| Because pancreatic ductal adenocarcinoma (PDAC) is one of malignant tumors with poor prognosis, early diagnosis is needed to improve its patient survival. Only 20% of the early-stage PDAC patients with stages 0 and 1 are symptomatic. Therefore, imaging is an essential tool for early diagnosis of PDAC. Indirect imaging findings such as dilatation of the main pancreatic duct and pancreatic cysts are possible clue findings to detect these early-stage PDACs. Among several imaging methods, the detection rate of these PDACs with endoscopic ultrasound (EUS) (76%) is higher than those with US (53%), CT (52%) and MRI (45%). In case that the other imaging methods depict one of the clue findings, subsequent EUS is recommended for their final diagnoses. During follow-up of branch-duct type IPMNs, 2-7% of patients are accompanied by PDACs elsewhere in the pancreas. EUS is expected to play the prominent role in early detection of these IPMN-concomitant PDACs. EUS-FNA has a good yield to obtain the pathological diagnosis of pancreatic cancer with a sensitivity of 90% and specificity of 95%. However, EUS-FNA has a limitation in diagnosis of small PDACs (≤10 mm), with its sensitivity being 40-70%. Contrast-enhanced harmonic EUS is useful for characterization of uncertain solid lesions in the pancreas and has a complimentary role to EUS-FNA, particularly for the small lesions with false-negative EUS-FNA findings. In conclusion, EUS is recommended to use in patients with indirect findings and uncertain solid lesions in the pancreas, which leads to early diagnosis of PDACs. |
