Distinct Prognosis of Biliary Tract Cancer According to Stage, Treatment and Tumor Location: A Population-Based Study

Abstract

Introduction: Biliary tract cancer (BTC) has a wide variety of tumor location which were inconsistently captured in epidemiological and clinical studies. This study aimed to investigate the treatment pattern and prognosis of BTC according to the tumor location, using a national population-based cancer registry data. Method: The Korea Central Cancer Registry data of 97,676 patients with BTC from 2006 to 2017 were retrospectively reviewed. The Surveillance, Epidemiology, and End Results (SEER) stage, first course of treatment (FT) administered within four months after cancer diagnosis, and 5-year relative survival rates (5YRS) were analyzed for gallbladder (GB), intrahepatic bile duct (IHBD), extrahepatic bile duct (EHBD), and ampulla of Vater (AoV) cancers. Results: The proportion of localized and regional (L&R) SEER stage was the highest in AoV (78.2%), followed by EHBD (68.3%), GB (52.6%), and IHBD (49.5%) cancer. Surgical FT rates among L&R stage patients increased over time, which were the highest in AoV (76.6%), followed by GB (69.4%), EHBD (54.1%), and IHBD (36.8%) cancer. The proportion of "no active treatment (NT)" in L&R stage was 38.9%. In each tumor location, elder patients had higher risk of receiving NT after adjusting for period and sex (p<0.001). The overall 5YRS was the highest in AoV (48.5%), followed by GB (28.5%), EHBD (19.9%), and IHBD (10.8%) cancer. Conclusions: BTC statistics should be reported separately according to tumor location, having distinct distribution of SEER stage, treatment pattern, and prognosis. Efforts are required to reduce NT to improve overall survival outcomes of BTC, especially in elder patients.