Comparison of Clinicopathological Features of Biliary Neuroendocrine Carcinoma with Adenocarcinoma.

OBJECTIVE This study aimed to demonstrate the clinical features and postoperative outcomes of extrahepatic bile duct (EHBD) neuroendocrine carcinoma (NEC) and compared with those of adenocarcinoma. METHODS We retrospectively analyzed patients with EHBD cancer operated in our institution between 1995 and 2015. RESULTS Of 475 patients, 468 had adenocarcinoma, while 7 had NEC/mixed adenoneuroendocrine carcinoma (MANEC) in this study. There were no notable preoperative and pathological features in patients with NEC/MANEC. However, patients with NEC/MANEC had a higher recurrence rate (51.8 vs. 100%, p = 0.016), poorer relapse-free survival (RFS) time (the median RFS time: 35 vs. 12 months, p = 0.006), and poorer overall survival (OS) time (the median OS time: 60 vs. 19 months, p = 0.078) than those with adenocarcinoma. Furthermore, patients with NEC/MANEC had higher rates of liver metastasis (11.9 vs. 85.7%, p < 0.001) than those with adenocarcinoma. In multivariable regression analysis, pathological type with NEC/MANEC was a risk factor for poorer RFS (p = 0.022, hazard ratio: 6.09). CONCLUSIONS Patients with NEC/MANEC have high malignant potential and poor outcomes. It is necessary to develop an effective approach and postoperative adjuvant treatment for patients with NEC/MANEC.