond six months in one patient.

Zollinger-Ellison syndrome (gastrinoma). Current diagnosis and treatment

Zollinger-Ellison syndrome is being detected at an earlier stage through liberal use of serum gastrin testing and application of secretin provocative tests if needed. The peptic ulcer disease of patients with Zollinger-Ellison syndrome can usually be controlled by large doses of one of the new potent gastric acid inhibitors. A battery of preoperative localizing tests can then be applied to guide exploratory laparotomy in non-MEN I patients. The tumor should be resected if possible, and continued low gastrin levels after operation provide evidence of a complete resection. It is reasonable to perform a parietal cell vagotomy at celiotomy because it will facilitate control of acid secretion if tumor resection is not successful. The only need for total gastrectomy is in a few patients whose acid secretion cannot be controlled with H2 receptor antagonists or who cannot comply with medical therapy. When no tumor is found at celiotomy, the prognosis for long-term tumor-free survival is excellent. Unfortunately, if unresectable hepatic metastases are present at operation, the patient is likely to die from metastatic tumor.

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

In 1982, a prospective study was initiated of 52 consecutive patients with proven Zollinger-Ellison syndrome (ZES), involving surgical exploration with the goal of removing the gastrinoma after an extensive protocol to localize the tumor. Each patient underwent ultrasound, computed tomography (CT) with oral/intravenous (IV) contrast, and selective arteriography. Eighteen patients had metastatic disease identified by imaging studies and confirmed by percutaneous biopsies, and two patients had multiple endocrine neoplasia type I (MEN-I) with negative imaging studies; therefore, these 20 patients did not undergo laparotomy. Each of the remaining 32 patients (3 with MEN-I and positive imaging studies) underwent laparotomy, and gastrinomas were removed in 20 patients. Preoperative ultrasound localized tumors in 20% of patients, CT in 40%, arteriography in 60%, and any of the modalities in 70% of patients. Infusion CT and arteriography were 100% specific. In 18 patients with either negative imaging (17) or false-positive imaging (1 ultrasound), gastrinomas were found and removed in six patients (33%). Twenty-four gastrinomas were found in 20 patients at laparotomy: eight in lymph nodes around the pancreatic head, four in the pancreatic head, one in the pancreatic body, three in the pancreatic tail, three in the pyloric channel, one in the duodenal wall, two in the jejunum at the ligament of Treitz, one in the ovary, and multiple liver metastases in one patient. If one excludes patients with MEN-I or liver metastatic disease, 12/28 (43%) of patients were biochemically "cured" immediately after operation. This result decreased to 7/23 (30%) with greater than 6 months follow-up. No patients with gastrinomas resected have developed recurrent gastrinoma on follow-up imaging studies (longest follow-up: 4 years). This study indicates that 95% of metastatic gastrinoma can be diagnosed before operation and that, by a combination of careful imaging studies and thorough exploration at surgery, 30% of patients with gastrinomas may be curable.

Aggressive resection of metastatic disease in selected patients with malignant gastrinoma

Fifteen patients with Zollinger-Ellison syndrome followed at the National Institutes of Health with extensive metastatic disease had an actuarial 5-year survival of 20%. Therefore, in 1982 a prospective study to examine the effect and feasibility of removing all gross tumor in selected patients with extensive metastatic disease was instituted. Five patients with extensive metastatic gastrinoma confined to the abdomen in whom imaging studies suggested the possibility of complete surgical resection were entered into this study and underwent attempted complete surgical resection and chemotherapy with streptozotocin, doxorubicin, and 5-fluorouracil. Median follow-up was 24 months. Surgical resection of all gastrinoma was possible in 4/5 patients attempted. In one patient in whom all gross disease could not be resected, the residual tumor progressed and the patient died 19 months after operation. All four patients with all disease resected appeared to benefit since all of them had a significant reduction in antisecretory medications and are enjoying normal activity and work. Three patients have had no detectable tumor on follow-up, and two of these patients are clinically and biochemically "cured" with normal fasting gastrin levels and negative provocative gastrin tests at 14 and 32 months. Therefore, aggressive resection of metastatic disease in selected patients with malignant gastrinoma is recommended.

Treatment of Zollinger-Ellison syndrome with exploratory laparotomy, proximal gastric vagotomy, and H2-receptor antagonists. A prospective study

Twenty-two patients with Zollinger-Ellison syndrome were managed by a combined medical and surgical approach. Patients were treated initially with cimetidine or ranitidine. A laparotomy was performed to remove easily resectable tumors and to carry out a proximal gastric vagotomy. Tumors were found in 9 patients (41%) and all visible tumors were removed from 6 of the 9 patients. Fasting serum gastrin concentrations and serum gastrin responses to intravenous secretin were normal 6 wk after surgery in each of the patients from whom all visible tumors were resected and are normal in 4 patients, 6 wk to 5 yr after surgery. Acid secretion was reduced after vagotomy in each patient, even when tumors were not found or completely resected. Thus, vagotomy decreased the acid secretory response to endogenous hypergastrinemia. In addition, vagotomy augmented the inhibitory effect of H2-receptor antagonists on acid secretion. Follow-up has ranged from 6 wk to 6 yr (median, 2 yr). Dosages of cimetidine or ranitidine have been reduced, compared with preoperative amounts, in all but 1 patient. Two patients are taking no antisecretory drugs. Only 3 patients have had occasional symptoms of ulcer disease. Complications such as bleeding, perforation, or obstruction have not occurred in any patient. Endoscopy was performed in all patients to estimate the point prevalence of active ulcers and an ulcer was found in 1 patient. Based on these results, it is our opinion that this combined medical and surgical approach is an effective treatment for patients with Zollinger-Ellison syndrome.

Removal of gastrinomas for control of Zollinger-Ellison syndrome

There are two distinct problems in patients with Zollinger-Ellison Syndrome (ZES): peptic ulcer diathesis and malignant tumors. Antisecretory drugs have allowed us to control the ulcer symptoms and acid output in 45 patients with ZES. We report here the initial seven patients selected for surgical exploration with the goal of removing their gastrinomas. Prior to surgery, an extensive and rigorous protocol to localize the gastrinoma was carried out, including hypotonic duodenography, abdominal ultrasonography, selective arteriography, portal vein sampling for gastrin, and computerized tomography. With this protocol of radiographic localization, gastrinomas were found in two of the seven cases and the syndrome was "cured" in three of the seven patients. The results also demonstrate that preoperative localization is not a substitute for careful surgical exploration as tumors were found in two patients in whom localization failed.

Multiple endocrine neoplasia syndromes

The multiple endocrine neoplasia (MEN) syndromes are characterized by autosomal dominant inheritance with a high degree of penetrance but varying expression. This review gives a classification of these syndromes and a short summary of the historical background. The pathogenesis of the disease and its possible origin in the APUD cell system are discussed together with the mechanisms underlying normal and ectopic hormone production by MEN tumors on the basis of recent findings in molecular endocrinology. The natural history and the clinical manifestations of the different syndromes are described. The sensitivity and discriminative capacity of the tests used to detect the syndromes in an early stage are compared. The choice of therapy and criteria for the timing and extensiveness of treatment are also considered. Lastly, problems associated with the ethical and legal aspects of screening, central registration, and monitoring of relatives at risk are described.

The gastrinoma triangle: operative implications

Operative experience with 45 gastrinoma patients has led to the identification of an anatomic area where occult tumors can be discovered and where excision of these tumors had led to apparent cure. Of 36 patients with histologically confirmed gastrinomas, 27 patients (75 percent) had obvious and 9 patients (25 percent) had occult tumors. All nine occult lesions were found within an anatomic triangle defined by the junction of the cystic and common bile ducts superiorly, the junction of the second and third portions of the duodenum inferiorly, and the junction of the neck and body of the pancreas medially. Although occult tumors from three patients (in the lymph nodes in two patients and in the duodenum in one patient) were removed primarily for histologic diagnosis, postoperative serum gastrin levels have remained within the normal range (follow-up of 86 to 99 months). Two patients had excision of the tumor with intent to cure. One patient with a solitary duodenal tumor was apparently cured but committed suicide 3 months postoperatively. The other patient had both obvious primary and occult metastatic tumors within the triangle and was eugastrinemic 9 months after excision. In all patients in whom tumor was found, it was locally excised, and no patient was subjected to radical pancreatic resection. There were no postoperative complications related to tumor removal. An aggressive approach towards curative tumor excision is now advocated for all gastrinoma patients who are suitable operative risks and have no evidence preoperatively of liver metastases or the multiple endocrine neoplasm-type I syndrome.

Cimetidine in the treatment of Zollinger-Ellison syndrome

From 1977 to 1983 we used cimetidine as primary therapy for 17 patients with the Zollinger-Ellison syndrome. All patients were treated with oral doses of cimetidine, 300 to 600 mg, four times a day, unless symptoms of hyperacidity developed or until evidence of a potentially resectable tumor became available, at which time they underwent definitive therapy. Eleven (65 percent) had no response to cimetidine therapy, 7 of whom had symptomatic recurrent ulcers, 3 of whom had esophagitis, and 2 of whom had severe diarrhea. Eight of these patients were treated with total gastrectomy, two with successful tumor resection, and one with parietal cell vagotomy (which facilitated the control of hyperacidity with cimetidine). All operations except one were performed electively and there was no operative mortality.

The role of surgery in the Zollinger-Ellison syndrome

When the Zollinger-Ellison syndrome was first identified, total gastrectomy was proposed as the most effective treatment for the secretory manifestations of the syndrome. Recently, however, great enthusiasm has developed for medical treatment by means of H2-receptor antagonists. The authors have cared for 27 patients with the Zollinger-Ellison syndrome at The University of Texas Medical Branch in the past 12 years and have been pleased with the results of total gastrectomy, which was performed in 23 of the 27 patients (one patient refused operation and three patients had lesser gastric operations). Twenty-three patients underwent total gastrectomy with Roux-en-Y esophagojejunostomy. There were no operative deaths. Primary tumors were found in 17 patients, seven of whom also had metastatic tumors. No tumors were found in nine patients. Nine patients are dead; the actuarial survival rate for all patients was 75% at 5 years and 52% at 10 years. Eleven of the 27 patients had the multiple endocrine neoplasia I syndrome. Of the 18 survivors, only three have normal serum gastrin levels, and all three had extrapancreatic gastrinomas, one in peripancreatic lymph nodes, one in the liver, and one in a cystic tumor attached to the stomach. Nutritional results were good to excellent, with a mean postoperative weight loss of 14.7% (mean follow-up period was 45 months). The authors conclude that treatment of the hypersecretory problems of the Zollinger-Ellison syndrome by total gastrectomy is safe and dependable. Results compare well with those of long-term medical management, whose success is dependent upon serial favorable responses to a lifetime of repeated challenges.