Long-term Surveillance of Branch-duct Intraductal Papillary Mucinous Neoplasms without Worrisome Features or High-Risk Stigmata

Long-term data evaluating clinical outcomes in patients with branch-duct Intraductal papillary mucinous neoplasms (BD-IPMN) without high-risk stigmata (HRS) or worrisome features (WF) remain limited.This observational cohort study included all patients diagnosed with BD-IPMN without HRS or WF between 2003 and 2019 who were enrolled in a prospective surveillance program. Time-to-progression analysis was performed using a cumulative incidence function plot and survival analysis was conducted using Kaplan-Meier.The median follow-up time for the 267 patient cohort was 44.5 months (interquartile range [IQR]: 24.1-72.2). Radiographic cyst growth was observed in 123 (46.1%) patients; 65 (24.3%) patients progressed to WF/HRS. Twenty-six (9.7%) patients were selected for resection during surveillance: 21 (80.8%) WF, 4 (15.4%) HRS; 1 (3.9%) transformed to mixed-duct. Of all the patients who underwent resection, 5 (19.2%) had adenocarcinoma, and 1 (3.8%) had carcinoma-in-situ. The probability of any radiographic progression was 21.3% (5-year) and 51.3% (10-year). For the entire cohort, there was 1.1% mortality secondary to pancreatic adenocarcinoma and 8.2% all-cause mortality. The 5-year overall survival rate was 91.5%, and at 10 years, 81.5%.Approximately one in four patients with nonworrisome BD-IPMN have progression to WF/HRS stigmata during surveillance. However, the risk of malignant transformation remains low. Surveillance strategy remains prudent in this patient population.