Only relatively recently has there been an increased clinical recognition and characterization of the heterogeneous group of rare gastroenteropancreatic neuroendocrine
neoplasms. Most have endocrine function and exhibit varying degrees of
malignancy. This review summarizes the derivation of these
tumors and the advances in their diagnosis and treatment over the past decade and a half. They are varied in their
biological behavior and clinical courses and, depending on their cell type, can produce different
hormones causing distinct clinical endocrine syndromes (
insulinoma [
hypoglycemia],
gastrinoma [
Zollinger-Ellison syndrome (ZES)], vasoactive intestinal peptideoma [
VIPoma], watery
diarrhea,
hypokalemia-
achlorhydria [
WDHA],
glucagonoma [
glucagonoma syndrome], and so forth). In addition to surgery for cure or palliation (by excision and a variety of other cytoreductive techniques), they each are treated with anti-hormonal agents or drugs targeted to each
tumor's specific product or its effects. The majority have benefited from the gut
hormone-inhibiting action of
somatostatin analogs. Because of their usual slow rate of growth it is recommended that, even when they are advanced and incurable, unlike in patients with common and more malignant
cancers, patients with
neuroendocrine tumors often can be palliated and appear to survive longer when managed with an active approach using sequential multimodality treatment. Advances in these various
therapies are reviewed and the beneficial emergence of global self-help patient support groups is noted.