Different biliary tract cancers, same operation: Importance of cancer origin in patients with hilar-invading tumors.

Background and aims: For patients with biliary tract cancer involving the hepatic hilum, major hepatic resection with extrahepatic bile duct resection may be required. In addition to perihilar cholangiocarcinoma (PHCC), the same extent of surgery is used in advanced gallbladder cancer (GBC) and intrahepatic cholangiocarcinoma (IHCC) with hilar involvement. Few studies compare prognostic factors and long-term outcomes across tumor types. This study compared risk characteristics and outcomes after surgery in all subtypes of biliary tract cancer with hilar involvement.

Methods: Patients with biliary tract cancer with hilar involvement undergoing major liver resection and extrahepatic bile duct resection between 2011 and 2021 at a single center were retrospectively analyzed. The primary postoperative outcome was overall survival. Secondary outcomes were recurrence-free survival and postoperative complications. Survival analysis was performed with Cox regression analysis and Kaplan-Meier method.

Results: One-hundred and eight patients were included. Seventy-three (67%) had PHCC, 24 (22%) had GBC, and 11 (10%) had IHCC. Hilar-invading IHCC and GBC had more adverse histopathological factors like lymph node positivity (p = 0.021), higher number of positive nodes (p = 0.043), and larger tumor size (p < 0.001) compared with PHCC. Peritoneal invasion and lymph node positivity were significant independent predictors for survival (p = 0.011 and p = 0.004, respectively). Median overall survival was 29 months for PHCC, 22 months for GBC and 21 months for IHCC (p = 0.53). IHCC tended to recur earlier (p = 0.046) than GBC and PHCC (6, 15, and 18 months, respectively).

Conclusion: Patients with biliary tract cancer with hilar involvement undergoing major liver resection and resection of extrahepatic bile ducts had similar overall survival regardless of subtype, while IHCC recurred earlier. Peritoneal cancer invasion was common in all subtypes, including PHCC, and was an independent prognostic factor. This finding may support routine reporting of peritoneal invasion-status in resected biliary tract cancer.