Zollinger-Ellison syndrome in 2006: concepts from a clinical point of view

Zollinger-Ellison syndrome (ZES) is characterised by peptic ulcers of the upper gastrointestinal tract failing to heal despite maximal medical therapy, diarrhoea and marked gastric acid hypersecretion associated with a gastrin-secreting tumour (gastrinoma). ZES might be associated with multiple endocrine neoplasia type 1. The main diagnostic features are hypergastrinemia and acid hypersecretion. When these parameters give borderline results, provocation test (with secretin or calcium) may be required. To identify the localisation of gastrinoma several imaging techniques have been proposed. Somatostatin receptor scintigraphy is capable to localise the tumour in 80% of the cases and to identify it even in anatomic sites other than pancreas and duodenum. Endoscopic ultrasonography has a sensitivity as high as 79-93% and a specificity of 93%. The 2 main principal therapeutic strategies are to control both the gastric acid hypersecretion and the growth of the neoplasia. Proton pump inhibitors (PPIs) are the drugs of choice for patients with ZES. Furthermore, safety of PPIs in the maintenance therapy has been proven both in short- and in long-term studies. The best surgical treatment is excision of gastrinoma before metastatic spread has occurred. Somatostatin-analogues can reduce both gastric acid hypersecretion and serum gastrin levels. Moreover, they have an antiproliferative effect. Chemotherapy, interferon and embolisation are indicated in rapidly evolving tumours or in cases in which the tumoral symptoms cannot be treated by other approaches.