In Canada, primary liver cancer (also known as hepatocellular carcinoma or HCC) accounts for 2% of cancer deaths in men and 0.7% in women, while in other parts of the world such as Africa, Southeast Asia and China, it might reach up to 83%. (GLOBOCAN: Cancer fact sheets) According to the Canadian Liver Foundation, the high prevalence of people carrying the hepatitis B virus and having liver cirrhosis may account for this geographic discrepancy.
Most often primary liver cancer is found in patients with a pre-existing or underlying disease. While the exact cause is not known, there are a number of risk factors to consider:
- Chronic liver disease.
- Hepatitis B or C.
- Inherited liver disease such as hemochromatosis (accumulation of iron in the liver), as well as alpha-1 antitrypsin deficiency, which leads to liver fibrosis.
- Cirrhosis (scar tissue in the liver), usually caused by excessive alcohol consumption and chronic hepatitis B or C or non-alcoholic steatohepatitis (fatty liver disease), which causes inflammation and can lead to scarring and fibrosis.
- Tobacco increases the risk if there is already an underlying disease.
- Anabolic steroids, both prescribed and non-prescribed, when used long-term.
- Obesity that may cause liver damage when excess fat accumulates in the liver, causing fibrosis and scarring.
- Betel quid leaf chewing. Consumed mostly in Southeast Asia, betel chewing is one of the most popular psychoactive substances in the world. (Centers for Disease Control and Prevention)
- Diabetes when combined with other risk factors, such as cirrhosis or chronic hepatitis.
- Schistosomiasis infection (a parasitic worm), prevalent in Africa, Southeast Asia, South America and the Middle East.
- Women who take birth control pills for more than 5 years may have a slightly higher risk of developing liver cancer. This risk was seen in older studies when birth control pills had different doses and formulations. More recent studies don’t note the same risk. (Canadian Cancer Society)
- Occupational exposure to toxic substances such as:
- Vinyl chloride, used in the plastics industry to make PVC. This chemical is used to manufacture plastics that are used in a variety of areas of everyday life, from construction to plastic toys and even to medical devices.
- Arsenic in drinking water has also been associated with a higher risk. There are many countries where industrialization produces contamination of the water with arsenic. In Canada, arsenic levels in drinkable water are capped to 10 micrograms per litre.
- Trichloroethylene, used to remove grease from metals.
- Polychlorinated biphenyls or PCBs, when they are released into the water or leech out of landfills