Gastrointestinal surveillance in patients with multiple endocrine neoplasia type 1 and Zollinger-Ellison syndrome.

Backgrounds and aims: No guidelines exist for gastric acid assessment (GAA) or endoscopic surveillance for patients with Multiple Endocrine Neoplasia Type 1-Zollinger-Ellison Syndrome (MEN1-ZES). We aimed to analyze how GAA via nasogastric tube (NGT) and esophagogastro-duodenoscopy (EGD) altered acid suppression therapy and identify pre-GAA factors associated with post-GAA medication changes to inform which patients benefit from GAAs and/or EGDs for surveillance.

Methods: We assessed the following data from patients at our institution with MEN1-ZES from 2004-2018: 1) pre-GAA gastrointestinal symptoms; 2) serum gastrin levels; 3) gastric acid output (GAO); 4) EGD findings; 5) post-GAA changes in acid suppressing medication. GAO of <10 milliequivalents (mEq) of hydrochloric acid per hour (hr) indicated adequate acid suppression.

Results: Fifty-one patients who underwent 313 EGD/GAAs were identified; 263 EGD/GAAs were included. 51/263 EGD/GAAs (19.4%) led to increased acid suppression medication. Of these, 47.1% had GAO > 10 mEq/hr. Patients who had increases in acid suppression medication had significantly more symptoms, abnormal endoscopic findings, and higher GAOs compared to patients treated with same or decreased dose after endoscopy. All patients without symptoms prior to EGD/GAA were adequately suppressed. 8 NGT/GAAs done in 6 asymptomatic patients demonstrated adequate suppression.

Conclusion: GAA is inadequately sensitive for detecting which patients with MEN1-ZES will benefit from increased acid suppression medication. Patients with symptoms should undergo EGD. A majority of patients without symptoms will not require increased acid suppressing medication following GAA, but a few asymptomatic patients may have endoscopic findings warranting increased therapy. There is no clear clinical benefit for NGT/GAA in asymptomatic patients.