Survival of patients with gastroenteropancreatic neuroendocrine tumors and diabetes mellitus

Objectives: Diabetes mellitus (DM) is associated with an increased risk of gastroenteropancreatic neuroendocrine tumors (GEP-NETs), but the association between DM and GEP-NET survival is unknown. We evaluated disease characteristics and survival in individuals with DM and GEP-NETs. Methods: Using the Surveillance, Epidemiology, and End Results registry linked to Medicare (SEER-Medicare) claims database, we examined sociodemographics, GEP-NET characteristics, and treatment in patients with and without DM before GEP-NET diagnosis. We compared survival using univariate and multivariate analyses. Results: We identified 1858 individuals with GEP-NETs: 478 (25.7%) with DM and 1380 (74.3%) without. Significant differences in race (P = 0.002) were found between the DM and non-DM groups. Compared with individuals without DM, those with DM had more gastric (9.7% vs 14.9%), duodenal (6.5% vs 10.0%), and pancreatic (17.0% vs 21.8%), and less jejunal/ileal (18.1% vs 12.8%) NETs (P < 0.0001). Patients with DM had earlier stages (stage I, 37.0%; stage IV, 30.8%) than those without (stage I, 30.6%; stage IV, 36.4%; P = 0.0012). We found no difference in survival (multivariate hazard ratio, 0.97; 95% confidence interval, 0.76-1.23) between groups. Conclusions: Among patients with and without DM before GEP-NET diagnosis, we found differences in tumor location and stage, but not survival.