Usefulness of Endoscopic Ultrasound Elastography and Contrast-Enhanced Endoscopic Ultrasound in the Diagnosis of Pancreatic Cancer of 10 mm or Less

Abstract

Abstract Background Pancreatic cancers (PCs) are often detected late, limiting patient prognosis. Early detection and accurate diagnosis, especially for small PCs, are thus crucial. This study investigated the use of endoscopic ultrasound elastography (EUS-EG) and contrast-enhanced harmonic EUS (CH-EUS) in diagnosing PCs of 10 mm or less. Methods This retrospective study at Nagoya University Hospital included 11 patients with pathologically confirmed PCs less than 10 mm. The patients underwent EUS with EUS-EG and/or CH-EUS between May 2005 and January 2022. The performance of these techniques and the interobserver variability was evaluated, with subsequent histopathological comparison. Survival outcomes were estimated using Kaplan–Meier survival analysis. Results The patients were predominantly male (63.6%) with a median age of 69 years and median tumor diameter of 9 mm. The EUS-EG showed excellent interobserver concordance (k-coefficient 0.815), with 80% of lesions classified as stiff. CH-EUS revealed a PC pattern that became hypovascular within 40 seconds during 1 minute of continuous observation in 63.6% of cases, with good to excellent interobserver concordance. Survival rates were 77.1% and 64.3% at 3 and 5 years, respectively. Differences in enhancement patterns on CH-EUS were observed based on histological type, differentiation, and tumor stage. Conclusions EUS-EG and CH-EUS demonstrated good concordance among observers and could distinguish stiffness and vascular patterns in small PCs. These techniques may aid early detection and accurate diagnosis of PCs less than 10 mm. Further larger prospective studies are needed to confirm these findings. Trial registration This study was retrospectively registered in the ethics committee of Nagoya University Hospital (Approval number: 2015 − 0316, date of approval: December 8th, 2015).