Background/aims: It is unclear whether tumor location, size, or the presence of multiple endocrine neoplasia type 1 (MEN-1) alters metastatic rate and survival in patients with pancreatic endocrine tumors. The purpose of this study was to determine the prognostic factors of survival and metastatic rate in patients with Zollinger-Ellison syndrome (ZES).
Methods: Data were analyzed from 185 consecutive patients with ZES who were followed up prospectively.
Results: Liver metastases were present in 24% of patients and correlated with the size of the primary tumor. Duodenal tumors were smaller than pancreatic tumors. Liver metastases occurred more often (P < 0.00001) with pancreatic than duodenal tumors, whereas the metastatic rate to lymph nodes was not different. Survival of patients with liver but not lymph node metastases was shortened. In patients with sporadic ZES, liver metastases were more common during the initial evaluation and survival was decreased compared with patients with MEN-1; however, during follow-up, an equal percentage of patients with and without MEN-1 developed liver metastases.
Conclusions: Survival was primarily determined by the presence of liver metastases. The frequency of liver metastases depends on the size and location of the primary tumor and on the presence of MEN-1 at the initial presentation. Metastases to the lymph nodes do not depend on these factors. A benign and malignant form of ZES exists.