Endoscopic ultrasound and fine-needle aspiration for pancreatic cancer

Background: Accurate staging of pancreatic cancer is essential for surgical planning, and identification of locally advanced and metastatic disease that is incurable by surgery. Advances in EUS, CT, and PET have improved the accuracy of staging and reduced the number of incomplete surgical resections. Tissue acquisition is necessary in non-surgical cases when chemoradiotherapy is considered. The complex regional anatomy of the pancreas makes cytologic diagnosis of malignancy at this region difficult without exploratory surgery. Although CT-guided fine-needle aspiration (FNA) is used for this purpose, reports of an increased risk of peritoneal dissemination of cancer cells and a false negative rate of nearly 20% makes this a less than ideal choice. The ability to position the EUS-transducer in direct proximity to the pancreas by means of stomach and the duodenum, combined with the use of FNA, increases the specificity of EUS in detecting pancreatic malignancies. Methods: The current literature regarding the accuracy of EUS with FNA in the evaluation of pancreatic cancer is reviewed. Results: EUS accuracy for tumor (T) staging ranges from approximately 78-94% and nodal (N) stage accuracy between 64 and 82%. EUS also enables FNA of lesions that are too small to be identified by CT or MRI, or too close to vascular structures to safely allow percutaneous biopsy. The accuracy for detecting invasion into the superior mesenteric artery and vein is lower than that for detecting portal or splenic vein invasion, especially for large tumors. EUS permits delivery of localized therapy such as celiac plexus neurolysis for pain control and direct intralesional injection of antitumor therapy. Conclusions: EUS in combination with FNA is a highly accurate method of preoperative staging of pancreatic cancer especially those too small to characterize by CT or MRI, and has the ability to obtain cytological confirmation.