It is expected that more
than 190,600 brain tumors will be diagnosed in the United
States during 2003. Among these cases, there are about 40,600
primary brain tumors and 150,000 secondary (metastatic) brain
tumors. In the United States, approximately 3,100 children
younger than age 20 are diagnosed annually with brain tumors.
Brain and CNS cancer is the leading cause of cancer-related
death in patients younger than age 35 in this country.
Primary tumors are tumors that begin in the
brain and tend to stay in the brain. Metastatic brain tumors
begin as a cancer elsewhere in the body and spread, or metastasize,
to the brain. Metastatic brain tumors are the most common
brain tumor, with an annual incidence more than four times
greater than that of primary brain tumors. The cancers that
most commonly metastasize to the brain are breast and lung
cancer.
Brain tumors are different from other cancers
in several ways. One important factor is that brain tumors
develop within the confined space of the skull where there
is little extra room into which they may grow. Thus, even
a small tumor can seriously affect normal brain function.
Also, brain tumors have relatively little tendency
to metastasize outside the nervous system regardless of histologic
type. Therefore, the terms "benign" and "malignant"
have different meanings from those referring to abnormal growths
elsewhere in the body. For brain tumor, benign means the tumor
is relatively slow-growing; malignant means the tumor is aggressive
or fast-growing. Most histologic types of CNS tumors can be
either benign or malignant. Remember that a benign CNS tumor
can become just as dangerous as a malignant one if the tumor
presses on a vital area of brain tissue.
Go to Types
of Brain and CNS Tumors to learn more about types of brain
and CNS tumors.
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