Rarely, they may be a part of the multiple endocrine neoplasia syndrome type 1. Small bowel carcinoids may occur in multiple sites in the same patient. Symptoms may be chronic, suggesting partial obstruction or intussusception. Patients with carcinoid tumor are at increased risk for synchronous or metachronous second malignancies. Because of efficient hepatic metabolism of vasoactive amines, the carcinoid syndrome rarely occurs in the absence of liver metastases.
Surgical resection is the standard curative modality.
Even in patients with distant metastasis, the disease is usually very indolent with median survivals of 2 years or more. For such patients, excellent palliation may be achieved by bypass surgery, or resection of large hepatic metastases that may produce the carcinoid syndrome. Radiation therapy has a minor role in patients with regionally unresectable disease and may palliate the pain of bone metastasis. Patients with carcinoid syndrome can usually be effectively palliated by injections of somatostatin analogue 2 to 3 times a day. Some patients benefit from the use of interferon alfa.