A Lower Cyst Fluid CEA Cut-Off Increases Diagnostic Accuracy in Identifying Mucinous Pancreatic Cystic Lesions

Context Carcinoembryonic antigen analysis of pancreatic cyst fluid is the tumor marker of choice for preoperatively differentiating mucinous from non-mucinous cystic lesions. Objective We aim to determine the most accurate cyst carcinoembryonic antigen cut-off value for distinguishing mucinous cysts from non-mucinous cysts with a focus on discriminating intraductal papillary mucinous neoplasms. Methods The results of pancreatic cyst aspiration carcinoembryonic antigen levels from a single center were retrospectively collected and evaluated for a diagnosis of a mucinous cyst and an assessment of malignancy using surgical histology as the diagnostic standard in 86 patients. Results The median cyst carcinoembryonic antigen level (ng/mL) was significantly higher in mucinous cysts compared with non-mucinous cysts (218 vs. 4.4; P=0.0006) and in intraductal papillary mucinous neoplasms compared with non-mucinous cysts (135 vs. 4.4; P=0.0027). A cyst carcinoembryonic antigen cut-off of 30.7 ng/mL was most accurate (87.2%) for differentiating mucinous from non-mucinous cysts and specifically for differentiating intraductal papillary mucinous neoplasms from non-mucinous cysts (82.7%). Cyst carcinoembryonic antigen levels were not significantly different between malignant and non-malignant mucinous cysts (68.5 vs. 238.1; P=0.51). Conclusions Pancreatic cyst fluid carcinoembryonic antigen can accurately differentiate histologically verified mucinous lesions, including intraductal papillary mucinous neoplasms, from non-mucinous lesions with an optimal cut-off that is much lower than previously reported values. Cyst carcinoembryonic antigen levels are not a reliable predictor of malignancy. Image: Sensitivity and specificity curves of cyst fluid CEA levels for differentiating mucinous from non-mucinous cysts.