Tumors of
the liver are classified as being either primary (originating from the
liver) or metastatic (spread from another body organ to the liver).
Primary liver tumors may be further divided into those that are benign
(not cancerous and remain in the liver) or malignant (cancerous and
may spread to other parts of the body).
Benign
Tumors
The
most common benign tumor of the liver is a cavernous hemangioma. This
tumor, as well as other benign tumors, is typically found by chance
on an imaging study of the liver, such as ultrasound or computed tomography
(CT). Cavernous hemangioma can be diagnosed with reasonable accuracy
by the use of various imaging tests. Unless it is extremely large, no
specific therapy is usually required. This tumor may enlarge in women
taking hormone pills; thus, physicians will often recommend discontinuing
birth control pills or postmenopausal hormone replacement therapy.
The
other common benign tumors of the liver are called hepatocellular adenoma
and focal nodular hyperplasia. Both of these tumors are also usually
found by chance, although hepatocellular adenoma has a substantial risk
of bleeding within the tumor and into the peritoneal (abdominal) cavity.
The use of a number of imaging tests, and occasionally hepatic arteriography
or biopsy, may be required to make the diagnosis of this tumor. Hepatocellular
adenomas are also quite sensitive to hormonal therapy and may regress
when birth control pills or hormones are stopped. If feasible, removal
of hepatic adenoma may be recommended if it is large in order to prevent
the possibility of bleeding and/or rupture.
Malignant
Tumors
The
most common primary malignant tumor of the liver is a hepatocellular
carcinoma. Primary liver cancer accounts for less than 1 percent of
all cancers in this country. However, in other parts of the world such
as Africa, Southeast Asia, and China, it is a major health problem,
causing up to 50 percent of cancer cases seen in those areas. This 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.
It
was recognized a number of years ago that chronic carriers of the hepatitis
B virus, particularly those with chronic hepatitis or cirrhosis, are
at substantially increased risk to develop hepatocellular carcinoma.
Recent evidence indicates that patients who have long-standing chronic
hepatitis C virus infection are also at increased risk for the development
of hepatocellular carcinoma, although the exact risk is uncertain.
Certain
toxins and chemicals are also rarely associated with liver cancer. In
Africa, aflatoxin, a product of mold found in badly stored peanuts or
other foods, has been recognized as a cause of liver cancer.
Finally,
certain diseases other than chronic hepatitis B or C are associated
with an increased risk of hepatocellular carcinoma. Iron overload cirrhosis
(hemochromatosis) is associated with a substantial risk of hepatocellular
carcinoma once cirrhosis has developed. Patients with long-standing
alcoholic cirrhosis are also at risk for developing this tumor. Two
congenital disorders, alpha-1-antitrypsin deficiency and tyrosinemia,
may also be complicated by the development of hepatocellular carcinoma.
Metastatic
or secondary tumors of the liver come from cancers 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.
Primary
liver cancer may be detected by screening high risk patients or by chance
on an imaging study of the abdomen performed for another reason, or
it may be detected because of symptoms such as abdominal pain. Studies
performed in several countries have demonstrated that the periodic use
of abdominal ultrasound and a blood tumor marker, called alpha-fetoprotein,
may lead to the early detection of small hepatocellular carcinomas in
patients at high risk. This screening strategy has not been widely adopted
because its cost-effectiveness has yet to be proven. In patients who
develop symptoms from more advanced hepatocellular carcinoma, weight
loss, periodic severe pain and other generalized symptoms may occur.
Health may deteriorate rapidly and jaundice (yellow skin) may appear.
The
diagnosis of primary cancer of the liver 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 needle biopsy, which is typically performed
by a radiologist who can direct the biopsy needle to the exact position
of the tumor. It may be necessary to also examine the arteries and veins
of the liver by hepatic arteriography, particularly if surgery is considered.
Treatment of primary cancer of the liver may be directed towards a cure,
or focused at 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 of cure. If the tumor is larger or
involves more than one lobe of the liver such that it cannot be removed,
liver transplantation has also been performed. In either case, the cure
rate averages only 20-30 percent, which has limited somewhat the use
of liver transplantation for this problem.
There
are a number of newer therapies that offer good palliation for hepatocellular
carcinoma. In particular, the direct injection of alcohol into the tumor
via a small needle or the embolization at the time of hepatic arteriography
of a specific chemotherapeutic agent (chemo-embolization) has resulted
in prolonged survivals. These measures may also be used together with
either surgical resection or liver transplantation.

The
American Liver Foundation is the only national voluntary health organization
dedicated to preventing, treating, and curing hepatitis and all other
liver and gallbladder diseases through research and education.
American Liver Foundation
1425 Pompton Avenue, Cedar Grove, NJ 07009
1-800-223-0179
Copyright
© 1995
The American Liver Foundation
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