Long-standing Diabetes Mellitus Increases Concomitant Pancreatic Cancer Risk in Intraductal Papillary Mucinous Neoplasms

Abstract Background: When monitoring patients with an intraductal mucinous neoplasm (IPMN), it is important to consider both IPMN-derived carcinoma and concomitant ductal adenocarcinoma (PDAC). The latter is thought to have a poorer prognosis. We retrospectively analyzed risk factors for concomitant PDAC in IPMN.Methods: In total, 547 patients with pancreatic cysts, including IPMN inappropriate for surgery on initial diagnosis, encountered from April 2005 to June 2019, were reviewed. We performed surveillance via imaging examination once or twice a year. Results: There were five intraductal papillary mucinous adenocarcinoma encountered. In comparison, there were 14 concomitant PDAC encountered. The prognosis was very poor in concomitant PDAC. All 14 PDAC patients had IPMN. In patients with IPMN, long-standing diabetes mellitus was the only significant risk factor for concomitant PDAC in both univariate and multivariate analysis ( P < 0.001 and P < 0.01, respectively). Further, patients with IPMN and diabetes mellitus had high frequency of concomitant PDAC (9.5%, 9/95) in a median 48-month surveillance period.Conclusions: When monitoring IPMN, concomitant PDAC should be considered, rather than IPMN-derived carcinoma. During this period, it may be prudent to concentrate on patients with other risk factors for PDAC, such as long-standing diabetes mellitus.