Limitations and suggestions for type 2 diabetes mellitus and pancreatic neuroendocrine tumors based on meta-analysis

We read with great interest the systematic review and meta-analysis by Cigrovski Berkovic et al published recently, which evaluated the association between type 2 diabetes mellitus (T2DM) and pancreatic neuroendocrine tumors (pNETs). The study identified T2DM as a risk factor for the development of pNETs and linked it to poor tumor-free survival. However, due to the limited number of studies and high heterogeneity, the role of metformin in the diagnosis and prognosis of pNETs remained inconclusive. We believe the study has some limitations regarding literature search, risk of bias assessment, and analysis of heterogeneity and publication bias. Expanding the search to more databases, applying more appropriate bias assessment tools, and using better statistical methods to evaluate heterogeneity and publication bias would strengthen the study's conclusions. Addressing these concerns could provide more robust evidence for understanding the diagnostic and prognostic impact of T2DM in pNETs.