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Additional Information
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The Kidneys
The kidneys are
a pair of organs on
either side of the spine in the lower abdomen.
Each kidney is about the size of a fist. Attached to the
top of each kidney is an adrenal
gland. A mass of fatty tissue and
an outer layer of fibrous tissue
(Gerota's
fascia) enclose the kidneys and adrenal glands.
The kidneys are part of the urinary
tract. They make urine by
removing wastes and extra water from the blood.
Urine collects in a hollow space (renal
pelvis) in the middle of each kidney. It passes
from the renal pelvis into the bladder through
a tube called a ureter.
Urine leaves the body through another tube (the urethra).
The kidneys also make substances that help control blood
pressure and the production of red
blood cells.
Understanding Cancer
Cancer begins in cells,
the building blocks that make up tissues. 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, they die, and new cells
take their place.
Sometimes this orderly process goes wrong. New cells form
when the body does not need them, and 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:
- Benign tumors are not cancer:
- Benign tumors are rarely life threatening.
- Usually, benign tumors can be removed, and they
seldom grow back.
- Cells from benign tumors do not invade tissues
around them or spread to other parts of the body.
- Malignant tumors are cancer:
- Malignant tumors are generally more serious than
benign tumors. They may be life threatening.
- Malignant tumors often can be removed, but they
can grow back.
- Cells from malignant tumors can invade and damage
nearby tissues and organs. Also, cancer cells can
break away from a malignant tumor and enter the bloodstream
or lymphatic
system. That is how cancer cells spread
from the original cancer (primary
tumor) to form new tumors in other organs.
The spread of cancer is called metastasis.
Several types of cancer can start in the kidney. This booklet
is about renal
cell cancer, the most common type of kidney cancer
in adults. This type is sometimes called renal
adenocarcinoma or hypernephroma.
Another type of cancer, transitional
cell carcinoma, affects the renal pelvis. It is
similar to bladder cancer and is often treated like bladder
cancer. Wilms'
tumor is the most common type of childhood kidney
cancer. It is different from adult kidney cancer and requires
different treatment. Information about transitional cell
carcinoma and Wilms' tumor is available from the Cancer Information
Service at 1-800-4-CANCER and at http://cancer.gov.
When kidney cancer spreads outside the kidney, cancer cells
are often found in nearby lymph
nodes. Kidney cancer also may spread to the lungs,
bones, or liver. And it may spread from one kidney to the
other.
When cancer spreads (metastasizes) from its original place
to another part of the body, the new tumor has the same kind
of abnormal cells and the same name as the primary tumor.
For example, if kidney cancer spreads to the lungs, the cancer
cells in the lungs are actually kidney cancer cells. The
disease is metastatic kidney cancer, not lung cancer. It
is treated as kidney cancer, not lung cancer. Doctors sometimes
call the new tumor metastatic or "distant" disease.
Kidney Cancer: Who's at Risk?
Kidney cancer develops most often in people over 40, but
no one knows the exact causes of this disease. Doctors can
seldom explain why one person develops kidney cancer and
another does not. However, it is clear that kidney cancer
is not contagious. No one can "catch" the disease from another
person.
Research has shown that people with certain risk
factors are more likely than others to develop
kidney cancer. A risk factor is anything that increases
a person's chance of developing a disease.
Studies have found the following risk factors for kidney
cancer:
- Smoking: Cigarette smoking is a major
risk factor. Cigarette smokers are twice as likely as nonsmokers
to develop kidney cancer. Cigar smoking also may increase
the risk of this disease.
- Obesity: People who are obese have
an increased risk of kidney cancer.
- High blood pressure: High blood pressure
increases the risk of kidney cancer.
- Long-term dialysis: Dialysis
is a treatment for people whose kidneys do not work well.
It removes wastes from the blood. Being on dialysis for
many years is a risk factor for kidney cancer.
- Von
Hippel-Lindau (VHL) syndrome: VHL
is a rare disease that runs in some families. It
is caused by changes in the VHL gene.
An abnormal VHL gene increases the risk of kidney
cancer. It also can cause cysts or
tumors in the eyes, brain, and other parts of the
body. Family members of those with this syndrome
can have a test to check for the abnormal VHL gene.
For people with the abnormal VHL gene, doctors may
suggest ways to improve the detection of kidney cancer
and other diseases before symptoms develop.
- Occupation: Some people have a higher
risk of getting kidney cancer because they come in contact
with certain chemicals or substances in their workplace.
Coke oven workers in the iron and steel industry are at
risk. Workers exposed to asbestos or cadmium also
may be at risk.
- Gender: Males are more likely than females
to be diagnosed with kidney cancer. Each year in the United
States, about 20,000 men and 12,000 women learn they have
kidney cancer.
Most people who have these risk factors do not get kidney
cancer. On the other hand, most people who do get the disease
have no known risk factors. People who think they may be
at risk should discuss this concern with their doctor. The
doctor may be able to suggest ways to reduce the risk and
can plan an appropriate 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/kidney/page4
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