The changing epidemiology and aetiology of hepatocellular carcinoma from 1969 through 2013 in A laska N ative people

BACKGROUND & AIMS: Alaska Native people have an increased rate of hepatocellular carcinoma compared to the United States population. Viral hepatitis is a risk factor for malignancy and the leading cause of hepatocellular carcinoma in Alaska. With the introduction of hepatitis B immunization in 1982, as well as the emergence of hepatitis C virus in this population, the epidemiology and aetiology of hepatocellular carcinoma in Alaska have changed. METHODS: Using the Alaska Native Tumor Registry, all cases of viral and non-viral hepatocellular carcinoma occurring from 1969 through 2013 were identified and reviewed. Incidence rates per 100 000 population were calculated for hepatocellular carcinoma overall and by aetiological category. RESULTS: One hundred and fifty-two cases of hepatocellular carcinoma were identified in 148 Alaska Native persons. Overall tumour rate was 3.82 per 100 000 and did not change significantly over the study period. Hepatitis B-associated cases decreased significantly over the study period (P = 0.048) and were eliminated in persons under the age of 20. Hepatitis C-associated cases increased significantly (P < 0.001). Undetermined hepatocellular carcinoma rates also decreased (P = 0.034). CONCLUSIONS: Overall hepatocellular carcinoma rates in Alaska Native people remained stable over the study period, but the epidemiology and aetiology are changing. Two decades after routine hepatitis B immunization, the hepatocellular carcinoma age distribution has shifted to cases presenting later in life. This is consistent with an ageing hepatitis B-infected population with no new infected young persons' coming into the population, as well as the emergence of hepatitis C in adults.