Objectives: Cirrhosis is a well-known risk factor for hepatocellular cancer, but the true risk in autoimmune hepatitis (AIH) is scarcely studied. Other cancers may arise after prolonged use of immune-modulating drugs. The aim of this study was to investigate the cancer risk in a large cohort of AIH patients.
Material and methods: Six hundred and thirty-four Swedish patients in a well-defined cohort were matched to the Cause of Death Registry and the Cancer Registry. Standard incidence ratios were calculated by relating the incidences in the cohort to an age-matched material from the Swedish background population.
Results: A higher overall incidence of malignancies than the background population was found, counting from the date of diagnosis (standard incidence ratio (SIR) 2.08, 95% CI 1.68-2.55). The highest risk was found for hepatocellular carcinoma (HCC). We found 10 cases (4.0%) in 248 patients with cirrhosis, which gives an incidence rate of 0.3%. Standard incidence ratio for developing hepatobiliary cancer was 54.55 (95% CI 19.92-99.99). HCC only occurred in cirrhotic patients. There was also an increased risk for non-melanoma skin cancer (SIR 9.87, 95% CI 6.26-14.81).
Conclusion: A slightly enhanced risk for malignancies in general compared to the background population was found. The risk of hepatobiliary cancer was increased, but the annual risk over the observational period was well under the postulated 1.5% when surveillance in cirrhotic patients is considered to be cost-effective.
Keywords: autoimmune hepatitis; autoimmune liver disease; cancer; extrahepatic cancer; hepatocellular carcinoma.