Pancreatic cysts are increasingly detected incidentally on imaging, yet clinical decision-making about who truly needs aggressive follow-up remains frustratingly imprecise. New prospective registry data from Italy offer some of the most reliable real-world evidence yet on which branch-duct pancreatic cysts can be safely monitored with minimal intervention — and which patients carry meaningfully higher malignancy risk.
The PANCY registry enrolled patients between 2015 and 2017 across multiple Italian centers, tracking 647 intraductal papillary mucinous neoplasms (IPMNs) prospectively through December 2021. Of 590 patients placed under active surveillance rather than immediate surgery, the overall malignancy rate for branch-duct IPMNs was 2.7%, rising sharply to 12.5% for mixed-type lesions. Two independent predictors of clinically relevant progression emerged at multivariate analysis: smoking history (odds ratio 2.2) and cyst diameter exceeding 15mm at diagnosis (odds ratio 7.1). Conversely, the combination of cyst size at or below 15mm plus age over 65 years conferred substantial protective effect (OR 0.1 on univariate analysis), most pronounced in non-smokers (OR 0.2).
This dataset matters for several reasons beyond its prospective design. Most prior IPMN surveillance literature is retrospective, introducing selection and ascertainment biases that prospective cohorts are specifically built to avoid. The finding that small cysts in older non-smokers carry very low malignancy risk challenges the reflexive intensification of surveillance in elderly patients — a group for whom repeated MRI or endoscopic ultrasound carries nontrivial burden and cost. That said, key limitations apply: this is an observational registry, not a randomized trial, and causal inference about risk factor contributions remains constrained. The cohort is also Italian and predominantly gastroenterology-referred, limiting generalizability. Additionally, the univariate protective combination of age and size was not confirmed at multivariate level, warranting cautious interpretation. Still, this represents genuinely useful confirmatory evidence for risk stratification frameworks currently guiding European and American IPMN guidelines.