The Levels of Tumor Markers in Pancreatic Neuroendocrine Carcinoma and Their Values in Differentiation Between Pancreatic Neuroendocrine Carcinoma and Pancreatic Ductal Adenocarcinoma

Objectives The levels of tumor markers in pancreatic neuroendocrine carcinoma (PNEC) are unknown, and imaging findings of PNEC and pancreatic ductal adenocarcinoma (PDAC) have overlaps. In this study, we show the tumor markers in PNEC and evaluate their values for distinguishing PNEC from PDAC. Methods Thirty-three cases of PDAC and 21 cases of PNEC were retrospectively evaluated. The demographic information and clinical data were reviewed. Results Pancreatic neuroendocrine carcinoma was usually misdiagnosed (57.1%) as PDAC based on imaging findings. Abnormal carbohydrate antigen (CA) 19-9, carcinoembryonic antigen (CEA), and -fetoprotein (AFP) were observed in 19.0% to 28.6% of PNECs. Abnormal CA 19-9 and CA 125 levels were more common in PDAC than in PNEC (P < 0.05). Higher level of AFP was more common in PNEC than in PDAC (33.3% vs 3.0%, P < 0.05). The cutoff value of CA 19-9 for detecting PNEC was calculated as 38.5 U/mL or less with 0.788 sensitivity and 0.800 specificity. Carbohydrate antigen 19-9 (odds ratio [OR], 22.9; 95% confidence interval [CI], 2.94-179.3), AFP (OR, 0.08; 95% CI, 0.012-0.564), and CA 125 (OR, 17.4; 95% CI, 1.13-267.3) were predictors in differentiating PDAC from PNEC. Conclusions Carbohydrate antigen 19-9, AFP, and CA 125 have potential for distinguishing hypovascularized PNEC from PDAC.