Biliary tract cancer (BTC) is a malignancy of the intrahepatic and extrahepatic bile ducts, including the gallbladder. BTC is diagnosed in approximately 1,000 patients annually in the Netherlands. The majority of patients are diagnosed at an advanced stage. Before the publication of the landmark ABC-02 trial in 2010, there were no standard systemic treatments for BTC. Over the past decade, there has been a substantial increase in the number of conducted clinical trials for BTC. Despite this, limited treatment options are available, all of which provide limited survival benefits. Real-world data is highly relevant to validate the results of clinical trials in daily practice and to monitor the quality of care in daily practice. The main aim of this thesis was to evaluate the effectiveness of available systemic treatments in daily practice using population-based data, and to identify subgroups of patients that may benefit most from these treatments. Additionally, we aimed to study the feasibility and efficacy of fluorouracil, leucovorin, irinotecan plus oxaliplatin (FOLFIRINOX) as a second-line treatment for biliary tract cancer
