Medical Management

With current medications, gastric acid hypersecretion can be effectively controlled in all patients with ZES. Total gastrectomy, once the only procedure for control of gastric acid hypersecretion, is no longer nec-

Figure 14-13. Endoscopic view of a gastrinoma. Here the tumor is seen as a submucosal mass on the wall of the duodenum (black arrow).

Figure 14-14. A, Using intraoperative endoscopy, a transillumi-nated duodenal gastrinoma appears as an opaque mass (white arrow) from the surgeon's perspective. Once identified, the tumor can be marked with a suture (Band C) and removed. In D, the gross specimen is shown (white arrow) contained within a margin of normal duodenal tissue.

Figure 14-13. Endoscopic view of a gastrinoma. Here the tumor is seen as a submucosal mass on the wall of the duodenum (black arrow).

Figure 14-14. A, Using intraoperative endoscopy, a transillumi-nated duodenal gastrinoma appears as an opaque mass (white arrow) from the surgeon's perspective. Once identified, the tumor can be marked with a suture (Band C) and removed. In D, the gross specimen is shown (white arrow) contained within a margin of normal duodenal tissue.

Figure 14-15. An illustration of the response in serum gastrin levels to secretin administration.The secretin bolus was administered at 0 minutes, and a significant elevation in serum gastrin is seen within 5 minutes after administration. The right panel shows the serum gastrin response to a standard meal in the same patient.

Figure 14-15. An illustration of the response in serum gastrin levels to secretin administration.The secretin bolus was administered at 0 minutes, and a significant elevation in serum gastrin is seen within 5 minutes after administration. The right panel shows the serum gastrin response to a standard meal in the same patient.

complete relief of symptoms. Omeprazole, lansoprazole, and pantoprazole are all members of a class of antisecretory drugs that inhibit gastric acid secretion by inhibiting the parietal cell apical H+, K+ adenosine triphosphatase. Recent studies have demonstrated that the intravenous dose of PPI is equal to the oral dose.18 H2 receptor antagonists are also effective, but progressively higher doses may be required to control symptoms and may be associated with a long-term failure rate. Relief of symptoms is not a reliable indicator of overall medical control of ZES, and measurement of BAO is necessary to adjust the dose of medication for effective treatment in each individual case. To allow healing of ulceration and prevent recurrences, gastric acid secretion should be maintained below 10 mEq/hour prior to the next dose of medication and should be maintained below 5 mEq/hour if prior ulcer surgery has been performed. It is particularly important to strictly control gastric acid secretion in cases of severe esophageal reflux with strictures because this promotes healing of lesions and reduces the need for esophageal dilation. With long-term medical control of ZES, there are also risks related to sustained achlorhydria. There have been cases reported of MEN type I patients who developed diffuse malignant gastric carcinoid tumors after prolonged treatment with omeprazole.4 It is therefore necessary to perform periodic gastric surveillance endoscopy on MEN type I patients treated with this agent for long periods.

Chemotherapy has been used in the treatment of gastrinomas but does not prolong survival. The most effective regimen involves a combination of doxorubicin, 5-fluorouracil, and streptozocin and may provide a 40% response.19 Hepatic artery chemoem-bolization has also been used but, again, with minimal efficacy. Likewise, the use of long-acting octreotide or interferon-a as antitumor agents has shown minimal effects on the malignant process.

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