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Endoscopic ultrasound-guided techniques for diagnosing pancreatic mass lesions: Can we do better?
Andrew C Storm, Linda S Lee
Andrew C Storm, Linda S Lee, Division of Gastroenterology, Hepatology and Endoscopy, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, United States
Author contributions: All authors contributed to the manuscript.
Conflict-of-interest statement: Both authors have no conflicts of interest to disclose including no pharmaceutical or industry support.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/ licenses/by-nc/4.0/
Manuscript source: Invited manuscript
Correspondence to: Linda S Lee, Assistant Professor, Division of Gastroenterology, Hepatology and Endoscopy, Brigham and Women’s Hospital, Harvard Medical School, 75 Francis St., Boston, MA 02115, United States. firstname.lastname@example.org Telephone: +1-617-2780359 Fax: +1-617-2645132
Received: July 1, 2016 Peer-review started: July 4, 2016 First decision: August 8, 2016 Revised: August 24, 2016 Accepted: September 14, 2016 Article in press: September 14, 2016 Published online: October 21, 2016
Abstract The diagnostic approach to a possible pancreatic mass
lesion relies first upon various non-invasive imaging modalities, including computed tomography, ultrasound, and magnetic resonance imaging techniques. Once a suspect lesion has been identified, tissue acquisition for characterization of the lesion is often paramount in developing an individualized therapeutic approach. Given the high prevalence and mortality associated with pancreatic cancer, an ideal approach to diagnosing pancreatic mass lesions would be safe, highly sensitive, and reproducible across various practice settings. Tools, in addition to radiologic imaging, currently employed in the initial evaluation of a patient with a pancreatic mass lesion include serum tumor markers, endoscopic retrograde cholangiopancreatography, and endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). EUS-FNA has grown to become the gold standard in tissue diagnosis of pancreatic lesions.
Key words: Endoscopic ultrasound; Fine needle aspiration; Pancreatic cancer; Pancreatic mass; Endoscopy
© The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
Core tip: Evidence-based techniques to increase the diagnostic yield during endoscopic ultrasound-guided fine needle aspiration (FNA) of pancreatic masses include: (1) use of general anesthesia; (2) use smaller (22 or 25G) needles for transduodenal FNA; (3) use If histology is desired, use 19G or core biopsy needles; (4) use suction; (5) use the “fanning technique”; and (6) use on-site cytopathologist or perform 7 needle passes.
Storm AC, Lee LS. Endoscopic ultrasound-guided techniques for diagnosing pancreatic mass lesions: Can we do better? World J Gastroenterol 2016; 22(39): 8658-8669 Available from: URL: http://www.wjgnet.com/1007-9327/full/v22/i39/8658.htm DOI: http://dx.doi.org/10.3748/wjg.v22.i39.8658
Submit a Manuscript: http://www.wjgnet.com/esps/ Help Desk: http://www.wjgnet.com/esps/helpdesk.aspx DOI: 10.3748/wjg.v22.i39.8658
8658 October 21, 2016|Volume 22|Issue 39|WJG|www.wjgnet.com
World J Gastroenterol 2016 October 21; 22(39): 8658-8669 ISSN 1007-9327 (print) ISSN 2219-2840 (online)
© 2016 Baishideng Publishing Group Inc. All rights reserved.
INTRODUCTION Peripheral blood tumor markers, among the least invasive diagnostic tests, are not yet useful in the initial evaluation of a patient with a pancreatic mass. Cancer antigen (CA) 19-9, the leading tumor marker used to monitor pancreatic adenocarcinoma, has sensitivity and specificity as low as 70% and 68% respectively in diagnosing pancreatic adenocarcinoma, which has led to recommendations that it not be used routinely for diagnosis of this condition[1,2]. The CA 19-9 marker is, however, useful for post-surgical cancer surveillance. Because of this, a CA 19-9 level may be checked prior to any surgical intervention with curative intent and serum concentrations of the marker followed thereafter to detect disease recurrence.
Prior to the introduction of the EUS-FNA technique in the early 1990’s, pancreatic masses were diagnosed using ERCP and percutaneous biopsy techniques (Figure 1). ERCP is limited by a sensitivity of 49%-66% with pancreatic duct brushing, and a reported complication rate of pancreatitis up to 6%[4,5]. Use of CT or ultrasound guided biopsy carries a sensitivity of 62%-90% and specificity up to 100% with a randomized study demonstrating higher sensitivity (84%) for EUS-FNA compared to CT or ultrasound-guided biopsy (62%)[6-10]. In addition, the risk of tumor seeding into the peritoneum or along the percutaneous needle tract has led to avoidance of the percutaneous approach to tissue diagnosis, and studies have suggested a significantly lower risk of peritoneal carcinomatosis using EUS- FNA.
STANDARD OF CARE: EUS-FNA EUS-FNA is a safe, effective and efficient diagnostic tool in the evaluation of pancreatic mass lesions (Figure 2). Cytopathological specimens, and more recently core biopsies, may be obtained with high sensitivity (75%-98%), specificity (71%-100%), positive predictive value (96%-100%), negative predictive value (33%-85%) and accuracy (79%-98%) in the diagnosis of pancreatic cancer as compared to other modalities (Table 1)[12-16]. The one caveat to the high diagnostic yield of EUS-FNA is in the presence of chronic pancreatitis where sensitivity decreases to 74% compared to 91% with normal surrounding pancreatic parenchyma. Studies have shown that repeating EUS-FNA does improve diagnostic yield by enabling definitive diagnosis in about 63%-84% of patients[18-20]. Thus, EUS-FNA is the standard of care approach with repeat procedure recommended when the initial procedure is nondiagnostic.
EUS-FNA TECHNIQUE Numerous studies have aimed at determining the ideal EUS-FNA equipment and techniques to obtain a diagnosis when evaluating a pancreatic mass. In
basic principal, the target lesion is visualized by EUS, the most ideal lesion puncture approach is located, a chosen needle is advanced to puncture the lesion, the stylet is removed (if used), suction is applied (or not), the needle is advanced and withdrawn through the lesion to obtain cellular material, and finally the needle is removed and the tissue is collected for cytopathological examination.
Within this basic technique, more complex issues of scope positioning, selection of the puncture site, selection of the FNA needle, use of a stylet and suction, the technique of needle puncture, the number of needle punctures and use of an on-site cytopathologist have been studied (Table 2).
Scope positioning and puncture site The first task in performing high quality EUS-FNA involves locating the target tissue and determining the ideal needle approach. Perhaps for this reason, use of general anesthesia has shown to be associated with increased diagnostic yield (83% with vs 73%
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Storm AC et al . EUS techniques for diagnosing pancreatic mass lesions
Table 2 Techniques to increase diagnostic yield and decrease complications during endoscopic ultrasound-guided fine needle aspiration of a pancreatic mass
General anesthesia may increase yield Goal platelet count greater than 50000 and INR less than 1.5 to reduce risk of bleeding Hold antiplatelet and antithrombotic agents except aspirin or NSAIDS
Take caution when duodenal diverticulum is present to reduce risk of perforation Use Doppler to identify vasculature prior to needle advancement to avoid bleeding Use smaller (22 or 25) gauge needles for transduodenal FNA of the pancreatic head and uncinate If core histology samples needed, use 19G (in body or tail) or core biopsy needles Use suction Use the “fanning technique” during FNA Traverse the least amount of normal pancreatic tissue to reduce pancreatitis
Use on-site cytopathology or perform 7 needle passes
EUS-FNA: Endoscopic ultrasound-guided fine needle aspiration.
Table 1 Sensitivity and specificity of various diagnostic approaches to a pancreatic mass lesion
Modality Sensitivity Specificity
CA 19-9 70%-92% 68%-92% CT 77%-97% 56%-89% Transabdominal ultrasound 89% 99% Percutaneous FNA 62%-90% 98%-100% ERCP 49%-66% 96% EUS-FNA 75%-98% 71%-100% EUS-FNB 85%-95% 86%-100%
EUS-FNA: Endoscopic ultrasound-guided fine needle aspiration; EUS- FNB: Endoscopic ultrasound-guided fine needle biopsy; ERCP: Endoscopic retrograde cholangiopancreatography.
without) during EUS-FNA of pancreatic mass lesions. However this was a single center retrospective study and further study is required to confirm these results.
Limitations in approaching a pancreatic mass include difficult location, small size, necrosis and vascularity. Ideally the mass should be located in the six o’ clock position with the ultrasound transducer firmly applied to the luminal wall