Zollinger Ellison Syndrome

The management of patients with MEN type I and gastrinoma is primarily medical. Because of the diffuse nature of the disease, surgical cure is only occasionally achieved. In most patients, management using H2 receptor antagonists and H+, K+-adenosine triphosphatase inhibitors can effectively control acid hypersecretion. The usual dose of omeprazole is 80 mg per day but can vary between 20 and 120 mg per day. Symptomatic relief only is insufficient to judge the adequacy of the dose of medication. Control of acid secretion must be confirmed using acid output measurements. Once acid output is controlled, the dose can be titrated down using acid output measurements and endoscopic findings as guides.55 It is important to decrease omeprazole to the lowest effective dose because long-term administration of omeprazole and other antisecretory agents may increase the risk of the development of gastric carcinoid tumors; rats treated with omeprazole had an increased risk of gastric ECLoma owing to achlorhydria-induced hypergastrinemia, which stimulates ECL cells.56 Security with medical management is based on the notion that this disease is considered relatively indolent compared with sporadic gastrinomas. However, the incidence of malignancy may be higher than previously thought. In a recent report, the incidence of malignancy was 47%, which is similar to that of sporadic gastrinomas.57 This has raised many questions as to when to intervene surgically. Surgery is usually reserved for patients who are good surgical risks and in whom the gas-trin-secreting tumor has been identified. Enucleation or resection in such patients may offer excellent palliation and occasionally cure. Our current practice is to use medical management for patients without imageable tumor (by CT scan or octre-oscan) and to explore and resect tumor in patients with imageable tumors. Some are more conservative and limit resection to those patients with larger tumors; for example, patients are medically managed when the tumor is no larger than 3 cm, and resection is employed when the primary gastrinoma is 3 cm or larger. This recommendation is based on data suggesting an increased risk of liver metastases with tumors > 3 cm.53 The risk in withholding the operative exploration until the tumor is 3 cm or greater is that the tumor will have metas-tasized to the liver prior to operation, possibly obviating a chance for cure. Furthermore, a recent study from our group has demonstrated a lack of correlation between tumor size and risk of metas-

Figure 16-7. Plot of primary enteropancre-atic tumor size versus metastases in patients with multiple endocrine neoplasia type I from Washington University. Tumor size did not correlate well with the presence or absence of metastatic disease, particularly with respect to nodal metastasis. Adapted from Lowney JK et al.54

Figure 16-7. Plot of primary enteropancre-atic tumor size versus metastases in patients with multiple endocrine neoplasia type I from Washington University. Tumor size did not correlate well with the presence or absence of metastatic disease, particularly with respect to nodal metastasis. Adapted from Lowney JK et al.54

tases, pointing out the hazard of a policy of monitoring known tumors.54 Still others recommend exploratory laparotomy and duodenotomy with resection of all duodenal and pancreatic tumors based on biochemical findings, even in the absence of imageable disease.

Was this article helpful?

0 0

Post a comment