Diagnostic Performance of Cyst Fluid Carcinoembryonic Antigen and Amylase in Histologically Confirmed Pancreatic Cysts

OBJECTIVES: The objective of this study was to evaluate and validate cyst fluid carcinoembyronic antigen (CEA) and amylase in differentiating (1) nonmucinous from mucinous pancreatic cystic lesions (PCLs), (2) benign mucinous from malignant mucinous PCLs, and (3) pseudocysts from nonpseudocysts (amylase only). METHODS: A retrospective analysis of patients with histologically confirmed PCLs from February 1996 to April 2007 was performed. Cyst fluid CEA (n=124) and/or amylase (n=91) were measured and correlated to cyst type. RESULTS: Carcinoembyronic antigen levels (P=0.0001), but not amylase, were higher in mucinous versus nonmucinous cysts. The sensitivity, specificity, and diagnostic accuracy of CEA 200 ng/mL or greater for the diagnosis of mucinous PCLs were 60%, 93%, and 72%, respectively. Carcinoembyronic antigen levels did not differentiate benign from malignant mucinous cysts. Whereas amylase levels were higher in pseudocysts than nonpseudocysts (P=0.009), 54% of noninflammatory PCLs had a level greater than 250 IU/L, including mucinous cystic neoplasms (median, 6800 IU/L; interquartile range, 70-25,295 IU/L). Malignant mucinous cysts had lower amylase levels than benign mucinous cysts (P=0.0008). CONCLUSIONS: Cyst fluid CEA and amylase levels are suggestive but not diagnostic in differentiating PCLs. Unlike CEA, amylase may help differentiate benign from malignant mucinous cysts. Novel biomarkers are needed.