The liver is the largest organ in the body. It’s surrounded by a fibrous capsule and is divided into two lobes: a large right lobe and a smaller left lobe. It’s in the upper part of the abdomen on the right-hand side of the body. It’s protected from injury by the lower ribs.
The liver is a very important organ that has many functions. These include regulating sugars and fats in the body so they can be used for energy. It also produces proteins that circulate in the blood. Some of these proteins help the blood to clot and prevent excessive bleeding, while others are essential for maintaining the balance of fluid in the body.
The liver also destroys harmful substances, such as alcohol and drugs, and gets rid of waste products. It does this by breaking down substances that aren’t used by the body so they can be passed out in urine or stools (bowel motions).
The liver is connected to the first part of the small intestine by a tube called the bile duct. This duct takes bile produced by the liver to the intestine. Bile breaks down the fats in food so they can be absorbed by the bowel (intestine).
A healthy liver is very good at repairing itself. It can function normally with only a small part of it in working order.
The exact cause of hepatocellular carcinoma (HCC) is unknown. It’s not infectious and can’t be passed on to other people. Some of the following risk factors may increase a person’s risk of developing HCC.
As people get older, their risk of developing HCC increases – 7 in 10 cases (70%) are in people over 65.
Cirrhosis is scarring throughout the liver, which can be due to a variety of causes. These include chronic infection (see below), heavy alcohol drinking over a long period of time, obesity that causes chronic fatty liver disease and a few rare conditions, such as hemochromatosis (a genetic condition) and primary biliary cirrhosis. Liver cirrhosis increases the risk of developing hepatocellular carcinoma (HCC). The risk varies depending on the cause of the cirrhosis. However, only a small number of people with liver cirrhosis will develop primary liver cancer.
Long-term infection with either the hepatitis B or hepatitis C virus can lead to liver cancer and can cause cirrhosis, which increases the risk of HCC. People with hepatitis B or C should avoid excessive amounts of alcohol, as this can further increase their risk of developing primary liver cancer.
Inherited medical conditions
Primary liver cancer is not caused by an inherited faulty gene so members of your family are highly unlikely to be at an increased risk of developing it because you have it. People who have certain inherited conditions have a higher chance of developing cirrhosis and HCC. These conditions include hemochromatosis (which causes excess deposits of iron in the body) and tyrosinaemia (when people have too much of an amino acid called tyrosine in their blood).
In Africa and Asia, a poison called aflatoxin is a major cause of HCC. The poison is found in moldy peanuts, wheat, soya and grain, and people who eat these foods over a long period of time are at risk of developing HCC. Aflatoxin has rarely been found in the UK, and imports of these foods are closely monitored for levels of contamination.
Other risk factors
People who take anabolic steroids over a long period of time have a slightly increased risk of developing primary liver cancer. Anabolic steroids are mainly used by bodybuilders to increase muscle bulk. Studies have shown that a medical history of diabetes and increased body weight can increase the risk of developing HCC.
Secondary cancer in the liver
This is cancer that has started somewhere else in the body and has spread to the liver. The cause of a secondary cancer is always a primary cancer somewhere else in the body. If the cancer cells pass into the bloodstream, the liver is a likely place for them to settle. The most common types of cancer that spread to the liver start in the bowel, breast, pancreas, stomach, lung, ovary or skin (melanoma).
Sometimes, even with thorough medical tests, it’s not possible to find out where the cancer started. This is sometimes known as cancer of unknown primary. Occasionally cancer can start in the liver; this is known as primary liver cancer. Primary liver cancer is relatively rare while secondary liver cancer is much more common.
Symptoms of secondary cancer in the liver
Secondary cancer in the liver may not cause any symptoms for a long time, and it may only be discovered by routine tests. Symptoms that might occur include loss of appetite, weight loss, feeling sick (nausea) and tiredness (fatigue). Some people may also have a high temperature and feel shivery.
People sometimes notice a vague discomfort in the upper abdomen, which may become painful. This is due to the liver becoming enlarged. Pain can sometimes also be felt in the right shoulder; this is known as referred pain. It’s due to the enlarged liver stimulating the nerves beneath the diaphragm (the sheet of muscle under the lungs), which are connected to nerves in the right shoulder. If the bile duct becomes blocked, bile produced by the liver will flow back into the bloodstream, causing jaundice. This will make the skin and whites of the eyes turn yellow and may make the skin very itchy. Other signs of jaundice are dark-colored urine and pale stools (bowel motions). Sometimes, fluid builds up in the abdomen and causes swelling known as ascites. There may be several possible reasons for this:
- If cancer cells have spread to the lining of the abdomen, they can irritate it and cause fluid build-up.
- If the liver is affected by cancer cells, there may be an increase in pressure in the veins that lead to it. Fluid from the abdomen then can’t pass quickly enough through the liver, so it starts to collect in the abdomen.
- If the liver is damaged, it may produce less blood protein. This can upset the body’s fluid balance and cause fluid to build up in the body tissues, including the tissues of the abdomen.
- Cancer cells may block the lymphatic system. The lymphatic system is a network of fine channels throughout the body. One of its functions is to drain off excess fluid, which is eventually passed out of the body in urine.
If some of these channels are blocked, the system can’t drain efficiently and fluid may build up. If ascites develops, a tube can be put into your abdomen to drain the fluid away. Whatever the cause, jaundice or ascites will always show a condition that needs medical attention and so should not be ignored. If you have these symptoms, get them checked by your doctor.