The majority of GBMs, roughly 65%, occur in the cerebral hemispheres, which
control higher functions like speech, movement, thought and sensation. They can
also develop in the part of the brain that identifies sensations such as
temperature, pain and touch and the region of the brain that controls balance
and motor function.
These tumors are usually diagnosed between the ages of 5 and 9, and occur in
boys and girls equally. GBMs occur with increased frequency in children with
certain genetic syndromes, including neurofibromatosis 1, Li-Fraumeni syndrome,
hereditary nonpolyposis colon cancer and tuberous sclerosis. Most GBMs,
however, have no known cause.
When doctors diagnose a brain tumor, they “stage” it, or give it a grade,
according to whether it has spread, and if so, how far. This helps us determine
treatment options and prognosis. The World Health Organization classification
scheme includes four grades of gliomas, which are:
Low-grade gliomas
High-grade gliomas
- grade III (anaplastic)
- grade IV (glioblastoma multiforme)
Glioblastoma multiforme is a grade IV tumor. These are aggressive tumors
that spread to adjacent healthy brain tissue.
Brain tumors can cause a variety of symptoms in children based primarily on
the location of the tumor, its size and whether it has spread. Keep in mind
that the symptoms of a brain tumor may resemble other more common conditions or
medical problems. It is important to consult your child's physician for a
diagnosis.
Most GBM symptoms result from increased pressure within the head. Other
symptoms relate to the tumor’s specific location, rate of growth and associated
inflammation.
Symptoms can develop slowly over time or begin very suddenly. The following
are the most common:
- headache and
lethargy (generally upon awakening in the morning)
- seizures,
depending on tumor type and location
- compression of surrounding
brain structures. Depending on the location, this can cause weakness and
other motor dysfunction, hormonal abnormalities or changes in behavior or
thought processes.
As a parent, you undoubtedly want
to know what may have caused your child’s tumor. It’s important to understand
that these and other brain tumors most often occur with no known cause. There’s
nothing that you could have done or avoided doing that would have prevented the
tumor from developing.
There are certain hereditary conditions that are linked to these tumors.
GBMs can occur with increased frequency in families with conditions including Li-Fraumeni
syndrome, hereditary nonpolyposis colon cancer, tuberous
sclerosis and neurofibromatosis
Type 1.
The first step in treating your child is forming an accurate
and complete diagnosis. In the case of GBMs, this is primarily done with a
combination of imaging and biopsy. Your child’s physician may order a number of
different tests including:
- A physical exam and complete
medical history.
- Computerized tomography scan (also called a CT or CAT scan), a diagnostic imaging
procedure that uses a combination of x-rays and computer technology to
produce cross-sectional images, often called slices, of the body from
horizontal and vertical perspectives. CT scans are more detailed than
general x-rays.
- Magnetic resonance imaging (MRI), a diagnostic
procedure that produces detailed images of the structures within the brain
and spine. An MRI uses a combination of large magnets, radiofrequencies
and a computer to analyze organs and structures within the body. No x-rays
or radiation are used.
- Magnetic resonance spectroscopy (MRS), done along with MRI at specialized facilities that can help identify tissue as
either normal or tumorous, and which may be able to distinguish between
different types of tumors.
- Lumbar puncture (spinal tap), to remove a small sample
of cerebrospinal fluid (CSF). This can determine if any tumor cells have
started to spread. In young children, this procedure can safely be
performed under sedation.
- Positron
emission tomography (or PET) scan, which measures the use of glucose
(blood sugar) within organs and tissues. Tumors use glucose more quickly
than normal tissues, causing them to show up brightly on these scans.
- Biopsy or tissue
sample, taken from the tumor to provide definitive
information about the type of tumor. This is collected during surgery.
There may be other diagnostic tests that your doctor will discuss with
you depending on your child's individual situation. After we complete all
necessary tests, our experts meet to review and discuss what they have learned
about your child's condition. Then we will meet with you and your family to
discuss the results and outline the best possible treatment options. All patients undergoing resection of brain tumors in our program are also
invited to participate in our ongoing research studies which allow genetic
profiling of each child’s tumor. These studies may potentially guide personalized (precision) medicine.
Your child's
physician will determine a specific course of treatment based on several
factors, including your child's age, overall health and medical history, the
type, location, and size of the tumor and the extent of the disease.
Treatments for GBMs include:
- Neurosurgery: The first treatment
is usually surgery to remove as much of the tumor as possible, ideally
using advanced techniques to maximize tumor removal, such as
intraoperative MRI (in which surgeons can visualize the tumor as they
operate). Complete resection, or surgical removal, of the entire tumor is
ideal when possible, though most high-grade gliomas cannot be completely
removed because they tend to infiltrate into adjacent healthy tissues. In
general, the more completely the tumor can be removed, the greater the
chances for survival.
- Radiation: High-energy waves
from a specialized machine damage or shrink tumors. Your child also may
receive precisely targeted and dosed radiation to kill cancer cells left
behind after surgery. This is important to control the local growth of
tumor, and it helps increase survival in high-grade gliomas.
- Chemotherapy: Chemotherapy refers
to drugs that interfere with the cancer cells' ability to grow or reproduce. To
date, no chemotherapy regimen has been demonstrated to increase survival rates
in children with GBM, though chemotherapy before surgery may help shrink the
tumor, making it possible to remove. A variety of chemotherapy regimens have
been tested in the treatment of newly diagnosed high-grade gliomas, and some
have produced responses but none have improved survival. Studies in adults have
suggested that certain drugs can produce modest responses in high-grade
gliomas, but they have less effect in children. High-intensity chemotherapy in
conjunction with a stem cell transplant also does not seem to improve chances
of survival.
Clinical trials, or research studies
evaluating new treatment approaches, are a major offering at Dana-Farber/Boston
Children’s Cancer and Blood Disorders Center. Clinical trials are very
important for children with hard-to-treat or relapsed conditions.
Clinical Trials
For many children with brain tumors or other rare or hard-to-treat
conditions, clinical trials provide new options.
It’s possible
that your child will be eligible to participate in one of our brain tumor clinical trials.
In addition to launching our own clinical trials, we also offer trials
available through collaborative groups such as the Children's Oncology Group
(COG), the Pacific
Pediatric Neuro-Oncology Consortium (PNOC). If your child has
progressive or recurrent tumor, she may be eligible for a number of
experimental therapies available through these groups, or from one of our
independent clinical investigators.
Clinical and basic scientists at Dana-Farber/Boston Children’s are
conducting numerous research studies to help clinicians better understand and
treat malignant gliomas. Through the consortia of researchers to which we
belong, a number of novel therapies are available for children with both newly
diagnosed and current brain tumors. Participation
in any clinical trial is completely voluntary. We will take care to fully
explain all elements of the treatment plan prior to the start of the trial, and
you may remove your child from the medical study at any time.
Unfortunately, the prognosis for GBM remains very poor. In general, more
complete surgical removal of the tumor, when possible,
results in greater chance of survival. Your child’s doctor will discuss
treatment options with you, including experimental clinical trials and
supportive care.
For children with relapsed GBMs, we offer access to the
latest clinical trials and experimental therapies. Current trials include novel
medications, as well as new methods for the delivery of more traditional
agents.
Our Pediatric Advanced
Care Team (PACT) is available to provide supportive treatments intended to
optimize your child’s quality of life and promote comfort and healing for
children with life-threatening illnesses. In addition, PACT can provide
psychosocial support and help arrange end-of-life care, when necessary.
Children successfully
treated for a GBM should visit a survivorship clinic yearly to manage disease
complications, screen for recurrence
and manage late treatment side effects. A typical follow-up visit is likely to
include a physical exam, laboratory testing and imaging scans.
Through our Stop
& Shop Family Pediatric Neuro-Oncology Outcomes Clinic, children are able to meet with their neurosurgeon, radiation
oncologist, pediatric neuro-oncologist and neurologists at the same follow-up
visit. Our multidisciplinary approach and depth of expertise will give your
child on-site access to endocrinologists, neuro-psychologists and
alternative/complementary therapy specialists. School liaison and psychosocial
personnel from the pediatric brain tumor team are also available. In addition, children needing rehabilitation may
meet with speech, physical, and occupational therapists during and after their
visit.