Liver cancer is a looming health threat in Australia, recent findings from the Australian Institute of Health and Welfare’s (AIHW) Burden of Cancer report suggest.
While rates of other cancers are falling or remaining static, liver cancer is the only “top ten” cancer for which rates increased between 2003 and 2011.
The “burden” of cancer is a measure also called “Disability Adjusted Life Years” (or DALYs), capturing quality and quantity of life. It combines the impact of the number of deaths (and how young people die) and number of people ill from a disease, accounting for how sick or disabled they are and for how long. This allows comparisons across different diseases.
Using “rates” allows comparisons across time, taking account of differences in population numbers and age profiles.
Liver cancer crisis?
While still not a common cancer, making up less than 1.5% of the 125,000 cancer cases diagnosed in 2013, liver cancer rates have increased fivefold since 1982. Action is required due to the poor five-year-survival rate of less than 20%.
But why are diagnosis rates going up?
Unpublished work in progress, which builds on a series of studies by the Cancer Control Group at QIMR Berghofer Medical Research Institute in Brisbane, suggests liver cancer is caused by five main factors.
Tobacco smoking caused 365 liver cancer cases, or about 21% in 2013 in Australia. Hepatitis C virus contributed to 330 cases (19%) of liver cancer. Hepatitis B virus accounted for 281 cases (16%), alcohol 266 cases (15%) and obesity 451 (25%).
What’s to blame?
Falling smoking rates suggest liver cancer figures should have been have been higher in the past. Due to the lag time between when people smoked and cancer diagnosis, tobacco is still a leading driver of liver cancer. Current smoking trends leave us optimistic these rates may drop in the future.
Similarly, alcohol consumption is on a modest decline and is unlikely to explain the increase in liver cancer.
Obesity is a different story. Well-documented increases in overweight and obesity will likely be a driver of liver cancer through the pathways of diabetes and non-alcoholic fatty liver disease, a condition where fat accumulates in liver cells.
But the major engine driving increased liver cancer is likely to be the rising prevalence of people infected with hepatitis B and hepatitis C viruses. Chronic hepatitis causes infection and inflammation of the liver, which can lead to scarring called cirrhosis. In some, this leads to cancer.
Around 450,000 Australians live with either hepatitis B or hepatitis C. The two viruses are passed on in quite different ways.
More than 90% of people with hepatitis B virus were born overseas in countries where the virus is common, such as the Asia Pacific or sub-Saharan Africa.