How is a medulloblastoma treated?
The first phase of treatment is surgery, which is done to remove as much of the tumour as possible. An important step in deciding
the treatment plan is staging. This is done to determine the most appropriate treatment.
In older children (three to five years of age), surgery is followed by radiation therapy and chemotherapy. Radiation therapy
is the use of high-energy X-rays, gamma rays, or electrons to kill tumour cells. Radiation is given to the brain and spine
(craniospinal radiation). This is different from focal radiation which focuses on the tumour only. Chemotherapy uses medicines
to kill tumour cells. Chemotherapy treatment lasts four months to one year. In some protocols, medulloblastomas are treated
with high dose chemotherapy and stem cell transplant.
The results from staging will determine the intensity of the radiation therapy and chemotherapy your child will receive.
Different protocols are used in infants and young children three to five years of age. Radiation therapy is avoided because
of concerns about the effect of radiation on the young developing brain. Chemotherapy can be used first to try to prevent
the tumour from getting bigger. Some protocols use intra-cerebrospinal fluid (CSF) chemotherapy. Radiotherapy can be used
if needed. Some protocols have used focal radiation (radiation targeted to the tumour itself) for infants with average risk.
What is the outcome for a child with a medulloblastoma?
The outcome for a child with a medulloblastoma depends on many factors. These factors include the child’s age, the location
of the tumour, how much or whether it has spread, and the type of treatment.
For medulloblastomas, the outcome is better if the child is in the “average risk“ category. In general, the tumour is more
likely to come back if the child is in the “high risk“ category.
The risk of recurrence is higher during the first two years after diagnosis. However, recurrences can happen further down
the road.
Five years after treatment, 60% to 80% of children with medulloblastoma will survive. For children under the age of three,
20% to 50% will survive after five years.
There is increasing evidence to show that the biology of the tumour is essential to outcome. For example, desmoplastic medulloblastomas
in infants have a better outcome while anaplastic medulloblastomas have a poorer outcome.
