Prospective study of the need for long-term antisecretory therapy in patients with Zollinger-Ellison syndrome following successful curative gastrinoma resection

Abstract

A long-term cure is now possible in more than 30% of selected patients with Zollinger-Ellison syndrome who undergo gastrinoma resection. The need, however, for continued gastric acid antisecretory therapy in these patients remains controversial. The current study was designed to determine whether post-operative antisecretory therapy is needed in patients who have undergone successful gastrinoma resection and, if so, to attempt to define criteria with which to identify patients who require therapy. Twenty-eight consecutive patients who had previously undergone curative gastrinoma resection were prospectively studied. When antisecretory therapy was discontinued, 43% (12/28) of these patients developed gastro-oesophageal reflux, diarrhoea, acid-peptic symptoms or endoscopic evidence of acid-peptic disease within 2 weeks and were deemed to have failed a trial of antisecretory drug withdrawal. The remaining 57% (16/28) of patients who successfully discontinued antisecretory therapy were followed for a mean time of 31 months after withdrawal of therapy. Analysis of acid output studies pre-operatively, as well as at the time of drug withdrawal, demonstrated that patients who were unable to discontinue antisecretory therapy exhibited higher pre-operative maximal acid output values and higher basal acid output values at the time of attempted drug withdrawal than patients who were able to discontinue therapy. Despite these findings, there was significant overlap in acid output values between groups so that it was not possible to define specific acid output criteria for successful drug withdrawal. Pre-operative clinical characteristics, such as the presence or absence of gastro-esophageal reflux or acid-peptic disease, or post-operative laboratory values, such as the fasting serum gastrin level, did not correlate with the ability to discontinue antisecretory therapy. We conclude that following successful curative gastrinoma resection, 40% of patients still require antisecretory therapy and that both symptom evaluation as well as upper endoscopy should be used to guide attempted drug withdrawal. Although patients who are not able to discontinue therapy have significantly higher acid output measurements than those who are able to discontinue therapy, neither acid output criteria nor any other laboratory or clinical characteristics are able to predict the need for continued antisecretory therapy in these patients.

Figure 1.

Preoperative MA0 values in 28 patients with Zollinger-Ellison syndrome who underwent curative gastrinoma resection. (a) Data for the 16 patients who subsequently were able to discontinue all antisecretory medication and (b) data for the 12 patients who subsequently were unable to discontinue all antisecretory medication. The difference in means (each represented by the longer horizontal bars) between the two groups was significant using the Mann Whitney U-test (P = 0.045). The shorter horizontal bars represent the 95% confidence limits for each respective mean value. The numbers in parentheses refer to each individual patient’s number (see Tables 2 and 3). F = Female, M = Male, *Previous partial gastrectomy.

Figure 2.

Basal Acid Output (BAO) values at the time of antisecretory therapy withdrawal in 28 patients with Zollinger-Ellison syndrome who had previously undergone curative gastrinoma resection. (a) Data for the 16 patients who were able to discontinue all antisecretory medication and (b) data for the 12 patients who were unable to discontinue all antisecretory medication. The difference in means (each represented by the longer horizontal bars) between the two groups was significant using the Mann Whitney U-test (P = 0.005). The shorter horizontal bars represent the 95% confidence limits for each respective mean value. The numbers in parentheses refer to each individual patient’s number (see Tables 2 and 3). F = Female, M = Male, *Previous partial gastrectomy.