Primary Site Predicts Grade for Gastroenteropancreatic Neuroendocrine Tumors.

: Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare and abstruse neoplasms with increasing incidence and clinical relevance. The National Cancer Data Base was examined to identify GEP-NET cases from 2004 to 2013. In total, 39,454 patients diagnosed with GEP-NET were identified. Median age was 61 years. Majority was female (50.13%), white (79.49%), and had low-grade neoplasms (84.39%). On univariate analysis, age, sex, race, primary site, tumor size, and regional lymph node involvement were associated with tumor grade (P < 0.0001). On multivariate analysis, older age [odds ratio (OR) = 9.57], gender (male, OR = 1.29), and race continued to be associated with high-grade neoplasms. The primary site also remained a significant predictor of tumor grade. High-grade neoplasms were more likely to arise from the esophagus (OR = 317.75), hepatobiliary system (OR = 23.15), colorectum (OR = 14.37), ampulla of Vater (OR = 11.61), and stomach (OR = 7.84) compared with the appendix (OR = 5.41), pancreas (OR = 5.31), and small bowel (referent). The tumor grade for GEP-NETs is highly dependent on the primary site, suggesting different sites may be biologically distinct diseases. A personalized approach to GEP-NET treatment, tailored to the site of origin, is imperative.