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Additional Information
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The Liver
The liver is
the largest organ in the body. It is found behind the ribs
on the right side of the abdomen.
The liver has two parts, a right lobe and
a smaller left lobe.
The liver has many important functions that keep a person
healthy. It removes harmful material from the blood. It makes enzymes and bile that
help digest food. It also converts food into substances needed
for life and growth.
The liver gets its supply of blood from two vessels. Most
of its blood comes from the hepatic
portal vein. The rest comes from the hepatic
artery.
Understanding Cancer
Cancer is a group of many related diseases. All cancers
begin in cells,
the body's basic unit of life. Cells make up tissues,
and tissues make up the organs of the body.
Normally, cells grow and divide to form new cells as the
body needs them. When cells grow old and die, new cells take
their place.
Sometimes, this orderly process goes wrong. New cells form
when the body does not need them, or old cells do not die
when they should. These extra cells can form a mass of tissue
called a growth or tumor.
Tumors can be benign or malignant:
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Benign tumors are not cancer. Usually,
doctors can remove them. In most cases, benign tumors
do not come back after they are removed. Cells from benign
tumors do not spread to tissues around them or to other
parts of the body. Most important, benign tumors are
rarely a threat to life.
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Malignant tumors are cancer. They are
generally more serious and may be life threatening. Cancer
cells can invade and damage nearby tissues and organs.
Also, cancer cells can break away from a malignant tumor
and enter the bloodstream or the lymphatic
system. That is how cancer cells spread from
the original cancer (the primary
tumor) to form new tumors (secondary
tumors) in other organs. The spread of cancer
is called metastasis.
Different types of cancer tend to spread to different
parts of the body.
Most primary liver cancers begin in hepatocytes (liver
cells). This type of cancer is called hepatocellular
carcinoma or malignant hepatoma.
Children may develop childhood hepatocellular carcinoma
or hepatoblastoma.
This booklet does not deal with childhood liver cancer. Material
is available at http://cancer.gov.
Also, the Cancer Information Service (1-800-4-CANCER) can
provide information about liver cancer in children.
When liver cancer spreads (metastasizes)
outside the liver, the cancer cells tend to spread to nearby
lymph nodes and to the bones and lungs. When this happens,
the new tumor has the same kind of abnormal cells as the
primary tumor in the liver. For example, if liver cancer
spreads to the bones, the cancer cells in the bones are actually
liver cancer cells. The disease is metastatic liver cancer,
not bone cancer. It is treated as liver cancer, not bone
cancer. Doctors sometimes call the new tumor "distant" disease.
Similarly, cancer that spreads to the liver from another
part of the body is different from primary liver cancer.
The cancer cells in the liver are like the cells in the original
tumor. When cancer cells spread to the liver from another
organ (such as the colon, lung, or breast), doctors may call
the tumor in the liver a secondary tumor. In the United States,
secondary tumors in the liver are far more common than primary
tumors.
Liver Cancer: Who's at Risk?
Researchers in hospitals and medical centers around the
world are working to learn more about what causes liver cancer.
At this time, no one knows its exact causes. However, scientists
have found that people with certain risk
factors are more likely than others to develop liver
cancer. A risk factor is anything that increases a person's
chance of developing a disease.
Studies have shown the following risk factors:
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Chronic liver
infection (hepatitis) --
Certain viruses can
infect the liver. The infection may be chronic. (It
may not go away.) The most important risk factor for
liver cancer is a chronic infection with the hepatitis
B virus or the hepatitis
C virus. These viruses can be passed from
person to person through blood (such as by sharing
needles) or sexual contact. An infant may catch these
viruses from an infected mother. Liver cancer can develop
after many years of infection with the virus.
These infections may not cause symptoms,
but blood tests can show whether either virus is present.
If so, the doctor may suggest treatment. Also, the doctor
may discuss ways of avoiding infecting other people.
In people who are not already infected with hepatitis
B virus, hepatitis B vaccine can
prevent chronic hepatitis B infection and can protect
against liver cancer. Researchers are now working to
develop a vaccine to prevent hepatitis C infection.
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Cirrhosis --
Cirrhosis is a disease that develops when liver cells
are damaged and replaced with scar tissue. Cirrhosis
may be caused by alcohol abuse, certain drugs and other
chemicals, and certain viruses or parasites.
About 5 percent of people with cirrhosis develop liver
cancer.
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Aflatoxin --
Liver cancer can be caused by aflatoxin, a harmful substance
made by certain types of mold.
Aflatoxin can form on peanuts, corn, and other nuts and
grains. In Asia and Africa, aflatoxin contamination is
a problem. However, the U.S. Food and Drug Administration
(FDA) does not allow the sale of foods that have high
levels of aflatoxin.
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Being male -- Men are twice as likely
as women to get liver cancer.
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Family history -- People who have family
members with liver cancer may be more likely to get the
disease.
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Age -- In the United States, liver
cancer occurs more often in people over age 60 than in
younger people.
The more risk factors a person has, the greater the chance
that liver cancer will develop. However, many people with
known risk factors for liver cancer do not develop the disease.
People who think they may be at risk for liver cancer should
discuss this concern with their doctor. The doctor may plan
a schedule for checkups.
To read the rest of this great article from the National
Cancer Institute, please click here: http://www.nci.nih.gov/cancertopics/wyntk/liver/page2
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