Pathological incidence of duodenopancreatic neuroendocrine tumors in the Netherlands: a Pathologisch Anatomisch Landelijk Geautomatiseerd Archief study.

Duodenopancreatic neuroendocrine tumors are rare, although current epidemiological studies worldwide suggest an incidence rate increase. We assessed the pathological incidence of duodenopancreatic neuroendocrine tumors for 18 years in The Netherlands. Standardized excerpts from pathological reports of all patients who had a diagnosis of duodenopancreatic neuroendocrine tumors from 1991 until 2009 were collected from the Pathologisch Anatomisch Landelijk Geautomatiseerd Archief and reviewed. This nationwide network and registry of histopathological and cytopathological data covers 100% of the pathological reports in The Netherlands. We identified 905 patients with pancreatic (n = 692) or duodenal (n = 213) neuroendocrine tumors. Most of these patients (69.4%) had a nonfunctional tumor. Functional tumors were diagnosed at a younger age compared with nonfunctional tumors (mean [SD] age, 52.3 [17.7] years vs 60.0 [14.6] years, respectively; P < 0.0001). The mean annual incidence rates per 1,000,000 persons over 1991 to 2009 were 2.54 for pancreatic and 0.81 for duodenal neuroendocrine tumors. The highest incidence was found in patients 65 to 79 years of age. The incidence of nonfunctional neuroendocrine tumors had increased significantly for 2 decades (P < 0.0001). The incidence of duodenopancreatic nonfunctional neuroendocrine tumors in The Netherlands increased over 1991 to 2009. The etiology for this change includes improved diagnostic techniques and clinical awareness, as discussed.