Intraoperative gastrin measurements during surgical management of patients with gastrinomas: experience with 20 cases

Despite recent advances in imaging techniques for endocrine tumors of the duodenum and the pancreas, preoperative localization of gastrinomas is inconsistent. Successful surgical management of patients with Zollinger-Ellison syndrome (ZES) and removal of all gastrin-secreting tumors remains a difficult task. The aim of the study was to evaluate the predictive value of intraoperative gastrin measurements for successful surgical treatment in patients with gastrinomas. Intraoperative gastrin measurements were performed in 20 patients with ZES who underwent resection of gastrin-secreting tumors. Gastrin was measured with a radioimmunologic assay in blood samples obtained from a peripheral vein and from the portal vein at the beginning of the operation (T0) and 20 minutes after removal of the lesion(s) (T1). In 16 patients gastrin was also measured 4 minutes after injection of secretin 3 U/kg (T2). Thirteen patients (65%) were cured by surgery. In two of them, peripheral and portal gastrin levels were normal at T0, precluding any further interpretation of the test. Completeness of surgery was confirmed by normalization of gastrin levels at T1 or the absence of stimulation at T2 (or both) in 10 patients. In only one case did the gastrin levels remain elevated at T1 despite a favorable outcome after surgery. In each of the seven patients (35%) who had persisting disease at 1 year, failure of the surgical procedure was predicted by persistence of high levels of gastrin at T1. In patients with hypergastrinemia, the positive predictive value of intraoperative gastrin measurement for completeness of surgery and the specificity were 100%. The negative predictive value was 88% and the sensitivity 91%. The overall accuracy of the test was 94%. In patients with ZES the normalization of systemic hypergastrinemia during surgery affirms the successful removal of all gastrin-secreting tumors. We conclude that intraoperative gastrin measurement is a valuable addendum for optimizing the surgical management of gastrinoma.