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.
-
Generally, benign tumors can be removed. They usually do not grow back.
-
Cells from benign tumors do not invade the tissues around them.
-
Cells from benign tumors do not 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 sometimes they grow back.
-
Cells from malignant tumors can invade and damage nearby tissues and organs.
-
Cells from malignant tumors can spread
(metastasize)
to other parts of the
body. Cancer cells spread by breaking away from the original
(primary)
tumor
and entering the bloodstream or
lymphatic system.
The cells invade other organs
and form new tumors that damage these organs. The spread of cancer is called
metastasis.
When prostate cancer spreads, cancer is often found in nearby
lymph nodes.
If
cancer has reached these nodes, it also may have spread to other lymph nodes,
the bones, or other organs.
When cancer spreads 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 prostate cancer spreads to bones, the cancer cells in
the bones are actually prostate cancer cells. The disease is metastatic
prostate cancer, not bone cancer. For that reason, it is treated as prostate
cancer, not bone cancer. Doctors call the new tumor "distant" or metastatic
disease.
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