OBJECTIVE: To evaluate the prognostic impact of invasive nodules (IN) detected by contrast-enhanced endoscopic ultrasound (CE-EUS) in intraductal papillary mucinous neoplasms (IPMNs) with high-risk stigmata (HRS) and their role in guiding surgery. SUMMARY OF BACKGROUND DATA: IPMNs with HRS are surgical candidates, but their long-term outcomes and the need for surgery in all patients remain unclear. METHODS: This single-center retrospective study included 257 patients with IPMN and HRS, comparing CE-EUS and CT for detecting IN. It evaluated overall survival (OS) and disease-specific survival (DSS) between surgical and observation groups and identified factors influencing OS through multivariate analysis. RESULTS: Median follow-up was 53.4 months. Of 257 patients, 226 (87.9%) underwent surgery and 31 (12.1%) were observed. Non-IN patients showed significantly better 5-year OS and DSS than IN patients in both groups (surgery, OS 87.9% vs. 53.2% and DSS 96.9% vs. 64.3%
observation, OS 84.7% vs. 23.3% and DSS 100% vs. 32.8%). Non-IN group that underwent surgery had better 10-year DSS than those in the observed group (96.9% vs. 66.7%). However, with an age-adjusted Charlson comorbidity index (ACCI) ≥5, there was no significant difference in 5-year OS between the groups (77.1% vs. 79.3%, P=0.7036). CE-EUS showed higher sensitivity than CT detecting IN (P=0.042). Independent predictors of poor OS included ACCI ≥5, nonsurgery, mural nodule ≥10 mm, and IN. CONCLUSIONS: CE-EUS effectively detected IN, significantly impacting the prognosis of IPMN with HRS. Its superior sensitivity to CT and ability to predict OS/DSS highlight its importance in guiding clinical management.