Gastroenterology

Liver Cancer:

What is liver cancer?

Liver cancer (hepatocellular carcinoma) is a cancer that is located in the liver. It is also known as primary liver cancer or hepatoma. The liver is made up of different cell types, such as bile ducts, blood vessels, and fat-storing cells. However, liver cells (hepatocytes) make up 80% of the liver tissue. Thus, the majority of primary liver cancers (over 90 to 95%) arises from liver cells and is called hepatocellular cancer or carcinoma.

Liver cancer is the fifth most common cancer in the world and can be terminal. Liver cancer will kill almost all patients who have it within one year. In 1990, the World Health Organization estimated that there were about 430,000 new cases of liver cancer worldwide, and a similar number of patients died as a result of this disease. About three quarters of the cases of liver cancer are found in Southeast Asia, and is also very common in sub-Saharan Africa.

What are the risk factors for liver cancer?

The hepatitis B virus is known to cause liver cancer. Patients with hepatitis B virus who are at greatest risk for liver cancer are men with hepatitis B virus cirrhosis and a family history of liver cancer. The majority of liver cancer that is associated with hepatitis B virus occurs in individuals who have been infected most of their lives. In areas where hepatitis B virus is not always present in the community, such as in the United States, liver cancer is relatively uncommon.

The hepatitis C virus infection is also associated with the development of liver cancer. As with hepatitis B virus, the majority of hepatitis C virus patients with liver cancer have associated cirrhosis. In several studies, the average time to develop liver cancer after exposure to hepatitis C virus was approximately 28 years. The liver cancer occurred about 8 to 10 years after the development of cirrhosis in these patients with hepatitis C.

Cirrhosis caused by chronic alcohol consumption is the most common association of liver cancer in the developed world. Researchers now understand that many of these cases are also infected with the hepatitis C virus. The usual setting is an individual with alcoholic cirrhosis who has stopped drinking for ten years, and then develops liver cancer. It is somewhat unusual for an actively drinking alcoholic to develop liver cancer. When the individual stops drinking, his or her liver cells try to heal by regenerating or reproducing. It is during this active regeneration that a cancer-producing genetic mutation can occur, which explains the occurrence of liver cancer after the drinking has been stopped.

Aflatoxin B1 is the most potent liver cancer-forming chemical known. It is a product of a mold called Aspergillus flavus, which is found in food that has been stored in a hot and humid environment. This mold is found in such foods as peanuts, rice, soybeans, corn, and wheat. Aflatoxin B1 has been implicated in the development of liver cancer in Southern China and Sub-Saharan Africa. It is thought to cause cancer by producing mutations in the p53 gene. These mutations work by interfering with the gene's important tumor suppressing functions.

Drugs, medications, and chemicals are also known to cause liver cancer. There are no medications that cause liver cancer, but female hormones and protein-building steroids are associated with the development of hepatic adenomas. These are benign liver tumors that may have the potential to become malignant (cancerous). Thus, in some individuals, hepatic adenoma can evolve into cancer.

Liver cancer will develop in up to 30% of patients with hereditary hemochromatosis. Patients at the greatest risk are those who develop cirrhosis with their hemochromatosis. Unfortunately, once cirrhosis is established, effective removal of excess iron (the treatment for hemochromatosis) will not reduce the risk of developing liver cancer.

What are the symptoms of liver cancer?

The initial symptoms of liver cancer are variable. In countries where liver cancer is very common, the cancer generally is discovered at a very advanced stage of disease for several reasons, including limited access to healthcare and screening examinations for patients at risk. In contrast, patients in areas of low liver cancer frequency tend to have liver cancer tumors that progress more slowly and, therefore, remain without symptoms longer. Common symptoms may include:

Unexplained weight loss
Abdominal pain
Jaundice
Deterioration of muscles
Unexplained fevers

Treatment options:

The treatment options will be determined by a physician and may be dictated by the stage of liver cancer and the overall condition of the patient. The only proven cure for liver cancer is liver transplantation for a solitary, small (<3cm) tumor. Presentely, many physicians may dispute this statement. They may argue that a small tumor can be surgically removed (partial hepatic resection) without the need for a liver transplantation. Moreover, they may claim that the one and three year survival rates for resection are perhaps comparable to those for liver transplantation.

However, most patients with liver cancer also have cirrhosis of the liver and would not tolerate liver resection surgery. The patient may, however, be able to tolerate the transplantation operation, which involves removal of the patient's entire diseased liver just prior to transplanting a donor liver. Furthermore, many patients who undergo hepatic resections will develop a recurrence of liver cancer elsewhere in the liver within several years. In fact, some experts believe that once a liver develops liver cancer, there is a tendency for that liver to develop other tumors at the same time or sometime in the future. Other treatment methods may include:

Chemotherapy
Chemoembolization (trans-arterial chemoembolization or TACE)
Ablation techniques
Proton beam therapy
Surgery
Liver transplantation
Liver resection

Additional patient resources:

University of Missouri Health Care

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This information is not intended to replace the advice of a doctor.