Causes & Risk Factors of Liver Cancer

What is Liver Cancer?

Liver cancer is malignant disease of liver cells. The altered liver cells grow fast and replace the healthy liver tissues. However, regardless of their quick growth, the sick cancer cells lose their functionality and cannot carry out their natural tasks anymore. Since the liver plays a central role in many metabolic processes in the body, the negative impact of these quickly growing cancer cells becomes even more noticeable over time.

There are various malignant types of liver cancer, but the most common types are hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCC).

Not every cancer that affects the liver is liver cancer, when the cancer originates in another area of the body such as the stomach and spreads to the liver is called metastatic cancer. The cancer will also be named after the organ where it originated, for example, metastatic stomach cancer, even though it now also is present in the liver. According to the Mayo Clinic, cancer that spreads to the liver is more common than cancer that begins in the liver cells.

According to CDC, around 24,000 men and 10,000 women are diagnosed with liver cancer every year in the United States. In individuals with chronic liver disease, it can take years or even decades to develop liver cancer. Once identified, liver cancer can grow rapidly and lead to death within a few years or months.

What causes liver cancer (HCC/CCC)?

The main causes of liver cancer in the United States are:

• Cirrhosis
• Alcohol overuse
• Being overweight or obese
• Chronic infections such as hepatitis A and B
• Chronic liver disease, especially in the cirrhosis stage
• Non-alcoholic fatty liver disease
• Diabetes type 2
• Metabolic diseases
• Genetic factors
• Smoking
• Frequent exposure to chemical substances
• Eating foods affected by fungus mold due to poor storage or preservation conditions

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What are the risk factors of liver cancer?

Let´s break down some of the key risk factors of liver cancer in details:

Risk factor: cirrhosis

The primary cause of liver cancer is cirrhosis and chronic liver inflammation. In fact, around 80% of people with cirrhosis tend to develop liver cancer. Cirrhosis is an advanced and irreversible liver disease that causes scar tissue to form in the liver and increases the chances of developing liver cancer. Cirrhosis develops as a result of a long-lasting liver damage. Over time, the liver becomes scarred and its ability to function weakens increasing thereby the risk of liver cancer.

Risk factor: fatty liver disease

Diseases such as fatty liver disease, which affects almost 80 million Americans, can also lead to liver cancer if left untreated and poor lifestyle choices are continued. Fatty liver disease is characterized by a buildup of excessive fat in the liver increasing the risk of liver cancer. Fatty liver disease does not directly lead to liver cancer but it may lead to other health complications that eventually may cause liver cancer. If left untreated, fatty liver disease can progress to non-alcoholic steatohepatitis (NASH) characterized by the inflammation of the liver. Over time, liver inflammation can worsen and lead to liver fibrosis, cirrhosis, and eventually — liver cancer. If you are suffering from any type of liver disease it is important to see your doctor regularly to monitor the progression of the disease.

Risk factor: diabetes

Since diabetes type 2 is often associated with obesity, it increases the risk of developing fatty liver disease (accumulation of fat in the liver) and eventually, cirrhosis and liver cancer. The results of one the latest studies showed that the individuals with diabetes type 2 are three times more likely to develop liver cancer as opposed to those without diabetes type 2.

Risk factor: being overweight or obese

Being overweight or obese is another factor that increases the risk of liver cancer. The latest CDC data show that over 70% of Americans aged 20 and older are considered overweight and obese. One of the main reasons of this is a poor-quality diet (high in sugar, fat, and salt) and sedentary lifestyle. Unhealthy weight can be a key contributing factor of diabetes type 2, fatty liver disease, and eventually liver cancer. There are no special diets that can prevent liver cancer. Make sure you are eating liver-healthy and leading an active lifestyle. Take the Liver Health Score to find out how liver-healthy your current habits are and what improvements are yet to make.

READ MORE: What is a liver-healthy diet? >

Risk factor: exposure to aflatoxins

One of the main liver cancer risk factors is eating foods contaminated with mycotoxins. Mycotoxins are toxic secondary metabolites produced my molds (fungi) that can occur at any stage of food harvesting, storage, production, and processing. Mycotoxins are resilient to any type of food processing. Aflatoxins are one of the most poisonous types of mycotoxins usually affecting crops such as cereals, tree nuts, spices, or oilseed, according to the World Health Organization. The FDA warns that large doses of aflatoxins can cause life threatening diseases such as liver and kidney damage as well as cardiac problems. In the United States, safety regulations limit aflatoxin contamination.

Risk factors: viral infections such as hepatitis B or C

Chronic infection with the hepatitis B or C virus can cause a chronic liver inflammation which increases the risk of liver cancer. The good news is that hepatitis B can be prevented through vaccination while hepatitis C can be often successfully treated.

Risk factor: alcohol consumption

Alcohol is one of the major risk factors for developing liver cancer. Longstanding alcohol consumption can lead to chronic liver inflammation (alcoholic hepatitis) and liver tissue destruction and as result of which — to liver cirrhosis and liver cancer. The liver is particularly vulnerable against alcohol when it is already affected by viral hepatitis or alcoholic fatty liver disease. In June 2020, the American Cancer Society (ACS) made a radical change in their guidelines on cancer reduction and prevention published in A Cancer Journal for Clinicians. It is for the first time that the ACS officially recommends avoiding alcohol completely instead of just limiting its consumption. “It is best not to drink alcohol”, stated the new guidelines of the ACS.

Risk factor: genetic diseases (for example, hemochromatosis)

There is a range of genetic metabolic disorders that can be linked to a higher liver cancer risk. Genetic diseases that can increase the risk of liver cancer include hemochromatosis and Wilson's disease. Hemochromatosis characterized by a gene mutation causing the body to absorb extra amount of iron from the food. Hemochromatosis is a hereditary condition passed from parents to children. It is estimated that 8-10% of patients with hereditary hemochromatosis tend to develop hepatocellular carcinoma, a type of liver cancer.

Risk factor: occupational exposure

There are certain occupation groups that due to the specifics of their work are exposed to a higher risk of liver cancer. These include medical professionals who regularly have contact with hepatitis B and C patients. Professionals have often deal with chemical substances, such as solvents, pesticides, or insecticides. These substances can enter a human body through the respiratory air or skin and should be processed and filtered by the liver. In the long run, this can start overloading the liver which may lead to liver damage.

Risk factor: smoking

According to CDC, tobacco is annually responsible for 40% of cancer cases in the United States, including liver cancer. The liver naturally detoxifies the body from harmful substances that make their way to the blood. Nicotine that enters the body through tobacco consumption is no exception — while being processed by the liver, it poses additional strain on this vital organ. If a smoker is already dealing with a chronic liver disease, smoking will only increase the risk of developing liver cancer due to liver cirrhosis.

Sources:

Hemochromatosis.org

World Health Organization

FDA

Cancer.org

Mayo Clinic