Facts on File Encyclopedia of Health and Medicine

brain tumor 237

nium). Deeper tumors may require guided stereo-
tactic techniques in which the neurosurgeon uses
an imaging procedure such as MRI to guide the
insertion of a biopsy instrument to the tumor with
minimal disturbance of other brain tissue. Labora-
tory examination of the tumor’s cells combined
with the visual images of the CT scan or MRI help
the neurosurgeon identify and grade the tumor.

Treatment Options and Outlook

The tumor’s type, grade, and location determine
the appropriate treatment options. Whenever pos-
sible, surgery to remove a primary tumor (or as
much of it as possible) is the preferred treatment.
However, tumors that deeply infiltrate brain tis-
sue, are very large, intertwine with BLOODvessels,
or are located in vital areas may be inoperable. As
well, surgery is generally not a viable option for
metastatic brain tumors. RADIATION THERAPYcan kill
tumor cells to shrink or eradicate the tumor. Most
often, treatment combines surgery and radiation
therapy. Outcomes are most promising when
treatment can remove 90 percent or more of the
tumor.
CHEMOTHERAPY is not generally an effective
treatment for primary brain tumors because it has
no effect on noncancerous tumors and because
primary brain cancer typically remains contained
within the brain, making it unnecessary to expose
the entire body to the effects of chemotherapy.
Chemotherapy may be the treatment of choice for
metastatic brain cancer, however, and for certain
brain cancers in very young children. For people
who have brain tumors beyond the reach of cur-
rent treatment options, neurologists and oncolo-
gists may recommend clinical trials that are
investigating new treatments. It is important to
fully understand both the risks and the potential
benefits of investigational treatments before agree-

ing to participate in a clinical trial. Among the

most promising investigational treatments are

medications that specifically target certain kinds of

cells such as cancer cells.

Metastatic brain cancer is very difficult to treat

because the cancer is generally widespread

throughout the body by the time it appears in the

brain. Treatment must target the original cancer as

well as the metastatic brain tumor. Chemotherapy

and radiation therapy are sometimes effective in

achieving REMISSIONof cancers that have metasta-

sized to the brain, though in general the outlook is

not favorable for metastatic brain cancer.

Risk Factors and Preventive Measures

Neurologists do not know what causes primary

brain tumors to develop. There is evidence that

exposure to certain toxic chemicals, notably vinyl

chloride, increases the risk for primary brain can-

cer. However, the correlations are not as yet con-

clusive. Primary brain tumors, cancerous and

noncancerous, occur in people of all ages and

about equally in men and women. Early diagnosis

allows the widest range of treatment options, and

early treatment offers the best opportunity for a

positive outcome. There are no known measures

to prevent brain tumors. However, lifestyle meas-

ures such as nutritious EATING HABITS, daily physical

exercise, maintaining healthy weight, and not

smoking all help support the body’s natural

IMMUNE SYSTEMefforts to resist disease and main-

tain the body in optimal health.

See also ACOUSTIC NEUROMA; BRAIN HEMORRHAGE;

CANCER TREATMENT OPTIONS AND DECISIONS; COGNITIVE

FUNCTION AND DYSFUNCTION; CONCUSSION; END OF LIFE

CONCERNS; MEMORY AND MEMORY IMPAIRMENT; METAS-

TASIS; MULTIPLE ENDOCRINE NEOPLASIA(MEN); NEUROFI-

BROMATOSIS; RETINOBLASTOMA; SURGERY BENEFIT AND

RISK ASSESSMENT; TRAUMATIC BRAIN INJURY(TBI).