Factors Associated With the Risk of Progression of Low-Risk Branch-Duct Intraductal Papillary Mucinous Neoplasms

Importance Branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs) are common pancreatic preneoplastic lesions, but their surveillance is not personalized. Objective To investigate patient- and cyst-related factors associated with progression into worrisome features (WFs) or high-risk stigmata (HRS) categories of BD-IPMNs. Design, Setting, and Participants Cyst- and patient-related factors of consecutive BD-IPMNs without WFs or HRS in 540 patients diagnosed from 2009 to 2018 with at least 12 months' surveillance until February 28, 2020, were registered in a 2-center ambispective cohort study in Italy. In a subgroup, the ABO blood group was studied for the first time in this setting. Exposure Cyst-related and patients-related factors and ABO blood group. Main Outcomes and Measures The study outcome was the appearance of WFs or HRS according to the 2017 International Association of Pancreatology guidelines. Survival probability was calculated using Kaplan-Meier curve and risk factors identified by Cox proportional hazards regression. ABO blood group was inferred through genotypes with DNA extraction. Results Of 540 patients with BD-IPMNs (median age, 66 years [interquartile range, 58.5-72.0 years]; 337 women [62.4%]) undergoing surveillance for a median of 51.5 months (interquartile range, 28-84 months) for 2758 person-years, 130 patients (24.1%) experienced progression. Probability of progression was 3.7% at 1 year, 23.4% at 5 years, and 43.3% at 10 years; 15 patients (2.8%) underwent surgery, 7 patients (1.3%) had malignant histologic findings, and 3 patients (0.56%) died of pancreatic-associated disease. Initial cyst size greater than 15 mm (hazard ratio [HR], 2.05; 95% CI, 1.44-2.91), body mass index greater than 26.4 (HR, 1.72; 95% CI, 1.19-2.50), and heavy smoking (HR, 1.81; 95% CI, 1.14-2.86) were significant independent factors associated with progression risk. The AA blood genotype was also associated with progression risk (HR, 3.49; 95% CI, 1.04-11.71) compared with the OO genotype in the investigated subgroup. Conclusions and Relevance This analysis of factors associated with progression of BD-IPMNs according to recent guidelines suggests that cyst size alone is not a reliable factor for estimation of progression risk; however, along with other readily available data, size is helpful for planning personalized surveillance of BD-IPMNs. This cohort study examines the use of patient- and cyst-related factors available at baseline for estimation of the risk of progression in patients with branch-duct intraductal papillary mucinous neoplasms. Question Can factors that are readily available at diagnosis be used to estimate the risk of progression of branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs)? Findings In this cohort study that included 540 patients under surveillance for a median of 51.5 months, initial cyst size greater than 15 mm, body mass index greater than 26.4, and heavy smoking were associated with progression risk of BD-IPMNs. The AA blood genotype was also associated with progression risk. Meaning Results of this study suggest that cyst size alone is not a reliable factor to estimate progression risk, but along with other readily available data, size is helpful for planning personalized surveillance of BD-IPMNs.