Real-world treatment patterns and outcomes in biliary tract cancer: a Danish retrospective cohort study

<h3>Background</h3> Despite recent treatment advancements, comprehensive real-world data on biliary tract cancer (BTC) treatment patterns and outcomes are essential. In this retrospective study, we assessed real-world treatment patterns and survival outcomes in a Danish cohort of patients with BTC. <h3>Methods</h3> Patients were identified using International Classification of Diseases, 10th Revision (ICD-10) codes in the Danish National Patient Register (period: 1 January 2010 to 31 December 2020). Prespecified data from the patients' medical files were recorded. <h3>Results</h3> We identified 1340 patients and confirmed the diagnosis in 1028. This high misclassification rate was partly due to a broad inclusion of ICD-10 codes, including non-BTC-specific codes, and partly due to a true misclassification of other cancers. Based on the initial treatment strategy, surgery was possible for 277 patients (27.0%) with five perioperative deaths (1.8%), a recurrence rate of 68.8%, and a median overall survival of 29.9 months (95% confidence interval 26.2-36.6 months). Palliative chemotherapy was administered to 504 (49.0%) patients; 247 (24.0%) received no treatment. Combining patients with upfront unresectable disease and those with recurrent disease, 628 initiated first-line palliative chemotherapy; most received a combination treatment containing either oxaliplatin (<i>n</i> = 294, 46.8%) or cisplatin (<i>n</i> = 232, 36.9%). The median overall survival for treatment with cisplatin/gemcitabine was 11.2 months (95% confidence interval 9.5-13.1 months). <h3>Conclusion</h3> We comprehensively described the real-world treatment patterns in a Danish cohort of patients with BTC; specific ICD-10 codes could reliably identify this cohort of patients. Our findings highlight the need for improved treatment strategies in adjuvant and palliative settings.