Endoscopic Ultrasound-Guided Fine Needle Biopsy without Rapid On-Site Cytologic Examination: A Time to Change the Paradigm?

the past 2 decades, endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) has become the preferred procedure to obtain tissue for the diagnosis of gastrointestinal (GI) tract and adjacent organ lesions with acceptable accuracy and safety. EUS-FNA is reported to be a highly accurate diagnostic test for solid pancreatic neoplasms. A recent meta-analysis indicated that the pooled sensitivity and specificity for malignant cytology in solid pancreatic neoplasms was 85% and 98%, respectively. 1 In addition, many studies reported that the diagnostic accuracy of EUS-FNA in combination with immunohistochemistry is more than 80% for most subepi-thelial lesions (SET) of the GI tract. 2 Although EUS-guided tissue acquisition is currently considered an accurate, safe, and relatively inexpensive method for diagnosing lesions within the GI lumen or in organs or lymph nodes adjacent to the GI tract, it has some limitations. First, to improve diagnostic accuracy, an on-site pathologist should be present. The sensitivity of EUS-guided tissue acquisition decreases by 10% to 15%, the number of needle passes increases, and the overall procedure time is prolonged in the absence of an on-site pathologist. 3,4 Second, for some GI tumors , including GI stromal tumors, cytology yield is limited, and core tissue is sometimes requested by cytopathologists to identify cellular arrangement and tissue architecture for ade-These limitations lead to the need for large needles capable of obtaining core tissue. To date, the questions that many endosonographers struggle with in everyday clinical practice are " Is it necessary to obtain core tissue for improving diagnostic accuracy? " and " How could the diagnostic accuracy be improved in the absence of an on-site cytopathologist? " With respect to pancreatic tumors, studies using EUS-guided Trucut needle biopsy to obtain core specimens failed to definitively demonstrate overall diagnostic improvement compared to EUS-FNA because of technical problems (limitation of the transduodenal approach); further, there was an increased risk of complications. 7,8 One randomized controlled study comparing approaches using more flexible core biopsy needles (22-gauge [G] FNA and fine needle biopsy [FNB]) for the assessment of pancreatic solid tumors found no significant difference in the diagnostic yield and accuracy, technical success , and complications. 9 A study by Wittmann et al. 10 reported that improvement of diagnostic accuracy and sensitivity was only observed in cases where a combination of FNB and FNA was performed. Thus, currently, there is no clear indication that EUS-FNB is preferable to EUS-FNA for the assessment of pancreatic …