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An Astrocytoma is a tumor that arises from Astrocytes
which are the most numerous of the different types of Glial
Cells. Glial cells have an enormous potential for abnormal
growth and are the chief source of CNS
tumors. Approximately half (1/2) of all Primary Brain
Tumors are Glial cell neoplasms (tumors) and more than
three quarters (3/4) of all Gliomas are Astrocytomas which,
themselves, are a heterogeneous group of tumors that are grouped by
The first symptom of a Brain Tumor of any type can be a
headache, caused by increased pressure in the
Brain and therefore, inside the Skull. The headache
associated with a Brain tumor, is frequently worse in the
morning, frequently accompanied by vomiting. Other symptoms
of a Brain tumor can include seizures (Epilepsy), weakness or
numbness of a side or part of the body, or subtle symptoms
such as changes in mood, thinking or general state of well
being. Increased intracranial pressure can cause
blurred, double or lost vision.
If a patient has any of the above symptoms without any obvious
explanation, further work-up is warranted. These tumors can be
best seen by Magnetic Resonance Imaging (MRI). CT scans
can also be used; however, the quality of Brain and
tumor substance detail is best provided by MRI.
Once a mass is confirmed by any of the neuroimaging
techniques, the diagnosis needs to be established
by a biopsy of the mass. The biopsy, which is usually
carried out in conjunction with a more definitive surgical excision,
will help differentiate tumor from other types of masses, such
as infection. The microscopic structure of the tumor is vitally
important in the pathologist's "grading" of the tumor.
Tumor grading is important for prognosis and therapy.
Tumors are graded by microscopic examination of the tumor
specimen. The specimen is evaluated for the most
malignant components. Varying "grades" of tumor cells can be found
in any one tumor. The biological behavior of the tumor will relate to
the highest grade (worst and most aggressive) component of that
tumor, even though that higher grade component comprises a small
portion of the entire tumor. In other words, if a tumor
is 99.5 % Grade 1 and only ½ percent Grade 3 or 4, the biological
behavior of that tumor, will be as if the entire tumor is Grade 3 or
Astrocytomas are neither histologically or biologically
uniform tumors. The borderline between low-grade (i.e.
"non-aggressive) and Anaplastic (Malignant) Astrocytoma,
can be quite indistinct. Although many patients with
low-grade Astrocytomas survive for extended periods, 50%
of surgically treated lesions evolve into Anaplastic
Astrocytomas or Glioblastomas. Degeneration into a higher-grade
neoplasm is the most common cause of death in patients with low-grade
Low-grade Astrocytomas are uncommon tumors and
occur less frequently than their more malignant
counterparts. They are generally found in a younger
population and have a more favorable prognosis.
Their true incidence is difficult to determine, because sampling and
grading vary substantially. Low-grade Astrocytoma probably
represents 10% to 15% of Gliomas. These are
neoplasms of children and adults from 20 to 40 years of age. These
tumors are rare in older adults. Low-grade Astrocytomas can
present with any of the symptoms previously described.
Surgery is important in order to remove the mass effect and
pressure caused by the tumor. However, surgery is
rarely curative for most infiltrating hemispheric Gliomas,
unless the tumor is located at the anterior (front) portion of
either a Temporal or Frontal Lobe.
Surgery is the principal treatment in the following situations
of low-grade Astrocytomas:
Radiation Therapy is the primary non-surgical treatment.
Radiation can be administered to the whole Brain, or it can be
relatively focused to a region of the Brain. Radiosurgery
(Focused Beam Radiation) allows for very precise focusing
of radiation beams into the area of Astrocytoma involvement,
with less risk for damaging the surrounding Brain.
Unfortunately, the energy from radiation is destructive to
normal Brain cells, as well as, abnormal tumor cells.
- Childhood Cystic Cerebellar Astrocytomas.
- Supratentorial Pilocytic Astrocytomas.
- Large tumors, or tumor cysts, causing severe pressure on the surrounding Brain.
- Obstruction of Cerebrospinal Fluid (CSF) flow.
- Seizure control for Epilepsy that is refractory to medical therapy.
In cases of incomplete removal of ordinary low-grade
Astrocytomas, post-operative radiation is probably indicated.
Consideration to WITHHOLD Radiation Therapy may be
appropriate in cases of apparent gross total surgical removal,
or incomplete removal, in cases of Pilocytic Astrocytoma
or Cystic Cerebellar Astrocytoma. Meticulous follow up is
required, since Radiation Therapy can be helpful where tumor
recurrence or progression is documented.
Chemotherapy is usually not offered for patients
with a low-grade Astrocytoma. Nevertheless, it may
become appropriate if any progression of the tumor is subsequently
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This page last edited on 2/19