Previous studies have demonstrated an association between type 2 diabetes mellitus (T2DM) and several types of cancers. However, the role of T2DM in pancreatic neuroendocrine tumors (pNETs) has not been systemically studied.
A retrospective, follow-up cohort analysis including 299 patients with pNETs was performed. The clinicopathologic characteristics between diabetics and nondiabetic were compared. The overall survival (OS) and progression-free survival (PFS) separated by diabetics and nondiabetic status were analyzed. The association between metformin use and survival was assessed to confirm whether metformin has an impact on prognosis of pNETs.
The prevalence of T2DM was 20.7% (n = 62) in the cohort. For both OS and PFS, diabetic status was associated with a dismal outcome in univariate analyses, and the association was not exist when controlled by stage. The proportion of grade 3 tumor, distant metastasis and nerve invasion was higher in pNETs patients with T2DM than that of patients without T2DM. According to the result of logit regression, pNETs patients with T2DM were at high risk of tumor metastasis (OR = 2.81, P = 0.001), nerve invasion (OR = 2.43, P = 0.029) and grade 3 tumor (OR = 4.97, P = 0.010). Multivariate analysis demonstrated that T2DM was not an independent predictor of OS (P = 0.742) and PFS (P = 0.917). In subset analysis, no significant differences were observed for OS and PFS in subgroup according to their metformin usage.
T2DM is associated with pNETs growth and metastasis, and is not an independent risk factor of poor prognosis in patients with pNETs. No significant association is found between metformin use and survival in pNETs patients.
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