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

Abstract

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