S79 EUS-Guided FNA Cytology and EUS-Guided FNB Histology Comparison for Solid Pancreatic Lesions: Single Tertiary Care Center Retrospective Study

Abstract

Introduction: Endoscopic Ultrasound (EUS)-guided fine needle aspiration (FNA) and fine needle biopsy (FNB) are the current standard of care for making a diagnosis in solid pancreatic lesions (SPLs). There is conflicting data on the diagnostic utility of cytology and histology for diagnosing SPLs. The aim of this study was to evaluate the diagnostic utility of cytology and histology for diagnosing SPLs. Methods: A retrospective chart review was performed and all patients greater than 18 years with solid pancreatic lesions who underwent EUS between October 2019 and June 2021 were included. All the procedures were performed by a single advanced endoscopist and same needle (Acquire 22G, Boston Scientific) was used for all the procedures. Primary outcomes assessed were diagnostic advantage of cytology and histology in terms of providing a final diagnosis and diagnostic accuracy of cytology and histology with surgery specimen being the gold standard. Secondary outcomes assessed were relation of diagnostic accuracy to specimen length, no. of passes and size of lesion using t-test. Results: A total of 59 patients were included in our study with majority of them being males (52.4%). Mean needle passes per patient were 4.25 and average size of lesion on EUS was 3.7 cm. Turnaround time of histology was superior (2.7 days) as compared to cytology (3.3 days). In 39 cases, there was agreement between histology and cytology and 36/39 (92%) of those were malignant. Of the remaining 20 patients, histology was found to be more advantageous for 17 (85%) patients while cytology was more advantageous for the other 3 patients (15%). All 3 cases where cytology was advantageous were malignant. Of the 17 histologically advantageous cases, 15 (88%) were malignant. The histological diagnosis and cytological diagnosis were accurate in 7/8 (88%) and 3/8 (38%) respectively. T-test did not show any significant difference between two groups in relation to diagnostic accuracy to specimen length, no. of passes and size of lesion using t-test. Conclusion: Histology provided more accurate diagnosis for discordant cases and had faster turnaround times. However, there were malignant cases diagnosed on cytology which could have been missed if only histology was performed. Histology and cytology are important in conjunction with each other for maximizing the diagnostic accuracy for SPLs.