Neuroendocrine Tumors of the Gastrointestinal Tract

Neuroendocrine tumors manifest in the gastrointestinal tract mainly as carcinoid and pancreatic islet-cell tumors. They comprise an interesting group of rare neoplasms that are derived from neuroendocrine cells interspersed within the gastrointestinal system amd throughout the body. Neuroendocrine tumors are well known for producing various hormonal syndromes and for their indolent clinical course in most patients, although some of these tumors do not produce hormones of clinical significance. Patients may have symptoms for many years before the diagnosis is suspected and confirmed. Therefore, the index of suspicion must be high in order to diagnose these tumors in a timely fashion.

Symptoms are caused by hormonal excess, local tumor growth, or metastatic spread. Therapy should be dictated by the severity of symptoms and the pace of the disease. Surgical extirpation remains the only curative modality for localized disease, but palliation of hormone-related symptoms can be achieved with the somatostatin analog octreotide (Sandostatin) in a significant proportion of patients. Combination chemotherapy, biologic response modifiers, vascular occlusion treatment, and newer somatostatin analogs are being used for the treatment of metastatic disease.