Control of the Zollinger-Ellison syndrome by excision of primary and metastatic tumor

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.

Forty-year appraisal of gastrinoma. Back to the future

OBJECTIVE

The author analyzed potential survival determinants in gastrinoma to characterize a possible uniform staging system and to determine whether complete surgical resection improves expected survival.

SUMMARY AND BACKGROUND DATA

Gastrinoma is an indolent yet malignant neuroendocrine tumor. The associated gastric acid hypersecretion can be controlled medically. Staging of gastrinoma is inconsistent and the role of surgical resection controversial.

METHODS

Seventy-four patients with gastrinoma with a minimum 5-year follow-up were assessed. Cox's proportional hazards regression model was used to examine the association of risk factors with survival.

RESULTS

The following factors had no effect on survival: age at diagnosis, sex, presence of lymph node metastases, associated multiple endocrine neoplasia, and method of ulcer treatment. The three unique determinants of survival were primary tumor size (relative risk, 1.534; p = 0.0005), liver metastases (relative risk, 2.947; p = 0.0209), and complete surgical resection (relative risk, 0.163; p = 0.0076). On the basis of these risk factors, a uniform staging system is proposed and predictive survival curves developed.

CONCLUSIONS

The primary determinants of survival in gastrinoma are the size of the primary tumor and liver metastases. Complete surgical resection reduces mortality, regardless of other factors.

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.

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.

Curative resection of multiple gastrinomas aided by selective arterial secretin injection test and intraoperative secretin test

Recently a number of surgeons have recommended radical resection of gastrinomas in Zollinger-Ellison syndrome (ZES). We have developed a useful technique for preoperative localization of gastrinomas--the selective arterial secretin injection test (SASI)--and we recommend an intraoperative secretin test (IOS) for deciding the radicality of resection of gastrinomas. Here the results of SASI and IOS tests in 11 patients with ZES are examined and compared with the results of other techniques. The SASI test localized gastrinomas in all of the patients, while the sensitivity of ultrasonography, computed tomography, arteriography, or portal venous blood samplings was between 1/11 and 5/11. On the basis of the results of the SASI test, radical resection of gastrinoma was performed in four patients (three pancreatoduodenectomies and one extirpation). After pancreatoduodenectomy, immunohistologic study of the specimen revealed multiple microgastrinomas and lymph node metastases in two patients and the coexistence of a microgastrinoma and a gastinoma in one patient. The IOS test was useful in the estimation of the advisability of radicality, and in two patients total gastrectomy was not performed because of the results of the IOS test. These four patients are well and have returned to work, and their serum gastrin levels are below 35 pg/mL. Thus we believe SASI and IOS tests are helpful for planning curative resection of gastrinomas.

Conservative surgery in Zollinger-Ellison syndrome: report of a case with an eight-year follow-up

The patient described here, with malignant non-beta islet cell tumor of the head of the pancreas, was treated by resection of the tumor and metastases. Additional pathology of perforated duodenal ulcer and pyloric stenosis required vagotomy and pyloroplasty. The maintenance of normal gastrin levels after the operation indicates a good prognosis. We believe that the low-risk Zollinger-Ellison patient should be treated surgically and the tumor removed. When no tumor can be detected, parietal cell vagotomy should be performed to assist the pharmacological control of the gastric acid hypersecretion. Extensive surgery, such as total gastrectomy, is no longer the treatment of choice and is reserved for the so-called "cimetidine failure."

Early surgical treatment of gastrinoma

Medical treatment of the Zollinger-Ellison syndrome has been generally accepted because of the proven efficacy of the histamine (H2)-receptor antagonists in achieving symptomatic relief, and because of early reports indicating that few, if any, gastrinomas were resectable for cure. Gastrin radioimmunoassay (RIA) has made earlier and more certain diagnosis possible, and therefore reevaluation of the surgical management of gastrinomas is necessary. Experience with 60 gastrinoma patients is reported. Comparison between the pregastrin RIA years (before 1970) and post-gastrin RIA years was made to determine whether there was evidence to support the continuation of medical treatment without attempts to resect the gastrinoma. Twenty-five cases were diagnosed in the pre-RIA years. Age at diagnosis ranged from 17 to 68 years (median, 45 years). All patients were operated on. Metastases were found in 56 percent. No tumor was identified in 8 percent. Tumor was resected for "cure" (normal fasting gastrin levels for two years postoperatively) in one patient. Seventeen patients have died, and tumor was the cause of death in 70 percent. The five-year survival rate was 44 percent; the 10-year survival rate was 40 percent. Thirty-five cases were diagnosed after 1970. Age at diagnosis ranged from 39 to 61 years (median, 46 years). Thirty patients were operated on. Metastases were identified in 23 percent and no tumor was found in 17 percent. Tumor was resected for "cure" in 30 percent of patients. Seven patients have died and tumor caused death in 42 percent. The five-year survival rate was 82 percent; the 10-year rate was 64 percent. Advances in diagnosis and surgical technique since 1970 have made early operative treatment applicable in patients with gastrinoma. Because death in most cases is caused by progression of the tumor, an aggressive surgical approach to resect the tumor is advised soon after the diagnosis of Zollinger-Ellison syndrome is established.

Benign and malignant gastrinoma

The advent of the histamine H2-receptor antagonists and the renewed interest in curative surgery in patients with gastrinoma have made the differentiation between benign and malignant tumors of critical importance. An analysis of 65 patients with gastrinoma followed for an average of 93 months revealed two distinct clinical groups: those with and those without hepatic tumors at initial examination or operation. Among the 14 patients with hepatic tumors, 12 had multiple liver metastases from pancreatic or duodenal primary tumors, and 2 had primary hepatic gastrinomas. Ten of the 14 patients (71 percent) died from tumor progression, and the total tumor-related mortality for this group was 79 percent. In contrast, only 1 of 15 patients (7 percent) with tumor in the lymph nodes died from a tumor-related cause (recurrent ulcer hemorrhage), and none died from tumor progression. Only a single patient with lymph node metastases at initial exploration went on to the development of liver metastases, which was found incidentally at autopsy 313 months later. Among 23 patients with either primary tumors only or no tumors found at laparotomy, there was only one tumor-related death and no deaths from tumor spread. Life-table analysis demonstrated a significantly decreased length of survival for patients with liver tumor compared with those without liver involvement. Multiple endocrine adenopathy syndrome was not a significant factor in survival. Serum gastrin levels were likewise nondiscriminatory. Six of 52 patients (12 percent), including three with tumor in the lymph nodes, were apparently cured by excision of all gastrinoma recognized at laparotomy. The cure rate was 23 percent for patients without multiple endocrine adenopathy syndrome or liver metastases. Hepatic metastases is a definitive marker for clinically malignant disease and portends a poor prognosis. Patients with gastrinoma confined to the lymph nodes uncommonly follow a malignant clinical course. Such patients have at least a 20 percent probability of surgical cure if they do not have multiple endocrine adenopathy syndrome.