Exercise ‘reduces liver cancer risk’ and may even prevent it, say scientists

EXERCISE reduces the risk of liver cancer, according to a new study.

Scientists have discovered that exercise could delay the onset of liver cancer and mitigate the severity, if not completely prevent it.

Liver cancer is the fourth most common cause of death worldwide and growing rapidly due to ‘diabesity pandemic’, meaning diabetes caused by obesity.

Lead researcher Dr Geoffrey Farrell, of Australian National University, said: “As yet there are very few effective therapies for liver cancer, so approaches to prevent liver cancer are greatly needed.

“Some population data suggest that persons who exercise regularly are less likely to develop liver cancer but, studies addressing whether this has a real biological basis, and, if so, identifying the molecular mechanism that produces such a protective effect, are few and the findings have been inconclusive.”

Fatty liver disease is the most common form of liver cancer and is a result of obesity and diabetes, with more than 800,000 cases diagnosed each year with this cancer.

To investigate if exercise reduced the development of liver cancer they used obese diabetic mice and injected a low dose of cancercausing agent during their early life.

Mice closely resemble humans with fatty liver disease as mice are genetically driven to eat more.

Half of the mice regularly exercised on the running wheel, while the other half did not exercise.

The active mice ran up to 40 kilometres a day as measured by rotations of the exercise wheel, slowing down their weight gain for three months - but they still remained obese after the six months of experiments.

Researchers found that most of the inactive mice had liver cancer but none of the exercising mice had developed it, suggesting that exercise can stop liver cancer in mice that have fatty liver disease related to obesity and type 2 diabetes.

They showed that the beneficial effects of voluntary exercise were exerted via molecular signaling pathways.

The tumour suppressor gene p53 stops the persistent growth of altered cells that turn into cancer and the stress-activated protein kinase JNK1 is switched off by exercise.

Dr Farrell said: “Exercise has already been shown to improve some outcomes for patients with cirrhosis.

“If the present studies in an animal model that closely resembles humans with fatty liver disease can be replicated in patients, it is likely that exercise could delay onset of liver cancer and mitigate its severity if not completely prevent it, thereby greatly improving patient outcomes.”

Dr Farrell added: “Also, knowing the molecular pathways involved points to ways that drugs or pharmaconutrients could be employed to harness the powerful protective effect of exercise to lower risk of liver cancer in overweight people with diabetes.”

The findings were published in the Journal of Hepatology.