Optimizing branch-duct intraductal papillary mucinous neoplasms surveillance: Data-driven dimensional grouping for risk stratification and cost-effectiveness

BACKGROUND The rising detection of branch-duct intraductal papillary mucinous neoplasms (BD-IPMN) has led to updated surveillance guidelines, yet the true malignant transformation rate and the cost-effectiveness of these strategies remain uncertain. Current protocols are based on expert opinion rather than validated data, leading to conflicting recommendations and significant healthcare costs. This study addresses the need for an evidence-based approach to optimize surveillance by identifying robust risk factors and creating a more efficient protocol. AIM To determine the rate of BD-IPMN malignant progression, identify independent risk factors, and develop a surveillance protocol optimized for both diagnostic accuracy and cost-efficiency. METHODS This is a multicentric retrospective cohort study using prospectively collected data from four Italian tertiary care centers. A total of 333 patients undergoing surveillance for BD-IPMN between January 2017 and August 2023 were included. Multivariate Cox regression and segmentation analysis identified predictors and derived novel size thresholds for malignancy risk stratification. We then compared the diagnostic accuracy and 3-year surveillance costs of a proposed protocol against the Fukuoka 2017 and Kyoto 2024 guidelines. RESULTS Among 333 patients (median follow-up, 4 years), malignant transformation occurred in 11 (3.3%). Independent risk factors for malignancy included high risk stigmata (HRS) [hazard ratio (HR) = 4.4, 95% confidence interval (CI): 1.1-17.8, P = 0.04], the development of ≥ 2 worrisome features (WFs) (HR = 5.8, 95%CI: 1.5-22.4, P = 0.01), and cyst size (HR = 2.0, 95%CI: 1.3-3.0, P < 0.001). Two new cut-offs (1.5 cm and 3.0 cm) defined dimensional categories with distinct malignant potential (HR = 6.6, 95%CI: 1.7-25.4, P = 0.007, HR = 9.8, 95%CI: 1.1-89.7, P = 0.04). A proposed surveillance protocol preserved diagnostic accuracy while reducing 3-year costs by 11% vs Fukuoka and 21.4% vs Kyoto (P < 0.001). Scenario analysis confirmed cost-effectiveness. CONCLUSION IPMN degeneration is rare. HRS and at least two WFs may independently predict malignancy. Our surveillance protocol based on data-driven size cut-offs (1.5 cm and 3 cm) may enhance cost-effectiveness over current guidelines while maintaining diagnostic precision.