Gastrointestinal endocrine cancers and nodal metastasis: biologic significance and therapeutic implications

Gastrointestinal endocrine tumors consist of pancreatic endocrine neoplasms and carcinoid tumors. Except for insulinoma, a majority of gastrointestinal endocrine tumors are malignant. With improved medical treatment of syndromes of hormonal excess, growth of the primary tumor and metastatic spread has increasingly become an important determinant of long-term survival. Although few randomized, prospective data are available given the rare occurrence of malignant gastrointestinal endocrine tumors, surgery appears to be the only potentially curative treatment for malignant endocrine tumors, and complete resection of localized or regional nodal metastases provides the highest probability of cure. Surgery may also be the most effective treatment for hepatic metastases if most or all of the tumor can be resected, and patients with solitary, localized metastatic disease appear to benefit most. Symptoms from extensive metastases may respond to chemotherapy or octreotide. Gastrointestinal endocrine tumors are generally indolent, slow-growing neoplasms, and when symptoms are adequately controlled, patients can live comfortably and productively for many years with metastatic disease.