Comparison of oncologic outcomes of extrahepatic cholangiocarcinoma according to tumor location: perihilar cholangiocarcinoma distal bile duct cancer.

Purpose: Extrahepatic cholangiocarcinoma is distinguished into perihilar cholangiocarcinoma (PHC) and distal bile duct cancer (DBC). The studies for each subtype have been conducted separately. This study compared oncological outcomes between PHC and DBC.

Methods: From 2001 to 2017, patients who underwent surgery at Seoul National University Hospital for PHC or DBC were enrolled. T stage was reclassified for tumor extent as 'confined to' or 'beyond' the bile duct (BD). In survival analysis, stage matching was performed based on tumor extent and lymph node (LN) metastasis.

Results: There were 680 patients enrolled: 295 with PHC and 385 with DBC. The R0 resection rate was higher in DBC (77.3% 89.9%, P = 0.001). Tumors confined to BD were more common in PHC (61.7% 37.7%, P = 0.001). The 5-year survival rate (5YSR) was higher in DBC patients (30.8% 47.8%, P = 0.001). After stage matching, DBC patients showed better 5YSR for tumors confined to BD/LN(-) (47.1% 64.3%), confined to BD/LN(+) (22.0% 35.0%), beyond BD/LN(-) (21.9% 49.8%), and beyond BD/LN(+) (9.6% 26.9%). The overall recurrence rate was higher in PHC (59.7% 51.9%, P = 0.045), with no difference in the recurrence types between two groups. Radiation therapy was effective for patients with advanced stage disease (5YSR: 35.8% 29.5%, P = 0.022); adjuvant chemotherapy was effective for patients receiving R1 resection (5YSR: 37.3% 13.2%, P = 0.040).

Conclusion: Differences were identified in oncological outcomes between PHC and DBC, including pathologic findings and survival outcomes.