Sa1443 CYST FLUID CARCINOEMBRYONIC ANTIGEN DIFFERENCE AMONG MUCINOUS CYSTIC NEOPLASMS AND INTRADUCTAL PAPILLARY MUCINOUS NEOPLASMS

Abstract

Cyst fluid carcinoembryonic antigen (CEA) is a useful marker for differentiating between mucinous from nonmucinous pancreatic cystic lesions (PCLs). However, the role of cyst fluid CEA levels in differentiation between mucinous cystic neoplasms (MCNs) and intraductal papillary mucinous neoplasms (IPMNs) as well as between the low risk (LR) and high risk (HR) mucinous lesions are scanty. We aimed to analyse this subject. This was a retrospective study of 52 patients with mucinous PCls diagnosed by cyto/histo-pathology out of 466 patients who underwent endoscopic-ultrasonography-guided fine-needle aspiration for PCLs over a seven-year period. On histology, low- and intermediate-grade dysplasia were considered as LR, and high-grade dysplasia and invasive carcinoma were considered as HR. Cyst fluid CEA was available for 52/102 mucinous and 44/121 nonmucinous PCLs with definitive diagnoses. The median cyst fluid CEA [Range] values were significantly higher in mucinous compared with nonmucinous cysts (1079 ng/mL [0.5-266510 ] versus 6 ng/mL [0.2-309]), and LR-MCNs compared with LR-IPMNs (7954.7 ng/mL, [299.6-53445] versus 51.3 ng/mL [16.8-132.2]), and HR-IPMNs compared with LR-IPMNs (2624 ng/mL [0.5-266510] versus 100 ng/mL [16.8-53445]). The AUROC was 0.930 (95% confidence interval [CI]: 0.5-0.8) to differentiate between LR-IPMNs and LR-MCNs and 0.921 (95% CI: 0.823-1.000) to differentiate between LR-IPMNs and HR-IPMNs using cyst fluid CEA. Both showed cutoff values of >100 ng/mL and demonstrated a sensitivity of 100/100, specificity of 75/75, and positive and negative predictive values of 66.7/78.9 and 100/100, respectively. Cyst fluid CEA is useful in differentiation between LR-MCNs from LR-IPMNs and LR-IPMNs from HR-IPMNs. Diagnosis using a cyst fluid CEA cutoff value of 100 ng/mL showed a 100% negative predive value in differentiating LR-IPMNs from LR-MCNs and HR-IPMNs.