Risk of Cancer and Subsequent Mortality in Primary Biliary Cholangitis: A Population-based Cohort Study of 3052 Patients.

Background And Aims: Primary biliary cholangitis (PBC) is a rare cholestatic liver disease. Incident cancer is a concern. Previous studies have described an increase in hepatocellular carcinoma (HCC), but the risk of nonhepatic cancer and cancer risk across subgroups is largely unknown.

Methods: We used the Swedish National Patient Register to identify all patients diagnosed with PBC between 2002 and 2019. Patients were matched for age, sex, and municipality with up to 10 reference individuals from the general population. Incident cancer was recorded from the National Cancer Register. Cox regression was used to investigate the rates of cancer and postcancer mortality, adjusted for potential confounders. The cumulative incidence of cancer was calculated while accounting for the competing risk of death.

Results: At 10 years of follow-up, the cumulative incidence of any cancer in patients with PBC (n = 3052) was 14.3% (95% confidence interval (CI) = 12.8-15.9), compared to 11.8% (95% CI 11.3-12.2) in the reference population (n = 26,792) (adjusted hazard ratio aHR = 1.4, 95% CI = 1.2-1.5). The rate of HCC was particularly high (aHR 30.9; 95% CI = 14.8-64.6). The rate of cancer was higher in patients with cirrhosis (aHR 2.1; 95% CI 1.4-3.0), but similar across categories of age and sex. Increased rates of other cancer subtypes, including gastrointestinal (aHR = 1.5, 95% CI = 1.1-1.9), lung (aHR = 1.5, 95% CI = 1.1-2.2), and lymphoma (aHR = 2.9, 95% CI = 1.9-4.6) were seen. Following a diagnosis of cancer, patients with PBC had higher mortality rates compared to reference individuals (aHR = 1.4, 95% CI = 1.2-1.7). This was mainly driven by HCC (non-HCC-related mortality: aHR = 1.1, 95% CI = 0.9-1.5).

Conclusion: Patients with PBC have a significantly higher risk of HCC compared to matched individuals from the general population, but only a low risk increase of non-HCC cancer.