Diabetes Is Associated With the Metastasis of Pancreatic Neuroendocrine Tumors.

Objectives Type 2 diabetes mellitus (T2DM) has been associated with several types of cancers, but the role of T2DM in pancreatic neuroendocrine tumors (pNETs) has not been systematically studied. Methods In this study, 299 patients with pNETs were recruited, and the clinicopathologic characteristics and prognosis of the diabetic and nondiabetic patients were compared. The association between metformin use and survival was assessed to examine whether metformin impacts the prognosis of pNETs patients. Results The prevalence of T2DM in the cohort was 20.7% (n = 62). The proportions of grade 3 tumors, distant metastases, and nerve invasion in pNET patients with T2DM were higher than those in patients without T2DM, and as a result, the survival was worse in patients with T2DM. After adjusting for the tumor stage, diabetic status was not associated with poor survival in the univariate analysis. The results of logistic regression showed that pNET patients with T2DM were at high risk for tumor metastasis (odds ratio [OR], 2.81; P = 0.001), nerve invasion (OR, 2.43; P = 0.029), and grade 3 tumors (OR, 4.97; P = 0.010). Conclusions Type 2 diabetes mellitus is associated with pNET metastasis and not an independent risk factor for poor prognosis in pNETs.