Gastrointestinal carcinoid tumors: Current management strategies

BACKGROUND: Carcinoid or neuroendocrine tumors of the gastrointestinal tract, although characteristically indolent are also quite heterogeneous both with respect to histologic and endocrine features and with respect to clinical presentation and behavior. PURPOSE: This study was undertaken to review and summarize the current literature on classification controversies, site, specific carcinoid presentation and behavior, and diagnostic and management strategies for primary and advanced carcinoid tumors and the carcinoid syndrome. RESULTS: For carcinoid tumors oncologic results depend on the location of the primary tumor, extent of locoregional and metastatic disease, functioning status of the tumor, and the feasibility of complete surgical extirpation. Whereas favorable survival rates are typically observed for appendiceal and rectal primaries, less favorable rates are often observed for colonic and ileal tumors. A search for additional tumors is generally advised because multiple carcinoids and second neoplasms are not uncommon. Because of the indolent nature of the tumor and because these therapies have been shown to improve quality and quantity of life, otherwise fit patients with advanced carcinoid disease should be treated with aggressive medical and surgical therapies. Development of a malignant carcinoid syndrome indicates the presence of a functionally active carcinoid tumor and portends a poor prognosis. CONCLUSION: Gastrointestinal carcinoids, although malignant, behave differently from other carcinomas. Results are highly variable and must be individualized according to the site of the primary tumor, extent of spread, and general condition of the patient. A prolongation of quality life can often be accomplished through aggressive medical and surgical therapies.