Submitted, Not Presented: Biliary/Pancreas.

Abstract

Introduction: Estimating malignant potential of cystic lesions of the pancreas poses a significant clinical challenge. Mucinous cysts, characterized by elevated carcinoembryonic antigen (CEA), are thought to have high malignant potential. Many physician rely upon a threshold CEA level of 192 ng/mL in assessing malignant potential of these lesion and whether invasive surgical resection should be recommended. This approach, however, is controversial, with some recent studies calling the usefulness and reliability of CEA testing into question. Herein, we review our experience with patients who have undergone endoscopic sampling of pancreatic cystic lesions via endoscopic ultrasound with fine needle aspiration (EUS-FNA) and opted for surgical. Methods: We conducted a retrospective study at our tertiary care institution of patients who underwent EUS-FNA of a pancreatic cystic lesion followed by surgical resection of the same lesion between 2009-2017. This cohort of patients was divided into patients whose surgical resection revealed benign surgical pathology and those whose resection revealed malignant surgical pathology. Our primary outcome was a comparison of CEA levels between these two groups. Secondary analysis included assessment of differences in patient or lesion characteristics including patient age, patient gender, cyst size, cyst location and other cyst molecular markers. Results: Our study identified 53 patients who met our inclusion criteria. Of these, 15 had benign surgical pathology and 38 had malignant surgical pathology. The group of patients found to have malignant surgical pathology was noted to have a significantly higher CEA level on their pre-operative EUS-FNA. In addition, we noted a trend toward a lower amylase in the group found to have malignant pathology. The two groups were similar in terms of patient age, patient gender, and lesion size. (Table 1) In assessing the CEA threshold of 192ng/mL, our data indicate a sensitivity of 63% and specificity of 60%.Table: Table. Comparison of pancreatic cyst characteristics in patients with benign or malignant surgical pathology after pancreatic surgical resectionConclusion: Our findings support the notion that higher CEA levels, in general, will correlate with higher malignant potential, however the relatively low sensitivity and specificity of the commonly used CEA threshold indicates that management decisions should not be solely based on the CEA value. Further study is needed to fully define indications for invasive surgical interventions in these complex cases.