Cholangiocarcinoma in Denmark: time-trends in mortality following resection.

Background: Cholangiocarcinomas have a poor prognosis, and resection is the only curative-intent treatment. We examined time-trends in mortality risk after resection in a nationwide Danish cohort.

Methods: We identified all Danish citizens diagnosed with cholangiocarcinoma in 2004-2022 who subsequently underwent liver resection, biliary tract resection, or a combination of the two. We computed the proportions of patients who received downstaging or adjuvant chemotherapy, and we estimated age- and sex-adjusted mortality risks.

Results: Between 2004 and 2022, 611 patients with cholangiocarcinoma underwent resection (13% of 4,572 patients with cholangiocarcinoma). The proportion who underwent resection increased from 9% in 2004-2012 to 16% in 2018-2022, the median age of resected patients rose from 65 to 69 years, and the proportion with comorbidities increased from 17% to 28%. In patients who underwent liver resection, the proportion who had received downstaging chemotherapy increased from < 7% in 2004-2012 to 12% (8-20), and the proportion who received adjuvant chemotherapy increased from 27% (18-39) in 2004-2012 to 49% (40-58) in 2018-2022. Despite the increasing use of chemotherapy before and after liver resection, age- and sex-adjusted mortality remained essentially the same, with 1-year mortality ranging from 14% to 20% (p-value = 0.37). In patients who underwent biliary tract resection, only 3% received downstaging chemotherapy, but the proportion who received adjuvant therapy increased from 17% (10-29) in 2004-2012 to 59% (48-68) in 2018-2022. Even so, these patients' age- and sex-adjusted mortality remained stable (1-year mortality ranging from 19 to 24%, p-value = 0.34).

Conclusion: The proportion of patients with cholangiocarcinoma who underwent liver or biliary tract resection increased, and more patients received downstaging chemotherapy and adjuvant chemotherapy. Nonetheless, age- and sex-adjusted mortality risks remained constant. The explanations for this pattern are unclear but likely involve changing patient characteristics other than age and sex.