A Prospective Study of EUS Features, Cyst Fluid CEA, and Lipase for Differentiation of Small Pancreatic Cystic Neoplasms: 61

Introduction: With the improvement of imaging technologies, pancreatic cystic lesions (PCLs) have been increasingly identified in recent years. Because of the risks of concurrent or later development of malignancy, the diagnosis and discrimination of these lesions are very important. However, the imaging modalities to differentiate the benign and malignant lesions remains limited. Methods: From April 2015 to May 2016, sixty-four cases before surgically resected firstly by endoscopic ultrasonography guided for fine-needle aspiration (EUS-FNA) were included in the analysis and according to the pathological results they were divided into two groups: low-risk and high-risk groups. Combined the clinical features with EUS images and cyst fluid of biochemical, tumor markers and cytological tests, the cases were compared with histopathology. Results: As the Sendai guideline of main duct 5 mm and cyst size 2.5 cm are the boundary values, using single factor chi-square analysis, both of them in low-risk and high-risk groups existed differences (P < 0.05). By analyzing the exponential cyst fluid of amylase, lipase, CEA and CA19-9, CA72-4, using nonparametric independent samples tests, the low risk and high risk groups had differences( P < 0.05). Cut-off point was obtained in ROC curve: the CEA was 10.33 ng/ml, the accuracy of 78.4%, sensitivity of 72.2% and specificity of 82.1%. When CA19-9 was 364.55 ng/ml, the accuracy of 75.7%, sensitivity of 72.2% and specificity of 75%. Further, using binary logistic regression analysis, it was found that cyst size, main duct, lipase and CEA were risk factors (P < 0.05), the cyst size OR: 5.362, 95% CI (1.437- 20.005), the main duct OR: 4.009, 95% CI (1.026 - 15.671), the lipase OR: 1.37, 95% CI (1.10 - 1.70), the CEA OR: 1.45, 95% CI (1.17 - 1.81). Cystic fluid cytology was compared with tissue pathology, using the matching design of card party test (McNemar) P = 0.267 (> 0.05), Kappa value: 0.594.Table 1: Binary logistic regression analysis of biochemical and EUS featuresFigure 1Conclusion: The risk factors of malignant pancreatic cystic neoplasms are as follows: the cyst size ≥2.5 cm, the main pancreatic duct ≥ 5 mm, CEA, and lipase. Cystic fluid cytology results and the tissue pathological results after surgical operation have no difference. For the surgical risk cases with the pancreatic cystic tumor, cyst fluid cytology analysis is helpful for selecting and making a best treatment plan.Figure 2Figure 3