What is a tumor?

A tumor is a growth of tissue in which the tissue cells multiply in an uncontrolled fashion. Tumors can be either benign (noncancerous) or malignant (cancerous).

The most common benign tumors of the liver are cavernous hemangioma, hepatocellular adenoma and focal nodular hyperplasia. Adenoma is a much more rare form of benign tumor which may arise in the liver. These benign tumors stay in the liver and do not spread to other areas or organs of the body.

Malignant tumors of the liver are classified as being either primary (originating in the liver) or metastatic (spread from another body organ to the liver).

What causes a tumor?

Chronic liver disease, especially if complicated by cirrhosis, can lead to liver cancer. This is especially true for liver disease due to hepatitis B or C viruses, hemochromatosis (iron overload) and alcoholic liver disease.

Metastatic or secondary tumors of the liver come from cancer originating elsewhere in the body. Because the liver filters blood from all parts of the body, it is often the site in which cancer cells will lodge and develop into metastatic nodules. An enlarged liver secondary to cancer may be an early sign of cancer in other organs. Secondary or metastatic cancer should not be confused with primary cancer of the liver (also called hepatocellular carcinoma).

Who is at risk?

Hepatocellular adenomas may enlarge in women taking hormone pills or during pregnancy. Bleeding within the tumors and into the abdominal cavity is also a risk associated with adenoma.

Hepatocellular carcinoma is a highly malignant tumor which is difficult to treat and often has a bad outcome. In the United States, hepatocellular carcinoma accounts for less than 1% of all cancers in this country. In other parts of the world, however, it is a major health problem, causing up to 50% of cancer cases. The difference is thought to be due to the much higher percentage of the population who are carriers of the hepatitis B virus, which predisposes to the development of hepatocellular carcinoma.

How is a tumor/liver cancer diagnosed?

Most benign tumors are found by chance on an imaging study of the liver, such as ultrasound or computed tomography (CT) scan. Occasionally, a biopsy may be required to make the diagnosis of hepatocellular adenoma.

Malignant tumors may be detected by screening high risk patients or by chance on an imaging study of the abdomen performed for another reason, or may be detected because of symptoms such as abdominal pain. In patients who develop symptoms from more advanced hepatocellular carcinoma, weight loss, periodic severe pain and other generalized symptoms may occur. The diagnosis of hepatocellular carcinoma is typically made by liver imaging tests, such as abdominal ultrasound and CT scan in combination with the measurement of blood levels of alpha-fetoprotein. The final diagnosis is confirmed by biopsy, which is typically performed by a radiologist who can direct the biopsy needle to the exact position of the tumor.

How is it treated?

Unless extremely large, no specific therapy is needed for cavernous hemangiomas. If feasible, removal of hepatic adenoma may be recommended if it is large in order to prevent the possibility of bleeding and/or rupture. This type of tumor may enlarge in women taking hormone pills, so physicians will often recommend discontinuing birth control pills or postmenopausal hormone replacement therapy.

Treatment of hepatocellular carcinoma primary cancer of the liver may either be directed towards a cure, or may focus on palliation (the relief of symptoms and prolongation of life). When the tumor is small and limited to one lobe of the liver, surgical removal offers a chance at cure. If the tumor is larger or involves more than one lobe of the liver such that it cannot be removed, liver transplantation may be performed. In either case, the cure rate averages 20-30%. The use of liver transplantation for this problem with aggressive chemotherapy before transplantation may offer better outcomes. Long term benefit may also be possible with treatments aimed at ablating (destroying) the tumor. This can be done by the direct injection of alcohol into the tumor via a small needle or the use of electro currents passed through a needle placed in the tumor (radiofrequency ablation).

Alcohol injection and radiofrequency ablation also offer good prospects for palliation of hepatocellular carcinomas. Hepatic arteriography through a catheter in a blood vessel supplying the tumor with the injection of a chemotherapeutic drug has also resulted in prolonged survivals. These measures may also be used together with either surgical resection or liver transplantation.

Patients at risk of hepatocellular carcinoma by virtue of having cirrhosis may benefit by being screened for cancer every six to 12 months.

Liver tumors are an increasingly common problem but extensive research is being conducted to find better and more effective treatment. Early recognition may allow use of more effective treatment options.

The information contained in this brochure is provided for information only. This information does not constitute medical advice and it should not be relied upon as such. The American Liver Foundation (ALF) does not engage in the practice of medicine. ALF, under no circumstances, recommends particular treatments for specific individuals, and in all cases recommends that you consult your physician before pursuing any course of treatment.

*The American Liver Foundation gratefully acknowledges the contribution of Keith D. Lindor, MD, and Adrian M. Di Bisceglie, MD, FACP, who reviewed and updated this information.

Courtesy of Mary Ingalls, Liver Transplant Coordinator, University of Michigan