Diagnosis and management of gastrointestinal neuroendocrine tumors.

Neuroendocrine tumors of the gastrointestinal tract pose substantial diagnostic and therapeutic challenges. The numerous biologically active peptides and amines produced by these lesions generate complex clinical syndromes. Unfortunately, little is known regarding the genesis of these lesions. Recent advances in understanding of the pathobiology of these lesions has facilitated characterization of the biochemistry of tumor secretions. Similarly, pharmacological blockade of tumor bioactivity using somatostatin analogs, pharmacotherapeutic probes, or specific antagonists has enhanced treatment options. Effective biochemical palliation of tumor symptoms has in turn motivated a more aggressive approach to cytoreduction of these tumors by surgery or hepatic embolization. The combination of chemical blockade and surgical therapy may permit more extended and symptom-free survival for a significant proportion of patients. We evaluate the basic principles of diagnosis and management of gastrointestinal neuroendocrine tumors.