Progression of pancreatic branch duct intraductal papillary mucinous neoplasms associates with cyst size

Abstract

Backgrounds: Most guidelines for management of patients with intraductal papillary mucinous neoplasms (IPMN) vary in proposed surveillance intervals and durations—these are usually determined based on expert opinions rather than substantial evidence. We evaluated the progression of branch duct (BD)-IPMN under surveillance at a single center, and determined optimal follow-up intervals and duration. Methods: We performed a retrospective analysis of 1369 patients with BD-IPMN seen the Seoul National University Hospital in Korea from January 2001 through December 2016. We included only patients whose imaging studies showed classical features of BD-IPMN, and collected data from each patient over time periods of at least 3 years. Results: The median annual growth rate of the cyst was 0.8 mm over a median follow-up time of 61 months. During surveillance, 46 patients (3.4%) underwent surgery due to disease progression after a median follow-up time of 62 months. Worrisome features were observed in 210 patients (15.3%) during surveillance, including cyst size of 3 cm or more (n=112, 8.2%), cyst wall thickening (n=51, 3.7%), main pancreatic duct dilatation (n=77, 5.6%), and mural nodule (n=43, 3.1%). Along with annual rate of cyst growth, incidences of main pancreatic duct dilatation and mural nodules associated with the sizes of cysts at detection (P< .001). Conclusion: In a retrospective analysis of patients with BD-IPMN followed for more than 5 years, we found most cysts to be indolent, but some rapidly grew and progressed. Surveillance protocols should therefore be individualized, based on initial cyst size and rate of growth.