l Differences Between Adult and Pediatric Brain

Dr Roger J Packer
Differences Between Adult
and Pediatric Brain ~umors
By Roger J. Packer MD, Senior VicePresident, Center for Neuroscience
and Behavioral Medicine; Director,
The Brain Tumor Institute; Director,
Gilbert Neurofibromatosis Institute;
Children's National Medical Center;
Professor, Neurology and Pediatrics,
The George Washington University,
Washington, DC, USA
brain tumors are not just the
same tumors that arise in adulthood.
Brain tumors in children and adults differ
in their incidence,
lesions are
in children. When considering
brain tumors: the
suprasellar region (the area behind the
only tumors that primarily arise in the
eyes and on top of the pituitary gland)
brain, adult tumors are ten times more
and the pineal region. Each has its own
common than those arising in children.
specific types of presentation
The majOrity of adult primary brain tumors
tumor types.
are malignant gliomas 6r meningiomas,
primarily occurring
In comparison,
in the cerebral cortex.
brain tumors
are rare, arising in 2.5 to 3 children per
and array of
As regards the types of tumors which
arise in children, more children than adults_
will develop embryonal tumors, the most
common of which is medulloblastoma.
100,000 at risk, but are the leading cause
Because of the primitive nature of
of canc\3r-related death in childhood
brain tumors, they
comprise the majority of all solid tumors
are likely to spread to other parts of the
central nervous system early in illness or
in those less than 18 years of
. age. Approximately
50% of childhood
type, and treatment. Overall, survival
brain tumors are benign (especially
rates for those with brain tumors are
pilocytic gliomas), and they
at time of relapse. This is why treatment
often has to be given to the entire brain
and spine at the time of diagnosis, where
tend to occur more frequently in the
this type of approach
However, the immaturity of the child's
lower portions of the brain, called the
needed in adult brain tumors.
brain makes treatment decisions difficult,
posterior fossa. Childhood
especially in infants.
can also arise in the cerebral cortex, as in
There are two other potential hotspots
rates are much better in children with
for the development
malignant lesions. As an example,
better in childhood
than in the adult years.
The majority of adult tumors are
metastatic lesions secondary
to tumors
such as cancers of the colon and
lung whereas metastatic
B\'aill Tumour
brain tumors
of childhood
is less commonly
Despite the primitive nature of many
brain tumors, overall survival
malignant tumors than in adults with
the survival rate for children with
ever, arise in adults, but make up a
young child, can result in significant
the most common
malignant tumor of childhood,
in tumors occurring
in children greater
tumors rarely, if
Such treatment,
of childhood
in the very
long-term cognitive,
brain tumors.
A major issue in the management
than three years of age and having
and psychological
damage. This is another major difference
brain tumors, in general, is the nihilistic
between adults and children. Other
is as high as 90% at five years; with the
attitude often present approaching
factors, including preoperative
majority of children cured of their disease.
malignant tumors compared
However, the price paid for this high
positive attitude mandatory to effectively
survival rate is daunting.
manage childhood
tumors amenable to complete
Even with apparent identical tumor
that some childhood
to the more
brain tumors. It is true
brain tumors, such
status, postoperative
molecular biology of brain tumors strongly
atypical teratoid/rhabdoid
suggests that brain tumors are different
young children, carry a poor prognosis.
in adults and children. The molecular
of childhood
tumors in very
However, overall, 75% or more of
children diagnosed
with a brain tumor
and poorly
host genetic susceptibilities
also playa significant
as diffuse intrinsic brain stem gliomas and
types, new information conceming
role in the
and severity of long-term
There is increasing hope that the
treatment of childhood
brain tumors
will improve significantly
in the near
gliomas does not fit neatly into the sub-
within the first 18 months of life can be
future. Over the past decade,
deal more has been learned about the
used for adults and they are
likely biologically different tumors.
to be alive five years later, at
least two-thirds
of whom are likely cured
a great
molecular makeup of childhood
of their disease. Since the majority of
tumors. In time, the goal is to translate
infrequently grade 2 tumors and are more
children with primary central nervous
this information into more personalized,
likely to be pilocyti~ (grade 1) tumors
system tumors can be expected
which have a significantly different
"cured" with initial treatment,
prognosis than adult low-grade tumors.
there has been a great deal of concern
into management
The majority of pilocytic tumors have a
raised over the quality of life of survivors.
tumors utilizing anti-blood
agents (antiangiogenesis
drugs), anti-
low-grade gliomas are
molecular signature and a
to be
The majority of children with malignant
safer treatment.
therapies are now being incorporated
of childhood
far better prognosis than grade 2 tumors,
brain tumors will require both radiation
growth factor agents, and other biologic
remaining benign throughout
and chemotherapy
The most common
low-grade tumor
for long-term disease
control. For the embryonal
Although exciting, a major challenge
type in adults is the grade 2 tumor which
radiation therapy usually needs to be
in the future will be to determine
has a tendency to mutate into higher
given to the entire brain and spine to
these biologic factors affect the immature
grade lesions over a three to five year
eradicate disease that has already spread
central nervous system and making
period of observation.
to the neuroaxis (which may not even be
sure that these treatments
types, such as the atypical teratoid/
evident on neuroimaging
not only in improved survival, but in an
rhabdoid tumor and some primitive
time of diagnosis.
Other tumor
studies) at the
actually result
improved quality of life.
Brain Tumour