This is a "family" of tumors, which arise from cells known as "GLIAL
CELLS". This series of cells comprises the "glue" cells of the Central
Nervous System (CNS), in contradistinction to the "Neurons", which
are the "action" cells of the brain and spinal cord. Glial cells are
the most common cellular component of the brain. They are five to ten
times more frequent than the trillion brain neurons and comprise half
the central nervous system (CNS) by volume. There are three (3)
different cell types in this cell series. The "Astrocyte" was so
named, because it resembles the shape of a star, when looked at under
a microscope. The next most common cell in this series is the
"Ependymal Cell", which lines the cavities of the brain (called
ventricles). These are normal chambers within the brain, where
cerebrospinal fluid (CSF) is manufactured. These cells are also found
within the central canal (a small cavity) within the spinal cord. The
last cell type is the "Oligodendrgogliocyte" (Oligo), which is the
cell within the brain and spinal cord responsible for making the
insulating material (called Myelin), that surrounds the fibers (axons)
which transmit electrical impulses within the brain and spinal cord.
Each of these cell types is capable of forming a tumor. The
Neurosurgeons of Neurosurgical Consultants regard ALL OF THESE AS
MALIGNANT TUMORS. The degree of malignancy, and therefore, biological
aggressiveness can vary from quite indolent to extremely aggressive.
These tumors are generally categorized according to their degree of
aggressiveness, as judged by a number of factors. Neuropathologists
(specialists trained to examine these tumors under powerful
microscopes), have tended to "grade" these tumors from 1 to 4, with
"4" being the most aggressive and "1" being the least malignant.
All of these tumors have a tendency to "infiltrate" within the brain
and/or spinal cord by tracking along the fiber pathways that
interconnect every part of the brain to every other part of the
brain. Very rarely do these tumors ever spread beyond the brain or
An Astrocytoma is a tumor that arises from Astrocytes which are the
most numerous type of Glial cell. Glial cells have an enormous
potential for abnormal growth and are the chief source of CNS
tumors. Approximately half 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 grades.
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. A first seizure (Epilepsy), in anyone over the age of 21
is considered to be due to a Brain Tumor UNTIL PROVEN OTHERWISE.
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 degree of brain and tumor substance detail that
can be picked up by CT is much less than 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 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 pathologistís "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 1/2 percent Grade 3 or 4, the biological behavior of
that tumor, will be as if the entire tumor is Grade 3 or Grade 4.
Astrocytomas are neither histologically or biologically uniform
tumors. The borderline between low-grade and Anaplastic (Malignant)
Astrocytoma, is at best 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 Astrocytomas.
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
The primary non-surgical treatment is radiation therapy. 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 damage to 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 flow.
- Seizure control for Epilepsy that is refractory to medical therapy.
Consideration to WITHOLD radiation therapy may be appropriate in cases
of 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.
In cases of incomplete removal of ordinary low-grade Astrocytomas,
post-op radiation is probably indicated.
Anaplastic Astrocytomas are among the most common primary malignant
brain tumors. These tumors represent approximately one third of all
Astrocytomas and about one quarter of all Gliomas. They occur at any
age but typically are found in older patients. Their peak incidence
is in the fifth and sixth decades of life. Seizures and focal
neurological deficits are common presenting symptoms. In addition,
any of the symptoms described previously, may be present at the time
Malignant Astrocytomas generally have a poor prognosis, with an
average survival of two (2) years. Both types of malignant Glial
tumors (Anaplastic Astrocytomas and Glioblastomas) spread through
the extracellular space and along the compact white matter tracts
that connect each part of the brain with every other part of the
Surgery to reduce the bulk of the tumor, followed by radiation therapy,
has become the standard against which other treatments are compared.
One must consider that these tumors cannot usually be cured with
surgery alone, although the Neurosurgeons of Neurosurgical Consultants
are encouraged by their increasing experience with long term
survival using a combination of aggressive approaches. The goals
of treatment, if "cure" is not possible, should be to prolong
survival, together with a higher quality of life.
Because of the infiltrative nature of Astrocytoma, it is unlikely
that surgery will ever be the definitive treatment for these
neoplasms. However, increasingly safe and aggressive tumor resection
is possible with the advent of technological advances such as
intra-operative MRI and Ultrasonic imaging systems, as well as,
actual tumor-brain interface "visualization", using Fluorescence
The Neurosurgeons of Neurosurgical Consultants firmly believe
that aggressive resection of the tumor, is the first definitive step
in the treatment of these tumors. Other steps include Chemotherapy
and Radiation Therapy. Some additional technologies have also helped
to improve their outcomes. For example, it is now possible to
culture the tumor and subject it to sensitivity testing against
various chemotherapy agents prior to initiating Chemotherapy.
Traditional management has been to use "standard" forms of
chemotherapy. Currently there are some unconventional chemotherapeutic
alternatives that offer considerable hope for improved quality and
length of survival. New therapies such as Temodar
(temozolamide), Avastin (bevacizumab which is an
anti-angiogenesis medication) and CPT-11 are currently
being used by one of our Neuro-oncologists. Preliminary results
have been encouraging. The reader may wish to view the "Virtual
Trials" website for additional information.
Ultimately we hope to see the availability of gene therapy to
In some tumor cases we choose to place a special chamber called an
"Ommaya Reservoir" under the scalp, with an attached catheter
residing in the "bed" of the tumor, after resection has been
completed. This permits the Neuro-oncologist to instill
chemotherapeutic medications directly into the tumor bed.
Radiation therapy continues to have an important place in the
treatment of many of these tumors. Refinements have been made that
make this treatment less toxic than in previous years.
Cerebellar Astrocytomas are one of the more common pediatric brain
tumors (10%), comprising 27% of pediatric Posterior Cranial Fossa
tumors. They are much less common in adults. The post-operative
survival is longer than other types of Astrocytomas. Surgical
excision of the maximal amount of the tumor that can be removed,
without producing neurological deficits, is the appropriate treatment.
In tumors composed of a nodule and a cyst, excision of the nodule
is usually definitive therapy. These patients generally have a high
rate of long term (5 to 10 or more year) survival. Radiation
therapy is not recommended in these cases, since the complication
rates of radiation therapy in the face of expected 5 or more years of
survival, is quite high. Careful attention to follow up is required
using repeat MRI scans. Repeat operation is appropriate, if there
is a recurrence of the tumor.
Brainstem Gliomas tend to occur during childhood and adolescence.
The most common initial presenting complaint is that of gait
(walking) disturbance. Following this are the complaints of:
These tumors are primarily diagnosed by MRI scans. Although treatment
is usually non-surgical, there are some significant exceptions,
such as in cases where there is an exophytic (extending outside the
brain stem) component, a large cystic component within the brainstem
or a small, discrete lesion that is close to a surface of the brain
- double vision
- facial weakness
- trouble swallowing
- hoarse voice
- motor weakness
Radiation therapy is generally regarded as the primary treatment
method with chemotherapy frequently being used as well. In some
recent cases we have used Radiosurgery (Focused Beam Radiation)
Ependymomas are tumors that arise from Ependymal cells, which make
up the thin layer of epithelium that lines the ventricular walls of
the brain cavities (called "ventricles", where Cerebrospinal Fluid
[CSF] is manufactured) and the central canal of the spinal cord.
Ependymal cells are the third type of cell in the "glial" cell
series, the others being Astrocytes and Oligodendrocytes.
In a manner similar to other "Gliomas", Ependymal Cells can form a
tumor known as an "Ependymoma". These tumors can occur within the
brain or spinal cord. The commonest sites of origin are:
These tumors have the potential to spread ("seed") through the CSF
(Cerebrospinal Fluid) pathway to other areas of the nervous system.
- Intracranial: This comprises only 5-6% of all intracranial
Gliomas, 69% occur in children (comprise 9% of pediatric brain tumors).
These are usually well circumscribed and "benign" - appearing. They
commonly arise in the floor of the fourth ventricle (60-70% are
infratentorial in region of the 4th ventricle).
- Spinal: These comprise approximately 60% of spinal cord Gliomas,
96% occur in adults
Ependymomas are four to six times more common in children compared to
adults. The peak age range is 1 to 5 years but there is a second,
smaller peak in the mid-30s.
The symptoms of these tumors are similar to those of other
intracranial masses. This includes headache (80%), nausea/vomiting (75%),
ataxia (difficulty with balance) or dizziness (vertigo), and
These tumors are primarily diagnosed by CT or MRI scans. The
diagnosis is then confirmed by microscopic examination of the tumor.
The goal of surgery is the resection (removal) of the greatest amount
of tumor maximal possible, without causing neurological deficits. When
invasion of the surrounding brain is extensive, total excision is not
possible, although we have had encouraging long-term experience with
the removal of the small portion of tumor that invades the floor of
the fourth (4th) ventricle in selected patients. The long term results,
in these patients, have been excellent.
Spinal Cord Ependymoma is more likely to occur in the thoraco-lumbar
junction region and involve the "Cauda Equina". The most common
presenting complaint is that of "PAIN". Weakness and/or tingling in
the lower extremities, bowel and bladder control may also be noted.
MRI scan is the most effective diagnostic screening method and is
often done when the tentative diagnosis is thought to be a herniated
lumbar disc. Treatment demands surgical excision to the maximum
extent possible. Minimally invasive microendoscopic spinal cord
removal techniques are now available. Nevertheless, not all
tumors can be entirely removed. For those where some residual is
known, or believed to be present, then radiation and chemotherapy
should be serious considerations.
The Neurosurgeons of Neurosurgical Consultants have a particular
interest in and significant experience with Spinal Cord Ependymomas.
We invite your attention to our website area devoted to the
discussion of this entity.
Ependymomas rank second only to Medulloblastomas in sensitivity to
radiation. Radiation Therapy is administered after surgical excision
to the tumor bed and if any metastases ("SEDING") through the CSF
are found. In 50% of patients survival time was 2 years longer with
radiation therapy than without.
The overall 5-year survival rate is 45%. Tumor recurrence or
progression at the primary site is by far the most common cause of
death in these patients. Spinal seeding is relatively uncommon and
occurs later in the course of the disease for most patients.
GBMs are the most common and most malignant of the primary CNS
neoplasms, representing 15% to 20% of these tumors. Approximately
half of all Astrocytomas are GBMs. GBM is the most common
supratentorial neoplasm in adults.
GBMs usually occur in patients over 50 and are unusual in patients
under 30. Like Anaplastic Astrocytomas, GBMs can occasionally be
found at any age; Anaplastic Astrocytomas and GBMs are among the
four most common primary brain tumors in infants and children under
2 years of age. Various symptoms occur with GBM, including seizure,
focal neurological deficits, and stroke like syndromes.
The first symptom of a brain tumor of any type can be a headache,
since these tumors act as masses within the boney skull and thus
cause increased pressure in the brain. The headache associated with
a brain tumor, is frequently worse in the morning and is accompanied
by vomiting. Other symptoms of a brain tumor can include seizures,
weakness or numbness of a side or part of the body, or such subtle
symptoms such as changes in mood, thinking or general state of well
being. Sometimes increased pressure in the brain can cause blurred,
double, or lost vision.
A seizure occurring for the first time in anyone over the age of
twenty is regarded as the indication of a brain tumor, until proven
otherwise. If a patient has any of the above symptoms, without any
obvious explanation, further work-up is warranted. These tumors can
be seen best by Magnetic Resonance Imaging (MRI). CT scans can also
be used; however, the degree of detail is much less than MRI. As
with other tumors and most particularly with any of the Gliomas,
once a mass is confirmed by any of the imaging techniques, the
diagnosis needs to be established by a biopsy of the mass. The biopsy
is done in conjunction with an aggressive resection of the tumor.
The biopsy identifies the particularities of the tumor and
differentiates it from other types of masses, such as infection.
Along with primary CNS Lymphoma, GBMs have the worst prognosis of
all primary brain tumors. GBMs disseminate early, rapidly, and widely.
Central Nervous System spread is common, but distant metastasis is
In selecting the treatment of High Grade Malignant Astrocytomas, it
should be kept in mind that the following three (3) statistically
independent factors affect the length of survival: 1) age at the
time of diagnosis, 2) histological features (Grade of the tumor and
additional characteristics such as Mitotic Index), and 3) performance
status (the level of the patient's neurological capabilities).
Older patients with high grade malignant brain tumors, who are
in poor neurological condition at the time of surgery, do less
The primary initial therapy is to gain control of the increased
intracranial pressure. Often times, these patients have significant
brain swelling, in addition to the presence of and as a consequence
of the tumor. Pre-treatment with a course of high dose intravenous
steroids, may well improve the condition of the patient prior to
surgery. In some cases, this may mean a strategic delay of surgical
intervention for three (3) to seven (7) days. The wait can be rewarded
by a far better initial outcome.
Aggressive surgical excision of the tumor is advocated in most patients.
The goal is to reduce the maximum amount of the tumor. In some cases
this may mean an extensive Frontal or Temporal Lobectomy. When tumor
is within the middle or posterior portions of the Temporal lobe, the
Parietal or Anterior or Middle Occipital Lobe, an aggressive internal
decompression of the tumor is warranted. There are some advanced
technologies that currently assist in the extent of resection. The
ability of the surgeon to "visualize" tumor is somewhat limited.
Magnification of vision, Intraoperative ultrasound imaging,
Intraoperative MRI scanning and Intraoperative Fluorescence
techniques are a few of the adjunctive technologies that may be
available to assist maximum resection, while limiting the risk of
injuring adjacent functioning brain.
The surgeon may choose to reserve a small part of the tumor for
tissue culture and sensitivity testing against various chemotherapeutic
agents. It can be helpful to know beforehand, if a certain drug has
any or limited effectiveness against this particular tumor, in this
The surgeon will also have the opportunity to place an "Ommaya
Reservoir" within the tumor bed for later use by the Neuro-oncologist,
to instill chemotherapeutic medications directly into the tumor bed.
It is imperative to understand that these are "infiltrative"
tumors which spread along the interconnecting fiber pathways (tracts)
of the brain. As such, these tumors can rarely be entirely removed
Radiation therapy, of which there are several forms, has become the
standard against which other treatments are compared. For most
patients, this will be the second major treatment option, in a
comprehensive therapeutic program.
Chemotherapy is the third arm of this comprehensive effort to prolong
and maintain a high quality of life. There are traditional and
commonly used regimens. However, one of our Neuro-oncologists
has utilized newer medications such as Temodar (temozolamide),
Avastin (bevacizumab, an anti-angiogenesis agent) and CPT-11, either
alone (or more commonly) in combination or with other drugs, to
produce encouraging results. Additional information regarding these
treatments is available at the "Virtual Trials" website.
Ultimately we continue to hope for the development of specific gene
Oligodendrogliomas are uncommon Gliomas which comprise approximately 4%
of primary brain tumors. These tumors arise from glial cells, called
Oligodendrocytes (the cells that are responsible for creating and
maintaining myelin, which is the insulating substance around the axons
of brain cell fiber networks). They are much less common than Astrocytes.
These are tumors of adults, with the peak incidence being between 35 and
45 years of age. Seizures (epilepsy) are the presenting symptom in 50-80%
of cases. The presenting symptoms of this tumor are not specific for
Oligodendroglioma. They are more often related to local mass effect and
less commonly to a generalized increase in intracranial pressure. These
symptoms are similar to those of any intracranial mass lesion and
include headaches, mental status changes, and nausea/dizziness. Patients
presenting with the above symptoms, should have an evaluation, which
includes and MRI or CT scan. Oligodendrogliomas commonly have some
calcification within them which can indicate to the surgeon that this
tumor has cells of this origin.
The initial treatment for Oligodendroglioma is aggressive removal. The
definitive diagnosis is made by microscopic examination of the tumor
tissue taken at the time of surgery.
Aggressive resection of this tumor leads to longer survival, and results
in fewer side effects than "partial debulking" operations. It is important
to recognize that a significant percentage of Astrocytoma tumors may also
have an Oligodendroglioma component as well. These tumors are called
"Mixed Gliomas". Treatment of a Mixed Glioma is similar to what
is described for an Astrocytoma.
Most Oligodendrogliomas are slow-growing tumors. Tumor grade is the
single most important prognostic variable. Patients with low-grade
lesions have 5- and 10-year survival rates of 74% and 46% respectively;
the rates are 41% and 20% for patients with grade 3 or 4 tumors.
Most Oligodendrogliomas respond to some form of chemotherapy. Newer
forms of medication, such as Temodar (temozolamide) and CPT 11, as well
as other agents are being used in addition to, or replacing more
conventional drugs such as PCV (procarbazine, CCNU, and vincristine).
Information regarding these newer treatments is available.
One of our Neuro-oncologists generally recommends radiation therapy as an
adjunct for these tumors. Benefits of postoperative radiation are somewhat
controversial, since some studies have shown improved survival, while
others have shown no increase in survival.
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This page last edited on 2/20