Comparative Study of Pathological and Imaging Findings in High-Grade Pancreatic Intraepithelial Neoplasia: A Multicenter Analysis by the Japan Study Group on Early Detection of Pancreatic Cancer (JEDPAC).
Abstract
Background
High-grade pancreatic intraepithelial neoplasia (HG-PanIN) is a non-invasive precursor of pancreatic ductal adenocarcinoma (PDAC) that is notoriously difficult to detect preoperatively because it lacks a discrete mass. Comprehensive imaging-pathology correlation studies focusing exclusively on HG-PanIN remain limited.
Methods
We retrospectively analyzed 50 patients with surgically resected, pathologically confirmed HG-PanIN without invasive carcinoma from 11 institutions participating in the Japan Study Group on Early Detection of Pancreatic Cancer (JEDPAC). Central pathological review classified lesions by ductal involvement pattern: Group A (main pancreatic duct [MPD] only), Group B (MPD plus branch ducts), and Group C (branch ducts only). Imaging findings on CT, MRI/MRCP, and endoscopic ultrasound (EUS) were correlated with pathological intraductal spread length. Diagnostic sensitivity of serial pancreatic-juice aspiration cytologic examination (SPACE) and EUS-guided fine-needle aspiration (EUS-FNA) was compared.
Results
The median follow-up was 63 months. Five-year overall survival was 92%, with remnant pancreas recurrence observed in 12%. MPD stenosis was consistently observed in MPD-involved lesions, even with minimal intraductal spread. Periductal hypoechoic areas and focal pancreatic atrophy increased with greater intraductal extension. Group C lesions frequently presented as cystic changes without MPD stenosis. SPACE showed a higher diagnostic yield than EUS-FNA in this cohort (77.1% vs. 25.0%), although this comparison was limited by the small number of EUS-FNA cases.
Conclusions
HG-PanIN exhibits distinct imaging patterns that correlate closely with ductal involvement and pathological extent. Localized MPD stenosis is the earliest imaging hallmark, and SPACE may be a useful diagnostic tool for non-mass-forming lesions. Integration of imaging, cytology, and pathology is essential for early detection of pancreatic cancer.