Zollinger-Ellison syndrome with fasting hypoglycaemia

Value of surgery in patients with negative imaging and sporadic Zollinger-Ellison syndrome

OBJECTIVES

To address the value of surgery in patients with sporadic Zollinger-Ellison syndrome (ZES) with negative imaging studies.

BACKGROUND

Medical control of acid hypersecretion in patients with sporadic ZES is highly effective. This has led to these patients frequently not being sent to surgery, especially if preoperative imaging studies are negative, due, in large part, to existence of almost no data on the success of surgery in this group.

METHODS

Fifty-eight prospectively studied patients with sporadic ZES (17% of total studied) had negative imaging studies, and their surgical outcome was compared with 117 patients with positive imaging results.

RESULTS

Thirty-five patients had negative imaging studies in the pre-somatostatin receptor scintigraphy (SRS) era, and 23 patients in the post-SRS era. Patients with negative imaging studies had long disease histories before surgery [mean ± SEM (from onset) = 7.9 ± 1 [range, -0.25 to 35 years]) and 25% were followed for 2 or more years from diagnosis. At surgery, gastrinoma was found in 57 of 58 patients (98%). Tumors were small (mean = 0.8 cm, 60% <1 cm). The most common primary sites were duodenal 64%, pancreatic 17%, and lymph node (10%). Fifty percent had a primary-only, 41% primary + lymph node, and 7% had liver metastases. Thirty-five of 58 patients (60%) were cured immediately postoperatively, and at last follow-up [mean = -9.4 years; range, 0.2-22 years], 27 patients (46%) remained cured. During follow-up, 3 patients died, each had liver metastases at surgery. In comparison to positive imaging patients, those with negative imaging studies had lower preoperative fasting gastrin levels; had a longer delay before surgery; more frequently had a small duodenal tumor; less frequently had a pancreatic tumor, multiple tumors, or developed a new lesion postoperatively; and had a longer survival.

CONCLUSIONS

Sporadic ZES patients with negative imaging studies are not rare even in the post-SRS period. An experienced surgeon can find gastrinoma in almost every patient (98%) and nearly one half (46%) are cured, a rate similar to patients with positive imaging findings. Because liver metastases were found in 7%, which may have been caused by a long delay in surgery and all the disease-related deaths occurred in this group, surgery should be routinely undertaken early in ZES patients despite negative imaging studies.

Serum gastrin in Zollinger-Ellison syndrome: I. Prospective study of fasting serum gastrin in 309 patients from the National Institutes of Health and comparison with 2229 cases from the literature

The assessment of fasting serum gastrin (FSG) is essential for the diagnosis and management of patients with the Zollinger-Ellison syndrome (ZES). Although many studies have analyzed FSG levels in patients with gastrinoma, limited information has resulted from these studies because of their small size, different methodologies, and lack of correlations of FSG levels with clinical, laboratory, or tumor features in ZES patients. To address this issue, we report the results of a prospective National Institutes of Health (NIH) study of 309 patients with ZES and compare our results with those of 2229 ZES patients in 513 small series and case reports in the literature. In the NIH and literature ZES patients, normal FSG values were uncommon (0.3%-3%), as were very high FSG levels >100-fold normal (4.9%-9%). Two-thirds of gastrinoma patients had FSG values <10-fold normal that overlap with gastrin levels seen in more common conditions, like Helicobacter pylori infection or antral G-cell hyperplasia/hyperfunction. In these patients, FSG levels are not diagnostic of ZES, and gastrin provocative tests are needed to establish the diagnosis. Most clinical variables (multiple endocrine neoplasia type 1 status, presence or absence of the most common symptoms, prior medical treatment) are not correlated with FSG levels, while a good correlation of FSG values was found with other clinical features (prior gastric surgery, diarrhea, duration from onset to diagnosis). Increasing basal acid output, but not maximal acid output correlated closely with increasing FSG. Numerous tumoral features correlated with the magnitude of FSG in our study, including tumor location (pancreatic > duodenal), primary size (larger > smaller) and extent (liver metastases > local disease). In conclusion, this detailed analysis of FSG in a large number of patients with ZES allowed us to identify important clinical guidelines that should contribute to improved diagnosis and management of patients with ZES.