INS and pancreatic neuroendocrine tumor: In addition, data on management of DM were recorded for oral versus insulin therapy, but data for the specific use of metformin was not collected, which would be important to evaluate as studies have recently shown metformin to be a potential contributor to survival in patients with pancreatic NETs [18,33,34] through a mechanism related to dose-dependent suppression of cell proliferation [35,36].