High pre-operative fasting blood glucose levels predict a poor prognosis in patients with pancreatic neuroendocrine tumour.

Background: Hyperglycaemia has been indicated as a pro-tumoural factor; however, the prognostic role of diabetes mellitus (DM) in pancreatic neuroendocrine tumours (panNETs) remains ambiguous, partly due to the effects of anti-diabetic drugs. We hypothesise that the blood sugar level per se affects the outcome of panNETs, and thus, we investigated the prognostic significance of the fasting blood glucose (FBG) level in resected panNET patients with no pre-existing DM.

Methods: A retrospective cohort study comprising 201 patients with radically resected non-functional panNETs was conducted. A total of 164 patients without pre-existing DM were further studied. An FBG level greater than 5.6 mmol/L was defined as high (otherwise, normal). Survival was evaluated using Kaplan-Meier methods and log-rank tests. Multivariate analyses for survival were performed using the Cox regression model.

Results: High FBG levels were significantly associated with poor overall survival (OS; p = 0.019) and recurrence-free survival (RFS; p = 0.011) in resected patients with panNET who had no pre-existing DM. The multivariable-adjusted hazard ratios (HRs) for mortality and recurrence comparing patients with high and normal FBG levels were 12.19 (95% confidence interval (CI) = 1.15-128.78, p = 0.038) and 2.43 (95% CI = 1.03-5.72, p = 0.042), respectively.

Conclusion: A pre-operative FBG level greater than 5.6 mmol/L is associated with poor OS and RFS metastasis for patients with panNET who undergo radical surgical resection.