How are liver cancers classified?
Liver cancer happens when cells begin to multiply at a faster rate than they should and the unwanted cells form a growth. There are many types of liver tumours, only some of which are cancers. The most important classification is whether the tumours are benign (relatively harmless) or malignant (capable of spreading from the liver and thus more serious).
What are Benign Tumours?
Hemangioma is the most common type of benign liver tumour. It is an abnormal growth of blood vessels of the liver that begins in the fetus. More than 10% of the normal population has hemanigomas in the liver. Most people with hemangiomas exhibit no symptoms and require no treatment. In rare cases, some hemangiomas may enlarge and bleed in which case they may need to be surgically removed.
Hepatic adenomas are benign tumours of liver cells. Most do not cause symptoms and do not require treatment. However, if they are large they may cause pain or blood loss in which case they may need to be removed. Hepatic adenomas occur more frequently in women and seem to be triggered in some cases by the birth control pill or by pregnancy.
Focal nodular hyperplasia (FNH) is a tumour-like growth of several cell types. Although FNH tumours are benign, it can be hard to distinguish them from liver cancers.
What are Malignant Tumours?
The most common form of primary liver cancer (cancer that starts in the liver) in adults is called hepatocellular carcinoma (HCC). It is a cancer of liver cells. This type of cancer can have different growth patterns. Some begin as a single tumour that grows larger. It may spread to other parts of the liver in later stages of the disease.
Liver cancer may also develop in more than one site in the liver and may grow into multiple tumours. This pattern is most often seen in people with liver cirrhosis.
Another liver cancer is called cholangiocarcinoma. It originates in the small bile ducts which are tubes that carry bile to the gall bladder.
Metastases
Most cases of liver cancer are cancers that began somewhere else in the body and spread to the liver. This is called metastases. Because of its very high blood flow and many biological functions, the liver is one of the most common places for metastases to grow. Tumors that originally arise in the colon, pancreas, stomach, lung or breast can spread to the liver. These types of cancers are named after the place where they began (primary site) and are considered secondary liver cancers or cancer metastases. For example, cancer that started in the lung and spread to the liver is called metastatic lung cancer with spread to the liver. Secondary liver cancers are 30 times more prevalent than primary liver cancers.
- Symptoms
- Causes
- Risk Factors
- Test & Diagnosis
- Treatment
- Prevention
What are the symptoms of liver cancer?
Liver cancer does not cause symptoms in the early stages. Common symptoms of advanced liver cancer include:
- Pain or discomfort in the upper abdomen.
- Weight loss.
- loss of appetite.
- Nausea and occasionally vomiting.
- High temperature.
- Jaundice - a yellow colouring of the skin and eyes, darkened urine and a pale colour to the stools.
- Fluid in the abdomen.
Many of these symptoms can be common to several other non-serious conditions, it is always best to have your doctor check any symptoms you are experiencing
What causes liver cancer?
Several factors may play a role in the development of cancer. Because the liver filters blood from all parts of the body, cancer cells from elsewhere escape into the bloodstream, embed in the liver and start to grow. Cancers that begin in the gut often spread to the liver. The ability of the liver to regenerate may also be linked to the development of liver cancers.
What are some of the risk factors associated with liver cancer?
Liver cancer is rare in the absence of chronic liver disease. However, in patients with underlying liver disease, liver cancer may be quite common. The exact cause of liver cancer has yet to be established. Scientists have identified many risk factors that can make someone more likely to develop liver cancer:
- Among people with chronic liver disease, men are more likely to develop liver cancer than are women. The reason for this is yet to be determined.
- The development of cancer may occur due to a viral infection of the liver, for example chronic infection with either hepatitis B or hepatitis C
- Certain types of inherited liver disease such as hemochromatosis, which results in accumulation of too much iron in the liver, as well as alpha-1 antitrypsin deficiency, and tyrosinemia can lead to the development of liver cancer later in life.
- Cirrhosis is the formation of scar tissue in the liver. This can often lead to cancer. Major causes of liver cirrhosis are alcohol use, chronic hepatitis B and C, and non-alcoholic steatohepatitis (NASH). Most causes of cirrhosis are also associated with the development of liver cancer.
- Alcohol: excessive alcohol use is a known risk factor for development of alcoholic cirrhosis and liver cancer
- Obesity increases the risk of liver cancer in those patients in whom it causes liver disease.
- Tobacco use increases the risk of liver cancer if you already have chronic liver disease.
- Anabolic steroids: prolonged use of anabolic steroids can increase the risk of liver cancer.
How is liver cancer treated?
The type of treatment to be opted will depend on the size and type of the cancer. Treatments will also vary according to the individual. The treatment of Hepatocellular carcinoma depends on the stage and the speed of tumour growth. Small primary cancers of the liver are curable. Cure rates generally decrease as the tumour size increases. Some of the possible treatments of liver cancer may include surgery, radiation therapy and chemotherapy or liver transplantation.
Surgery
Surgery can remove a small liver tumour through a procedure known as resection, in which a piece of the liver containing the tumour is removed. If all of the cancer can be removed, a patient has a good outlook for survival. If the cancer is too large, is found in many different parts of the liver, or has spread beyond the liver, it may not be possible to remove it completely. For many people with cirrhosis there is insufficient healthy liver to allow removal of even a small part of the liver. In this case, surgery is not an option.
Tumour ablation or embolization
Ablation refers to methods that destroy the tumour without removing it. Examples include destroying the tumour by using high-energy radio waves (RFA), freezing it with a very cold metal probe, or injecting alcohol directly into the tumour to kill cancer cells. The blood supply to the cancer can be reduced by blocking the artery that feeds the cancer or by injecting materials that plug the artery. This is called embolization. Because this kind of treatment also reduces blood supply to the normal liver tissue, it can be dangerous for people with diseases such as hepatitis or cirrhosis.
Chemoembolization involves combining embolization with chemotherapy. Chemoembolization prolongs life in patients in whom cure is not possible.
Radiation therapy is treatment that uses high-energy rays (such as x-rays) to kill or shrink cancer cells. This type of treatment may be used to shrink a liver tumour or to provide relief from symptoms, but it does not cure the liver cancer.
Chemotherapy refers to the use of drugs to kill cancer cells. Usually the drugs are given into a vein or by mouth. Liver cancer does not respond well to most chemotherapy drugs.
How is liver cancer detected?
Your doctor will have a feel of your liver from a physical examination and may also recommend the following for more detailed results.
- ultrasound
- blood test to check for increased levels of alpha-fetoprotein (AFP)
- computer tomography scan (CT)
- magnetic resonance imaging (MRI)
Is there anything I can do to prevent liver cancer?
Fortunately, yes. Prevention is, to date, the best defense against liver cancer. Chronic hepatitis B and C infection is the most common risk factor all over the world. Therefore, prevention of these forms of liver disease is the need of the hour. All children as well as adults at high risk should be vaccinated as a matter of routine against hepatitis B. Since there is no vaccine for hepatitis C, it is important to reduce our risk factors, prevent the spread of this disease, and to identify and assess for treatment all those who are already infected with the hepatitis C virus.
Alcohol consumption should be curtailed to the minimum possible. If you drink, do so in moderation, no more than one to two standard drinks per day. Drinking alcohol every day as well as binge drinking can be extremely damaging to your liver. If you have already been diagnosed with a liver disease, the safest amount of alcohol is no alcohol at all.
It is equally important to make simple lifestyle changes. Introducing an exercise routine into your daily life and maintaining a healthy, balanced diet can greatly reduce your risk factors.
People identified to be at high risk of liver cancer should necessarily be screened on a regular basis to ensure early detection. Early detection of small liver cancers greatly improves the chances of effective treatment and cure, using techniques such as radiofrequency ablation. All people at risk for the development of primary liver cancer should undergo regular screening by ultrasonography at six monthly intervals. Any hint of abnormal ultrasound results should prompt a visit to a liver specialist.
