Introduction : Biliary intraepithelial neoplasia (BilIN) is a noninvasive precursor lesion which can progress to Cholangiocarcinoma (CC). BilIN is often found synchronously adjacent to the tumor or at the surgical resection margin of resection CC.The aim of this study was to elucidate its prognostic effect on survival after resection for CC.

Methods : We retrospectively analyzed patients with CC who underwent curative surgery from 2010 to 2017. Patients whose resection margins were positive for invasive cancer were excluded. CC associated with IPNB were excluded from analysis.

Results : There were 142 patients who underwent curative surgery for CC. BilIN was detected in 42 patients (29.5%) and showed a significantly higher prevalence in extrahepatic CC (90.5%) than in intrahepatic CC (9.5%).T3 stage and N1 stage were significantly more common in the BilIN-negative group than in the BilIN-positive group. On univariate analysis, extrahepatic hepatic CC patients with BilIN lesions significantly showed better disease free survival (p=0.05). Also, although not significant, extrahepatic CC patients with BilIN lesions revealed better overall survival. In addition, presence of any type of BilIN lesion at the resection margin was not associated with survival. On multivariate analysis, presence of BilIN lesion, irrespective of location, was significantly associated with better disease free (HR=1.959, 95% CI 1.026-3.743, p=0.042) and overall survival (HR=2.140, 95% CI 1.006-4.552, p=0.048) in extrahepatic CC patients.

Conclusions : The presence of BilIN lesions was significantly associated with better disease free and overall survival in extrahepatic CC patients. However, larger studies with longer follow up are needed to accurately determine its clinical significance.