Zollinger-Ellison syndrome. Diagnosis and therapy.
Zollinger-Ellison syndrome (ZES) is characterised by refractory peptic ulcer disease, severe diarrhoea and gastric acid hypersecretion associated with an islet-cell tumor of the pancreas (gastrinoma). ZES is sporadic in 62-80% of cases and in 20-38% of cases is associated with multiple endocrine neoplasia type 1 (MEN 1). The diagnosis of ZES is certain when the plasma gastrin is >1000 pg/mL and the basal acid output is >15 mEq/h in patients with an intact stomach, >5 mEq/h in gastrectomised patients, or when the hypergastrinemia is associated with a pH <2. Treatment is based on the control of gastric acid hypersecretion and of the malignant tumor and its possible metastases. Proton pump inhibitors are the most effective antisecretory drugs and can be administered at high dosages without drug-related adverse effects. All sporadic, localised gastrinomas should be excised if possible. When liver metastases are also present, their debulking may improve symptoms and survival, and facilitate medical treatment. There is some controversy as to the surgical approach for gastrinomas associated with MEN 1. Somatostatin analogues can be useful in reducing gastric acid hypersecretion, serum gastrin and gastric enterochromaffin-like cells, and can thus contribute to treating the disease more effectively. Their antiproliferative effect can be used in treating liver metastases. Chemotherapy and/or interferon are indicated only in patients with malignant progressive disease. Embolisation and chemoembolisation are effective in controlling clinical symptoms; however, they do not seem to improve survival.