Obesity and hepatitis C drive up global liver cancer rates

Researchers fear winning the global battle against liver cancer through better management of viral hepatitis and food safety in developing nations could be offset by rising levels of obesity and metabolic disease.

A new study forecasts the future burden of liver cancer based on medical trends in 30 countries for the first time, predicting an overall 35 per cent spike in new cases across the world by 2030.

Liver cancer is the second most common cause of cancer deaths in the world and the sixth most common cancer.

QIMR Berghofer Medical Research Institute Cancer and Chronic Disease Research Group head, Associate Professor Patricia Valery, said the study predicted an increase in the number of cases of liver cancer worldwide from 339,000 in 2005 to 459,000 in 2030.

She said the main risk factors for liver cancer included chronic Hepatitis B virus or Hepatitis C virus infection, mould-contaminated food, heavy alcohol intake, obesity and type 2 diabetes, but varied from region to region.

“Overall, global rates of liver cancer will rise as countries grapple with growing obesity and fatty liver disease, particularly in developed nations but also increasingly in poorer countries as fast food becomes more common,” Associate Professor Valery said.

“We expect to see a decline in liver cancers associated with Hepatitis B and Hepatitis C as countries take action to prevent and treat those diseases.

“We also expect a fall in liver cancers caused by aflatoxin mould, as developing countries in Africa and parts of Asia improve the safety of food production and storage.

“Sadly, we predict rising levels of obesity and metabolic disease – particularly in settings like Australia and the United States – will outweigh any gains made by improving living standards in poorer countries.”

The study found Japan was one of a handful of countries where rates of liver cancer were predicted to decline, due to lower rates of Hepatitis C infection. In China, a predicted decrease in rates of liver cancer was attributed to declining levels of aflatoxin mould in the population.

A vaccine against Hepatitis B virus became available in 1982 and is anticipated to drive down infection rates even further in China and Africa by 2030.

Associate Professor Valery said the future burden of Hepatitis C was a significant factor, but blood screening, public education, needle and syringe programs, targeted screening and the availability of new therapies would help to stymie disease transmission.

“Hepatitis C, if left untreated, can cause liver damage and even cirrhosis or liver failure. It’s a tricky virus because many people are asymptomatic,” Associate Professor Valery said.

“That means it can be many years after exposure that a person realises they have the disease. That’s particularly concerning because the longer a person’s Hepatitis C is untreated, the higher the likelihood of liver damage that is a risk factor for liver cancer.”

But Associate Professor Valery said that metabolic disorders associated with obesity and conditions like type 2 diabetes and fatty liver disease were fast overtaking Hepatitis C as the main driver of burgeoning liver cancer rates.

“We’re already seeing this trend borne out in the United States and in about two-thirds of the countries in the study, the prevalence of obesity is now 20 per cent or greater,” she said.

“With many lower and middle income countries in Africa and Asia undergoing large-scale nutrition transition, increasing obesity rates are likely to continue and lead to greater rates of liver cancer.

“This is why primary prevention strategies for obesity should be core components of programs designed to reduce the future burden of liver cancer.”

Associate Professor Valery said the study also found heavy drinking contributes to between 15 and 34 per cent of liver cancer in many developed countries, pointing to the need for continued investment in public health policies discouraging harmful alcohol consumption.

The study was conducted in collaboration with the National Cancer Institute in the United States, the Princess Alexandra Hospital, the Mater Hospital, The University of Queensland, and the International Agency for Research on Cancer in France. It has been published in the journal Hepatology.