Analysis of Clinical Characteristics and Survival in Patients With Functional Neuroendocrine Tumors of Gastrointestinal Origin.

OBJECTIVES: Functional neuroendocrine tumors (FNETs) are characterized by excess secretion of disease-specific hormones. In this study, we attempted to define survival trends in patients with some of these uncommon tumors.

METHODS: Using the Surveillance, Epidemiology, and End Results database, 529 patients with FNETs (gastrinoma, insulinoma, glucagonoma, VIPoma, and somatostatinoma) were identified. We analyzed patient and tumor characteristics, overall survival, and cancer-specific survival.

RESULTS: Functional neuroendocrine tumors were found to be more predominant in White patients older than 50 years. Most common FNETs were gastrinoma (56.3%) and insulinoma (23.8%). Most FNETs were found in the pancreas, with the second most common location being the small bowel. Surgery was the primary modality of treatment, used in 55.8% of the cases. Median overall survival was 9.8 years (95% confidence interval [CI], 7.9-11.8) with a median cancer-specific survival of 18.5 years (95% CI, 12.8-24.2). In multivariate analysis, age >50 years (hazard ratio [HR], 2.7; 95% CI, 2.02-3.64), no surgical resection (HR, 1.88; 95% CI, 1.43-2.46), metastasis (HR, 3.0; 95% CI, 2.0-4.5), and poor differentiation were associated with poor survival. Site and histology did not have a significant impact on survival (P = 0.82 and 0.57 respectively).

CONCLUSIONS: Our study highlights the most important prognostic factors for gastrointestinal FNETs.